Spring 2010: Hardware in the Loop Simulation
Contents
1. 5 Scaling the entire model to the meter by multiplying the model with the correct unit conversion For example to scale a model from Feet to Meter one has to be multiplying by 0 3048 to have the right transformation 6 Saves the newly transformed file to aircraft m blend and exports it to Ac3d ac file again 7 Inside of the model folder files that are named aerosonde 1 blend are the associated back up files that generated by Blender automatically It shall be removed to avoid confusion A figure of all components of Aerosonde being selected in Object Mode is shown below Applications Places System WODO a0 Mon Apr 30 1 36 PM d 2 sR2 Model___ X Scescene x Background Image XY Transform Properties Models File Browser a Blender hsli homes c project File Browser lt report docx read only E3 LL Figure 7 Aircraft model with all components being selected Aerosonde Change of Names of Components in aircraft model xml After the completion of the modeling of aircraft in Blender users shall check the names of each component in Blender match the names in aircraft model xml Names in aircraft model xml are crucial for the animations of the parts of aircraft Furthermore users are also required to set the values associated to each of the name in aircraft model x2. Object Mode l MER Gmo m Global 2 2 a o sjoMicla Mz 1 Object and Links GS Models File Browser 4 Blender hslhomes c project File Browser lt gt report docx read only Figure 3 The demonstration of function Drawing Procedures used in this semester Drawing procedures used in this semester are discussed in this section For the ease of explanation aircraft Aerosonde will be used as an example to better explain the procedures of modeling Aerosonde The procedures discussed in below can be applied to future aircrafts that shall be modeled 1 Search the corresponding side view and top view images of Aerosonde Import the found Aerosonde images to Blender as the background images at the correct views 2 Sketch of Aerosonde is started at the origin Mirror images are always used for the ease of constructing the model 3 Scale Aerosonde to the size of the background images Note The inserted background images are for the use of reference The interested model should always be drawn according to the dimensions provided in the given spreadsheet Input of Background Image One of the basic steps before started the modeling of the desired aircraft is to input a precise top view and side view image of the actual model This is done for a rough estimation of the scale of the model An example is shown as below see figure 4 Appl
3. flapCut is renamed to be rightFlap Modifier Boolean shall be applied to rightFlap The object is chosen to be wingShape and the option is chose to be Difference to substract wingShape from the modified mesh 4 Onthe body wing modifier Boolean shall also be applied The object is chosen to be rightFlap and the option is chosen to be Intersect 5 To replicate flap to the left wing a duplication of the rightFlap shall be first done and be renamed to leftFlap 6 Aconstraint copylocation is added to leftFlap target is chosen to be rightFlap to duplicate the location of the rightFlap 7 on the right of y is pressed to replicate it on the negative y axis Note Scaling in the size of any object without shifting the center of the object remains stationary is risky The center of the object remains at the same position although the object becomes asymmetric because of the rescaling process Figure 5 Object with center offset As can be seen from figure 5 the original center is the orange color dot However after the rescaling of one side of the object the center is required to be reset to have the object to be symmetric about the center of the object Elevators and Rudder Elevators and rudder are constructed in very similar ways to the constructions of flaps and ailerons However modifier Union is chosen instead of
4. 4 436 beta 1 252 throttle 0 748 elevator 0 253 aileron 0 050 rudder 0 049 cost 4 632e 01 rtol 1 42le 00 alpha 4 436 beta 1 252 throttle 0 748 elevator 0 253 aileron 0 050 rudder 0 049 cost 2 568e 01 rtol 1 657e 00 alpha 4 224 beta 1 473 throttle 0 805 elevator 0 267 aileron 0 047 rudder 0 066 i 12 cost 2 568e 01 rtol 1 588e 00 alpha 4 224 beta 1 473 throttle 0 805 elevator 0 267 aileron 0 047 rudder 0 066 i 13 cost 2 568e 01 rtol 1 536e 00 alpha 4 224 beta 1 473 throttle 0 805 elevator 0 267 aileron 0 047 rudder 0 066 i 14 cost 2 568e 01 rtol 1 533e 00 alpha 4 224 beta 1 473 throttle 0 805 elevator 0 267 aileron 0 047 rudder 0 066 it 15 east 2 SARe A1 rtal 1 527e AM alnha 4 324 heta 1 A72 thrattle A RAS elevatar A PAT aileran A M47 rudder A ARA Figure 20 Trimming running in Terminal When it is able converged the result will be shown and all the output values with initial conditions are shown in the terminal In general the cost will converge when its value is at the power of negative 2 10 The figure below depicts the output skeonglim w5 hsl homes skeonglim Projects jsbsim File Edit View Terminal Help i 48 cost 1 023e 02 rtol 2 746e 01 alpha 4 266 beta 1 518 throttle 0 783 elevator 0 252 aileron 0 048 rudder 0 068 fa simplex converged aircraft state vt alpha deg theta deg q rad s thrust lbf beta deg phi deg p rad s 0 000 r r
5. Difference which used in the constructions of flaps and ailerons on the wing The following highlighted steps are advisable to be followed for the constructions of the elevators More explanations can be found in Details if necessary 1 The construction of the cube on the second layer 2 The move of the cube to the first layer 3 Renamed of the cube and the addition of modifier to the cube 4 Addition of modifiers to the tail 5 The construction of the rightRuddervator 6 Addition of constraint to the leftRuddervator 7 Completion of the build of leftRuddervator Details 1 Onthe second layer a cube of the same dimension to the length of the flaps provided in the spreadsheet is constructed it is then moved to the correct locations on the positive y axis The cube is named to be ruddervatorCut 2 Duplicate the constructed cube on the second layer and move it to the first layer the above instructions can be done by following Ctrl d gt m gt 1 gt Enter 3 On the first layer ruddervatorCut is renamed to be rightRuddervator Modifier Boolean shall be applied to rightRuddervator The object is chosen to be wingShape and the option is chosen to be Difference to subtract tailShape from the modified mesh 4 On the body tail modifier Boolean shall also be applied The object is chosen to be rightRuddervat
6. create the plots and open the folder of the plots This knowledge will speed up the time during debugging and testing Notes 1 The program is very sensitive thus when editing it is advisable to compile make after a slight changes 2 Most of the input is self explanatory and the basic descriptions for the inputs are given as comment 3 Main variable that was confusing were between SSPNE and SSPN The difference is shown in the figure below where b 2 is SSPNE and SSPN is b 2 Figure 8 Aircraft with dimensions SSPNE amp SSPN 4 DATCOM does not produce all output without all the basic part of the airplane above Hence for a V tail aircraft for example shadow and aerosonde a vertical tail were added into the Figure 9 Aerosonde with on the right and without on the left vertical tail As can be seen from figure 9 vertical tail is added on the right Although it does not present the best representation of Aerosonde this addition of vertical tail is necessary because Datcom doesn t accept dihedral angle horizontal tail or V tail in the computation of some of the aerodynamics properties With the addition of V tail the replicated aerodynamics graphs are more logical 5 To have a guideline on what graphs output should look like compare the graphs shape and values with the example given by DATCOM which is shown as below see figure 10 To confirm the outputs of the aerodynamics graphs you are suggested to
7. 2 Obtaining all the graphs output of DATCOM correctly compared with example a Checked all the input values again b Ensure all the dimensions are show in the AC3D view in DATCOM c Make sure all the basic part of aircraft are present example is V tail d IF fail to find the error redo by copying small part of the aircraft and remake the model part by part to identify the problem 3 Aircraft does not fly right in FlightGear a Change cg value b Change the Moment of Inertia in aircraft_name xml 4 JSBSim does not converge a Check which values are max out if aileron are max increase surface area in aileron in DATCOM before Blender b Change the CG till it converge but ensure that the model still fly right in FlightGear 5 JSBSim is very slow a Use a lower Ixx value for engine propeller b Change the Hz requirements of the program Review of Aircraft Models Spring 2012 i Missile SM 3 Figure 22 Missile SM 3 Missile is modified based on the X15 model the difference between this model than the other aircraft models is that Missile uses Missile Datcom to generate the aerodynamics properties instead of Datcom that is used by other aircraft models ii Orbiter Figure 23 Orbiter The orbiter model in Blender is drawn from scratch The main difference between the outlines of orbiter than the other models is the control surfaces Orbiter only has ailerons at the trailing edges of its wing Orbiter has to ta
8. Go Bookmarks Help ce Back v X 100 tconviw Q Placesy gt lt skeonglim Projects uas nas aircraft shadow ma Datcom Engines Models scripts shadow rgb shadow xml shadow set xml shadow sound xml skeonglim Desktop O File System Network Trash Documents Music Pictures E Videos Downloads E Aircraft E jsbsim E Projects FlightGear E sm 3 arkhangar aircraft 8 items Free space 16 3 GB Figure2 File location Example used shadow The basic explanations of the purposes and contents of each file Note aircraft_name stands for the aircraft s name in this case shadow 1 DATCOM file a Contains all files that will be used by DATCOM to generate the aerodynamics output of the aircraft model b The main output of DATCOM will be the aircraft_name_aero xml which will be accessed later in aircraft_name xml file 2 Engines file a Contains the engine file xml type that will be accessed later in aircraft_name xml file 3 Models file a Contains all files that will be used by Blender which produces the 3D model of the aircraft b Basically contains 4 files which are i aircraft_name m blend aircraft in meters ii aircraft_name bend aircraft in feet iii aircraft_name ac AC3D model of aircraft 4 5 6 7 8 iv aircraft_name_model xml contains the animations path and the A
9. air of the aircraft should be accurate to the real model Engines The engine information that is inputted to the aircraft_name xml is obtained from Aeromatic website http jsbsim sourceforge net aeromatic2 html This website is used because it produces the engine configurations files that are usable by the JSBSim flight dynamic model jsbsim sourceforge net aeromatic2 htm in iazza NSWEF jaybank2u com On loney Pay O me Perso jool of Engineeri n Of Study Login ontract al ropbox Get Star ing 2012 Pi Ask Ai Maybank2 On P Send Money Pay O CHASE Home P School of Engineeri 8 Plan Of Study Logi c Renewal Dropbox Get Stai For more detailed instructions see the How to Step l The Engine configu ration This step is not necessary if you are using an already existing engine configuration file In any case you will have to edit the propulsion section of the aircraft configuration file to ensure that the engine name is the same as the name of the engine configuration file Engine Name my_engine Engine Type piston turbine turboprop rocket Engine Power or Thrust per engine without afterburning 1000 0 horsepower kw pounds newtons ad Augmentation afterburning Installed Oyes no Water Injection Installed yes no You are now ready to have Aeromatic generate your file Aeromatic will create a file called engine php which is your engine configuration file You will ne
10. make a comparison between the aerodynamics graphs of the UAV that is being worked on and the successfully constructed UAVs Figure 10 Sample aerodynamics graph on the right Aerodynamics graphs without V tail on the left From figure 10 the removal of the V tail results in getting a lot of not remarkable outputs The focus here is on the roll moment coefficient and side force coefficient plot The differences between the other plots are not considered because the correlations of the mismatching of the other plots remain in doubt Difference between the model output in Blender and FlightGear ep sA2 Modei__ x e scescene x Jr View select obec e onec mose 18 A GE Biola k Bakel oo ume 000 Figure 11 Aircraft model in Blender Shadow ac3dview Figure 12 Aircraft model in Datcom Shadow From the figures above figure 11 and 12 there are differences between the model that Datcom produces based the data inputted into the program and the model which was made in Blender The Datcom s model does not have boom and wheels and the fuselage is not an exact representative of the real model This is due to limited data that could be entered into Datcom Nonetheless the model that produced by Datcom should be a close representative on defining the aerodynamics of the aircraft shadow The wings dimensions tails dimensions and the size of the fuselage generally govern the aerodynamic flow of
11. 43 0 004163 113 08326048 24 2 2 0 4 735435453 4 341018609 0 006317 24 14000 114 7710703 0 003986 0 004203 114 77107034 2 2 1 6 0 4 405809932 3 204596358 0 005872 16000 116 4588802 0 004419 0 004419 116 45888020 1 6 1 1 0 3 251722775 2 235712642 0 005447 Em 18000 118 1466901 0 004008 0 004416 118 14669006 i 0 6 0 2 268114274 1 237206631 0 005048 27 28 Cruise Climb Descent 29 Mass kg Mass kg Mass kg Mass kg Mass Ho z 4 Sheetl Sum 0 A 12 28 PM 5 4 2012 a a Px al Figure 16 Data Output Shadow Insert path location of engine system and model JSBSim Trim Linearization Tim Stop Linearize Simulate Set initial Save ready N Trim Algorithm Aircraft Trim Conditions Solver Input initial Guess Output Model Sim Rate 10 Aircraft Name shadow Aircraft Path hsl homes skeonglim Projects uas nas aircraft shadow Engine Path thsl homes skeonglim Projects uas nas aircraft shadow Engines Systems Path hsl homes skeonglim Projects uas nas aircraft shadow Figure 17 JSBSim in Aircraft Path view Figure 17 shows the location of the aircraft path engine path and system path which needs to be set JSBSim Trim linearization Tim stop Linearize Simulate Set initial at Save ready Trim Algorithm amp Aircraft Trim Cqyditions Solver input Initia
12. C3D model that will be accessed in aircraft_name xml file Scripts file a Contains all different flight conditions of aircraft Shadow rgb rgb a A picture of shadow that shown in FlightGear Shadow xml a Main file which contains all the data of the aircraft detail explanation will be given below Shadow set xml a First file that are accessed by FlightGear and which direct all the necessary paths including the main file shadow xml file Shadow sound xml a The aircraft sound file The examples on how the following file and uses will be explained below Main Procedure for Modeling brief the order is advisable 1 2 3 4 5 6 7 8 9 Obtain all required aircraft information Copy entire file from the similar model a Previous model Arkhangar Easystar Shadow Aerosonde Orbiter b Or reference from model from FlightGear Edit the name and change the paths for all in the aircraft_name set xml Edit name and change all the paths for all in the aircraft_name xml Use Blender to obtain the model Use Datcom to obtain the aerodynamics data Use FlightGear to test the aircraft model Use JSBSim to obtain all required output Edit Spring Coefficient 10 Edit aero xml Blender Blender is a free open source 3D modeling site that can be downloaded at http www blender org download get blender Blender is able to run at most of the common used operating systems Blender is used in the project this semest
13. Modeling Unmanned Vehicle System Ser Keong Lim Chua Ching Hao Purdue University Department of Aeronautics and Astronautics Abstract The main objective of this research is to obtain a realistic model of an Unmanned Vehicle System The method and procedures used are compiled below The model of the aircraft will be made based on the given data information and finally the aircraft will be analyzed The main output data from the research will be the trim conditions of the aircraft in different flight condition What had been done in Spring 2012 1 Finalizing the JSBSim graphical interphase window 2 Revising the Shadow Model 3 Created the numeric_analysis of Moments of Inertia MOI of an aircraft 4 Obtain the output of JSBSim for Shadow UR 7 5 Modeling of the missile using missile DATCOM adaptation taken from X 15 6 Modeling the entire orbiter 7 Modeling the entire Aerosonde 8 Start on Cargo UAS incomplete need to be continued next semester Moments of Inertia of an Aircraft The moments of inertia of an aircraft are crucial information which affects the rotation of the aircraft in the 3 axis Hence basic estimated relationships between the weight of the aircraft to the value of moments of inertia Ixx lyy and Izz are made Real data on the weight and moments of inertia of a few aircraft are obtained The plots of moments of inertia are made with respect to the weight of the aircraft Polynomials of 3 are used to estimate
14. ad s 0 000 mass lbm 407 000 118 150 4 227 h 4 227 0 000 23 635 1 524 0 000 actuator state throttle e 78 446 elevator 24 811 aileron 4 841 rudder 6 782 nav state altitude ft 1000 000 psi deg 0 000 lat deg 0 000 lon deg 0 000 aircraft d dt state d dt vt 0 000e 00 d dt alpha deg s 1 11le 01 d dt theta deg s E 0 000e 00 d dt q rad s 2 A 3 344e 03 d dt thrust lbf 0 000e 00 d dt beta deg s i 3 551e 01 d dt phi deg s H 0 000e 00 d dt p rad s 2 1 909e 02 d dt r rad s 2 1 264e 02 d dt actuator state d dt throttle s 1 110e 15 d dt elevator s 6 116e 11 d dt aileron s 0 000e 00 d dt rudder s 8 557e 12 d dt nav state d dt altitude ft s 3 18le 11 d dt psi deg s 0 000e 00 d dt lat deg s 3 0 000e 00 d dt lon deg s 0 000e 00 propulsion system state tank 0 fuel lbm 7 400e 01 engine O fuel flow rate lbm s 4 665e 03 Figure 21 JSBSim output Remark 1 A descent model of the aircraft would want the elevator condition output to be as close to zero during cruising Hence the best guideline to judge the model would be obtaining a low elevator deflection when cruising Problem may be encountered and the recommended solutions Note Use this way of solving only if you had double checked that all inputted values are correct and accurate to the data given and the DATCOM output has been generated correctly
15. ed to save this file with a filename of the form engine_name xml Figure 13 Aeromatic website Engine configuration and Propeller configuration are required for the aircrafts that have been modeled in this semester Propeller configuration is needed only if the aircraft has propeller Some of the information that is required for the generation of the engine configurations are engine type engine power or thrust augmentation installed yes or no and water injection installed yes or no On the other hand the engine power maximum engine rotation speed RPM pitch fixed or variable and the propeller diameter are required in order to generate the propeller configuration Remark Propeller diameter has to be in feet The other options such as meter or inch will produce inaccurate outcomes FlightGear FlightGear is a free open source flight simulation that can be downloaded at http www flightgear org download FlighGear is used for the flight path simulation of the desired aircrafts in this semester The steps of adding the desired aircraft to FlightGear and the checks of flight properties in FlightGear simulator are discussed by parts as below 1 Linking Process 2 Modification of the fgfsrsc file 3 Start of FlighGear 4 Checks of aircraft in FlightGear Linking Process All sketching modeling and changing of the aircrafts properties are done in a different folder than FlightGear A symb
16. er to replicate the model of the aircrafts by the provided dimensions from the given spreadsheets A useful shortcut key is provided below and the method used to replicate the desired models in Blender in this semester is discussed as followed Importance of shortcut keys In Blender unlike many other 3D modeling tools shortcut keys are vital and used frequently to achieve best proficiency A list of useful shortcut keys is provided in Table 1 as future references A full list of shortcut keys in Blender can also be found at http www katsbits com tutorials blender useful keyboard shortcuts ph Table 1 Useful Shortcut Keys in Blender Shortcut Key Description Specifying on the interest part A Selecting all M Choosing of layer N Transformation properties spacebar Properties S Scale s gt x Scale in x direction s gt y Scale in y direction s gt z Scale in z direction P Make Parent 1 9 number pad View at different directions Ctrl z Undo Ctrl d Duplicate all functions Shift d Duplicate Show all components in all layers Tab Switch between Edit and Object Mode An example of the function in the list of shortcut key is shown below see figure 3 Applications Places system MODO 30 Mon Apr 30 1 37 PM a X Y Background image Use CTIE IE XY Transform Properties jal lal EJs View Select Object
17. f keyboard keys It incorporates many shortcut keys to perform some of the functions In order to allow future groups can be more easily learn the vital function keys in FlightGear A list of shortcut keys is provided below as references A full list of shortcut keys can be also retrieved wiki flightgear org Keyboard_ shortcuts Table 2 Useful Shortcut Keys in FlightGear V Change of views P Pause X Zoom in Ctrl x Return to default view H Head Up Display Flaps down Flaps up Shift gt s Ignite the engine Animations Graphical movements on the desirable components shall be checked before any other actions are taken If some of the desirable movements aren t performed as expected users shall first check the names and values inputted in aerosonde model xml to seek for the differences in the names and values than aerosonde blend If such approach is not successful users shall check for the offsets in the dimensions that are shown in aerosonde blend and the provided spreadsheet View Properties View properties shall be checked to make sure the controls of each control surface are in well conditions It is important for users to get an access to view the internal properties of the aircraft such as the controls aerodynamics orientations and the translations of the aircraft see figure14 M FightGear Figure 14 View Properties in FlightGear Takeoff Condition One of the key features t
18. fting 3D axis shown on the screen in the desirable direction Steps of constructing Flaps and Ailerons The adjustments of flaps and ailerons can be done easily by resizing the dimensions of the flaps and ailerons However the resizing process can be hazardous if it is done improperly Thus the constructions of flaps and ailerons will be introduced below for the future references The following highlighted steps explain the ideas of constructing flaps and ailerons More explanations on each step can be found in the remarks if necessary The ways of constructing ailerons are not discussed below because they follow the same logic as the construction of flaps The construction of the cube on the second layer The move of the cube to the first layer Renamed of the cube and the addition of modifier to the cube Addition of modifiers to the wing The construction of the leftFlap Addition of constraint to the leftFlap Completion of the build of leftFlap worst Be WO Nek Details 1 On the second layer a cube of the same dimension to the length of the flaps provided in the spreadsheet is constructed it is then moved to the correct locations on the positive y axis The cube is named to be flapCut 2 Duplicate the constructed cube on the second layer and move it to the first layer the above instructions can be done by following Ctrl d gt m gt 1 gt Enter 3 On the first layer
19. hat we are observing on FlightGear is the takeoff condition of the aircraft After making sure the aircraft properties are correct we have to test its take off ability and observe the behavior and flight pattern when the aircraft is off from the ground to the air Aircraft shall be takeoff nicely with the correct Aerodynamics and engine applied If a smooth take off condition and flying pattern was not met we are required to check the input values in the Datcom and adjust the values accordingly to get a good takeoff condition Dropping Condition Well flying Aerosonde is expected to fly in a smooth pattern Smooth pattern is defined as the periodic curve liked movement Aerosonde will dive down to seek for acceleration and be raised up by gaining enough velocity and lift The aerodynamics of the aircraft shall be first checked if such flying pattern is not met Input values in aircraft dcm shall also be checked and adjusted to meet such flying requirements However there is always a tradeoff between the smooth flying pattern and the trimmed conditions of the aircraft Applications Places system WOOD im graphs File Browser BE chinghao w5 Pro FightGear Figure 15 Aircraft in smooth descent Aerosonde We shall better understand the trimmed conditions of the aircraft so that we get the best balance between the trimmed conditions and the smooth flying pattern Remark In order to get a smooth flight we change the center
20. ications Places system WODO 30 Mon Apr 30 1 38 PM f a5 Fo Blender hsl homes chinghao Projects Was nas aircraft aerosonde Models aerosonde blend oog SR 2 Model X SCE Scene x w Select Object Object Mode a es a Global alm B e S OOO R eSa a fe 1 F l f Thadale Cila Denwenrl ES Treninet Cila Denen A iranat dary irand anl A nmail fna euihinnt V ranar da L Ez Figure 4 The insert of the background image sideview As can be observed from figure 4 images at different view angles are inserted for the users ease to model the aircrafts as accurate as possible to the given dimensions Users are able to compare their sketching models to the actual images inserted to prevent significant errors in the modeling from happening Modifications of Aerosonde Aerosonde is built on top of Shadow The process of modification from Shadow to Aerosonde will be discussed below The basic steps are highlighted and more explanations can be found on the details section Steps of constructing winglets Winglets are added by playing around with the extrude function The following steps explain the method of extruding a desirable plane 1 On the Object Mode select the desirable component 2 Change the Object Mode to be Edit Mode by pressed tab once 3 Select Face Select before select the desirable plane 4 Select the desirable plane 5 Extrude the plane by shi
21. ke the roll and pitch control in one surface control because Orbiter doesn t have a tail iii Aerosonde Figure 24 Aerosonde The 3D model of Aerosonde in Blender was built on top of Shadow There were many problems during modeling The methods to handle the errors were determined based on trials and errors were 1 Flight is unstable when dropped in FlighGear After trying to search for errors w found out that the aerodynamics graphs are not the same as the standard aerodynamics graphs 2 The flight pattern of Aerosonde in FlightGear was sill very unstable We changed the roll moment of inertia of Aerosonde in order to increase Aerosonde s stability in x direction 3 We later observed that Aerosonde didn t have enough maneuverability and controls We increased the sizes of the controls surfaces such as ailerons flaps rudders in order to increase our control of Aerosonde in FlightGear 4 After achieving well flight path in FlightGear we relized that Aerosonde couldn t be trimmed in JSBSim We later figured out the reason was due to the insufficient output thrust of the engine that was estimated by Aeromatic We then increased the horsepower of the engine in Aeromatic in order to reproduce a engine that matches the output thrust given by the company 5 We were able to get Aerosonde to be trimmed in JSBSim However the trimmed conditions show a high elevator deflection during cruise We change the position of the center of g
22. l Guess Output velocity 118 15 fts altitude 1000 ft roll rate o rad s flight path angle o deg pitch rate o rad s flap position o yaw rate o rad s payload o Ibs 0 variable prop pitch F stability axis roll fuel 100 Figure 18 JSBSim in Trim Condition view Figure 18 depicts where the inputs are put for desired flight condition cruise climbing and descent The parameters that defines the flight condition includes velocity altitude flight path angle flap position payload and percentage fuel The example shows an empty payload aircraft cruising at 1000ft with 110 15 ft s JSBSim Trim Linearization Tim Stop Linearize Simulate Set initial Save ready Trim Algorithm amp Aircraft Trim Conditions Solver Input Initial juess Output Guess Lower Bound Upper Bound Initial Step Size Throttle 87 0841 o 100 5 Aileron 3 74025 5 5 1 Rudder 11 5829 100 100 5 Elevator 17 4178 100 100 5 Alpha 4 14703 10 20 5 deg Beta 1 92673 2 2 1 deg Figure 19 JSBSim in Initial Guess view Figure 19 shows the initial guess values that the user can input The closer the input to the output conditions the faster JSBSim will trim The lower and upper bound would control the limit of the 6 Degree of Freedom based on the aircraft specification A go
23. ml according to the Transform Properties given in Blender because these values affect the outcomes of the animations significantly lt Ruddervators gt lt animation gt lt type gt rotate lt type gt lt obj ect name gt leftRuddervator lt object name gt lt property gt surface positions left ruddervator pos deg lt property gt lt axis gt lt x1 m gt 2 215 lt x1 m gt lt y1 m gt 607 lt y1 m gt lt z1 m gt 0 178 lt z1 m gt lt x2 m gt 2 215 lt x2 m gt lt y2 m gt 0 02 lt y2 m gt lt z2 m gt 0 796 lt z2 m gt lt axis gt lt animation gt Figure 8 Name and Values Associated in aerosonde model xml From figure 5 it can be observed that the object name is named exactly the same as the way it is named in Blender The values that are named x1 m y1 m and z1 m are the values of the furthest left point on the left rudder While the values that are named x2 m y2 m and z2 m are the values of the furthest right point on the left rudder DATCOM Introduction DATCOM is a free program that produces the aerodynamics data of the aircraft model It is very user friendly The outputs of the following program are mainly a Various aerodynamic graphs jiff format b Output aerodynamics data aircraft_name out which consist of the numerical data calculated based on the parameters of the aircraft input c Aerodynamics data aircraft_
24. name_aero xml which will be used for aircraft_name xml As it is a free program accessible to everyone the link to download the program is http www holycows net Datcom The user manual document is available in the following website for future references Procedure 1 Open aircraft_name dcm file 2 Input the dimensions of the aircraft based on the model that are made in Blender 3 Basic body properties include O O O O O O Wing Flaps Aileron Elevator Flaps Horizontal tail Vertical tail 4 To make file type command make in the terminal Makefile file defines the command Remarks vi Makefile Makefile Projects uas nas aircraft aerosonde Datcom VIM File Edit View Terminal Help all aerosonde_aero xml clean rm rf fort dat lfi csv ac aerosonde_aero xml dist clean rm rf jiff xml out aerosonde_aero xml aerosonde dcm datcom aerosonde dcm sed i e 1446s n lt independentVar Lookup column gt fc s left aileron pos deg lt independentVar gt g aerosonde_aero xml graph aerosonde_aero xml jiff f nautilus aerosonde jiff test figfs aircraft aerosonde altitude 3000 Makefile 18L 436C 18 2 5 All Figure 8 Content of Makefile in Datcom folder vi Makefile The Makefile file in Datcom folder helps you to create various commands for the program For example typing make graph in the terminal will create the aircraft_name_aero xml file
25. od practice that is recommended for a faster trimming time is to set the initial after each run of the trim This facilitates the trimming time because the initial guess values that are reset are much closer to the exact trim values than before Once the trim button at the top is clicked the program will run and the terminal will show as follow skeonglim ws5 hsl homes skeonglim Projects jsbsim File Edit View Terminal Help PEE i cost 5 869e 00 rtol 8 099e 01 alpha 4 147 beta 1 927 throttle 0 871 elevator 0 174 aileron 0 037 rudder 0 116 2 cost 5 868e 00 rtol 8 986e 02 alpha 4 147 beta 1 927 throttle 0 871 elevator 0 174 aileron 0 047 rudder 0 116 3 cost 2 234e 00 rtol 9 438e 01 alpha 3 939 beta 1 093 throttle 0 840 elevator 0 258 aileron 0 046 rudder 0 074 24 cost 2 234e 00 rtol 8 992e 01 alpha 3 939 beta 1 093 throttle 0 840 elevator 0 258 aileron 0 046 rudder 0 074 5 cost 1 958e 00 rtol 1 000e 00 alpha 6 161 beta 2 000 throttle 0 823 elevator 0 227 aileron 0 050 rudder 0 052 6 cost 1 943e 00 rtol 1 005e 00 alpha 6 161 beta 1 433 throttle 0 823 elevator 0 227 aileron 0 050 rudder 0 119 ET cost 1 943e 00 rtol 1 005e 00 alpha 6 161 beta 1 433 throttle 0 823 elevator 0 227 aileron 0 050 rudder 0 119 8 cost 1 943e 00 rtol 7 973e 01 alpha 6 161 beta 1 433 throttle 0 823 elevator 0 227 aileron 0 050 rudder 0 119 cost 4 632e 01 rtol 1 435e 00 alpha
26. of gravity accordingly based on the rule of thumb The change in the cg of the aircraft is advisable for future group in order to get a good balance between the trimmed speed and the smooth flying pattern JSBSIim Introduction JSBSim is a library that can be called supplied with inputs such as control inputs from the pilot and returning outputs describing the aircraft s state at any moment in time This software would work for both windows and linux However this software works best with linux system Debian as it has a terminal This is as when trying to find the output the iteration can be observed in the terminal thus would know the problem easier Procedure 1 Insert path location of engine system and model 2 Aircraft condition cruise initial speed 3 Guess trim condition 4 Converge values 5 The converge values can be made 6 Obtaining data the figure below shows a sample output data of an aircraft shadow a Ensure weight and flight condition b Cruise data normally empty weight mid weight and full weight c Maximum throttle when climbing to find flight path angle d Min throttle when descent to find flight path angle DEBEIAS XBOle mx i ba for Sans k 00A HAns sVs s Blera 15 x A B E EEE F G i I ls l
27. olic link shall be made between the aircraft folder in FlightGear and our working folder in order to link them together With such linkage changes made on the aircrafts are reflected on the models that will be used in FlightGear simulator directly The linking process can be done by typing the following commands in Terminal Commands to do symbolic link Modification of fgfsrc file Aircrafts that will be simulated in FlighGear are stored at fgfsrc file Modification on that file shall be made in order to get the correct aircraft in place It can be done by typing the following command in the Terminal 1 vi fgfsre 2 the undesirable aircraft add the name of the desirable aircraft on the file 3 Save the file Details 1 vi fgfsrc to open the fgfsrc file to change the aircraft to be represented in FlightGear 2 Commented out the undesired aircraft by inserting before the aircraft Typed in the new aircraft s name in the list 3 Saves and closes the fgfsrsc file Start of FlightGear The selected aircraft will be ready to be visualized in FlightGear by typing fgfs in the Terminal Four interested aspects of the aircraft are attempted to observe from the FlightGear simulator this semester These include animations view properties takeoff conditions and flying conditions are focused in this semester FlighGear may be strange for most of the undergraduate students because of its high frequent use o
28. or and the option is chosen to be Union to combine two meshes in an additive way 5 To replicate rudder to the left wing a duplication of the rightRuddervator shall be first done and be renamed to leftRuddervator 6 A constraint copylocation is added to leftRuddervator target is chosen to be rightRuddervator to duplicate the location of the rightRuddervator 7 on the right of y is pressed to replicate it on the negative y axis Importance of having consistency in the naming process For every component created in Blender an arbitrary name is generated automatically associated with the created component At the ease of future modifications on the model and the creation of the animation of the model in FlighGear the names of each component are crucial and shall be in the same consistency see figure 6 The idea of having the first letter of the second word to be capitalized was implemented in this semester to prevent confusions in the names of each component An example of the naming procedure is shown as below a Global ir MitailShapes aileronCut 004 Camera Cylinder Cylinder 001 extendedWing vor extendedWing 001 flapCut fuselage fuselageShane Figure 6 Sample Names of Components From the above figure flap at the right side of the aircraft on the positive y direction is named as rightFlap The aileron right beside the rightFlap is named as rightAile
29. ravity cg of Aerosonde in order to solve this issue iv Shadow Figure 25 Shadow Shadow was not able to trim to the given ceiling height that was provided as a requirement by the company Also Shadow has a much slower take off speed than the information given by the company A vertical is added on the modeling of Shadow in Datcom in order to generate the logical outcome of the roll moment coefficient plot Flight Performance Easystar This model is not a model that was accomplished in this semester but should be used for comparison as it has the best flight path among all of the other aircraft models Orbiter Good flight path when dropped from the certain altitude above the ground and has a good maneuverability Aerosonde Unstable flight path in yaw and pitch direction The instability in the yaw direction is due to the increase of the moment of inertia in x direction Ixx and the instability in the pitch direction is due to the change in the location of the center of gravity However it still represents a good maneuverability Shadow Unstable in pitch direction due to the change in the location of the center of gravity The maneuverability is considered as controllable Future Improvements Changes that were done to previous models which are inaccurate and need to be rechecked a Shadow a Increase engine stroke to reach ceiling height b Aerosonde a Increased Ixx value of aircraft s model b Increased hor
30. ron Such analogy in the naming of the Aerosonde s components is also implemented for the other components of the Aerosonde Export method Ac3d is used and supported by FlightGear simulator In order to export the completed part into the desired modeler Ac3d the methods that will be discussed below shall be followed By different provided spreadsheet information some of the aircrafts are sketched in feet or meter or other different units FlighGear adapts meter in recreating the sketched model Hence the unit of the output Ac3d ac file shall be changed to meter if it was not If the model wasn t sketched in meter the following procedures shall be followed in order to change the unit of the model to be in meter Selecting all components of aircraft Exports the file to Ac3d ac Open a new blend file Import the previously saved ac file Scale the aircraft to desirable unit Saves and exports the file to Ac3d ac again Remove the unnecessary aircraft 1 blend files N gi Gt eS a Details 1 At the object mode select the entire model by pressing a once see figure 7 2 File gt Export gt ac saves the Ac3d ac file in the correct folder with logical name 3 File gt New gt Delete the existing gt deletes the cube that is shown in the new page of Blender 4 File gt Import gt ac find the saved Ac3d ac file and import it to the present page by clicking the desired file
31. sepower of aircraft Supposed to be 6hp but 20hp were used Main Issue that need to be checked a Engines generated by Aeromatic website are inaccurate Future Model a Cargo UAS a Copied and changed name and path name from Shadow b Blender model has been done by James Goppert Conclusion The discussions act as a reference for the future group Instructions mentioned are based on the rule of thumb If such results replicated above can not be reproduce users shall consult their instructors for a more precise analysis of the problems that they have encountered
32. t M N o P Q 1 set up comment for mass 4 2 ft s to knots 0 592483801 1 use 1 Fuel for low mass 3 Ibs to kg 0 45359237 2 use 55 5 payload and 50 Fuel for nominal 4 Ibm s to kg min 27 2155422 3 use 60 payload and 100 Fuel for high mass 5 pi 3 14159265 4 All Fix speed Varied flight path angle accuracy up to 0 1 deg 6 5 For Climb ensure that throttle is approximately 100 7 8 9 Cruise Climb 10 Mass Ibs Mass lbs Mass lbs Mass lbs 11 333 425 5 467 333 425 5 467 333 425 5 467 425 5 12 Altitude ft Speed ft s Fuel_flow lbm s comments Speed ft s Gamma deg Rate of Climb ft s Fuel_flow Ibm s comments 13 100 0 94 517352045 7 3 6 2 0 12 00981033 10 20781311 0 009428 14 500 0 96 205161903 7 6 0 11 7244599 10 05617772 0 009308 Boa 1000 0 97 892971761 6 8 5 8 0 11 59091631 9 892701235 0 009177 EGE 1500 0 99 580781619 6 5 5 6 0 11 27286450 9 71738142 0 009029 2000 0 101 26859148 6 1 54 0 10 76121282 9 530216325 0 008892 3000 102 9564013 0 003599 0 004013 102 95640133 5 7 4 9 0 10 22560400 8 794219009 0 008606 Eu 4000 104 6442112 0 003609 0 003843 104 64421119 53 45 0 9 666047250 8 210290174 0 008328 20 6000 108 0198309 0 003636 0 003881 108 01983091 4 5 3 8 0 8 475138244 7 158895507 0 007792 8000 109 7076408 0 003667 0 004159 109 70764077 4 3 0 7 652818154 5 74165428 0 007275 2 10000 111 3954506 0 003727 0 004175 111 39545062 3 4 2 7 0 6 606460202 5 247444298 0 006784 12000 113 0832605 0 0039
33. the relationship The equations are y is moment of inertia slug ft x is weight Ibs Ixx 1 50936e 7x 0 000145021x 0 535851x 1 lyy 1 24339e 7x 0 000120154x 0 655246x 2 Izz 4 31686e 7x 0 0007283x 1 32361x 3 z z z z eon a ee Ra 0 9530 Rascal110 13 1 95 1 55 1 91 son c172p 1500 348 1346 1967 Senecall 3300 5596 5334 11945 B2rg 1700 348 1346 1967 storch Fi 156 2006 1974 1714 3346 dragonfly 517 395 200 562 Shadow 333 167 9306177 209 465 375 942 Orbiter 13 67 7 298368821 8 93508 17 9588 aerosonde 48 9 25 87398721 31 7688 63 0335 bx Iyy Izz 1 0 535851 0 655246 1 32361 2 0 000145021 0 00012015 0 0007283 y 12030e OD x 00010154 0 624 3 1 5054E 007 1 243E 007 4 3169E 007 Ka 099700 om s0 0 x0 20 1000 Figure 1 Moment of Inertia Computation table chart The picture depicts 3 plots obtained in Microsoft excel These estimations are quite close to the real values Modeling of Unmanned Aircraft In the entire process of modeling the unmanned aircraft there are 4 main programs that will be used throughout there are Blender DATCOM FLightGear and JSBSim This report will entirely explain in detail the entire process File Storing and location Basically the file for the folder will be the name of the aircraft itself The figure below is the explorer on the content of an example aircraft shadow shadow File Browser File Edit View
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