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3. Data input program

1. 3 52 3 4 6 4 Position and Orientation of GE 3 53 3 4 6 5 Inertia parameters of GE 3 54 3 4 6 6 Curve editor 3 55 3 4 7 Input of bodies 3 58 3 4 7 1 Image and visualization of a body Body fixed SC 3 59 3 4 7 2 Inertia parameters 3 60 3 4 7 3 Adjust adjusted joint 3 60 3 4 7 4 Connection points 3 60 3 4 7 4 1 Adding general connection points 3 61 3 4 7 4 2 Adding oriented connection points
2. 3 35 3 4 1 Data Input Sequence 3 35 3 4 2 Input of subsystems 3 36 3 4 2 1 Setting connection with external subsystems 3 37 3 4 3 Standard interface for setting local system of coordinates 3 38 3 4 4 Assigning Graphical Image to Object Element 3 40 3 4 5 Assignment of graphic images to rods linear and bipolar force elements 3 40 3 4 6 Input of Graphical Objects 3 40 Universal Mechanism 5 0 Chapter 3 Data input program 3 2 3 4 6 1 Lists of Graphical Objects and Graphical Elements 3 41 3 4 6 2 Input of graphical elements GE 3 42 3 4 6 2 1 Polyhedron
3. 3 42 3 4 6 2 2 Ellipse 3 43 3 4 6 2 3 Box 3 43 3 4 6 2 4 Spiral 3 44 3 4 6 2 5 Ellipsoid 3 44 3 4 6 2 6 Cone 3 45 3 4 6 2 7 Parametrical GE 3 45 3 4 6 2 8 Profiled GE 3 47 3 4 6 2 9 Z surface 3 49 3 4 6 2 10 GO as a graphic element 3 51 3 4 6 3 GE colors
4. 3 15 3 3 1 2 2 Modes of animation window 3 15 3 3 1 2 3 Basic system of coordinates pop up menu 3 16 3 3 1 2 4 Tool bar 3 17 3 3 2 Data inspector and some features of object element description 3 18 3 3 2 1 List of object elements and access to element description 3 18 3 3 2 2 General object parameters and options 3 19 3 3 2 3 Lists of elements of a definite type 3 20 3 3 2 4 Data types 3 21 3 3 2 4 1 Numeric constants 3 21 3 3 2 4 2 Identifiers
5. 3 62 3 4 7 4 3 Adding vectors 3 64 3 4 7 5 3D Contact 3 65 3 4 8 Joints and force elements some features of description 3 68 3 4 8 1 Assignment of bodies 3 68 3 4 8 2 Type of element 3 68 3 4 8 3 Attachment points 3 69 3 4 8 4 Visual assignment of bodies and attachment points 3 69 3 4 8 5 Transformation of coordinates 3 69 3 4 9 Input of joints 3 70 3 4 9 1 Visualization of joints
6. 3 70 3 4 9 2 Weight of joint 3 70 3 4 9 3 Convertion of joint type 3 70 3 4 9 4 Input of rotational and translational joints 3 72 3 4 9 5 Input of 6 d o f joint 3 74 3 4 9 6 Input of joint of generalized type 3 76 3 4 9 6 1 Elementary transformation tc 3 76 3 4 9 6 2 Elementary transformation rc 3 76 3 4 9 6 3 Elementary transformations tv rv 3 77 3 4 9 6 4 Elementary transformations tt rt 3 77 3 4 9 7 Input of quaternion joint
7. 3 9 3 2 2 Object 3 10 3 2 3 Tools 3 10 3 2 4 Edit 3 11 3 2 5 Help 3 11 3 2 6 Tool panel 3 11 3 3 Object constructor 3 12 3 3 1 Basic elements of constructor 3 12 3 3 1 1 List of object elements 3 13 3 3 1 2 Animation window 3 15 3 3 1 2 1 Visualization of object elements
8. 3 21 3 3 2 4 3 Standard functions and constants 3 23 3 3 2 4 4 Constant symbolic expression 3 25 3 3 2 4 5 Expression explicit function 3 25 3 3 2 4 6 External functions 3 26 3 3 2 4 7 External identifiers 3 27 3 3 2 4 8 Time function from text file 3 28 3 3 2 4 9 Timetable as a method of description of time functions 3 29 3 3 3 Curve editor 3 30 3 3 3 1 Modes of curve editor 3 30 3 3 3 2 Tool bar 3 30 3 3 3 3 Ad
9. 3 79 3 4 9 8 Input of rod constraint 3 80 3 4 10 Input of force elements 3 81 3 4 10 1 Input of bipolar force elements 3 81 3 4 10 1 1 Linear force element 3 82 3 4 10 1 2 Friction and elastic frictional elements 3 82 3 4 10 1 3 Elastic frictional element 2 3 82 3 4 10 1 4 Viscous elastic element 3 83 3 4 10 1 5 Points numbers 3 83 3 4 10 1 6 Points expressions 3 86 3 4 10 1 7 Hysteresis 3 88 3
10. 3 3 2 Data inspector and some features of object element description 3 3 2 1 List of object elements and access to element description Fig 3 16 List of object elements List of elements allows creating and modification of all the object elements bodies force elements etc All the parameters and data describing the corresponding element are presented in the Inspector window The list included the following items Object some general data direction of gravity and options Sect 3 3 2 2 Subsystems input of standard or included external subsystems for UM version with subsystem technique abilities only Images creation of graphic objects of bodies force elements and environment Sect 3 4 6 Bodies creation of bodies input inertia parameters Sect 3 4 7 Joints joints degrees of freedom joint forces Sect 3 4 9 Bipolar forces bipolar springs dampers etc Sect 3 4 10 1 Linear forces general springs and dampers Sect 3 4 10 2 Contact forces point plane sphere plane etc Sect 3 4 10 4 General forces usually for external programming of forces Sect 3 4 10 5 Special forces gearing cams etc Sect 3 4 10 6 Connections connection of external elements for UM version with subsystem technique abilities only Indices useful information on indices of all the elements of the object Summary information about correctness of the object description as well as list of errors and warnin
11. Mathematical model of the force is described in Chapt 2 Sect Types of scalar forces Hysteresis Example of hysteresis data input window Compression Stretching Example of hysteretic element with symmetric operation relative to length 1 m Universal Mechanism 5 0 Chapter 3 Data input program 3 89 The Type of element operation group stretch ing the element works only if coordinate value is greater than the value in the L box compress ion the element works only if coordinate value is less than the value in the L box symm etric the element works symmetrically both by stretching and by compression The L box the element length coordinate value corresponding to the zero value of abscissa of points The buttons of operations with the list of points add a point delete selected point copy selected point and draw data in the graphic window 1 2 3 5 7 4 6 Graphic window with hysteresis data Coordinates of points can be parameterized Numbers of points separated by commas for hysteretic curves are entered in the lowest table of the data window Orders of interpolation polynomials are set in the last column of the table order 1 corresponds to a polyline More details about hysteretic element can be found in Chapt 2 Sect Types of scalar forces Hysteresis Universal Mechanism 5 0 Chapter 3 Data input program 3 90 3 4 10 1 8 Fancher leaf spring The mathematical model o
12. delete the current element Ctrl Alt Gray copy the current element Ctrl Alt N edit name For elements connecting a pair of bodies joints force elements Ctrl Alt 1 choose the first body from the list of bodies Ctrl Alt 2 choose the second body from the list of bodies Ctrl Alt T choose element type Universal Mechanism 5 0 Chapter 3 Data input program 3 35 3 4 Data Input 3 4 1 Data Input Sequence The following sequence of object data input is recommended 1 Bodies their graphical images and the corresponding joints The sequence of description of bodies is usually defined by the kinematical scheme of the object At first the bodies connected with the base body SC0 are described and then the bodies connected with already described bodies and so on By such a description sequence of kinematical scheme of object all its bodies are drawn not only in the current element animation window but also in the whole object mode of the animation window Sect 3 3 1 2 2 It is important to remember that in the mode of whole object animation the described body is drawn in the animation window only if there exists a path from the current body to the base body through the described joints 2 Force elements and their graphical images After describing the object kinematical scheme force element images are drawn in the animation window both in the current element and the full object animation mode which allows the us
13. insert element component from clipboard Read from file add all elements from file to the object 3 2 5 Help Lessons access to several lessons teaching UM environment It is recommended to study the lessons before working with UM About short information about UM version and the list of developers 3 2 6 Tool panel Buttons located on the tool panel have the following functions creates a new object opens an existing object saves the active object saves the active object with a new name opens the text editor opens symbolic calculator verifies correctness of the active object description generates and compile equations for the active object compiles equations for the active object runs simulation of the active object Universal Mechanism 5 0 Chapter 3 Data input program 3 12 3 3 Object constructor 3 3 1 Basic elements of constructor Inspector of data Animation window List of elements Sheets with components List of identifiers Main menu Buttons duplicating main menu Constructor of objects Fig 3 11 Object constructor Constructor allows describing an object multibody system as a set of standard elements bodies joints force elements Basic parts of the constructor are Inspector of Data is used for input modification and representation of object elements as well as some other information about the object Anim
14. Click on a list item Fig 3 12 causes appearance of the corresponding information in the object data inspector 3 3 2 The list contains the following items Object general object options object type gravity background color etc 3 3 2 2 Subsystems list of subsystems wheelsets vehicle suspensions caterpillar including user s subsystems in the object For UM version with subsystem technique only Images list of images which are used for visualization of the scene bodies and force elements 3 4 6 Bodies list of bodies and their parameters mass moments on inertia coordinates of centers of mass etc Sect 3 4 7 Joints input of joints rotational translational etc as well as coordinates of bodies Sect 3 4 9 Wizard of forces is not used in this UM version a perspective future development for construction of complex force models Bipolar forces list of bipolar forces i e forces acting along the axis of element which connects two points of bodies Sect 3 4 10 1 The force element is used for modeling dampers dogs etc Linear forces list of generalized linear force elements described by 6 6 stiffness or damping matrices Sect 3 4 10 2 The element is used for modeling springs resistance of the environment etc Contact forces list of force elements which models contact interaction between bodies Sect 3 4 10 4 Universal Mechanism 5 0 Chapter 3 Data in
15. Selecting copying deleting and moving fragments and curves To select a fragment a set or points draw a rectangle region in the lot area by dragging the mouse cursor Fig 3 25 Universal Mechanism 5 0 Chapter 3 Data input program 3 32 Fig 3 25 Fragment selection by mouse There exist to methods for the selection of a curve 1 Select the name of a curve in the list of curves Figure 3 26 Figure 3 26 Selection of a curve in the lst of curves 2 Move the mouse cursor near the curve until it changes to call the pop up menu click the right mouse button and select the Select whole curve menu item To select all points call the pop up menu click the right mouse button and select the Select all menu item To remove a selection click by the left mouse button anywhere outside the selection rectangle To move a fragment or a curve select it move the mouse cursor until it changes to press the left mouse button and drag the fragment Moving a fragment is forbidden in the mode of creation of a function To delete a fragment or a curve select it and press the Delete key To copy a fragment or a curve select it press the Ctrl C and Ctrl V hot keys and move the copied fragment into a desirable position 3 3 3 5 Closing curve Two methods of closing a curve 1 move one of the curve end point by the mouse to a small neighborhood of another one 2 use the key over the list of points 3 3 3 6 Smoothing To smooth a curve
16. The orientation is set as a sequence of tree successive elementary rotations Here five methods for adding oriented points LSC are described 1 Use the add or the copy button Set point coordinates as constant symbolic expressions Sect 0 Set rotation axes and angles in degrees to define the orientation Universal Mechanism 5 0 Chapter 3 Data input program 3 63 Adding a LSC by a normal and a point 2 Visual adding by a normal and a point Click the button Select a vector or a point on a plane for the origin and the Z axis of the LSC Select a point in the XZ plane 3 Visual adding by an opposite normal and a point Click the button Select a vector or a point on a plane for the origin and the Z axis of the LSC The Z axis is directed opposite to the vector or inside the plane surface Select a point on the XZ plane Visual adding a LSC by tree and by four points 4 Visual adding by three points Click the button Select a point for the origin of the LSC Select a point on the X axis Select a point in the XY plane 5 Visual adding by four points Click the button Universal Mechanism 5 0 Chapter 3 Data input program 3 64 Select two points The middle point of the section is the origin of the LSC and the vector 12 r connecting the points set the X axis Select the 3rd and the 4th points The cross product 34 12 r r sets the Z axis 3 4 7 4 3 Addi
17. length 0 55 Length of rod ix mass length 2 12 0 0282333333 Moment of inertia of the rod relative to X axis iy ix 0 0282333333 Moment of inertia of the rod relative to Y axis Remark Expression can only include identifiers located above the current identifier Universal Mechanism 5 0 Chapter 3 Data input program 3 22 The same principle is used in the built in calculator the menu Tools Symbolic calculator command Universal Mechanism 5 0 Chapter 3 Data input program 3 23 3 3 2 4 3 Standard functions and constants The following standard functions are used for description of data of several types explicit function identifiers expressions sin cos trigonometric functions arguments are set in radians arcsin arccos arctan inverse trigonometric functions rad arctan2 x y computes an angle y x tan a a in radians in the interval from p to p quadrant for the angle is defined by signs of arguments x y as if a a cos sin y x exp natural exponent ln natural logarithm abs absolute value sign lt gt 0 1 0 0 0 1 x x x x sign power function the expression a b corresponds to b a the exponent must be an integer if the base is negative sqr square sqrt root square Heavi Heavi x gt 0 0 0 1 x
18. parameters if the Calculate stiffness box is checked These data can be parameterized Universal Mechanism 5 0 Chapter 3 Data input program 3 107 3 4 10 6 4 Rack and pinion Rack and pinion is a particular case of a gearing Fig 3 90 Rack and pinion parameters The following parameters describe rack and pinion mechanism Fig 3 90 Attachments points in SC of connecting bodies center of pinion and point on the axis of the rack Unit vectors along the pinion and rack axes rotation and translation axes respectively Pinion radius Contact stiffness and damping parameters All parameters except unit vectors can be parameterized Example Use of the rack and pinion force element in a car steering system is shown in Fig 3 91 see the car model Samples Automotive Vaz21_09 Universal Mechanism 5 0 Chapter 3 Data input program 3 108 Fig 3 91 Rack and pinion in the car steering system Universal Mechanism 5 0 Chapter 3 Data input program 3 109 3 4 10 6 5 Bushings The mathematical model of the element is described in Chapt 2 Sect Special forces Bushings To describe a bushing set positions of SCB1 Body 1 and SCB2 Body 2 with a standard interface for specifying positions of local system of coordinates select element type Linear Nonlinear in case of linear bushing enter stiffness and damping constants for shifts CX CY CZ and rotations CAX CAY CAZ relative to axes of CSB1 in ca
19. 4 10 1 8 Fancher leaf spring 3 90 3 4 10 1 9 Impact bump stop 3 90 3 4 10 1 10 List of forces 3 91 3 4 10 2 Input of scalar torque force element 3 92 3 4 10 3 Input of generalized linear force elements 3 94 3 4 10 3 1 Some features of description of elastic element 3 95 3 4 10 4 Input of contact force elements 3 97 3 4 10 4 1 Points Plane contact 3 97 3 4 10 4 2 Sphere Plane contact 3 98 3 4 10 4 3 Circle Plane contact 3 99 Universal Mechanism 5 0 Chapter 3 Data in
20. Cl NameOfObject old If the box is not checked the new file is created as Cl NameOfObject new This is important if the object description contains external functions or and the user write its own procedures in the Control file Run simulation module if on will start UM Simulation program with automatical loading the current model The Generate button starts the derivation of equations for the active object Use the Generate all button to derive equations for the object as well as for all external subsystems added to the object Use the the Object Compile equations or the Ctrt F9 hot key to compile the equations if the Control file has been modified but the equations have not been changed Universal Mechanism 5 0 Chapter 3 Data input program 3 119 3 7 Compilation of equations of motion If you chosen symbolic method of generation of equations of motion you need to compile generated equations with the help of one of supported compilers Universal Mechanism supports using Borland Delphi Borland C Builder Microsoft Visual C as external compilers To compile equations of motion use Object Compile equations menu item or check Compile equations flag in the Deriving and compile equations dialog see Sect 3 6 2 To setup external compiler paths select Tools Options menu item Your further actions depend on what external compiler you are going to use Delphi 1 Select Paths Delphi tab 2 Click Search Delphi button Borland C Builde
21. Parameters of the axis curve are Type of curve possible values are Straight line Circle Curve given by points Expression given by analytical formulas Length the length of the axial line in case of straight axis curve Number of points to approximate the axial curve Universal Mechanism 5 0 Chapter 3 Data input program 3 48 Using various combinations type of profile curve type of axis curve it is possible to get different shapes of GE Examples of profiled elements After choosing the profile type Curve 2D or Curve 3D a new input parameter Description appears Fig 3 41 Fig 3 41 Profiled GE a Curve 2D section Clicking mouse button on the user can open a window of the curve editor see Sect 3 4 6 6 and input the section If several curves are presented with the Curve 2D type then the profile section will be multiple connected Fig 3 41 In case of the Curve 3D section type several curves are treated as a set of consecutive sections along the axis curve Fig 3 42 Fig 3 42 Profiled GE a Curve 3D section After choosing the Expression type of profile section a new parameter group appears Fig 3 43 x p y p parametric equations of the profile contour depending on p Pmin Pmax limits of changing p Universal Mechanism 5 0 Chapter 3 Data input program 3 49 Fig 3 43 Profiled GE section given by formulas Analogously the axis curve can be descr
22. a connection point corrsponding to point B2 or an oriented point for SCB2 see Fig 3 92 4 Click one of the buttons on the component panel The design help window opens the window contains instructions and comments to the element adding process 4 1 Select point oriented point at 1st body select by the left mouse a point for the point A or an oriented point for SCA If the selected point is not an oriented point axes of SCA are set to those of SC1 the body1 fixed SC see Fig 3 92 4 2 Select point at 1st body for element end select a connection point for B1 see Fig 3 92 4 3 Select point oriented point at 2nd body This stage selects point B2 or SCB2 is assigned If the selected point is not an oriented point axes of SCB2 are set parallel to those of SC2 the body2 fixed SC see Fig 3 92 5 Correct names and values of identifiers parameterizing the force element Remarks Universal Mechanism 5 0 Chapter 3 Data input program 3 115 Fig 3 94 Visualization of element SC 1 In the single element mode of the animation window SCA SCB1 and SCB2 are visualized the origin of SCB1 is marked by the icon Fig 3 94 Images of SCB1 and SCB2 should usually coincide when the geometrical data of the element are correct Fig 3 95 Turning on auxiliary drawings for linear force elements 2 In the single element mode of the animation window these systems of coordinates can be visualized if the corresponding option is on Fi
23. adjusted joint is the nearest joint which lies on the path from the body to the base Use this joint to change the position of the body 3 4 7 4 Connection points Connection points are assigned to the body They are used by operations with visual components describing joints and force elements visual assignment of bodies joint and attachments points assignment of bodies as will as the corresponding joint and attachment points to external joint and force elements for subsystem technique only There exist three types of connection points general oriented local body fixed SC vectors Universal Mechanism 5 0 Chapter 3 Data input program 3 61 The following parameters should be set for each point coordinates in the body fixed SC coordinates are parameterized comments simplifying operations with points auxiliary parameter orientation of point fixed SC relative to the body fixed SC for oriented point the orientation is set by three rotations An icon marks a connection point in the animation window Fig 3 57 A point fixed SC are additionally drawn for oriented points and a line section is drawn for a vector along its direction Fig 3 57 Frame with general and oriented connection points Note Connection points are used to assign their positions and or orientation to object elements joints and forces At the same time the connection between the element and the points is not kept This mean
24. bodies kinematical pair connected by the joint is drawn A GO may be assigned for a rod constraint only In the full object mode of the animation window the bodies of the kinematical pair are drawn as active Optionally an icon marks a position of the joint point and visualizes its degrees of freedom Sect 3 3 1 2 1 Visualization of object elements Click near the active region of the icon to call the description of the joint in the inspector Sect 3 3 1 2 1 If the joint is cut except rod mate and CV joints the second body is drawn twice in the full object mode in the positions determined by adjusted and the cut joints Sect 3 4 9 1 It is recommended to change coordinate values in such a way that the both images of the body were close The exact values of the coordinates are calculated in the Simulation program Note By default some information about the joint is hidden Use the button to make it visible 3 4 9 2 Weight of joint Fig 3 65 Setting joint weight A weight coefficient can be assigned to each of the joints This parameter is used when the object has closed kinematical loops Chapt 2 Sect System graph Closed kinematical loops If a large weight e g 1000 is assigned to a joint in a closed loop it will be cut Note By default the weight information is hidden Use the button to make it visible Fig 3 65 3 4 9 3 Convertion of joint type Joints of types rotational translational six degrees of
25. contact manifold for the rigid body is selected from prepared in advance graphical objects that are available in the drop down list Coordinate system of the contact manifold coincides with the coordinate system of the body In the Single element mode see Sect 3 3 1 2 2 Modes of animation window page 3 15 the contact manifold is drawn in yellow lines see Fig 3 60 There is no possibility to assign a contact manifold for Base0 body If it is necessary you should create an extra rigid body with 0 d o f and assign the contact manifold of Base0 with this extra body Universal Mechanism 5 0 Chapter 3 Data input program 3 66 Fig 3 60 3D Contact parameters between pair of bodies Types of contact manifold Polyhedron In general case use Polyhedron type for describing the contact interaction between bodies Graphical objects that are chosen as contact manifolds should consist of graphical elements of the following types Box Polyhedron and ASC Graphical elements of Polyhedron and ASC types should be convex and closed Z surface This type of contact manifold is used to describe contact between all bodies and the ground Restrictions of convexity and closure are not applied for graphical objects for contact manifold of Z surface type Some comments concerning preparing a graphical object for using as a contact manifold of Z surface type are given in Sect 3 4 10 4 5 Points Sphere Circle Z surface contact page 3 100 3D Contact simulation
26. key to cancel the assignment of the scene image The Options tab contains values of stepwise changing angular and linear variables when special buttons in edit boxes are used Angular variables are measured in degrees within the Input program and in radians in the Simulation program Use the Animation window tab to set the background grid colors rotational style as well as the axis color saturation in the animation window Click the color box by the mouse to choose the color Check on off the Drag body option to turn on off visual dragging bodies by the mouse in the animation window Dragging is used for simple object only as well as at a study level Universal Mechanism 5 0 Chapter 3 Data input program 3 20 3 3 2 3 Lists of elements of a definite type Each object multibody system is presented by sets of elements most of which are grouped as lists Every list contains elements of a single type e g lists of bodies joints bipolar force elements and so on Each element of a list has its own name which is an arbitrary set of symbols The name of element is the base of its identification and it must be unique within the corresponding list that is it is not allowed setting one name for two elements of the same type e g for two bodies Elements of different lists as well as elements which belong to different subsystems may have the same names So the body and its image or some joint can have equal names Standard interface pos
27. line spline or circle see Fig 3 54 Fig 3 54 Pop up menu for primitive Actions allowed for a primitive are Convert into changes the type of the selected primitive Insert point a new point will have the coordinates defined by the current position of the mouse pointer double clicking the left mouse button has the same effect Delete removes the selected primitive Properties calls a primitive property dialog box Universal Mechanism 5 0 Chapter 3 Data input program 3 57 Select whole curve selects the curve continuum containing the selected primitive Closed a tag for closing the curve containing the selected primitive Reverse order for inverting the ordering of points Rotate 90 turns the current continuum through 90 degrees counterclockwise Universal Mechanism 5 0 Chapter 3 Data input program 3 58 3 4 7 Input of bodies Fig 3 55 Bodies item of the object element list and Body parameters The Bodies item of the object element list Fig 3 55 left Sect 3 3 2 1 is used for access to procedures of creation and modification of the list of bodies and their parameters Alternative ways are the Ctrl Alt B hot key or clicking by the mouse on the corresponding body image in the whole object mode of the animation window Sect 3 3 1 2 2 The right picture in Fig 3 55 shows the inspector with parameters of a body Universal Mechanism 5 0 Chapter 3 Data input progra
28. of description of time functions Timetable is a generalization of time function description by an expression This method is used if the function can be described by different symbolic expressions on several time intervals For instance the function in figure satisfy the following relations w 2 1 1 1 1 cos 0 t t t t t vt t t vt t f A standard interface is used for setting such dependencies Use a pop up menu to add delete insert a line into the timetable The Plot item is used for plotting the functions The table can contain any number of lines Time in the left column can be set by expressions identifiers t1 t2 in our example Note 1 The user should take care of a continuity of the function Note 2 When the current simulation time exceeds the latest time point in the timetable the function value is constant equal the latest one in the table Universal Mechanism 5 0 Chapter 3 Data input program 3 30 3 3 3 Curve editor Fig 3 23 Curve editor and its elements Curve editor is a tool for input of data in a graphic form The editor allows the user to create a curve a function or a set of curves by a set of points Here we consider some features of working with the editor Additional information about usage this tool for creation of 2D graphic images can be found in Sect 3 4 6 6 3 3 3 1 Modes of curve editor There exist two mode
29. of orientation angles turned on degrees of freedom check the presented degrees of freedom and turn off the others the three upper rows correspond to translational d o f Fig 3 69 Use the buttons in the edit boxes to set initial values as well as to verify the correctness of the joint description Remark 1 Cut joints with six d o f are ignored in the Simulation program Remark 2 6 d o f joint can be converted to the generalized type to introduce joint forces for some degrees of freedom Sect 3 4 9 3 Example An example of a joint used for setting six degrees of freedom of a box relative to SC0 according to data in Fig 3 69 left for x0 1m alpha 30 degrees is shown in Fig 3 70 The box is shown in the position corresponding to zero values of joint coordinates Features of the joint are the parametric description of both the SC1A origin shift along the X axis x0 and angle of rotation about the X axis alpha As a result two translational and two rotational degrees are specified along inclines axes Y and Z Universal Mechanism 5 0 Chapter 3 Data input program 3 75 Fig 3 70 Example of a joint with six degrees of freedom Universal Mechanism 5 0 Chapter 3 Data input program 3 76 3 4 9 6 Input of joint of generalized type The joint description consists of a sequence of elementary transformations ET Chapt 2 Sect Generalized joint Fig 3 71 Generalized joint The list of ET is created with the help of
30. rather a fast algorithm that is suitable for simulation of some models based on multibody system dynamics approach but surely is not suitable for detailed analysis of contact problem contact stresses deformations wear plastic effects and so on Comparison of the contact models Universal Mechanism software has to approaches to simulate contact interaction between rigid bodies The first approach suppose using contact forces of point plane and other types and the second approach is based on 3D Contact described above 3D Contact based on using point plane contact forces and in this sense can be considered as an algorithm that detecting interpenetration of rigid bodies arranges contact points and identifies nearest faces as contact planes At the same time calculation of interpenetration of contact manifolds is rather time consuming operation that takes quite many CPU efforts That is why simulating models with contacts it necessary to understand clearly advantages and disadvantages of both approaches Detailed overview of contact forces see in Sect 3 4 10 4 Input of contact force elements page 3 97 3D Contact often makes simulation of contact interaction more easy to use intuitive and more suitable for parameterization as well as widens contact interaction for edge edge penetration case see Chapter 2 Sect 3D contact To simulate edge edge penetration with the help of contact forces of point plane type it needs to cr
31. x gt lt 0 3 0 2 0 1 v3 v2 v1 c if c v c v c v Fig 3 19 Step function step x x0 h0 x1 h1 gt lt 1 1 0 1 0 2 0 1 0 0 0 2 3 x x h x x x x d d d h h h x x h x x0 x1 h0 h1 Universal Mechanism 5 0 Chapter 3 Data input program 3 24 As a rule the Step function is used for a smooth but fast transition of expression from one value to another Example of the function step t 0 1 0 2 0 15 0 3 is shown in Fig 3 19 Standard constants pi number 1415926536 3 p e number e 2 7182818285 rtod factor converting radians to degrees e g arctan 1 rtod 45 dtor factor converting degrees to radians e g 90 dtor pi 2 Universal Mechanism 5 0 Chapter 3 Data input program 3 25 3 3 2 4 4 Constant symbolic expression An constant symbolic expression is an expression which contains identifiers numbers additions subtractions divisions and multiplication standard functions Sect 3 3 2 4 3 It is not allowed usage of identifier t time Example of correct constant symbolic expressions sqrt 2 b1 sqrt a1 a2 2 The constant symbolic expression can be used for most of the element parameters inertia and geometric parameters coordinates of attachment points of the most type of fo
32. 3 1 Select point oriented point at 1st body select by the left mouse a point for the point A or an oriented point for SCA If the selected point is not an oriented point axes of SCA are set to those of SC1 the body1 fixed SC see the figure 3 2 Select element end point first body or point oriented on second body If a point at the second body is selected the point B2 or SCB2 is assigned If the selected point is not an oriented point axes of SCB2 are set parallel to those of SC2 the body2 fixed Universal Mechanism 5 0 Chapter 3 Data input program 3 114 SC Point B1 is computed automatically coinsiding with B2 see Fig 3 92 and the process of selection geometric paremeters is over Otherwise the next step is necessary 3 3 Select the second body click by the mouse on the image of the second body Point B2 and SCB2 are computed automatically conisiding with B1 SCB1 Note that axis of SCB1 are parallel to SCA see the Fig 3 92 Fig 3 93 Identifiers parameterizing a force component 4 Correct names and values of identifiers parameterizing the force element Fig 3 93 The User s mode The linear spring or the Linear spring damper components correspond to linear force components without automatic positioning 1 Add to the first body a connection point corrsponding to point A or an oriented point for SCA see Fig 3 92 2 Add to the first body a connection point corrsponding to point B1 3 Add to the second body
33. 4 1 All the data except the normals are parameterized 3 4 10 4 4 Sphere Sphere contact The element description contains parameters for two body fixed spheres Center a point in SC of the corresponding body Radius These data are parameterized Universal Mechanism 5 0 Chapter 3 Data input program 3 100 3 4 10 4 5 Points Sphere Circle Z surface contact The contact points sphere circle belong to the first body Sphere is described with the help of its center and radius Circle is described with the help of its center radius and normal to its plane A Z surface belongs to the second body The surface function corresponds to the second body and can be described by An explicit expression z z p1 p2 2 1 p p An external function z z p1 p2 which should be programmed in the Control file Sect 3 3 2 4 6 A Graph ical object which is selected in the drop down list of graphical objects in the model Fig 3 86 Examples of graphical objects for z surface One complex graphical object for contact z surface Graphical element of ASC type Graphical element of Polyhedron type Universal Mechanism 5 0 Chapter 3 Data input program 3 101 Please note the following things using z surface as a Graph ical object Selected graphical object can include one or several graphical elements of Polyhedron ASC1 Box Ellipsoid Cone Z surface In t
34. 5 1 Basic notions 3 111 3 5 2 Adding a component in visual mode 3 112 3 5 2 1 Visual adding generalized linear elastic or viscous elastic forces 3 112 3 5 2 2 Saving object data 3 116 3 6 Generation of equations of motion 3 117 3 6 1 Numeric iterative method 3 117 3 6 2 Symbolic method 3 117 3 7 Compilation of equations of motion 3 119 Universal Mechanism 5 0 Chapter 3 Data input program 3 4 3 Data input program Program for description of objects is intended for creation correction multibody systems as well as for automatic generation of equations of motion and their compilation List of files in the program bin UMInput exe bin um rsc file of string resources bin GraphRes rsc fil
35. It is accessible with the inspector tab Images Notice that it is recommended to describe the rest of object elements after the complete description of graphical images In this case the visual verification of input data is possible and it allows avoiding a lot of input errors Universal Mechanism 5 0 Chapter 3 Data input program 3 41 3 4 6 1 Lists of Graphical Objects and Graphical Elements To visualize any system element body joint force element and others bodies will only be mentioned below it is necessary to assign a graphical object to it GO is a set of graphical elements GEs which should be created using the built in graphical editor The same GO may belong to different geometrically identical bodies For example for description of GO of a bogie having four similar wheels even if their have different masses it is enough to create two GOs a body and a wheel The same wheel GO is assigned to each of the wheels It is desirable to create a full set of GOs before input of data for bodies joints etc In this case the visual verification of input data is possible After assigning a GO to an object element UM superposes the SC of GO with the element SC in a certain rule but it should be remembered that the shape and sizes of GO are not connected at all with inertia parameters of body stiffness of spring and other parameters of the object elements which should be described separately Exclusion presents the case when the opti
36. Sect Elastic frictional element 2 Viscous elastic Sect Viscous elastic element Points numeric Sect Points numbers Points express Sect Points expressions Expression Sect Expression explicit function External function Sect External functions List of forces Sect Fancher leaf spring 3 4 9 6 4 Elementary transformations tt rt Fig 3 72 Time function Universal Mechanism 5 0 Chapter 3 Data input program 3 78 In addition to transformation vector enter a time function for the coordinate as an explicit expression Sect 3 3 2 4 5 an external function Sect 3 3 2 4 6 a time table Sect 3 3 2 4 9 a function from a text file Sect 3 3 2 4 8 Remark Use the type rt for entering a rotation with a constant angle which can be set as an identifier or an explicit expression In this case chose the Expression type of description and enter an expression which does not depend on time t Fig 3 72 left Cut joints with 6 d o f are ignored in the Simulation program Universal Mechanism 5 0 Chapter 3 Data input program 3 79 3 4 9 7 Input of quaternion joint A detailed description of a quaternion joint can be found in Chapt 2 Sect Quaternion joint The following data can be set in addition to bodies and joint points Sect 3 4 7 5 Initial orientation of the second body relative to the first one angle is entered in degrees Translational coordinates can be turned off to obtain a spherical jo
37. Universal Mechanism 5 0 Chapter 3 Data input program 3 1 3 DATA INPUT PROGRAM 3 4 3 1 1 Setup of symbolic generation of equations of motion 3 5 3 1 1 1 Delphi 3 5 3 1 1 2 C 3 6 3 1 2 Paths to external subsystems 3 6 3 1 3 Paths to user s units 3 7 3 1 4 General options of the Input program 3 7 3 1 5 Component libraries 3 8 3 2 Main menu commands and tool panel 3 9 3 2 1 File
38. Universal Mechanism 5 0 Chapter 3 Data input program 3 60 3 4 7 2 Inertia parameters Inertia parameters of a body are mass symmetric inertia tensor coordinates of center of mass in the body fixed SC symmetric added mass matrix The icon marks the position of the center of mass in the animation window Important remark and warning Moments of inertia and elements of the added mass matrix should be calculated in SC which origin coincides with the center of mass and axes are parallel to those of the body fixed SC There exist two modes for entering the inertia parameters except the added masses Use the Automatic calculation button to switch them Fig 3 55 User s defined inertia parameters All parameter boxes are enabled in this mode All parameters might be constant symbolic expressions Sect 0 Automatic calculation of inertia parameters The parameters are calculated automatically according to the body image Sect 3 4 6 5 Parameter boxes are not available for the user Remarks Automatic calculation is enabled after assigning a GO to the body The corresponding GO must include at least one GE with the assigned material which density is not zero Inertia parameters are recalculated every time when the GO is modified in particular when identifiers parameterizing the GO are changed 3 4 7 3 Adjust adjusted joint Use the button to create or modify an adjusted joint for the current body Sect 3 4 9 The
39. act force elements Standard variables are p1 p2 parameterize a Z surface The corresponding edit boxes in the data inspector have the standard interface shown in Fig 3 21 Functions of description of profiled graphic elements Sect 3 4 6 2 8 A standard variable is p parameterizes the corresponding profile of section or an axis curve The corresponding edit boxes in the data inspector have the standard interface shown in Fig 3 21 3 3 2 4 6 External functions Usage of external function is directly connected with programming in the UM environment based on a Control file As a rule these functions are used when the corresponding mathematical model is too complicated for description as an implicit function Sect 3 3 2 4 5 There exist three types of external functions which are different with respect to arguments Time functions t are used for joint of generalized type elementary transformation of types tt rt Sect 3 4 9 6 4 as well as for rotational and translational joints in the cases when the joint coordinate is an explicit function of time Sect 3 4 9 4 Function of three arguments x v t are used for description of a bipolar force element type of element external Sect 3 4 10 1 a joint force and torque in the cases of joint of general type elementary transformations rv tv type of force expression Sect 3 4 9 6 3 as well as for translational and rotational joints Sect 3 4 9 4 x value of coor
40. adii of the upper and bottom circle bases h height of cone Angles starting and finishing angles in degrees that form a plate angle at the Z axis which delimits the conic surface The angles are counted from the X axis counterclockwise In case if both angles are zeros then the full cone cylinder is generated Number of points on the circle bases and the generating line which define a discretization of the conic surface Closing this switch has three positions None Sector Segment and defines how the conical surface should be closed 3 4 6 2 7 Parametrical GE The GE provides the wide possibilities to describe the complex surface as analytical surface in a parametric form Fig 3 37 Description of 3D curves and surfaces is allowed The user should describe them as arbitrary functions of a single p1 or p2 or the two parameters p1 and p2 Universal Mechanism 5 0 Chapter 3 Data input program 3 46 Fig 3 37 Parametrical GE The parameters of the parametrical GE are Standard there are a set of standard parametrical elements Plane Ellipsoid Ring Torus Cone Paraboloid Spring Horn Molecule Fig 3 37 Smooth cube Gear Elliptic gear Equation analytical expressions describing the dependence of the Cartesian coordinates X Y and Z on a parameter p1 or p2 for a 3D curve or p1 and p2 for a 3D surface Parameter limits for each parameter the minimal and the maximal values sho
41. alar torque description Description of a scalar torques includes the following steps Choice of interaction bodies Setting additional local coordinate systems SCA1 and SCB2 Fig 3 80 left These systems of coordinates can be assigned visually by mouse using preliminary created oriented connection points for the necessary bodies Systems of coordinates are drawn in animation window like in Fig 3 80 middle If the Autodetection mode is selected position of SCB2 is computed by the program automatically SCB2 coincides with SCA1 for zero values of all coordinates Selection of the torque mathematical model type from the standard list of scalar forces see Sect Input of bipolar force elements for more details Fig 3 81 Example of scalar torque Universal Mechanism 5 0 Chapter 3 Data input program 3 93 Fig 3 82 Nonlinear elastic torque component Example Consider an example of usage of the scalar torque In a model of a locomotive a scalar torque appears when a car body turns relative to the bogie frame about the vertical axis Fig 3 81 The torque includes two components The first one is a friction torque with the magnitude 2000Nm The second one is a nonlinear elastic torque which plot is shown in Fig 3 82 left In this case the torque type is List of forces The list of forces includes two elements a frictional Fig 3 80 right and Points symbolic Fig 3 82 right Universal Mechanism 5 0 Chapter 3 Data in
42. amming forces with complex Universal Mechanism 5 0 Chapter 3 Data input program 3 28 mathematical model This method is used exclusively for force elements of general type Sect 3 4 10 5 Projections of a force and a moment are identifiers which values should be calculated in a standard procedure of the control file See the chapter devoted to programming in the UM environment for more information 3 3 2 4 8 Time function from text file Here we consider how to set dependences on time of angular and translational coordinates with the help of text files The file can contain both full scale test and simulation results Coordinates as time functions are realized in the following joints generalized joint elementary transformations tt rt 3 4 9 6 4 translational and rotational joints when the coordinate is a time function 3 4 9 4 Format of a text file A text file with a time function should contain two columns separated by space symbols The first column contains time in seconds starting with zero or small value The second column contains the corresponding values of the function in meters for a translational coordinate and in radians for an angular coordinate First symbol in comment lines should be The file should be created beforehand and located in the directory of the model which uses it If UM does not find the file zero value is set for the corresponding function Creation of files with a time function as a simulatio
43. and character _ The first symbol in the identifier cannot be a digit or character _ Identifiers with the character _ as the first symbol are reserved for internal presentation of identifiers in equations of motion generated by the program Reserved words of Pascal and C languages cannot be used as identifiers The program verifies syntax of entered expressions If a new identifier is found it is added to the list of identifiers of the object Sect 3 3 1 Example of correct identifiers mass_1 length_of_rod cdiss cstiff Examples of wrong identifiers 2mass the first symbol is the digit 2 _length the first symbol is the character _ mass prohibited character do as while reserved words of the Pascal language There exist two types of identifiers Identifier number Identifier expression Values of identifiers of the first type can be changed both in the Input and in the Simulation programs Identifiers of the second type are presented by arbitrary expressions which include numbers identifiers of the first and the second types standard functions Sect 3 3 2 4 3 Expressions for identifiers of the second type are entered in the List of Identifiers Chains of calculations may be programmed with the help of identifiers of the second type An example of a chain including identifiers of the both types is shown below Name Expression Value Comments Mass 1 12 Mass of rod
44. ation window gives the object image or its parts according to active elements presented in the inspector It can be use also for visual construction of models List of elements presents the list of all object s elements and organizes access to parameters of separate elements List of identifiers is used for modification of identifiers of the model It is a base of the full parameterization of UM models Sect 3 3 2 4 2 Sheets with components can be also considered as a basic element of the constructor This tool allows adding to the model some simple standard elements bodies joints force elements or graphic objects This tool is used at a study level The drag and dock technology is used for the element list and the inspector They can be removed from the constructor window and placed on a separate window with the help of the Universal Mechanism 5 0 Chapter 3 Data input program 3 13 mouse If the list and the inspector are located as separate windows the hot keys F11 F12 Alt I are used to bring them in front Separate location of the list and the inspector are used to increase the animation window size when creating complex objects if necessary 3 3 1 1 List of object elements An object is a multibody system which consists of separate typical elements Access to the elements is realized by means of the list of elements Fig 3 11 visually 3 3 1 2 or with the help of hot keys 3 3 3 Fig 3 12 List of object elements
45. between Polyhedrons and Z surface is based on using Points Z surface contact force that is described in Sect 3 4 10 4 5 That is why it is also possible to describe contact interaction between polyhedrons and Z surface with the help of Points Z surface contact force The only difference between both variants is that 3D Contact generates all contact forces of Points Z surface type automatically without necessity to create the forces for each body and the Z surface manually At the same time both variants are identical from point of view of results of simulation of dynamics of the system Treating the Points Z surface contact forces in 3D Contact does not consider the interaction of edges and Z surfaces so contact forces will not appear in the case which is depicted in the Figure below Z surface Polyhedron Vertex Universal Mechanism 5 0 Chapter 3 Data input program 3 67 Note 1 CPU efforts for simulation of near contact are proportional to square of count of faces and edges To accelerate simulation process it is recommended to simplify contact manifolds 1 as far as possible for solving the particular problem Note 2 3D Contact model as any mathematical model is just an approximation of real physical processes that take place between two bodies contacting bodies Certainly the model has confined area of effective applications as well as there are cases where the model describes real processes incorrectly 3D Contact model is
46. bing position and orientation of the current GE in the SC of the current GO Material parameters defining inertia properties of the GE material such as density They are used for automatic calculation of inertia parameters of bodies 3 4 6 2 1 Polyhedron A polyhedron is used when a GE of irregular shape is needed An UM polyhedron is a set of 3D vertices forming one or more polygons The polygons may be drawn both in line and filled modes To describe a polyhedron the following parameters should be set Fig 3 32 Coordinates of vertices If only vertices are given then the result is a single broken line formed with these vertices But if several polygons are needed then the lower part of the form shown in Fig 3 32 is to be filled For each polygon vertex indices delimited with commas should be pointed filled polygons should be marked with Universal Mechanism 5 0 Chapter 3 Data input program 3 43 Fig 3 32 Polyhedron Example Four vertices might set a tetrahedron 0 0 0 1 0 0 0 1 0 0 0 1 and four polygons 1 2 4 4 2 3 1 4 3 1 3 2 3 4 6 2 2 Ellipse Parameters of an ellipse Fig 3 31 a b semi axes starting and ending angles for a elliptic sector Default values 0 0 correspond to a full ellipse discretization is the number of points approximating the ellipse filled option determines the element either as plane or a line 3 4 6 2 3 Box All ribs of a box a
47. d body use up to three rotations If the orientation does not set the SCB2 coincides with SC of the second body These data is not necessary for the second body if the Automatic computation for 2nd body option in on This option is used exclusively if the object is described in such a way that points B1 and B2 coincide at zero values of model coordinates This case is quite usual for models of railway vehicles If you click the Compute for the second body button UM computes coordinates of point B1 in SC of the 2nd body and inserts these values as coordinates of point B2 even if the Automatic computation for 2nd body is off The stationary value of the force acting on the second body can be entered too The force is resolved in SC of the first body Coordinates of attachment points components of stationary force elements of the element matrix are parameterized Sect 0 Remarks 1 Points A B1 B2 as well as systems of coordinates attached to them are visualized in the single element mode Sect 3 3 1 2 2 The icon marks point B1 2 These points are visualized in the whole object mode if the corresponding option is chosen Sect 3 3 1 2 2 Click the icon to call the window with element parameters Universal Mechanism 5 0 Chapter 3 Data input program 3 96 3 Use general and oriented connection points Sect 3 4 7 4 to set points A B1 B2 together with the attached SC The connection points must be preliminary described for the correspo
48. d parameters Smoothing turn on off of smoothing mode Perspective turn on off of orthogonal projection Background color setting the background color of the animation window Contour graphic mode is used to obtain contrast black and white image which is suitable for printing Show icons is used for visualization of icons for joints force element of general type generalized linear force element etc for the whole object mode in the animation window only Sect 3 3 1 2 2 Mode switching the animation window modes whole object active element Sect 3 3 1 2 2 3 3 1 2 4 Tool bar Copy the window to clipboard or to a file bmp Zoom in the selected area of animation window Show all F9 Zoom in out of a selected point on the object click the button and immediately click the left right mouse button on an image point to zoom in out the object and to shift the point in the window center Use also Alt Shift mouse click on an object point Shift mode Ctrl left mouse button Zoom mode Shift left mouse button Rotation mode left mouse button Choice of wire or surface graphics mode Turn on off perspective Choice of one of standard views Switch full object single element mode Sect 3 3 1 2 2 Show joint images See also Sect 3 3 4 3 for a list of hot keys Universal Mechanism 5 0 Chapter 3 Data input program 3 18
49. dinate v its time derivative an axle force in the case of a special force of the Combined friction type The corresponding edit boxes in the data inspector have the following standard interface Fig 3 21 Function of two arguments p1 p2 are used for description of Z surfaces surfaces given by the function z f x y in the cases of graphic element type Z surfaces Sect 3 4 6 2 9 and contact forces Z sphere Universal Mechanism 5 0 Chapter 3 Data input program 3 27 To describe an external function the user should enter its name identifier in the corresponding edit box of the inspector without arguments for instance Syntax rules for name of function as the same as for identifier Sect 3 3 2 4 2 UM generates a template for each external function in the control file This means that special functions will be added to the control file where the external function will be initialized by zero values The user should rewrite the corresponding procedures Consider a template of a time function Let the identifier alpha were used as the name of external function UM inserts the following procedure in the control file Cl NameOfObject procedure alpha _isubs integer _t real var _Value _dValue _ddValue real_ var _ _platfVarPtr begin _ _PzAll SubIndx _isubs _Value 0 _dValue 0 _ddValue 0 end The input parameters are _isubs the global index of subsystem _t the current time valu
50. ding positioning and deleting separate point on a curve 3 31 3 3 3 4 Selecting copying deleting and moving fragments and curves 3 31 3 3 3 5 Closing curve 3 32 3 3 3 6 Smoothing 3 32 3 3 3 7 Usage of clipboard for creating curves and functions 3 33 3 3 4 Hot keys 3 33 3 3 4 1 Constructor 3 33 3 3 4 2 Inspector 3 33 3 3 4 3 Animation window 3 33 3 3 4 4 Inspector tab with a list 3 34 3 4 Data Input
51. e The output values value of function identifier _Value as well as its first and second derivatives _dValue _ddValue Wrong programming of derivatives leads to wrong simulation results Consider a template for a function of t x v Let the identifier bforce1 was used for external function corresponding to a bipolar or joint force UM inserts the following function in the control file Cl NameOfObject function bforce1 _isubs integer _t _x v real real_ var _ _vehicleVarPtr begin _ _PzAll SubIndx _isubs Result 0 end The input parameters are _isubs the global index of subsystem _t the current time value the current x and v values _x _v The user should change the function code to calculate the output value Result Remarks 1 Functions of the one and same type which have coinciding identifiers are identified That is only one template of function or procedure will be generated for them in the control file Different identifiers must be used for external functions of different types 2 Detailed information about the control file and programming in the UM environment can be found in the corresponding chapter of the user s manual 3 The Simulation program calls external functions automatically 4 After adding or deleting external functions the user should verify the correctness of the old control file 3 3 2 4 7 External identifiers External identifiers give one of the possible forms for progr
52. e One of the bodies is the first one Body 1 in Fig 3 61 another the second one Body 2 Use two upper drop down lists to set the bodies Fig 3 62 Fig 3 62 The lists contain all bodies included in the object as well as the base body Base0 and an external body the second list only The Base0 is used for attachment of a body to a fixed point to the base The External body is used to make the element external the subsystem technique The first and the second bodies must be different 3 4 8 2 Type of element A type must be chosen for the most of elements with the help of a drop down list Fig 3 61 Fig 3 63 Changing the type leads to deleting of previous element description Universal Mechanism 5 0 Chapter 3 Data input program 3 69 Fig 3 63 3 4 8 3 Attachment points Attachment points have different notations for elements of different types joint points attachment point etc Anyway two points should be assigned for each element One of the points belongs to the first body another point to the second one The coordinates of the point should be entered in SC of the corresponding body as constant symbolic expressions Sect 0 3 4 8 4 Visual assignment of bodies and attachment points To assign visually a body and the corresponding attachment point click one of the buttons and select a point an oriented point or a vector which should be preliminarily described see Sect 3 4 7 4 Conn
53. e full object mode should be on the button Points Every type of listed visual elements has active regions which are used for visual selection of the corresponding object elements with the mouse GO the active region is the whole image Icon the active region is a small neighborhood of the left bottom part pointed out by the arrow e g for the joint icon Point active region is a small neighborhood of the point Image the set of bitmaps for representation of enabled degrees of freedom Used for joints only Fig 3 14 Images for enabled degrees of freedom a rotational b translational c three rotational spherical joint 3 3 1 2 2 Modes of animation window Animation window has two modes of visualization of an object The button or a pop up menu are used to switch them Whole object mode Universal Mechanism 5 0 Chapter 3 Data input program 3 16 The whole object is visualized In this mode a mouse click on the active region of an image makes the corresponding element active body joint and force element Sect 3 3 1 2 1 Single element mode A separate element is visible in this mode GO body joint or force element together with connected bodies Graphic mode wire of surface graphics can be changed with the help of two buttons Orthogonal projection is turned on off by means of the command Perspective of the pop up menu or the button Parameters of the orthogonal project
54. e method of generation of equations of motion as simpler in usage The symbolic method might be recommended for more experienced users which work with more or less complex models 3 6 1 Numeric iterative method To set numeric iterative method of generation of equations of motion select Object in the tree of elements and then set Generation of equations to Numeric iterative see Inspector window in the right part of the constructor window 3 6 2 Symbolic method To set symbolic method of generation of equations of motion select Object in the tree of elements and then set Generation of equations to Symbolic see Inspector window in the right part of the constructor window Universal Mechanism 5 0 Chapter 3 Data input program 3 118 Generation and compilation of equations of motions are performed within UM Input program Choice of an algorithm for generation the equations allows optimizing the number of floating point operation in the equation codes The group Language for output files lets you to specify the program language for output files You should select that language which compiler is installed on your computer The Compile equations checkbox presents an option for the user If it is checked the compilation will run right after the successful generation of equations most often used If the Rewrite Control File checkbox is checked the new version of the Control File will replace the old one The old Control File will be renamed as
55. e of string resources Basic elements of program UMInput exe are the following Fig 3 1 The main menu The tool panel with buttons which duplicate some most often used command of the main menu The set of sheets with typical elements for visual construction of simple objects The object constructor the main tool for object description and correction The Data input program is a multitasking tool which allows opening several constructors with description of various objects An object whose constructor is placed over all others is the active one Fig 3 1 Data inspector Animation window Element tree Sheets with components List of identifiers Main menu Buttons duplicating main menu Constructor of objects Universal Mechanism 5 0 Chapter 3 Data input program 3 5 Options of Input program To set or modify options of the Input program Run UMInput exe Call the option window with the Tools Options main menu command Use the OK button of the window to store changes in the computer registry 3 1 1 Setup of symbolic generation of equations of motion UM generates equations of motion of objects with the help of a built in specialized computer algebra system To simulate the object dynamics the equations should be compiled with the help of an external compiler Delphi 4 0 7 0 Visual C 5 0 6 0 Borland C Builder 3 0 5 0 BDS 2005 2006 which is not delivered with UM First o
56. eate contact points on each edge with quite small distance between them that significantly increases CPU efforts that neglect the only benefit in comparison with 3D Contact Please note that 3D Contact widens possibilities of simulation of contact interactions but needs extra computational efforts At the same time approach based on using contact forces generally faster but not so universal as 3D Contact one Examples Please find some examples of using 3D Contact in the following models Samples Misc Clockwork Samples Misc DominoDay Samples Misc Earthquake Samples Misc FallingFigures Samples Rail vehicles WedgeTest3DContact Samples Robots Manipulator Samples Robots krt_200 Universal Mechanism 5 0 Chapter 3 Data input program 3 68 3 4 8 Joints and force elements some features of description Joint and force elements have some parameters which entering is quite analogous e g a pair of bodies attachment points or images should be assigned for the most of elements of these types The standard interface is used for entering these parameters for instance the corresponding interface for a 6 d o f joint looks like this Fig 3 61 Body1 Body2 Image Element type Attachment point to Body1 Attachment point to Body2 Fig 3 61 3 4 8 1 Assignment of bodies A pair of bodies should be assigned for each joint or force element else the object description is considered as incomplet
57. echanical system which are fixed relative to the base SC0 e g plane supporting a rolling ball obstacles etc should be presented by a single GO which is assigned to the scene image Common Scene image inspector tab While drawing GO in the animation window UM superposes the point 0 0 0 with the first connection point of the first interconnected body and the point 0 0 1 with the second connection point at that UM properly changes the length and the orientation of the GO All elements bodies joints force elements having graphical image can be selected by the mouse pointer in the animation window and then be accessed in the element inspector form This feature is very useful in cases if the object description contains many elements 3 4 5 Assignment of graphic images to rods linear and bipolar force elements A GO can also be assigned to a linear or bipolar force element Sect 3 4 10 2 3 4 10 1 or to a weightless rod constraint Sect 3 4 9 8 These elements link two points of different bodies UM automatically puts the assigned GO between the points There is an obligatory condition while creating such a GO A GO corresponding to a linear or bipolar force element or to a rod constraint must be located along the Z axis of the SC GO between the points 0 0 0 and 0 0 1 that is the GO must have the unit length 3 4 6 Input of Graphical Objects For description of graphical objects GO a built in graphical editor is used
58. ection points Note 1 The type of the point should be chosen depending on the element For example description of a generalized linear force element requires both oriented points and general point The description of a bipolar force element requires two general points Note 2 If the element requires coordinates of a point only all types of connection points can be used If the element requires a vector an oriented point can be used Z axis of the LSC is used as the vector 3 4 8 5 Transformation of coordinates Attachment points of force elements are set in body fixed SC that is why a tool for transformation of coordinates of points into different SC could be useful To call the corresponding tool use the Tools Transformation of coordinates ore use the hot key Alt T Fig 3 64 Choose two bodies with the help of drop down lists and set coordinates of a point in SC of one of the bodies where the coordinates are known After that click either the button if the coordinates are known for the first body or the button if the coordinates are known for the second body and the coordinates are computed for SC of another body Analogously can be computed projections of a vector onto axes of different SC Fig 3 64 Example of transformation of coordinates Universal Mechanism 5 0 Chapter 3 Data input program 3 70 3 4 9 Input of joints 3 4 9 1 Visualization of joints In the single element mode of the animation window a pair of
59. el of the element before start its usage because the model in quite not trivial See Chapter 2 Universal Mechanism 5 0 Chapter 3 Data input program 3 113 Fig 3 92 Systems of coordinates related to linear force elements Description of geometric data for an elastic force element includes the following systems of coordinates SC Fig 3 92 SC1 local SC of body 1 with origin O1 SC2 local SC of body 2 with origin O2 SCA fixed relative to body 1 begin of the linear force element origin at A SCB1 fixed relative to body 1 end of the linear force element in unloaded state or under the static load origin at B1 SCB2 fixed relative to body 2 end of the linear force element in unloaded state or under the static load origin at B2 Automatic positioning mode The linear spring with autopositioning or the Linear spring damper with autopositioning components This mode is usually used for dymanic objects created as a result of data conversion from the CAD programs 1 Add to the first body a connection point corrsponding to point A or an oriented point for SCA see Fig 3 92 2 Add to the first body a connection point corrsponding to point B1 or optionally add to the second body a connection point corrsponding to point B2 or an oriented point for SCB2 see Fig 3 92 3 Click one of the buttons on the component panel The design help window opens containingh instructions and comments to the element adding process
60. emoves the element Usually the multiplier is set by an identifier a b Fig 3 78 Elastic bipolar force element with 4 mm gap option Positive compression is off a and on b Universal Mechanism 5 0 Chapter 3 Data input program 3 85 The Compression positive option is used for choice of the positive abscissa value on the force law plot If the option is not checked the default value abscissa increases with the growth of the length coordinate in this case the force usually decreases with the growth of abscissa If the option is checked on the contrary abscissa decreases with the growth of the length coordinate and the force usually increases with the growth of abscissa To insert data from a text file use the clipboard Sect 3 3 3 7 Abscissa matching Abscissa matching is often used in the case of a bipolar force element when the force depend on the element length Matching means that abscissa value on the plot must correspond to a definite length L of the element which value should be set in the L edit box Fig 3 77 Often L value is the element length for zero values of coordinates Two methods can be used for assignment of abscissa value to the element length according to the Type of abscissa matching group Fig 3 77 If the X value option is selected the abscissa value corresponding to L is directly set in the X L F L edit box Often this value is zero X L 0 If the F value option is selected the force value co
61. er to control geometrical parameters of force elements visually Universal Mechanism 5 0 Chapter 3 Data input program 3 36 3 4 2 Input of subsystems Subsystems are widely used for modeling of complex and specific mechanical systems see Chapter 2 Sect Subsystems There exist the following buttons create a subsystem copy an existing subsystem delete a current subsystem There are three types of subsystems included external and standard ones Standard subsystems are prepared subsystems which are delivered together with additional modules of UM and described in the corresponding part of user s manual for example subsystem wheelset delivered and described in the railway module UM Loco After choice of subsystem type included or external user needs to open UM object which will be a subsystem in the current object Fig 3 27 Data inspector for subsystems Universal Mechanism 5 0 Chapter 3 Data input program 3 37 Main parameters of external and included subsystems are almost the same They are name comment position of the subsystem identifiers used in the subsystem and the identifier of the subsystem used for programming Also an external subsystem has one more parameter Ancestor which is the path to the folder with ancestor of the subsystem To convert an external subsystem to an included one click the button Convert to included on the tab General 3 4 2 1 Setting connection with external subs
62. erify this the buttons can be used for visual entering both the joint points and the joint vectors A joint vectors can be obtained from connection points of vector and oriented point types see Sect 3 4 8 4 Visual assignment of bodies and attachment points Thus selection of a vector or an oriented point allows the user to assign simultaneously a body a joint point and a joint vector Further description of joint depends on type of the joint coordinate The coordinate can be a degree of freedom or a time function Coordinate is a degree of freedom All parameters are optional value of the coordinate the box is usually used to verify the correctness of the joint description stepwise changing of the value leads to motion of bodies type of the joint force torque Chapter 2 Sect Joint forces and torques can be chosen from the drop down list Fig 3 67 on the Joint force tab Universal Mechanism 5 0 Chapter 3 Data input program 3 73 Fig 3 67 Types of joint force After the type has been chosen the boxes for force parameters appear Some features of description of the force torque see in Linear Sect Linear force element Frictional Sect Friction and elastic frictional elements Elastic friction Sect Friction and elastic frictional elements Elastic friction 2 Sect Elastic frictional element 2 Viscous elastic Sect Viscous elastic element Points numeric Sect Points numbers Points express Sect Points expres
63. es T Forces Special forces gearing and combined friction 3 4 10 1 Input of bipolar force elements Fig 3 73 Bipolar force element General parameters of a bipolar element are Adjusted bodies Attachment points constant symbolic expression Type use the drop down list Other parameters of the element depend on its type and should be entered in boxes which appear after choice of the type Some features of description of the force as an explicit expression can be found in Sect 3 3 2 4 5 as an external function in Sect 3 3 2 4 6 Mathematical model of a bipolar force includes often the element length the distance between the attachment points Use the current Length parameter to verify the correctness of description of the element A GO is usually assigned to the bipolar force Sect 3 4 5 Type of forces Linear Sect Linear force element Frictional Sect Friction and elastic frictional elements Elastic friction Sect Friction and elastic frictional elements Elastic friction 2 Sect Elastic frictional element 2 Viscous elastic Sect Viscous elastic element Points numeric Sect Points numbers Points express Sect Points expressions Expression Sect Expression explicit function Fancher leaf spring Sect Fancher leaf spring External function Sect External functions List of forces Sect List of forces Universal Mechanism 5 0 Chapter 3 Data input program 3 82 3 4 10 1 1 Linear force elemen
64. f all make sure that a proper compiler is installed on your computer or on a server Then use the General tab to set the default external compiler In fact UM can use numeric iterative method of the generation of equations of motion without an external compiler 3 1 1 1 Delphi Fig 3 2 Paths to Delphi Use the Paths Delphi tab Fig 3 2 to specify paths to a Delphi compiler and the Delphi VCL files If the current computer has Delphi 4 0 7 0 or higher installed it is enough to click the Search Delphi button to set the paths If Delphi can be found in the local net try to find it automatically using the same button and the option Net turned on In this case the paths will be found if the registry of the corresponding net computer is available for reading If reading of the registry is not allowed the paths should be set manually To do this use the buttons in the right hand side of two boxes and find Delphi compiler dcc32 exe usually path to Delphi bin Directory containing Delphi VCL dcu files usually path to Delphi lib Example D Delphi5 bin dcc32 exe D Delphi5 lib Universal Mechanism 5 0 Chapter 3 Data input program 3 6 3 1 1 2 C Fig 3 3 Paths to C Use the Paths C tab Fig 3 3 to specify paths to a C compiler If the current computer has Visual C 5 0 6 0 or Borland C Builder 3 0 5 0 installed it is enough to click the corresponding button to set the paths If C can be found i
65. f the element can be found in Chapt 2 Sect Fancher leaf spring Force model parameters Stiffness compressed the spring vertical stiffness in the compressed state c Stiffness stretched the spring vertical stiffness in the stretched state c f friction compressed the value of friction coefficient in the compressed state f f friction stretched the value of friction coefficient in the stretched state f Beta the exponential suspension parameter b Height the height of the spring in the unloaded state 0x All the parameters are constant symbolic expressions see Sect 0 Remark The user should remember that bipolar force elements degenerate at zero length The lengths of the Fancher elements in the model of the leaf spring must be at least two times greater than the maximal dynamic shortening the element even if the real prototype has a less height 3 4 10 1 9 Impact bump stop Mathematical model of the force element of this kind is described in Chapt 2 Sect Impact The model has the following parameters L is the length of the element at zero clearance when force element starts to work l cStiff is a stiffness coefficient in a contact c cDiss is a damping coefficient in a contact d dLDiss is the contact deflection where damping coefficient reaches its maximal value cDiss d D eStiff is the force curve exponent is not used in the current version of UM software assumed to be 1 All the parameter
66. freedom 6 d o f can be converted to the generalized joint type For example a 6 d o f joint can be converted to the generalized type to introduce joint forces for some degrees of freedom A rotational or a translational joints is recommended to be transformed to the generalized joint type e g to add degrees of freedom or to parameterize inclination of the joint axis To convert the joint type use the button to open additional joint information Fig 3 65 click the button to make the conversion Universal Mechanism 5 0 Chapter 3 Data input program 3 71 Example User s manual Chapt 7 Sect Joint type conversion Parameterization of axis inclination Universal Mechanism 5 0 Chapter 3 Data input program 3 72 3 4 9 4 Input of rotational and translational joints Fig 3 66 Parameters of a rotational joint Notions of translational and rotational joints are discussed in Chapter 2 Sect Translational and rotational joints The following parameters should be entered in addition to bodies and joint points Sect 3 4 8 1 3 4 8 3 projections of the joint vector on axes of two body fixed SC the Geometry tab Fig 3 66 the vector cannot be zero additional shift and rotation the Description tab the Configuration group the parameters are optional If the bodies connected by the joint are is in the tree visible in the full object mode of the animation window set the button in the down state to v
67. g 3 95 Universal Mechanism 5 0 Chapter 3 Data input program 3 116 3 5 2 2 Saving object data Use the main menu File Save as command or the button to save the active object for the first time or to make a copy of the object Sect 3 2 1 Just here a name is assigned to the object To save a modified object use the File Save command of the main menu the Ctrl S hot key the button Data are stored in the input dat file located in the object directory Universal Mechanism 5 0 Chapter 3 Data input program 3 117 3 6 Generation of equations of motion Universal Mechanism supports two methods symbolic and numeric iterative Let us consider them more detailed Before generation of equations UM saves modified object and verifies correctness and fullness of the object description If the object description contains errors or not full the program opens the Protocol tab of the object inspector The protocol contains a list of errors and warnings Click a line with an error or a warning to go to the corresponding element of the object Zero mass and moments of inertia are errors by default Use the General tab of the UM option window Sect 3 1 4 to change the status of this error to a warning and back Symbolic method assumes generation equations of motion as source files in C or Pascal with posterior their compilation by one of the supported external compilers As a result of compilation the UMTask dll appears Thi
68. gram 3 111 3 5 UM Components 3 5 1 Basic notions UM components give an efficient tool for development of models The following elements and substructures can be converted into a component form body with without image joint with without image force element with without image images subsystem object Two files are assigned to any UM component a text file with description of the component on UM language and a bitmap bmp file with the component icon The standard extensions for the component text files are Joints jnt Bodies bdy Bipolar force elements bfc Images img Subsystem UM object sbs Generalized linear force element s lfrc Contact forces cfrc General type forces afrc Special forces sfrc Each UM component can be parameterized The corresponding identifiers and their default values are included in the component description file Component panel List of components A set of component can be grouped in a component library which description is stored in a umc file A tab on the tool panel corresponds to each of the linked component libraries The library tabs or the list of component window are used for both visual and non visual adding to the active object all elements included in the component The component list window is available by then Tools List of components menu command Universal Mechanism 5 0 Chapter 3 Data input program 3 112 The bu
69. gs Remark Access to parameters of visualized elements can be achieved by clicking the element image in the animation window if the window is in the whole object mode Sect 3 3 1 2 2 Universal Mechanism 5 0 Chapter 3 Data input program 3 19 3 3 2 2 General object parameters and options Use the Object tab of the inspector to set some general parameters and options for the current object Fig 3 17 Fig 3 17 Object general parameters and options Type of object General or Railway Vehicle for program version with support of dynamics of railway vehicles only Direction of gravity is set by a vector which specifies the direction of gravity relative to SC0 Vector components can be set as constant expressions or identifiers Sect 0 To turn off the gravity set zero value for the vector components If the vector has not the unit length the acceleration of the free falling decreases or increases its value proportionally Direction of gravity for all subsystems of the objects is set by the main object This means that the directions entered in the subsystems both included and external are ignored Characteristic size allows decreasing increasing the default size of images in the animation window This parameter is used for obtaining proper vector sizes for small or large objects Scene image assignment of a graphic object which corresponds to fixed elements of the object as well as to environment Press the Delete
70. he case if there are several possible z coordinates for any x y point the biggest z coordinate will be considered It is desirable that graphical object be smooth enough Using essentially non smooth surfaces might lead to incorrect results of simulation 3 4 10 5 Input T forces Fig 3 87 Example of a harmonic following force Use the T Force tab to enter a set of force elements of T type An element is described by A pair of interacting bodies A reference body for the force moment components A point the force is applied to a point of the second body in the SC of this body the button allows the visual setting the second body as well as the point of application using connection points Sect 3 4 7 4 Connection points Force and moment components Remark 1 To describe a following force set Base0 as the first body and the reference body coinciding with the second one Remark 2 Forces of this type are either explicit functions of time or are programmed by the user in the Control file Example Description of a following harmonic force directed along Z axis of the body1 fixed SC and applied to the point pos_x pos_y 0 is shown in Fig 3 87 1 Graphical objects of ASC type are created automatically during model import from external CAD programms Universal Mechanism 5 0 Chapter 3 Data input program 3 102 3 4 10 6 Special forces 3 4 10 6 1 Gearing Fig 3 88 Gearing parameters A gearing is desc
71. ibed by points Fig 3 44 Fig 3 44 Profiled GE a 2D axis curve given by points 3 4 6 2 9 Z surface A GE of this kind is intended for programming graphical image of an arbitrary surface in the control file The surface should be described as y x f z where x and y coordinates correspond to parameters p1 p2 Universal Mechanism 5 0 Chapter 3 Data input program 3 50 Fig 3 45 Z surface parameters The GE description includes name of function parameter ranges limits of changing both p1 and p2 parameters and numbers of pointes to approximate the surface When generating equations of motion a template for zSurface function is included in the control file for example as Pascal code function ZGraphicElementFunctions _index _isubs integer _p1 _p2 real_ real_ begin _ _PzAll SubIndx _isubs case _index of 0 begin Function zSurface Result 0 end end end For each function of type Z surface introduced for representation of graphical images an operator Result 0 is inserted and the user should replace it with a proper calculation GE of type Z surface is used to represent images with the help of complex implicit functional expressions including time dependent ones For example the Z surface was used to get a traveling wave Fig 3 46 Fig 3 46 Z surface Universal Mechanism 5 0 Chapter 3 Data input program 3 51 More detailed information concerning this GE i
72. inds of colors Diffuse color of material Specular color of the reflected light black color means no reflection Emissive the object shines with this color it is off if the color is black Ambient usually not used To choose each of the colors click mouse button on the corresponding color rectangle Use the button to select one of the standard color sets The parameter Shininess defines size of the reflected light s spot Check the Wired option to convert the element into the wire mode simultaneously the Width of curves parameter set the line width Universal Mechanism 5 0 Chapter 3 Data input program 3 53 3 4 6 4 Position and Orientation of GE Fig 3 49 Position and orientation of GE Each GE contained in GO is described in its own system of coordinates SC GE which can be positioned in SC GO in an arbitrary way it can be turned through some angles about the three axes in an arbitrary order and can be translated Rotation angles are given in degrees rotation axes being chosen previously Universal Mechanism 5 0 Chapter 3 Data input program 3 54 3 4 6 5 Inertia parameters of GE Fig 3 50 Inertia parameters of GE material Inertia parameters of bodies mass tensor of inertia coordinates of center of mass can be computed automatically according to the body image A necessary condition for that is filling the material properties for graphic elements at least for one of them On the Materia
73. int Remark Cut quaternion joints with 6 d o f are ignored in the Simulation program Universal Mechanism 5 0 Chapter 3 Data input program 3 80 3 4 9 8 Input of rod constraint A detailed description of a rod joint can be found in Chapt 2 Sect Weightless rod constraint In addition to the bodies and attachment point Sect 3 4 7 5 the length of the rod should be entered The length can be either constant of a time function Set a length as an explicit expression Sect 3 3 2 4 5 an external function Sect 3 3 2 4 6 a time table Sect 3 3 2 4 9 a function from a text file Sect 3 3 2 4 8 As a rule a graphic object is assigned to the rod Sect 3 4 5 The current distance between the rod attachment points is presented in the Current length box Use this parameter to verify the correctness of the length description Remark The rod is a constraint It does not introduce coordinates but restricts relative position of connected bodies Exact calculation of positions in this case can be done in the Simulation program That is why the current length of the rod in the Input program can differ from the real length entered by the user Universal Mechanism 5 0 Chapter 3 Data input program 3 81 3 4 10 Input of force elements The following constructor tabs are used for description of different force elements Chapt 2 Sect Force elements Bipolar forces Linear forces generalized linear force elements Contact forc
74. ion are modified with the help of the Window parameters command of the pop up menu 3 3 1 2 3 Basic system of coordinates pop up menu The basic system of coordinates SC0 is optionally presented in the animation window Use the Coordinate system command of the pop up menu to visualize of hide the axes Coordinates of all elements attached the base must be given in this SC A color principle is used to identify the SC0 axes RGB axis X Red axis Y Green axis Z Blue A coordinate grid coincides with one of the coordinate planes Use the Window parameters command of the pop up menu to change the grid size and step Use the right mouse button to call a pop up menu Fig 3 15 Fig 3 15 Universal Mechanism 5 0 Chapter 3 Data input program 3 17 Menu commands Orientation choice of one of the standard object orientations Grid choice of one of the standard grid locations Click an image of the SC0 axis to set the grid perpendicular to the corresponding axis Rotational style choice of style of rotation for objects in the animation window Z style used by default from UM 3 0 On sphere the style usually used in CAD systems Selection style the style of graphical visualization of an active element of the object image contours or box rounding the element image Coordinate system turn on off visualization of SC0 Window parameters call of a window with perspective and gri
75. l options of the Input program Fig 3 6 General options Use the General tab parameters Fig 3 6 to specify the following parameters Error when zero mass of a body if turned on zero mass is considered as a input error else as a warning Error when zero moment of inertia of a body if turned on zero inertia moment is considered as a input error else as a warning Universal Mechanism 5 0 Chapter 3 Data input program 3 8 The default language for automatically generated equations of motion and programming in the UM environment choice depends on the presented compiler Sect 3 1 1 Open the last object if checked the latest active object will be opened automatically when the Input program starts Open Pascal source files in allows selecting an editor for programming on Pascal language Open C source files in allows selecting an editor for programming on C language Remark Handling zero inertia parameters as an error is recommended for beginners only to avoid the degeneration of the mass matrix at the simulation of objects These options are ignored for railway vehicle models 3 1 5 Component libraries Fig 3 7 Component libraries Use the Libraries tab to add or remove component library files To add new component library click the button and select necessary file using standard dialog window Open To remove selected library use the button Universal Mechanism 5 0 Chapter 3 Data input
76. l tab Fig 3 50 set Density Type of graphic element solid hollow or frame for wire element Sect 3 4 6 3 A thickness and a section square should be set for a hollow and a wire GE Warning Automatic computing of inertia parameters may lead to wrong results if separate graphic elements intersect The intersected volumes are taken into account several times For example the mass of the body is computed according to the formula i m m where i m is the mass of a separate GE calculated independently on possible intersections Universal Mechanism 5 0 Chapter 3 Data input program 3 55 3 4 6 6 Curve editor The window of the curve editor is shown in Fig 3 51 See Sect 3 3 3 for basic information about this tool Fig 3 51 Curve editor Main elements of the editor are marked by indices graphical primitives 1 straight lines 2 cubic splines 3 beta splines special kind of splines 4 circle arc points vertices 5 a point of smooth conjugation of primitives 6 a point of non smooth sharp conjugation of primitives continuous curves continuums 1 5 2 6 2 1 4 1 and also 3 non closed curves 4 7 closed curves other controls and possibilities of the editor 8 drop down list of types of primitives 9 selection of a group of primitives by means of the mouse 10 panel of control buttons 11 list of curves 12 grid with coordinates and paramete
77. ll as two additional variables x coordinate v velocity The function is used for description of mathematical models of forces in the following cases Universal Mechanism 5 0 Chapter 3 Data input program 3 26 Description of a bipolar force element the force type should be expression x length of the element v time derivative of the length Sect 3 4 10 1 Description of joint forces in the case of joint of general type elementary transformations rv tv type of force expression Sect 3 4 9 6 3 as well as for translational and rotational joints Sect 3 4 9 4 x value of coordinate v its time derivative Description of an axle force in the case of a special force of the Combined friction type The corresponding edit boxes in the data inspector have the following standard interface Fig 3 21 Fig 3 21 Exit box for Pascal C expressions The letter p Pascal in the right top part of the box points out that the data is a time function Functions of description of parametrical graphic elements Sect 3 4 6 2 7 Standard variables are p1 p2 parameterize a surface or a curve The corresponding edit boxes in the data inspector have the standard interface shown in Fig 3 21 Description of Z surfaces Surfaces y x f z in 3D space are used in description of a Z surface graphic element Sect 3 4 6 2 9 as well as in Point Z surface and Sphere Z surface cont
78. lt C opens the Control file for the active object in the text editor File of elements creates a file n NameOfObject txt in the object directory and opens it in the text editor The file contains lists of all the object elements bodies joints identifiers force elements etc and their names Graphical converter opens a graphical converter of 3ds and ASC formats in the UMI UM graphical format Utility is used for import of external graphical objects Transformation of coordinates Alt T opens the forms for transformation of coordinates of points into different system of coordinates Sect 3 4 8 5 Wizard of components tool for edition of component libraries List of components open window with the list of loaded components Universal Mechanism 5 0 Chapter 3 Data input program 3 11 Options opens a dialog box with UM options paths to external compiler standard and user s libraries etc Sect 0 3 2 4 Edit Copy in clipboard copy parameters of selected elements to clipboard In clipboard as component write parameters of the selected element and the graphic object connected with it to clipboard If the element has no graphical object the option is disabled Copy into file write parameters of the selected element into file Save as component save parameters of the selected element and the graphic object connected with it in file Insert
79. m 3 59 3 4 7 1 Image and visualization of a body Body fixed SC The Graphic image pull down list contains all entered graphical objects see Sect 3 4 2 Click the button to access the assigned GO parameters or to create a new GO which will be assigned to the body The SC of the assigned GO coincides with the body fixed SC That is why the image moves when the body changes its position and orientation Use the single element mode of the animation window Sect 3 3 1 2 2 to see the body fixed SC and the body image a b c Fig 3 56 Visualization of an active body in different modes of the animation window Fig 3 56 shows visualization of a motor body in different modes of the animation window a Full object mode the active body is drawn as selected axes of the SC0 are drown b Single element mode the window contains the body image in the body fixed SC which axes are drawn c Single element mode wire graphics Important remark A body is drawn in the full object mode of the animation window if there exists a path from the body to the Base0 through the joints Chapt 2 Sect Compendency of systems and the definition of a joint For example if body2 is connected to body1 and body1 is connected to Base0 by means of two rotational joints both body1 and body2 are visible in the full object mode If the joint between body1 and Base0 is removed both bodies disappear If the joint between body2 and body1 is removed body1 disappears
80. n result Each plot in graphic windows can be saved in a text file after simulation of a UM model Chapt 4 Sect Graphical window Copying graphs to clipboard text file and file of calculated variables The file format matches the above requirements if symbol is set as a prefix for comments Chapt 4 Sect Options of simulation program General otherwise comments should be deleted from file manually one variable is saved time is laid off as abscissa Fragment of an automatically generated compatible text file with a time function 1 time 2 dyWheelset4 Lateral position of Wheelset4 2 00000002337219E 7 2 82372854E 15 1 03125004097819E 2 2 03257468E 6 2 09375005215406E 2 7 46718570E 6 3 21874991059303E 2 1 76279409E 5 4 21875007450581E 2 3 07774899E 5 Standard interface for setting the file Fig 3 22 Time function from file To set a name of the file use the button or write the name directly Universal Mechanism 5 0 Chapter 3 Data input program 3 29 Note 1 UM uses a spline interpolation of discrete file data to get function value in intermediate time moments as well to compute the first and the second derivative which are necessary for simulation Note 2 The user should take care of a sufficient smoothness of data in file Note 3 When the current simulation time exceeds the latest time point in the file the function value is constant equal the latest one in the file 3 3 2 4 9 Timetable as a method
81. n the local net try to find it automatically using the same button and the option Net turned on In this case the paths will be found if the registry of the corresponding net computer is available for reading If reading of the registry is not allowed the paths should be set manually To do this use the buttons in the right hand side of two boxes and find C compiler cl exe bcc32 exe Paths to C libraries lib files Paths to the standard h files Example for Visual C installed on computer Suvorov SUVOROV Program Files Microsoft Visual Studio VC98 bin cl exe SUVOROV Program Files Microsoft Visual Studio VC98 lib SUVOROV Program Files Microsoft Visual Studio VC98 Include 3 1 2 Paths to external subsystems Fig 3 4 Paths to external subsystem Universal Mechanism 5 0 Chapter 3 Data input program 3 7 Use the Paths Subsystems tab Fig 3 4 to add delete paths to directories with external subsystems UM uses these paths to search DLL with equations of external subsystems as well as other files necessary for simulation Remark Option is important if your version of UM has the Subsystem Module 3 1 3 Paths to user s units Fig 3 5 Paths to user s units and files Use the Paths Search paths Fig 3 5 tab to add delete paths to directories with user s units and file which are used as parts of user s code programming in UM environment The paths are used by the external compiler 3 1 4 Genera
82. nding body The buttons start the mode of visual selection of connection points Universal Mechanism 5 0 Chapter 3 Data input program 3 97 3 4 10 4 Input of contact force elements Use the Contact forces tab for description of the list of contact forces Chapt 2 Sect Contact forces Types of a contact force element Points Plane Sphere Plane Circle Plane Sphere Sphere Sphere Z surface Remark Changing the type deletes all previous description of the element The first interacting body always contains the first type of contact manifold in the name of the contact For instance the first body contains points and the second one a plane in the case of the Points Plane contact There exist two tabs for description of an element The Parameters tab contains some general contact parameters such as static and dynamic friction coefficient contact stiffness and damping coefficient etc The Geometry tab contains parameters depending of the element type 3 4 10 4 1 Points Plane contact Fig 3 85 Point Plane contact Universal Mechanism 5 0 Chapter 3 Data input program 3 98 Check the Close contact box to set the mode of automatic detection of the normal to the plane and the point on the plane Fig 3 85 Some deviation of the normal as well as a clearance could be set in this mode Geometrical parameters of the contact are entered in the Geometry tab Fig 3 85 Contact points belong to the first bod
83. ng local SC for scalar torques Sect 3 4 10 2 Setting local SC for 6 d o f joint Sect 3 4 9 5 Universal Mechanism 5 0 Chapter 3 Data input program 3 40 3 4 4 Assigning Graphical Image to Object Element Graphical images graphical objects GOs can be assigned to the most of UM elements for example to the scene bodies some kinds of joints e g a rod some kinds of force elements bipolar linear and so on Clicking a graphical image of element by mouse the user can open the element description in the object inspector For this purpose the whole object animation mode must be set in the animation window Sect 3 3 1 2 2 Graphical image is assigned to an object element from the list of the previously described GOs using a drop down list in the inspector of the current element body for example Fig 3 30 Assignment of a GO The drop down list contains names of GOs which have been set by the user while describing graphical objects or by default To make choosing GO easier it is recommended to give sensible names to GOs Fig 3 30 Activate the corresponding drop down list and press the Delete key to cancel the assignment of a GO to the element There are some features by assigning GO to the object element GO can be assigned to each body the same GO may correspond to several bodies this is the main principle The GO system of coordinate is automatically superposed with the SC of the corresponding body All elements of m
84. ng vectors Fig 3 58 Use the Vectors tab to add a vector Its description includes coordinates of the points and components defining the direction of the unit vector in the body fixed SC The vectors are used for visual correction and adding joints and some special force elements Here five methods for adding vectors are described 1 Use the add or the copy button Set point coordinates as constant symbolic expressions Sect 0 Set numeric values for the vector components 2 Visual adding by a normal and a point Click the button Select a point on a plane for the vector which is the external normal to the plane 3 Visual adding by two points Click the button Select a point for the vector point Select the second point for the vector direction 4 Visual adding by three points o Click the button Repeat actions for setting the LSC by three points from the previous section The vector corresponds to the Z axis 5 Visual adding by four points Click the button Repeat actions for setting the LSC by four points from the previous section The vector corresponds to the Z axis 6 Visual adding as a normal to the center of a circle passing through 3 points Click the button Select three points lying on a circle The resulting vector begins at the circle center The direction of the vector is perpendicular to the circle plane according to the right hand screw rule according to sequence of selected point
85. nimation window active If the animation window is active move the object X Shift X Y Shift Y Z Shift Z rotate the object around the corresponding screen axis positive and negative directions GrayPlus GrayMinus zoom in out R reset position and orientation Universal Mechanism 5 0 Chapter 3 Data input program 3 34 Combination of keys and mouse operations Sect 3 3 1 2 4 Shift mouse click on a button for shift zoom rotation the corresponding action but with a small step size Ctrl mouse click on a button for rotation rotation around axis of SC0 instead of screen axis Ctrl Shift mouse click on a button for rotation rotation around axis of SC0 with a small step size Ctrl Shift mouse click on an object point zoom in left button zoom out right button from the selected point Mouse move over a body image allows the user to get coordinates of the corresponding points of the body relative to SC0 If the Shift key is pressed the coordinates will be given in the body fixed SC If the Ctrl key is pressed the coordinates of body fixed SC origin in SC0 are shown 3 3 4 4 Inspector tab with a list Ctrl Alt Ctrl Alt Home to the first element of the list Ctrl Alt Ctrl Alt End to the last element of the list Ctrl Alt to the next element of the list Ctrl Alt to the previous element of the list Ctrl Alt GrayPlus add element Ctrl Alt GrayMinus
86. of a fragment select it and choose one of the smoothing type from the list Fig 3 23 Universal Mechanism 5 0 Chapter 3 Data input program 3 33 3 3 3 7 Usage of clipboard for creating curves and functions For input from the clipboard points should be written as a text in two columns The first column contains abscissa values the second one the ordinate values 68 9 11 7 66 4 8 88 63 9 6 98 61 4 6 48 58 9 5 99 To get points from the clipboard Copy the new data to the clipboard from any text editor in a standard manner Activate the curve editor by the mouse and paste data from the clipboard Ctrl V or Shift Insert 3 3 4 Hot keys 3 3 4 1 Constructor Ctrl Alt W make animation window active Ctrl Alt X make list of elements active F11 bring to front the list of elements if it is located as a separate window F12 bring to front the data inspector if it is located as a separate window 3 3 4 2 Inspector Open element data a tab of the constructor Ctrl Alt O object Ctrl Alt S subsystems Ctrl Alt B bodies Ctrl Alt G graphic objects Ctrl Alt J joints Ctrl Alt F bipolar forces Ctrl Alt L linear forces Ctrl Alt C contact forces Ctrl Alt A forces of general type Ctrl Alt E special forces Ctrl Alt Z external connections Ctrl Alt I indices Ctrl Alt P protocol 3 3 4 3 Animation window Ctrl Alt W make the a
87. ogram 3 105 3 4 10 6 3 Spring The mathematical model of the element is described in Chapt 2 Sect Special forces Spring Generalized linear force element Examples of description and or usage Chapt 7 Sect Models of Springs demo ac4 versions UM Loco UM Demo Coordinates of point A Coordinates of point B2 Orientation SCB2 Fig 3 89 Spring parameters Description of spring parameters similar to that for a generalized linear force element to a considerable extent namely coordinates of points A B2 orientation of SCB2 usage of the Compute for the second body button and the Autocomputing for 2nd body option stationary force It is supposed therefore that the user have already studied input of generalized force element Here we consider some features of the spring description only 1 Some equivalent information is entered instead o the point B1 direction of the spring axis in SC of the first body radio group Direction and the length of the spring under the static load which is set in the Stationary force group If this force is zero the length of free spring is set 2 Stiffness parameters should be set at the Parameters tab shear lateral stiffness Cs longitudinal stiffness Cl bending stiffness Cphi torsion stiffness Ca Universal Mechanism 5 0 Chapter 3 Data input program 3 106 These coefficients can be computed automatically according to spring geometrical and material
88. on element 2 The following parameters should be specified Dynamic coefficient of friction f Static coefficient of friction f0 usually equal to the dynamic one Stiffness of the first spring c1 Stiffness of the second spring c2 Element length in the unloaded state All parameters are constant symbolic expressions Sect 0 3 4 10 1 4 Viscous elastic element General information about force element of this type can be found in Chapt 2 Sect Types of scalar forces Stiffness and damping in series and in parallel The following parameters should be specified Stiffness cStiff in series N m c in figure Damping constant cDiss Ns m Stiffness cStiff 1 in parallel N m c1 in figure can be zero Length of unloaded element L0 ignored if c1 0 Parameters are constant symbolic expressions Sect 0 3 4 10 1 5 Points numbers General information about force element of this type can be found in Chapt 2 Sect Types of scalar forces Points model Universal Mechanism 5 0 Chapter 3 Data input program 3 84 Fig 3 77 Parameters of Points numbers element Curve editor is used to set a de of the force by a set of points Sect 3 3 3 Fig 3 78 use the button to call the editor The force can depend on the coordinate x its velocity v or time t Use the Type of variable group to select a necessary dependence The Factor parameter changes scale of ordinate values Zero value of the factor in fact r
89. on for automatic calculation of body inertia parameters is turned on To go to describing or changing graphical objects or elements GOs or GEs use the Graphical images tab Fig 3 11 The object inspector is shown in Fig 3 31 Fig 3 31 Graphical object in the data inspector On top of the inspector tabs for graphical elements marked with their names are located The user can rename GOs using the corresponding edit box The current GO can be replaced from or stored in a text file using buttons Each GO is a set list of graphical elements GE which is shown a bit below Lower buttons are intended for adding a new GE copying duplicating the current GE deleting the current GE Universal Mechanism 5 0 Chapter 3 Data input program 3 42 To set change the type of the current GE a drop down box is used which contains names of the standard GEs polyhedron ellipse box spiral ellipsoid cone parametrical GE profile GE Z surface While describing almost all parameters of GEs identifiers and symbolic expressions may be used Remark Changing a type deletes previously entered data for the current GE 3 4 6 2 Input of graphical elements GE Each GE has four groups of parameters located in the different tabs Fig 3 31 Parameters a tab with GE parameters depending on its type Colors a tab with GE color information Position a tab with parameters descri
90. program 3 9 3 2 Main menu commands and tool panel 3 2 1 File New object Ctrl N opens constructor of a new object with the default name UmObj Index Open object Ctrl O calls a special dialog box for choice an existing object Fig 3 8 The dialog box contains a tree of objects found in the directory for reviewing objects To set the default path to the directory for reviewing objects use the menu command Tools Options and the page Paths Objects in the window Options or use the button in the top edit box to choose the root directory and the Accept as default button right after that Fig 3 8 Open object dialog box Use the F5 button or the pop up menu to refresh the tree of objects in the Open object dialog box Use the upper edit box for changing the current directory Reopen allows the user to open recently used objects Save Ctrl S saves the active object in the object directory The command is executed if the active object has been modified and the object directory has already been created If the directory does not exist the Save as command is executed Save as saves the active object in a directory pointed out by the user Use the Save as dialog box to select or enter a path to the object including its name If necessary new directories are created The object takes the last directory in the path as its own name Fig 3 9 Remark Object name i e the last directory in the pa
91. put program 3 14 General forces list of forces used mainly for their programming in the UM environment Sect 3 4 10 5 Special forces models of special force interactions gearing cams combined friction etc Sect 3 4 10 6 3D Contact setting for 3D contact model Reserved for future use For more detailed description of using 3D Contact see Sect 3 4 7 5 Connections a tool for assignment of attachment points for external joints and force elements For UM version with subsystem technique only Indices internal UM indices of object elements and coordinates useful for programming in the UM environment Summary contains information about correctness of the object description as well as lists of errors and warnings Universal Mechanism 5 0 Chapter 3 Data input program 3 15 3 3 1 2 Animation window 3 3 1 2 1 Visualization of object elements The whole object or their active elements are visualized in the animation window depending on the window mode Sect 3 3 1 2 2 The following types of visual elements are used for visualization of different elements Graphic objects GO created by the user for bodies bipolar and generalized linear force elements special force elements spring rod constraint images Sect 3 4 6 Fig 3 13 Visualization commands Icons for force element of general type linear and special force elements connection points external elements Fig 3 13 th
92. put program 3 3 3 4 10 4 4 Sphere Sphere contact 3 99 3 4 10 4 5 Points Sphere Circle Z surface contact 3 100 3 4 10 5 Input T forces 3 101 3 4 10 6 Special forces 3 102 3 4 10 6 1 Gearing 3 102 3 4 10 6 2 Cam 3 103 3 4 10 6 3 Spring 3 105 3 4 10 6 4 Rack and pinion 3 107 3 4 10 6 5 Bushings 3 109 3 5 UM Components 3 111 3
93. put program 3 94 3 4 10 3 Input of generalized linear force elements Fig 3 83 Linear force element parameters Mathematic model of the element is described in Chapt 2 Sect Generalized linear force element Examples of description and or usage Chapt 7 Sect Models of Springs model demo Manchester benchmarks Vehicle1 versions UM Loco UM Demo model demo wedgetest General parameters of a linear element are Adjusted bodies Attachment points constant symbolic expression and element system of coordinates Elements of stiffness and damping matrix use the button in the corresponding box A GO is usually assigned to the linear elastic force Sect 3 4 2 Universal Mechanism 5 0 Chapter 3 Data input program 3 95 Coordinates of attachment points as well as elements of the stiffness damping matrix are parameterized Sect 0 3 4 10 3 1 Some features of description of elastic element Fig 3 84 Some details relevant to the elastic force element can be found in Chapt 2 Sect Generalized linear force element There can be found notations used in figures as well The following parameters should be entered for the first body attached to the element Coordinates of points A B1 in SC of the first body For the second body if the option Automatic computation for 2nd body is off Coordinates of point B2 in SC of the second body Orientation of SC connected with point B2 relative to the SC of the secon
94. r Microsoft Visual C 2 Select Paths C tab 3 Click one of the following buttons Search Visual C or Search Borland C Builder depending on which C compiler is installed on your PC If UM successfully detects external compiler all paths are set automatically If not you should set all paths manually
95. rce elements sizes of graphic elements coefficients of stiffness and damping and so on The corresponding edit boxes in the data inspector have the standard interface Fig 3 20 Exit box for constant expressions The letter c in the right top part of the box points out that the parameter can be a constant expression Double click the box or use the pop up menu to call a tool for visual construction of the expressions 3 3 2 4 5 Expression explicit function The expression of this type includes numbers identifiers standard functions standard variables t x v p1 p2 p depending on type of function Double click the edit box or use the pop up menu to call a tool for writing the expressions The corresponding window contains the list of identifiers and buttons with allowed functions Types of explicit functions Function of time t The standard variable is t time The function is used for description of joints Joint of generalized type elementary transformation of types tt rt Sect 3 4 9 6 4 Rotational and translational joints in the cases when the joint coordinate is an explicit function of time Sect 3 4 9 4 The corresponding edit boxes in the data inspector have the following standard interface The letter t in the right top part of the box points out that the expression is a time function Force description force functions x v t Standard variables are t time as we
96. re parallel to the axes of the GE fixed SC The box parameters are Fig 3 33 Box parameters Universal Mechanism 5 0 Chapter 3 Data input program 3 44 Length width height A B C constant symbolic expressions Discretization 0 4 specifies the number of finite elements on a box side about 2n elements on each side in the line mode 3 4 6 2 4 Spiral This GE is used customarily as to draw elastic linear of bipolar force elements The spiral parameters are Fig 3 34 coil radius r a constant symbolic expression spring height H a constant symbolic expression the number of coils coil discretization Fig 3 34 Parameters of a spiral The axis of the spiral coincides with the z axis of the GE fixed SC 3 4 6 2 5 Ellipsoid This GE allows showing an ellipsoid or particularly a sphere Fig 3 35 Fig 3 35 Parameters of an ellipsoid The parameters of an ellipsoid are a b c its semi axes Slices Stacks number of points to approximate the ellipsoidal surface The center of the ellipsoid is placed into the begin of the GE SC Universal Mechanism 5 0 Chapter 3 Data input program 3 45 3 4 6 2 6 Cone The dialog form for input of a cone is shown in Fig 3 36 Fig 3 36 Cone The GE allows getting such images as cylinder cone and truncated cone also only a part of these surfaces For description of conic surface the user should input the parameters R1 R2 r
97. ribed by Fig 3 88 Interaction points centers of gears in SC of the corresponding bodies Gear axes unit vectors in SC on the bodies Gearing parameters gear ratio clearance optionally stiffness and damping coefficients of tangential contact of teeth Check the external internal option for plane gearing All the data except the gear axes are parameterized Sect 0 Gear axes and gear contours are visualized in the single element mode Sect 3 3 1 2 2 Universal Mechanism 5 0 Chapter 3 Data input program 3 103 3 4 10 6 2 Cam A plane cam connection is realized as a variant of a contact interaction of two bodies see Chapt 2 Special forces Cam Example use usage model demo cams The cam piston parameters are presented in the figure The mathematical model of such the interaction is similar to the contact interaction described in Chapt 2 Sect Contact forces To create a cam element select the Special forces item in the element list add a new element Set the type of the special force as Cam As a result the inspector shows some boxes for the parameters of the cam Body 1 and for the piston or the link Body 2 The user should enter the following parameters Characteristic points in SC of each body The first point is a point of a cam profile plane in the profile is not imported from the body image The second one is a point of Universal Mechanism 5 0 Chapter 3 Data input program 3 104 con
98. rresponding to the length L is set and program compute the corresponding abscissa value automatically It is clear that in the last case the user must ensure the existence and uniqueness of solution X F To the notion of abscissa matching The Compression positive option is not checked Universal Mechanism 5 0 Chapter 3 Data input program 3 86 To the notion of abscissa matching The Compression positive option is checked 3 4 10 1 6 Points expressions General information about force element of this type can be found in Chapt 2 Sect Types of scalar forces Points model Fig 3 79 Elastic bipolar force element with a gap which value is set by the gap identifier The force element is similar to the previous one but both abscissa and ordinate coordinates of points can be set by expressions Use the buttons to add copy or delete a selected point The button is used for preview the function in a graphical window In the figures of this section we consider a description of the same function as in the previous one but the length of element clearance and stiffness are parameterized Parameterization allows changing these parameters in the simulation Universal Mechanism 5 0 Chapter 3 Data input program 3 87 Nonlinear damper The Compression positive option is not checked Nonlinear damper The Compression positive option is checked Universal Mechanism 5 0 Chapter 3 Data input program 3 88 3 4 10 1 7 Hysteresis
99. rs of the current selected curve For adding points vertices double clicking the left mouse button is using To copy duplicate a curve select it using mouse pointer put it to the Windows clipboard insert from the clipboard Universal Mechanism 5 0 Chapter 3 Data input program 3 56 Exchange with the clipboard is performed using a text format So the user can type coordinates of vertices as two columns of numbers in any text editor and insert them into the curve editor Pop up menus are used for various actions with primitives and points of curves It appears after clicking the right mouse button over the corresponding element For example clicking over the free field of the curve editor results in appearing a pop up menu shown in Fig 3 52 Fig 3 52 Curve editor main pop up menu The menu has two items Start new curve the next point being input will be the start point of the new curve continuum Select all is used to select all curves in the editor Clicking right mouse button over any vertex results in appearing a pop up menu for a point Fig 3 53 Fig 3 53 Pop up menu for a point Actions allowed for a selected point are Properties opens a point property dialog box intended for changing the point coordinates Delete removes the selected point Smooth turns on off the smooth conjugation of primitives A pop up menu for a primitive appears after clicking any primitive
100. ry to define the position of SC relative to SCO First an auxiliary SC with the origin in point A SCA is introduced which position relative to SCO is set by the shift vector 1 r and by a set of up to three sequential rotations After that the position of point B relative to SCA is specified by the vector 2 r Thus axis of SCA and SCB are parallel In particular case 0 2 r and SCB coincides with SCA The auxiliary SCA is sometimes useful when shifts could be specified simpler relative to already rotated exes i e relative to SCA Fig 3 29 Window for specifying an LSC The standard interface for setting LSC is shown in Fig 3 29 Data are entered in three groups Translation Projections of vector 1 r in SCO are entered O A B r1 r2 Universal Mechanism 5 0 Chapter 3 Data input program 3 39 Rotation Sequence of rotations specifies orientation of SCA and SCB relative to SCO It is allowed up to three rotations Angles of rotation are set here in degrees Shift after rotation Projections of vector 2 r in SCA are entered i e shifts along axes of SCA Both projections of vectors and angles of rotation can be parameterized The interface is used for input of the following data types Position of a graphic object Sect 3 4 6 Position of a graphic element relative to SC of graphic object Sect 3 4 6 4 Setting local SC for special force element of the Bushing type Sect 3 4 10 6 5 Setti
101. s Universal Mechanism 5 0 Chapter 3 Data input program 3 65 3 4 7 5 3D Contact There is a possibility to assign a contact manifold described as a graphical object see Sect 3 4 6 Input of Graphical Objects page 3 40 to a rigid body All bodies that have such a contact manifold will interact between each other during simulation dynamics of a mechanical system in UM Simulation Parameters of a contact interaction as well as turning on off contact between pairs of bodies are available in UM Simulation 3D Contact supports parameterization of graphical objects that are used as contact manifolds Firstly parameterized graphical objects for contact manifolds you can consider various configuration of contacting bodies in quite wide range simply changing corresponding parameters without remaking the graphical object itself Parameterization of graphical object may be effectively used for example for searching the optimal shape of the friction wedge for so called three piece bogie for freight cars Fig 3 59 below a Graphical object GO b Contact manifold CM c GO and CM Fig 3 59 Graphical object and contact manifold for a body of wheeled robot A graphical object that is assigned as a contact manifold for a body may differ from a graphical for the body It is absolutely not necessary that it should be the same graphical objects It is recommended to use simplified contact manifolds for decreasing the CPU efforts for simulation The
102. s parameters of the plot area Fig 3 24 Fig 3 24 Parameters of the plot area 3 3 3 3 Adding positioning and deleting separate point on a curve There exist too methods for adding a point to a curve 1 Double click by the left mouse button in the position off the adding point With this method a point can be added both to begin and the end of a non closed curve as well as inside the closed or non closed curve When a point is added to the begin or to the end of e curve it is recommended to put it near the corresponding first or last point of the curve and then to drag it to the desirable position 2 Button over the list of points Fig 3 23 With this method you can add point to the end of the curve only Positioning the point means setting its desirable position Two methods are realized for this purpose 1 Positioning by the list of points Find the point in the list e g by clicking on its image in the plot area and set its new coordinates 2 Positioning by dragging This is the most often used method for approximate positioning points Move the mouse cursor near the point image The cursor must change to Press the left mouse button and drag the point to the desirable position To delete a point either select it in the list of point and click the button or move the mouse cursor near the point image until it changes to call the pop up menu click the right mouse button and select the Delete menu item 3 3 3 4
103. s dll is used by UM Simulation program for numerical integration of equations of motion A dynamic linked library dll which contains the object equations must be created for each UM object as a result of generation and compilation of equations of motion Use the Tools Generate equations command of the main menu to generate and optionally compile equations of motion with the help of the built in specialized computer algebra system Numeric iterative method assumes generation of equations of motion on each step of numerical integration directly in UM Simulation program Let us consider advantages and disadvantages of both methods In terms of CPU efforts the symbolic method is faster It provides decreasing CPU efforts up to 10 30 for complex more than 10 20 degrees of freedom models For rather simple models CPU efforts for both methods are roughly the same The symbolic method during generation of source code fulfils its optimization from the point of view of CPU efforts On the other hand the symbolic method of generation of equations of motion expects any external compiler to be installed on the same computer Universal Mechanism supports Borland Delphi Borland C Builder Microsoft Visual C as external compilers At the same time the numeric iterative method does not suppose explicit steps of generation and compilation of equations of motion and seems to be simpler in usage For beginner users it is recommended to use the numeric iterativ
104. s are constant symbolic expressions see Sect 0 Universal Mechanism 5 0 Chapter 3 Data input program 3 91 This force element can works as a border for compression and stretching modes Let us consider the compression case While the length of the force element more or equal to L than force is zero As soon as the length of the element becomes less than L the viscoelastic force starts to act In the case of the stretching mode the force starts to act if the length of the element exceeds L If force element of Impact type acts as joint force than the L parameter should be considered as a joint coordinate So introduced two force of this type one for stretching another one for compression as joint forces in a joint we can define limits for the joint coordinate Dimensions of parameters for bipolar and joint forces are given in the table below Parameters Dimension Bipolar of joint force along translational degree of freedom Joint force along rotational degree of freedom L m rad cStiff N m Nm rad cDiss Ns m Nms rad dLDiss m rad 3 4 10 1 10 List of forces This type of force creates an arbitrary set of forces of the above types which work in parallel Use the buttons to add copy or delete a separate force Universal Mechanism 5 0 Chapter 3 Data input program 3 92 3 4 10 2 Input of scalar torque force element Mathematic model of the element is described in Chapt 2 Sect Scalar torque Fig 3 80 Sc
105. s discussed in the manual for programming in UM environment Remark Since the real description of the GE is located in the control file and is accessible in the UM Simulation program only so in the input program the element is showed as a rectangle of sizes defined by change limits of parameters p1 p2 3 4 6 2 10 GO as a graphic element A previously created GO can be included in the current GO as a graphic element type GO of the graphic element This feature allows the user to create a many time repeating group of graphic elements as a separate GO and insert it several times in another GO After that the correction of included GO leads to modification of all the GE GO For example consider an image of a fright couch body It includes a lot of repeating parts stiffening ribs one of which is selected in the picture Fig 3 47 It should be created a GO corresponding to a separate rib and then this image is dozens of times included in the image of the body as GE GO and positioned by a proper way If the image of the rib must be modified e g its height must be reduced the only GO of the rib should be corrected and all the ribs included in the image of the coach body are changed automatically Fig 3 47 Graphic image of a fright couch body Universal Mechanism 5 0 Chapter 3 Data input program 3 52 3 4 6 3 GE colors Colors of a GE are set by parameters on the tab Color Fig 3 48 Fig 3 48 Colors of GE There are several k
106. s of the editor depending on the problem to be solved Mode of creation of a set of curves Mode of creation of a function The second mode imposes a number of restrictions and additional features one curve only ordering points according to abscissa value plots the first and second derivative as well as a curvature in a separate window is available 3 3 3 2 Tool bar Consider functions of buttons on the tool bar Note that sets of buttons differ for different modes of the editor left or right shift depending on the mouse button up or down shift depending on the mouse button zoom in out depending on the mouse button horizontal zoom in out depending on the mouse button vertical zoom in out depending on the mouse button zoom in of a rectangle area selected by the mouse optimal view of inputted data delete a selected fragment copy to clipboard as a picture or as a text data List of points List of curves Type of smoothing Tool bar Curve Universal Mechanism 5 0 Chapter 3 Data input program 3 31 preview of data in a 3D animation window for 3D graphic elements only Sect 3 4 6 2 8 shift of the left border of the plot area read data from file save data to file buttons for plotting the first and second derivative as well as a curvature in a separate window is available for an inputted function switch on off a mode of equal scales along abscissa and ordinate axe
107. s that if the user changes the point parameters after its usage for description of an element the corresponding changes are not transferred to the element automatically 3 4 7 4 1 Adding general connection points List of points Tools for list modification Tools for visual creation of points The Points tab is used to create or modify the list of points To add a point the user should set its coordinates in the body fixed SC Here are instructions how to do this 1 Use the add or the copy button Set point coordinates as constant symbolic expressions Sect 0 2 Click the button select by the mouse a point on the body image and click the mouse button again The selected point is added automatically Universal Mechanism 5 0 Chapter 3 Data input program 3 62 First click Second click Result Selection of image vertex Adding a point as a middle point of a section 3 The button allows the user to get a point as a middle point of a section selected by the mouse Use vertices on the body image for exact positioning of points Near the vertex the mouse cursor is changed to After visual adding the point can be corrected or removed by the button 3 4 7 4 2 Adding oriented connection points Use the Oriented points tab to add an oriented connection points a local system of coordinates LSC Its description includes coordinates of the points and the orientation of axes of the LSC in the body fixed SC
108. se of nonlinear bushing enter damping constants and nonlinear plots for force and torque components versus the corresponding displacements and rotations a b c Linear bushing compliant ball joint b Nonlinear bushing Autodetection mode is on c Position of SCB1 if necessary set static values of force and torque 0 0 M F FX FY FZ MX MY MZ and or static offset for SCB2 0 0 p D Dr d_x d_y d_z d_ax d_ay d_az Universal Mechanism 5 0 Chapter 3 Data input program 3 110 Example of a bushing model VAZ21_09 from then Samples Automotive directory Busing icon is visible in the animation window in the single element mode as a red wired cylinder like in the figure above SCB1 and SCB2 are drawn as well Example of a nonlinear bushing which is used for modeling support and gaps between a side frame and an axle box in the model of a three piece bogie of a freight car Remark 1 The following agreement about signs is assumed by description of nonlinear force and torque components Positive value of elastic force torque in a plot corresponds to positive value of displacement rotation see the above plot Remark 2 The autodetection mode is often can be recommended At this mode position of SCB2 is computed automatically coincident with SCB1 for zero values of object coordinates All the parameters including angles of rotations are constant symbolic expression Sect 0 Universal Mechanism 5 0 Chapter 3 Data input pro
109. sibilities are used to manage the lists within the data inspector a b Fig 3 18 Lists Fig 3 18a shows an empty list in the inspector Fig 3 18b shows the list which contains several elements bodies Every element of the list has its own tab or page The name of a page coincides with the name of the corresponding element Edit box for the name and three buttons are located in the top of the tab adds a new element to the list creates an exact copy of the current element and adds it to the list deletes the current element See also Sect 3 3 4 4 Remark Press the Enter key after modification of the name else the changes can be lost Universal Mechanism 5 0 Chapter 3 Data input program 3 21 3 3 2 4 Data types Information about each element of an object element parameters is entered in boxes of the data inspector UM uses several standard data types The user must know features of each data type to work with UM correctly A very important feature of object description using UM is the data parameterization This means that many element parameters could be set not only by its numeric values but by expressions including numbers identifiers operations and functions Consider the basic types of data presented in UM 3 3 2 4 1 Numeric constants UM uses standard syntax for numbers Examples 1 23 0 256e 3 3 3 2 4 2 Identifiers Identifier is a set of symbols which includes Latin letters digits
110. sions Expression Sect Expression explicit function External function Sect External functions List of forces Sect Fancher leaf spring Coordinate is a time function Use the Prescribed time function check box to set this type of the coordinate Fig 3 68 Time function The time function can be set as an explicit expression Sect 3 3 2 4 5 an external function Sect 3 3 2 4 6 a time table Sect 3 3 2 4 9 a function from a text file Sect 3 3 2 4 8 Remark Both rotational and translational joints is recommended to be transformed to the generalized joint type e g to add degrees of freedom or to parameterize inclination of the joint axis Sect 3 4 9 3 Example User s manual Chapt 7 Sect Joint type conversion Parameterization of axis inclination Universal Mechanism 5 0 Chapter 3 Data input program 3 74 3 4 9 5 Input of 6 d o f joint Detailed description of the joint can be found in Sect Chapt 2 Sect Six d o f joint Fig 3 69 Description of 6 d o f joint In addition to connected bodies Sect Sect 3 4 8 1 the user should set positions of local joint system of coordinates SC1A and SC2B relative to SC1 and SC2 in the Geometry tab For this purpose the sheets Body1 and Body2 are used Fig 3 69 left The standard interface is used for parametric setting the SC positions see Sect 3 4 3 The following parameters should be entered to specify the joint coordinates Fig 3 69 right type
111. t General information about force element of this type can be found in Chapt 2 Sect Types of scalar forces Linear force Fig 3 74 Parameters of linear force element describing a linear viscous elastic interaction The boxes in the window Fig 3 74 correspond to the following parameters of the element F0 constant component of the force cStiff stiffness constant cDiss damping constant x0 the coordinate for zero value of the elastic component Q w a amplitude frequency rad s and initial phase rad of the harmonic excitation All the parameters are constant symbolic expressions Sect 0 3 4 10 1 2 Friction and elastic frictional elements General information about force element of this type can be found in Chapt 2 Sect Types of scalar forces Friction force and Types of scalar forces Elastic friction force Fig 3 75 Parameters of friction element The following parameters should be specified Friction force value F Static dynamic coefficient of friction ratio f0 f Stiffness at sticking cStiff Damping constant at sticking cDiss All parameters are constant symbolic expressions Sect 0 3 4 10 1 3 Elastic frictional element 2 General information about force element of this type can be found in Chapt 2 Sect Types of scalar forces Elastic friction force 2 Universal Mechanism 5 0 Chapter 3 Data input program 3 83 Fig 3 76 Parameters of elastic fricti
112. tact contact type Point the center point of a roller contact type Roller or a point on a contact plane contact type Plane Profile of the cam can be chosen as one of the graphic elements in the body 1 image From body image or as a planar closed curve created with the Curve editor Set separately Use Unilateral contact flag to choose either uni or bilateral type of the contact Set the point normal to the profile plane and angle of rotation about the normal to define the location of the separately defined profile in the body1 SC Cam profile can be chosen as one of the graphic elements in the body 1 if the image contain one of the following GE cone if top and bottom radii are equal ellipse with equal semi axes circle element of the profiled type Curve 2D profile type axis should be a straight line see Sect 3 4 6 2 8 Piston parameters Here the user can set dynamic and static coefficients of friction except the Roller contact type coefficients of contact stiffness and damping and also radius of the roller contact type Roller Additional parameters for the Plane contact type external normal to the piston plane type of contact Sliding Rollong the Rollong contact type in particular allow modeling the rolling of non circular wheels on a plane All of the data except the normals and points on the cam profile points can be parameterized Universal Mechanism 5 0 Chapter 3 Data input pr
113. th must be an identifier that is then name contains the letters a z A Z digits 0 9 and the _ The first symbol must be a letter Exit Alt X closes the program Universal Mechanism 5 0 Chapter 3 Data input program 3 10 3 2 2 Object Verify data F7 verifies correctness and fullness of the object description Generate equations F8 saves modified active objects deletes old UMTask dll file of equations and verifies the object description If no errors are found the window for generating and compiling equations starts Fig 3 10 Compile equations Ctrl F9 runs compiling of equations if they are generated Simulation F9 verifies whether the UMTask dll file exists for the active object and runs the simulation 3 2 3 Tools Editor runs the built in text editor Calculator of expressions runs the calculator of chains of symbolic expressions Sect 3 3 2 4 2 Inspector F12 brings to front the Data Inspector for the active object if it is located on a separate window Sect 3 3 2 List of elements F11 brings to front the List of elements for the active object if it is located on a separate window Sect 3 3 2 1 Identifiers Alt I brings to front the List of Identifiers of the active object if it is located on a separate window List of windows Alt 0 calls the window containing the list of open windows Control File A
114. the standard interface To specify a type of ET use the pull down menu Fig 3 71 Boxes for ET parameters appear after the choice of the type A unit transformation vector should be entered for all ET types except tc the vector cannot be zero Use the pull down list to set a standard value of the vector 3 4 9 6 1 Elementary transformation tc Enter a shift vector which components are constant symbolic expressions Sect 0 3 4 9 6 2 Elementary transformation rc Angle of rotation in degrees must be entered in addition to the transformation vector Remark Use the rt type to set the constant rotation angle as an identifier or constant expression Universal Mechanism 5 0 Chapter 3 Data input program 3 77 3 4 9 6 3 Elementary transformations tv rv The following parameters can be optionally set in addition to the transformation vector Numeric initial value of the joint coordinate an angle coordinate is entered in degrees use the buttons in the edit box to get the animation of motion corresponding to changing the coordinate Mathematical model of a joint force torque Choose the force type from the list After the type has been chosen the boxes for force parameters appear Some features of description of the force torque see in Linear Sect Linear force element Frictional Sect Friction and elastic frictional elements Elastic friction Sect Friction and elastic frictional elements Elastic friction 2
115. tton is visible in the visual mode otherwise it is invisible To switch between the modes click the right mouse button on the tab with components use the Visual design menu command in the pop up menu 3 5 2 Adding a component in visual mode Visual adding components requires a preliminary description of connection point for bodies Sect 3 4 7 4 In this mode the components can be connected with the elements already presented in the object by a very simple and intuitively clear manner This is the advantage of visual adding in comparison with the non visual one To add a component in the visual mode Click by the left mouse button on the component button or double click on the component name in the component list window The full object mode of the animation window is switched on automatically Sect 3 3 1 2 2 and connection points are visualized Design help window Follow instructions in the design help window by selecting connection points List of identifiers of a component If necessary set desired values of identifiers included in the component To cancel the process of visual adding a component clicks either the button on the component panel or the Interrupt button on the report window 3 5 2 1 Visual adding generalized linear elastic or viscous elastic forces The generalized linear force element is an important tool for description of springs and viscous elastic elements We recommend to study the mathematical mod
116. uld be given and the number of points inside the interval to approximate the surface too for example the values p1 from 1 4 to 1 2 p2 from 0 2 to 4 8 modify the surface above as shown in Fig 3 38 Fig 3 38 Influence of the parameters p1 p2 on the GE shape Closing there is a possibility to complete the surface to the closed one by adding lids since the parameters p1 and p2 are equivalent so a lid can be treated either as the p1 const or as the p2 const surfaces Fig 3 39 for this purpose the corresponding switch is intended Fig 3 37 Universal Mechanism 5 0 Chapter 3 Data input program 3 47 Fig 3 39 Different ways of making the parametric GE closed 3 4 6 2 8 Profiled GE This GE has many possibilities It defines a surface formed by moving a certain profile curve along another axis curve a number of ways to build the curves being possible Fig 3 40 Profiled GE a cylinder An example of the profiled GE is shown in Fig 3 40 Parameters of the profile are Type of section possible values are Circle semi axes are Scale X Scale Y Curve 2D a section given by a number of points holes are allowed too Spline 3D a set of consecutive sections given by points Expression a section given by analytical formulas Scale X Scale Y scales in X and Y axes Number of points to approximate the section Close a switch for automatic adding lids to make the surface closed
117. y Use either keyboard or mouse to enter any set of the point Visual input of points Select the single element mode of the animation window Sect 3 3 1 2 2 It is often more simple to add a contact point by the mouse if the perspective is off and in the line graphics Use the image of the first body and the left mouse button to add a new contact point to the list Use the right mouse button to select visually a point already presented in the list The left lower point of the corresponding icon is active To set the contact plane for the second body enter the following parameters if the close contact option is not set A point on the plane in SC of the second body Outer normal a unit vector perpendicular to the plane directed to the first contacting body All the data except the normal are parameterized Sect 0 3 4 10 4 2 Sphere Plane contact The contact sphere corresponds to the first body The sphere is described by Center a point in SC of the first body Radius These data are parameterized The plane parameters are described in Sect 3 4 10 4 1 Universal Mechanism 5 0 Chapter 3 Data input program 3 99 3 4 10 4 3 Circle Plane contact The contact circle belongs to the first body The circle is described by Center a point in SC of the first body Radius Normal to the circle plane in SC of the first body The plane parameters are described in Sect 3 4 10
118. ystems Two methods can be used to connect bodies of different subsystems with joints or force elements 1 create necessary element joint or force element in the main object 2 use external bodies in subsystems 3 4 8 1 In the second method it is necessary to point bodies and characteristic points of these bodies for joints and force elements which use external bodies For that user should select the element Connections from the List of elements The element Connections is the list which contains all joints and force elements with the second body that is external Setting a connection means to point which body is external for considered element and which point of this body is characteristic for the element Double click checks the box on the left of the element in the List of elements and opens the object tree where the lower level is the level of connection points Select the necessary connection point of the body The connection is ready If it is needed to reset the connection uncheck the box of the element and use double click to set it again Universal Mechanism 5 0 Chapter 3 Data input program 3 38 3 4 3 Standard interface for setting local system of coordinates Fig 3 28 Setting position of local SC The interface allows the user to define a fully parameterized position of a local system of coordinates LSC relative to SC of a body a graphic object or a graphic element Consider a SC with an origin in point O SCO It is necessa

3. Data input program

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