WAM User`s Guide.
Contents
1. nm Figure 7 Pendants and Cables Of these two cables connect the pendant box with three colored buttons and a red E Stop to the socket on the WAM marked Pendant Control Connect the other pendant box with only a red E Stop to the socket on the WAM marked Pendant Display 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 6 of 33 WAMTMArm User s Guide service barrett com www barrett com Installing the PC Physical Installation Install the PC shipped with the WAM as you would any other You will need to add a monitor while performing initial setup of the PC Afterwards you may use the PC for development or remove the monitor and use remote terminal software such as ssh to operate the PC remotely Software installation The PC comes with the WAM software loaded You will need to edit etc network interfaces to set an IP address that is compatible with your network We do not recommend using DHCP as we have found that periodic address renegotiation interferes with the realtime operation of the WAM The Barrett Technology software library uses syslogd to log all error messages to a file It is highly recommended to make sure that syslogd 1s running Error messages may be found in the var log syslog text file Figure 8 Shuttle PC Connecting the WAM Wrist optional Figure 10 shows that the outer link can be removed to accommodate the WAM Wrist if the 7 DOF WAM is purch2. Group broadcast F From ID Host 00000 Motor N N T To ID or group Examples MsgIDs 00000000011 gt Directed message from host to motor 3 3 00011 binary 10001100100 gt Group broadcast from motor 3 to group 4 Motor IDs and Groups Each motor in the robot has a unique communication ID Each motor listens and processes messages bound for its ID There are 32 possible groups 0 31 00000 11111 Each motor may be assigned to be a part of any 3 groups GRPA GRPB GRPC Each motor also listens and processes messages bound for any of those 3 groups Motors 1 4 belong to groups 0 1 and 4 by default Motors 3 7 belong to groups 0 2 and 5 by default Host belongs to groups 3 and 6 by default Summary of default groups 0 All actuators 1 Lower arm torgues motors 1 4 2 Upper arm torques motors 5 7 3 Position feedback 4 Lower arm property 5 Upper arm property 6 Property feedback CAN frame data payload CAN specifies a maximum of 8 bytes frame payload our typical payload consists of 4 6 bytes APPPPPPP 00000000 LLLLLLLL mmmmmmmm MMMMMMMMI HHHHHHHH A Action 0 Get property 1 Set property P Property 128 possible values 0 127 0000000 1111111 0 Second byte almost always set to zero see exceptions below L Low byte of data value m mid low byte of data value M Mid high byte of data value H High byte of data value If sending a single 16 bit integer value only LLLLLL
3. a robot diagnostic application and example program If you edit the btsystem or btwam libraries the procedure to recompile is make lib make install 4 3 The configuration file wam conf The configuration file wam conf is read by the OpenWAM function to set up the operating parameters for the WAM This file must be located in the same directory as your executable application and may be a symbolic link to a configuration file that describes your particular WAM parameters If you add or remove the wrist or change any link or tool masses you will need to edit your active configuration file You should take a look at the contents of this file to familiarize yourself with its contents It contains the default home position the Denavit Hartenberg parameters and the inertial parameters and many other useful numbers 4 4 Operating modes The WAM has a number of operating modes IDLE POSITION press p to toggle In IDLE mode the WAM does not try to maintain its present position In position mode it will try to maintain its position using a PID controller JOINT CARTESIAN press tab to toggle In JOINT mode the WAM will report joint angles in radians and control joint torques in Nm In CARTESIAN mode it will report the end effector position in world coordinates and control tool forces in Newtons In both cases the Move command executes a trapezoidal velocity profile and generates a stream of torque commands based on position
4. ID 10 It is a 5th puck in your 4DOF WAM located in the base of the unit not attached to a motor Its job is to listen to the CANbus traffic and shut the WAM down in the event of an over torque over velocity voltage problem or heartbeat error missing communication from any puck or the PC It also controls the pendant lights and switches The safety module is what you need to configure with VOLTL H 1 2 TL1 2 VL1 2 and ZERO these values are irrelevant in the motor pucks To set the initial positions of the pucks please see the DefineW AMpos function as you must also set IFAULT Ignore Fault at that time to prevent the giant instantaneous position change from causing an over velocity fault in the safety module If IFAULT 0 IFAULT is decremented each time a fault is observed by the safety system If IFAULT gt 0 the fault is ignored VLI VL2 TL1 and TL2 are SAFETY MODULE properties They apply to the whole arm on a global basis For example if the torque of ANY motor exceeds TL2 the safety system will force the arm into IDLE mode all phase leads tied together There are 40960 encoder ticks per motor revolution for each motor even the wrist motors though they have different IPNMs You can set AP in a puck to anything you want only when the puck s MODE 0 Just be careful to set IFAULT in the safety module before you do this like previously described else you will likely get a velocity fault Sometimes when you exit
5. WAM is homed zeroed or cartesian velocity limit after zeroing VOLTHI Set the safety system s high voltage warning limit begin bleeding off bus voltage through a resistor VOLTH2 Set the safety system s high voltage fault limit disconnect the bus and clamp it VOLTLI Set the safety system s low voltage warning limit no action warning light only VOLTL2 Set the safety system s low voltage fault limit disconnect the bus and clamp it ZERO After sending the pucks their known initial position set the safety system s ZERO parameter to 1 so it can start calculating Cartesian velocities Additional Information on parameters Setting STAT 0 forces a reset which will actually leave the motors free spinning no torque no braking MOFST is the distance in encoder counts between the index pulse of the encoder and the start of an electrical cycle for that motor a point where the magnets are aligned with a single phase coil It is calibrated here so you shouldn t need to worry about it unless you replace an encoder wheel some day MECH tells you how many encoder counts away from the index pulse you are Unless you want to try writing your own cogging or torque ripple cancellation code these parameters are not important Knowing the orientation of the rotor magnets inside the stator is really only important for the low level commutation and any types of perturbation cancellation you may wish to implement ZERO is only meaningful in the SAF
6. a WAM control program the torque warning light will stay on That just means that the last torque that the safety system saw go by was beyond the warning level for the present state gt 0 for E STOP or IDLE or gt TL1 for ACTIVATED As long as you send one or more zero torque commands to the pucks the warning light should extinguish If you press Shift Activate you must request encoder values in a constant loop until you press Shift Idle again Else the safety system will register a heartbeat error and shut down the WAM The pucks will apply the last received torque until a new torque is sent or the MODE changes to MODE IDLE 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 32 of 33 WAM Arm User s Guide service Abarrett com www barrett com Here is the CANbus timing 75uS to ask for position 75uS per puck to respond with the positions 125uS to send a packed torque to the lower 4DOF 125uS to send a packed torque to the wrist plus controkside processing time on PC For the 7DOF it is 75 7 75 2 125 PC 850uS PC For the 4DOF it is 75 4 75 125 PC 500uS PC These numbers are limited by the 1 Mbps CANbus Each message has a 47 bit frame 47uS plus payload data 3 bytes 24uS typ CAN transceivers are not rated above 1 Mbps due to slew rate limitations 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 33 of 33 WAMTMArm User s Guide service barrett com www
7. holes for M 10 or 3 8 Socket Head Cap Screws in four locations Bottom of Robot Figure 3 Screw hole locations Figure 2 Mounting Hole Locations General Safet Proper precautions should be taken when selecting the location and setup of your WAM system DO NOT set up the system such that any part of the robot s workspace resembling a sphere with a Im radius Figure 4 below reaches into a pedestrian pathway in the lab space The WAM is an unusually quiet mechanism thereby providing very little intrinsic warning of its enabled state 1 e little or no servo or transmission noise Shown below is a model of the WAM tool workspace Figure 4 WAM Workspace 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 5 of 33 WAMTMArm User s Guide service barrett com www barrett com Electrical Connections There are three types of electrical cables shipped with the WAM in addition to the standard AC lines cords and Ethernet cable Figure 5 DC Power Cable blue Plug this into a DC voltage source or into the AC Mode Converter To WAM 6 meters To PC Figure 6 Network Cable purple Plug the female end into the CAN card socket on the lower right side viewed from back of computer Plug the male end into the WAM socket labeled CAN To WAM L 6 meters A i Es I 99 302 39232 BO
8. is also a rotation about joint 2 use the parameters in the second row of Table 3 below as follows fiin sin 9 cos T 2 sin 0 sin T 2 o i sin 0 cos cos m 2 cos 0 sin 7 2 sin 0 0 2 0 sin 1 2 cos n 2 0 0 0 0 1 cos O sin 0 o i sin 0 0 cos 0 0 T 0 1 0 0 0 0 0 1 Equation 2 D H Matrix Example 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 23 of 33 WAMTMArm User s Guide service barrett com www barrett com Each of the joints has a mechanical stop that limits the motion Refer to Table 5 below for a complete listing of the joint limits for each axis Table 5 Joint Limits Joint Positive Joint Limit Negative Joint Limit Rad deg Rad deg 2 6 150 2 6 150 2 2003 200113 3 2807 28057 4 3108 09C3 5 1308 Bon 6 1600 1609 Forward Kinematics for the 4DOF WAM The forward kinematics of the 4 DOF WAM system is used to determine the end tip location and orientation These transformations are generated using the parameters in Table 3 on page 23 and the matrix in Equation on page 23 U V W Px u V W p 4 y y y y Toot u V W P 0 0 O0 Equation 3 Tool frame matrix You define the T Too rame for your specific end effector The forward kinematics are determined for any frame on the robot by mulitplying all of the transforms up to and including the final frame To determine t
9. only respond to STAT and VERS commands while in RESET for safety Host sends MsgID 10000000000 gt Group 0 Data 10001000 00000000 00000010 00000000 gt Set property 8 MODE to 2 MODE TORQUE The motors default to MODE 0 MODE IDLE Setting MODE to MODE TORQUE tells the motors to apply any torque sent to them When MODE MODE IDLE motors will ignore any torque commands sent and apply braking When using a WAM the safety system will set the MODE when you press the IDLE ACTIV ATE buttons Do not try to bypass the WAM s safety system by setting the MODE directly this will cause undesired operation Host sends MsgID 10000000000 Group 0 Data 00011010 gt Get property 26 AP Motors send MsgID 10010100011 gt From ID 5 to Group 3 Data 00000000 00000000 0000010 gt My position is 2 encoder cts MsgID 10011000011 gt From ID 6 to Group 3 Data 00000000 00000000 0000111 gt My position is 7 encoder cts MsgID 10011100011 From ID 7 to Group 3 Data 00111111 11111111 11111110 gt My postion is 2 encoder cts Host uses these positions to calculate a torque then sends MsgID 10000000010 gt Group 2 Data 10001010 AAA AA Aaa aaaaaaBB BBBBbbbb bbbbCCCC CCcccccc cc000000 00000000 gt Set torques to new values AAAAA Aaaaaaaaa etc 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 30 of 33 WAM Arm User s Guide service Abarrett com www
10. power converter is not used Figure 13 AC Power Converter Covers There may be occasions to remove one or more of the covers for maintenance or upgrades Typical reasons for cover removal include cable replacement or tensioning firmware upgrades and access to baseplate mounting holes The base cover is removed by opening all four latches If necessary the hinged back door may be swung down by removing the single M6 flat head screw in the upper left of the back door To reinstall the base cover first make sure the hinged back door is in place and the screw is secure Wrap the cover in place swing the lower two latch hooks away from the backplate and place the upper two latch hooks in the grooves on each side of the backplate Hold the upper latches one in each hand and align the cover such that there is an egual gap between the cover edges and the edge of the hinged door With egual pressure slowly close the two upper latches They should snap into place Repeat with the upper two latches The plastic side covers or shoulder covers snap into place To remove wrap hands around the sides about halfway down and lightly pull the sides apart Pull the cover out and up to remove To reinstall pull the sides out slightly and feed the sides through the gaps formed by the Joint 2 stop covers and the large vertical aluminum plates To access the motor controller for Joint 1 the silver colored disc on top of the upper base plate must be remov
11. 50 280 348 rs 4x M10 THRU 220 Figure 15 WAM 4 DOF dimensions and D H frames Figure 15 shows the 4 DOF WAM system in the zero position A positive joint motion is based on the right hand rule for each axis Figure 17 thru Figure 20 on the following pages show explicitly each of the four joint kinematic parameters and joint limits 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 17 of 33 WAMTMArm User s Guide service barrett com www barrett com ZTool 910 To 850 Wrist J5 J6 J7 45 Common Offset Elbow J4 Shoulder J1 J2 J3 M R 4x M10 THRU 220 Figure 16 WAM 7 DOF dimensions and D H frames Figure 16 shows the entire 7 DOF WAM system in the zero position A positive joint motion is based on the right hand rule for each axis The seven figures on the following pages show explicitly each of the seven joint kinematic parameters and joint limits 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 18 of 33 WAMTMArm User s Guide service barrett com www barrett com 2 0rad 113 Figure 18 WAM Arm Joint 2 Frames and Limits 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 19 of 33 WAMTMArm User s Guide service barrett com www barrett com Figure 20 WAM Arm Joint 4 Frames and Limits 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 20 of 33 WAMTMArm
12. ETY MODULE Use the DefineWAMpos function in src btwam btwam c to set the initial positions This is called automatically during the normal Open WAM call anyway 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 31 of 33 WAM Arm User s Guide service Abarrett com www barrett com TL1 and TL2 are specified in puck units of torque as is TORQ IPNM is never actually used in the pucks themselves It is simply a non volatile place to store the conversion constant so that the controlling PC can read it upon startup and use it to convert between puck units and SI units of torque for the end user VLI VL2 after zeroing the WAM switches to limiting the Cartesian velocity instead of each motor s velocity You can t specify two sets of values You could try changing them dynamically if you wish TEMP and THERM should not go above 70C VBUS should be between 25 and 90V for safe operation MT OpenWAMO calls InitializeSystem which sets MT to 4731 for each puck A value of 1024 corresponds to 1 01A of current in the motor windings Let s say MT 750 TL1 2500 TL2 4000 You send a TORQ of 2800 The safety system is okay with this it just shows the warning light on the pendant The puck notices that abs 2800 exceeds 750 so it sets its own torque output to 750 sign 2800 Also note for sanity s sake the WAM library saturates packed torques at 14 bits That s 8192 8191 SAFETY MODULE The safety module is puck
13. LL and mmmmmmmm are used for a total of 4 payload bytes The CAN frame data length code DLC is set to the number of bytes being transmitted Properties Each motor controller has several properties see property list below Most of these properties may be read and written via Get property and Set property messages 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 29 of 33 WAMTMArm User s Guide service Abarrett com www barrett com Exceptions 1 Actual Position property is a 22 bit 2 s complement number It is packed into a 3 byte frame payload OOMMMMMM mmmmmmmm LLLLLLLL Itis always sent to Group 3 2 Command torque can be sent as a set of 4 14 bit 2 s complement numbers It is sent to the motor controllers in 8 bytes max 0 1 2 3 4 5 6 7 APPPPPPP AAAAAAaa aaaaaaBB BBBBbbbb bbbbCCCC CCcccccc ccDDDDDD dddddddd A Action 0 Get 1 Set P Property A Upper 6 bits of first value a Lower 8 bits of first value B Upper 6 bits of second value b Lower 8 bits of second value Each motor has a property PIDX 1 4 which tells it which torque to use from the set of 4 Full example 3 motors with IDs 5 6 and 7 Host with ID of zero Host sends MsgID 10000000000 Group 0 Data 10000101 00000000 00000010 0000000 gt Set property 5 STAT to 2 STATUS READY The motors start up with STAT 0 STATUS RESET Setting STAT to READY gets the motors ready to receive additional data Motors will
14. Motor Joint Transformations 0 0 eeeeeeeeeeeeeeenenenenrerenenenrnnenenen renn ete ttn re aeaa a iS REEE tette SR R RER ear a SEE RR RE HEHE RR GEAR RE RE He RR 27 6 Appendix B CAN Communication Spec a a a a os Uti s du EE 29 T Appendix C BarretHand aska deseas iet ad is ia lg a la a again aa paai iiare iai 34 Barrett Technology Inc 625 Mount Auburn Street Cambridge MA 02138 U S A US 617 252 9000 service barrett com 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 2 of 33 WAMTMArm User s Guide service barrett com www barrett com 2 Getting Started This section is meant to help you develop a familiarity with the WAMTMArm system Use this Getting Started section as a supplement to the Ouick Start Guide included separately 2 1 Unpacking Figure 1 below illustrates everything that is shipped with a standard 4 degree of freedom WAMTMArm keyboard not shown Please ensure that all components are accounted for In addition to the components shipped you will need a computer monitor to connect to the supplied PC Modular outer link PC Ethernet cord and line cord Network cable DC power cord Converter for AC mode User s Manual with line cord Pendants Maintenance Kit software Figure 1 WAM Arm components 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 3 of 33 WAMTMArm User s Guide service barrett com Details WAM Arm Four
15. S jo o lt M8 n Je 7 0 0 0 N Equation 8 Arm Joint to Motor position Equation 9 Wrist Joint to Motor position transformations transformation Motor to Joint Torque Transformations Similar to the position transformations the following equations determine the joint torque from the motor torque Jt N 0 0 0 Mt i Jr E 0 0 Mt Js SN N Mt Ji 0 gt 0 Mt JT 0 Mt s n l Jt s ls Mt Jt 0 0 0 N Mt 7 0 0 N 7 Equation 10 Arm Motor to Joint torque Equation 11 Wrist Motor to Joint transformations transformation The following equations determine motor torque from the joint torque 1 0 0 0 N 2 E Mt 0 1 hg Jt MT e 2N JE Mt 2N 2N Jt Mt 2 o0 J d 4 2N 2N Mt 0 3 o YT Mt 100 Mt 2N 2N Jr 0 0 N l 7 0 0 0 N Eguation 13 Wrist Joint to Motor torque transformations Equation 12 Arm Joint to Motor torque transformations 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 28 of 33 WAMTMArm User s Guide service barrett com www barrett com 6 Appendix B CAN Communication Spec 1Mbaud CANbus 8 time guanta per bit 759 sampling point Sync jump width 1 time guanta TO 11 bit MsgID standard CAN Proprietary protocol not DeviceNet or CANopen Recommended reading Controller Area Network by Konrad Etschberger MsgID spec GFFFFFTTTTT 11 bits binary G Group 0 Directed message 1
16. User s Guide service barrett com www barrett com M7 Body Figure 21 WAM Arm Joint 5 Frames and Limits 1 6rad Figure 22 WAM Arm Joint 6 Frames and Limits 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 21 of 33 WAMTMArm User s Guide service barrett com www barrett com 2 2rad 128 128 Figure 23 WAM Arm Joint 7 Frames and Limits 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 22 of 33 WAMTMArm User s Guide service barrett com www barrett com Eguation 1 below gives the transform between two adjacent D H coordinate frames The D H parameters that were derived from this equation ae located in Table 3 below Note that c and s stand for cos and sin respectively c0 s9 ca s9 sa a c s c0 ca cOsa a s0 T i 0 SOL cQ d t t ti 0 0 0 1 Equation 1 D H generalized transform matrix Table 3 4 DOF WAM frame parameters with blank Table 4 7 DOF WAM frame parameters outer link installed d a xd N a et NS E r I O UA CA oes sn 0 Jo T 0 0 loss ala gt R o c QN 99 Notes Units of meters and radians T Tool frame ele elele e ele N CA A w N 4 0 045 2 6 For example to generate the transform from coordinate Frame 2 to coordinate Frame 1 i e the position and orientation of Frame 2 described in terms of Frame 1 which
17. WAM Arm User s Guide F e Barrett Technology Inc Documen t D1001 Version AE 00 WAMTMArm User s Guide service barrett com www barrett com 1 Table of Contents MEL UU GPC Ores rcc 2 MM Get ne Started M 3 2 1 LOL ER MEME AN 3 2 2 SEEN R P R O O P O O O A O OH ean aenreninh itis 4 2 3 DY SECM S LAKE P ERES A ten ere ee re e PH ORE FOROR A a Dre RERBA dg Pea o ee E A UR VE ornou Re ENSE EE s a 8 BL c er 9 3 1 MEAM TIBI P a DE 9 3 2 WAM Wrist Optional E RER Neat 12 4 PC Control SoftWare sooten e a a Shad sedne a ese a i a aa N EA eb Eque 13 4 1 PO Spee ACA ONS E E E E pa ES E EET 13 4 2 Fil system Lay Out siiicar E SE RA R UN ESRA SEESE E EE EE S EE EEKE E KE ENEE 13 4 3 The c nfisuratr n file wWam C0 sessa ina EE Ra a aAA EE D EEE EEEE ITERE SK EEE R e EREET ra 13 4 4 Operating MOS e M ETENEE 13 4 5 Handling safety faults eerte n a A IE ehe li tmt meine BED E E 14 4 6 Additional information o Are dere TR RS 14 4 7 TroublesbOGUnB nonien E hp i top eia REIS RS unb imet ep pd ries 16 5 Appendix A Kinematics Transmission Ratios and Joint Ranges esee I7 5 1 4 DOF and 7 DOF Kinematics amp Joint Ranges sse eterne entente tente tenete tenen RE E RER HEHE RR RKK RE PR RR 17 52 ADORF Gum Balls Kit M a 25 5 3
18. ach axis The D H parameters that were derived from Figure 24 are located in Table 6 below Table 6 4 DOF WAM Gimbals DH Parameters kose o To EA 9 82 of 0 x2 0150 aca 70 of 0 amp 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 26 of 33 WAM MArm User s Guide service barrett com www barrett com 5 3 Motor Joint Transformations Motor to Joint Position Transformations The following transformations show the change in joint positions as a function of motor positions The input transmission ratios and the differential transmission ratios are calculated from known pulley pinion and cable diameters Table 7 Arm Transmission Ratios 42 0 28 25 28 25 1 68 18 0 10 27 10 27 14 93 1 0 0 0 N 1 1 0 JO M6 Je A a Me JB ees s MB 70 eh Me sai 2 n E os 3 0 3 0 Je M8 Je 2N 2N MO f 0 0 0 0 0 n NG i Equation 7 Wrist Motor to Joint position Equation 6 WAM Motor to Joint position transformations transformations 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 27 of 33 WAMTMArm User s Guide service barrett com www barrett com The motor position can also be derived from joint space by taking the inverse of the multiplying matrix For convenience they are as follows N 0 0 N M8 N Je Ns 0 0 N 2 0 M9 6 J M9 n Je N M N 0 J M9 0 N a N 0 JO nc 2 MO
19. ased To avoid damaging the WAM electronics please make sure the WAM is powered off before detaching or attaching any outer link The WAM Wrist is connected after removing the outer link by aligning the metal shells of the integrated D sub connectors at its base with the mating connector s shells on the end of the WAM s elbow and threading the quick connect ring onto the wrist base No special wrenches fasteners or tools are required however it may be necessary to shake the outer link or Wrist back and forth while tightening or loosening the ring This ring should only be hand tightened It is normal for there to be a small number of threads left when fully tightened This single operation also makes all electrical connections to the WAM Wrist Figure 9 shows the electrical connector at the end of the WAM Figure 9 Wrist Connector Figure 10 Separating the Outer Link 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 7 of 33 WAMTMArm User s Guide service barrett com www barrett com Final Setup Once all components are connected your system should look as shown in Figure 11 Although the WAM is intrinsically safer than other robotic systems you may wish to integrate standard safety measures such as mats gates light curtains etc into the lab space surrounding the WAM WAM to power AC converter Figure 11 Typical system setup 2 3 System Startup You are now ready to start controlling the mo
20. barrett com 7 Appendix C BarrettHand The BarrettHand can be readily integrated into the WAM system There are two methods by which Hand control can be integrated with Arm control The first method allows the user to control the Hand from a separate window while the Arm is running The second method is integration of hand commands with Arm commands within the same program Both methods require the following setup procedure E Turn power to entire system OFF Plug in hand connector that extends from the modular outer link or Wrist into base of Hand Align holes on Hand Base Ring with holes on connector strain relief plate Align pins on Tool Plate with holes on Hand Base Ring Attach Hand to modular outer link or Wrist by turning Tool Plate Attachment Ring clockwise The pins must engage completely for Hand to be securely attached to Wrist Plug End Effector extension cable from base of Arm to rear of Hand Power Supply Box Plug power cord into Power Supply Box Attach a standard serial cable from COM port to rear of Hand Power Supply Box The hand is attached and ready for operation Read the BarrettHand User Manual before proceeding with Hand operation Before operating both Hand and Arm together the Hand should be tested on the end of the Arm Place Arm in a configuration that allows the Hand to move through its full range of motion Follow the procedures in the BarrettHand User Manual for testing Hand operation If Hand operation is succes
21. barrett com Motor Controller Parameters ANAO ANA1 if you solder analog sensors to the puck read them here 0 3V only AP Actual motor position in encoder counts DIGO DIG1 if you solder wires to these contacts on the puck you can read write them here 0 3 3V only IPNM you can store the puck torque unit to Nm conversion here set at factory LOAD Load a parameter from non volatile memory into active puck memory via the CAN bus setProperty 0 4 LOAD FALSE MT for example MECH how many encoder counts away from the index pulse you are MOFST how far is it from the index pulse to the start of an electrical cycle calibrated MT torque limit puck units SAVE after setting a non volatile property save it to non volatile puck memory with setProperty 0 4 SAVE FALSE MT for example STAT 0 RESET 1 Unused 2 READY TEMP read the puck temperature THERM read the motor thermistor temperature TORQ Set the puck torque VBUS Read the present bus voltage on a puck volts VERS Get the firmware version or the monitor version if the puck is in reset Safety System Parameters TL 1 Set the safety system s motor torque warning level puck torque units TL2 Set the safety system s motor torque fault level VLA Set the safety system s motor velocity warning limit before the WAM is homed zeroed or cartesian velocity limit after zeroing VL2 Set the safety system s motor velocity fault limit before the
22. degree of freedom robotic arm WAM PC Shuttle PC including CAN card used to communicate with the WAM AC mode converter For optional AC power this connects the WAM to 50 60 Hz 100 240V outlet power Control Pendant Used to activate and deactivate the WAM show the safety status of the system and has an emergency stop button Display Pendant Like the Control pendant this displays the safety status of the components and has an emergency stop button but cannot activate the WAM Arm WAM DC power cable blue Connects the WAM to DC power or to the AC converter for AC power Network cable purple for use in communication between the PC and the WAM 2 2 System Setup Ethernet cable for PC Standard Ethernet cable for use in connecting PC to a local network Computer AC line cord 6 Standard AC line cord shorter and thinner of the two line cords AC converter line cord 10 Standard heavy gauge AC line cord longer and thicker of the two line cords Maintenance kit kit containing replacement parts maintenance tools clamps for recabling and mounting hardware for the WAM Documentation Includes this manual a cable maintenance manual a guick start guide and a 1 year warranty WAM Wrist not shown optional replaces the Outer Link on the WAM adds three additional powered degrees of freedom Passive Gimbals not shown optional replaces the Outer Link on the WAM adds three add
23. dpoint m s elbow m s with floating point values from 0 0 to 6 9 getProperty bus node property amp reply bus 0 no other value has been tested node 1 31 inclusive 0x400 is not valid property 0 108 inclusive use the enumerations in btcan h amp reply pointer to a long integer If you want to get the properties of several pucks at one time you will have to write your own routine using an array for the replies along with canSendMsg and canReadMsg see the getPositions function in src btsystem btcan esd c as an example Otherwise you can use getProperty to get a single property of a single puck at a time The setProperty function in contrast DOES allow nodeIDs OR group messagelDs to be used interchangeably So setProperty 0 0x400 STAT FALSE STATUS READY is okay However if the 4th parameter is set to TRUE verify TRUB then it is effectively calling getProperty with the 0x400 which is illegal NOTE Calling getProperty with 0x400 will prompt at least 4 responses one from each puck but getProperty will only read the first one leaving 3 in the queue to be read by some later call to getProperty or canReadMsg I strongly recommend rebooting the system to clear out these messages otherwise they could cause a LOT of confusion even if you start to do things correctly Alternatively you could call canReadMessage with a non blocking read until no messages are found see getBusStatus for an exa
24. ed Use a flat head screwdriver with a sharp tip and gently pry the cover off To reinstall ensure that all electrical wires are away from the sides of the hole in the upper plate align the silver colored disc and snap into place 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 11 of 33 WAMTMArm User s Guide service barrett com www barrett com 3 2 WAM Wrist optional The servomotors for joints 5 amp 6 are located at the base of the wrist to minimize their inertial effects on the host robot arm The final roll joint in the WAM Wrist motor joint 7 is the only geared axis Since cable circuits generally have a size versus torque relationship that limits the minimum characteristic size of a transmission gears were an appealing trade off in this axis only for the significant decrease in distance between the grasp center of an attached end effector and the wrist center The 1 and 2 stage transmission cables for joints 5 amp 6 are accessed by sliding the cover clamp off the Wrist cover and pulling the cover around the wrist To access the final stage cables the user is required to remove 4 socket cap screws from each black nylon guard at the top of the wrist and then to pull off each guard Since the final cable stages for motor axes 5 amp 6 require infrequent maintenance removal of these guards will rarely be necessary The threaded base of the WAM Wrist is fully compatible with the mechanical and elect
25. encoder counts into joint angles calculates the desired joint torques converts these into motor torque commands then sends out the calculated torques to the motors All force or position control is calculated on the PC and converted to motor torques as a final step the WAM itself is entirely motor torque controlled For a source code example of this process see the WAMControlThread function in src btwam btwam c Please note that as of Nov 2005 the CAN card driver used under LinuxRTAI is not realtime If interrupts occur while the CAN driver is processing data the WAM may jitter slightly Common sources of interrupts are DHCP renegotiation and XWindows GUI processing To minimize the chance of jitter please use only static IP addressing and run the PC in terminal mode or log in via SSH 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 14 of 33 WAM Arm User s Guide service Abarrett com www barrett com When the WAM is first powered on the motor controllers use hall effect sensors and six step commutation for control until an initial hall transition occurs Then they switch to using the incremental encoders for smoother commutation until the encoder index pulse is observed once per motor revolution Then they begin a factory calibrated commutation loop for precise torque control A good example of setting the velocity is in the btdiag program btclient src btdiag btdiag c You can call setSafety Limits rad s en
26. error GRAVITY COMPENSATION press g enter a scaling value 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 13 of 33 WAM Arm User s Guide service Abarrett com www barrett com If you set the gravity scaling value set to 1 0 and have appropriate mass parameters defined in wam conf then the WAM will apply the necessary joint torgues to float in normal Earth gravity The normal operation of the Move command is to remember the initial IDLE POSITION mode when the move was commanded and restore the WAM to that mode when the move completes It is advisable to activate POSITION mode press p and Gravity Comp press g type 1 lt Enter gt before issuing a Move command 4 5 Handling safety faults If the safety system registers a fault during WAM operation you will need to clear the fault before continuing to use the WAM The most common safety faults over velocity over torque leave the WAM safety system in the IDLE state yellow button is lit To reset the fault from this state when using the btdiag example application 1 Stop any running Teach amp Play playback press 2 Set the position controller to IDLE mode press p to toggle mode 3 Turn off gravity compensation press g 4 Reset the safety fault press lt Shiftt Reset Idle on the control pendant 5 Re activate the WAM press lt Shift Activate gt on the control pendant 6 Turn on gravity compensation press g I
27. f the safety system encountered a critical fault that resulted in an E STOP of the WAM no pendant buttons are lit then you should follow these steps to recover from the fault 1 Exit the application press x 2 Reset the safety fault press lt Shift Reset Idle gt on the control pendant 3 Grab the WAM and move it back to the home position the joint positions are lost after an E STOP 4 Re launch the control program and follow the on screen instructions 4 6 Additional information The world coordinate frame is right handed and its origin is in the center of the shoulder with X pointing toward the front rounded part of the WAM and Z pointing up see frame docs in this manual Move command arguments for JOINT mode must be entered in units of radians In CARTESIAN mode the units are meters from the world frame origin All arguments should be specified and comma separated 4 arguments for a 4 DOF JOINT Move 7 args for a 7 DOF JOINT Move 3 args for any CARTESIAN Move We do not yet have Cartesian angular control built into the WAM library The default home position specified in wam conf is J2 folded about 2 rad back against its large rubber stop and J4 folded in against the inner link pi rad It looks like the WAM is trying to touch its shoulder In the examples the PC closes a 500Hz position torque control loop with the WAM over the CAN bus The PC asks the motor controllers for their present positions converts the received
28. he tool end tip location and orientation use the following equation T T T T i T Too Equation 4 Tool end tip position and orientation equation for the 4 DOF WAM Forward Kinematics for the 7 DOF WAM As with the previous example you define the T frame for your specific end effector The forward kinematics are determined for any frame on the robot by mulitplying all of the transforms up to and including the final frame To determine the end tip location and orientation use the following equation oT ED TL TI TL LT Tool Tool Equation 5 Tool end tip position and orientation equation for the 7 DOF WAM 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 24 of 33 WAMTMArm User s Guide service barrett com www barrett com 5 2 4 DOF Gimbals Kinematics A 4 DOF WAM Arm can be outfitted with an optional 3 axis non motorized gimbals that give precise angular feedback The kinematics of the first 4 joints is identical to a 4 DOF WAM Arm The kinematics for the additional 3 axes is shown in Figure 24 Gimbals J5 J6 J7 Elbow J4 Shoulder J1 J2 J3 4x M10 THRU 220 Figure 24 Denavit Hartenberg Frames 4 DOF Gimbals 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 25 of 33 WAMTMArm User s Guide service barrett com www barrett com Figure 24 shows the WAM Gimbals in the zero position A positive joint motion is based on the right hand rule for e
29. itional unpowered degrees of freedom www barrett com This section describes in detail the steps reguired to connect the components of the WAM system power up the system and perform some routine system checks Unless explicitly noted all setup instructions referencing the optional WAM Wrist can be ignored if the user is setting up only the 4 DOF WAM Power Source The standard WAM system requires an input voltage of 18 90VDC The power requirements for both 4 DOF and 7 DOF WAMs are summarized in Table 1 For AC operation a converter for AC mode is supplied The converter requires 50 60 Hz single phase 100 120 VAC 7A or 200 240 VAC 3 5A for proper operation Table 1 DC Power Requirements 4 DOF 7 DOF Q 18W Q 27W Typ 28W Typ 45W Peak 600W Peak 800W Q Quiescent powered up no torques applied Typ Typical operation with 2 kg payload 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 4 of 33 WAMTMArm User s Guide service barrett com www barrett com Mounting Reguirements The mounting surface for the WAM should be designed to handle the large reaction forces generated at the base of the arm during high acceleration operation The WAM can be fastened to the prepared mounting surface via the four bolt holes in the base plate Use four M10 or 3 8 screws The holes are located on the base of F 250mm the WAM according to Figure 2 and Figure 3 The plate thickness is 8mm Counterbored
30. le the WAM is in the IDLE state the yellow Reset Idle button is lit the safety system will display a torque warning prohibiting the WAM Arm from being activated If the WAM Arm is in the ACTIVATED state the green Activate button is lit and the PC sends torques which exceed the default torque warning or fault levels the torque warning or fault light will be lit and the offending motor number will be shown in the single character display The voltage status lights indicate the state of the WAM Arm s motor bus voltage When the system is first powered up the bus is off there is no motor power and the safety system registers a voltage fault This fault is cleared by pressing Shift Idle on the control pendant Placing the WAM Arm into the IDLE state applies a DC voltage 18 90V depending on input voltage on the motor bus and clears the fault If the voltage approaches the limits the voltage warning light is lit If the voltage exceeds the limits the voltage fault light is lit The heartbeat status lights indicate the state of the communication between the PC and each motor controller in the WAM Arm If the WAM is in the IDLE state and no control loop is active between the PC and robot the pendants will display a heartbeat warning If the WAM is in the ACTIVATED state and any controller or the PC fails to issue any communication for longer than 16ms a heartbeat fault is registered The Other status lights presently only indicate whether a
31. mple 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 15 of 33 WAMTMArm User s Guide service barrett com www barrett com 4 7 Troubleshooting 1 The most obvious thing to check is that the two E Stop buttons are reset up 2 If you are using your own power supply try using the power supply supplied with the WAM 3 Check the CAN connection from the pucks at the safety board It is not a locking connector and sometimes it gets loose from the safety board located near the base motor side of the safety board 4 Check the little white cylindrical fuse 4A 250V in the fuse holder on the safety board under the grey plastic cover Mfg P N Littelfuse 0216004 H 5 Check for wires coming loose in their connectors crimps may be suspect 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 16 of 33 WAMTMArm User s Guide service Abarrett com www barrett com 5 Appendix A Kinematics Transmission Ratios and Joint Ranges 5 1 4 DOF and 7 DOF Kinematics 8 Joint Ranges A good introduction to coordinate frames transformations and kinematics is beyond the scope of this document There are several good introductory robotics books available We recommend Spong M Vidyasagar M Robot Dynamics and Control 1989 John Wiley amp Sons We use the Denavit Hartenberg D H method to establish the coordinate frames particularly the variant used in Spong Shoulder 23 250 1
32. n E STOP has occurred If this is the case the fault light will be lit and the single character display will show E Table 2 Pendant lights amp errors Error occurs in state E STOP IDLE ACTIVE Velocity exceeds VL1 No action Warn Warn Velocity exceeds VL2 No action Fault E STOP Fault IDLE Wait 1 4s Torque exceeds TL1 Warn for non zero Warn for non zero Warn Torque exceeds TL2 Fault Fault Fault IDLE Heartbeat missing Warn Warn Fault E STOP Voltage lower than VOLTL1 No action Warn Warn Voltage lower than VOLTL2 Fault Fault Fault IDLE Voltage higher than VOLTH1 No action Warn Bleed voltage Warn Bleed voltage Voltage higher than VOLTH2 No action Fault E STOP Fault E STOP E Stop pressed Fault E STOP Fault E STOP Fault E STOP NOTE Warnings are cleared automatically critical faults are cleared through a RESET Request occurs in state E STOP IDLE ACTIVE E STOP E STOP E STOP E STOP Clear faults power up bus enumerate IDLE ACTIVATE No Action RESET IDLE Clear faults IDLE REQUEST If no warnings or faults ACTIVE No Action 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 10 of 33 WAMTMArm User s Guide service barrett com www barrett com AC Converter The AC power converter should be used when hooking up the WAM Am to normal 100 120 or 200 240 VAC power For mobile applications or applications that reguire alternate DC power sources the AC
33. pendant then press the Activate button green and release both buttons This state may only be reached when all of the status lights are showing OK green All warnings or faults must be cleared before activating the WAM The green Activate button will light up indicating that the WAM Arm is now in the ACTIVATED state Before the WAM Arm s joint positions are initialized by the PC control software the velocity status lights indicate the state of the 4 DOF s angular joint speed By default there is a yellow LED warning when any joint exceeds 0 5 radians sec and a red LED fault when any joint exceeds 2 radians sec The joint number responsible for the warning fault is indicated by the single character display on each pendant After the WAM Arm s joint positions are initialized the safety system begins calculating and monitoring the 4 DOF elbow and endpoint velocities in Cartesian space instead of monitoring individual joint velocities By default there is a warning 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 9 of 33 WAMTMArm User s Guide service barrett com www barrett com when either the elbow single character E or arm endpoint single character A exceeds 0 5 m s and a fault when either one exceeds 2 m s These defaults are modifiable in software The torque status lights indicate the state of the torque commands being received by the WAM Arm from the PC control software If the PC sends nonzero torques whi
34. rical quick connect features on the WAM Arm VERY IMPORTANT You MUST turn off the main power to the WAM before connecting or disconnecting the wrist Nylon guards Removable transmission cover Thread for quick connect to WAM Arm Figure 14 WAM Wrist Components 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 12 of 33 WAMTMArm User s Guide service barrett com www barrett com 4 PC amp Control Software 4 1 PC Specifications Mainboard Shuttle SK43G or Via EPIA M10k Processor Type AMD Duron Applebred x86 1 8GHz or 1GHz C3 Nehemiah Memory 128MB 16MB of that is used as a video framebuffer Hard drive 80GB but only a fraction of that is partitioned and formatted Optical Standard ATAPI CD ROM Kernel Linux 2 6 and the RealTime Application Interface RTAI patches Distro Zenwalk slackware based PCI One slot used by CAN network card 4 2 File system layout The Barrett Technology robot control client software btclient is divided into multiple parts examples example source code for robot control software development doc source code documentation Doxygen HTML RTF lib location of library binaries include common include directory for libraries src btsystem software library with general robot routines src btwam software library with WAM specific routines src btutil utility for enumerating the motor controllers restoring defaults updating firmware src btdiag
35. sful the system is ready for use To operate the Hand separately from the Arm e Turn Hand Power Supply Box ON e Open a serial terminal application such as TeraTerm HyperTerminal minicom and connect to the COM port of the BarrettHand at 9600 baud No parity 8 bits One stop bit No flow control Put Arm in a configuration that allows for full joint motion of the Hand Initialize Hand Type HI The Hand is now ready for operation while executing Arm programs Execute desired Arm program While Arm program is running switch to the serial terminal window Type Hand commands see the Grasper Control Language section of the BarrettHand manual To operate Hand and Arm from the same program Integration of the Hand and the Arm in the same program requires opening and initializing the serial port from within your WAM control application then sending the desired Grasper Control Language GCL commands from the application See the directory of example code for details about how this is implemented 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 34 of 33
36. tors in the robot Before writing new C code you should verify the functionality of the WAM Refer to the QuickStart sheet for instructions on how to use the btdiag application located in root btclient src btdiag This will confirm that the WAM runs properly and will demonstrate some of the basic functionality of the software library 2006 Barrett Technology Inc Document D1001 Version AE 00 Page 8 of 33 WAMTMArm User s Guide service barrett com www barrett com 3 Hardware 3 1 WAM Arm Overview The WAM Arm is a 4 degree of freedom 4 DOF manipulator with human like kinematics With its aluminum frame and advanced cable drive systems including a patented cabled differential the WAM is lightweight with no backlash extremely low friction and stiff transmissions All of these characteristics contribute to its high bandwidth performance The WAM Arm is the ideal platform for implementing Whole Arm Manipulation WAM advanced force control techniques and high precision trajectory control Safety System Pendants The WAM Arm system comes standard with two safety pendants a control pendant and a display pendant Both pendants show the present safety status of the WAM Arm with status lights for the velocity torque voltage and heartbeats of the robot There is also a segment LED single character display which shows additional information related to any existing errors Each pendant has a large mushroom type emergency stop bu
37. tton which can be reset popped up by rotating the button face clockwise The control pendant has three additional buttons Shift Idle and Activate The WAM Arm has three safety states E STOP IDLE and ACTIVATED E STOP means there is no motor bus voltage in fact the motor bus power and ground lines are tied together resulting in a resistive braking effect on the joints of the WAM Arm The motor controllers are off line and do not keep track of their motor positions in this state E STOP is achieved by pressing the E STOP button on either pendant IDLE means there is voltage applied to the motor bus and the motor controllers are on line and keeping track of their motor positions but they are commanded to tie their motor phase leads together also resulting in a braking effect and they will ignore any command torque sent to them To put the WAM Arm into the IDLE state which will also reset any existing faults press and hold the Shift button on the control pendant Figure 12 Pendants then press the Reset Idle button yellow and release both buttons The yellow Idle button will light up indicating that the WAM Arm is now in the IDLE state Make sure both ESTOP buttons are reset popped up before attempting to change modes ACTIVATED means the motor controllers are actively applying any commanded torque they receive from the control PC To put the WAM into the ACTIVATED state press and hold the Shift button on the control
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