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LittleDog Robot 1.0 - Computational Learning and Motor Control Lab

1. The menu contains the following options File Menu Options Hotkey Displays a Select Data File dialog Ctrl C Not currently supported Print Ctrl P Prints the plots in the data window The Options Print to Image menu item see below determines whether printing happens to a printer or to a file ou Window Menu Options Ctrl G Toggles grid on and off Print to Ctrl l Toggles whether the Fi I e Pri nt command sends output to mage a printer or to a JPEG file Show Video rl V Not currently supported 4 2 3 1 Using View Controls The view controls modify the appearance of plots in the data window View Autoscale Hescale Smallecale oom In oom Out Click Autoscale Rescale and Smallscale to modify the vertical axis scaling of a selected plot Click Zoom In and Zoom Out to modify the horizontal axis scale in the right hand plot on each row 44 LittleDog Robot 1 0 User Guide View Controls Autoscale ClickAutoscal e and click a plot to set vertical axis scaling to include maximum and minimum points of all data traces Rescale ClickRescal e and click a plot to manually set the vertical axis scale of a plot Enter desired maximum and minimum vertical axis values in the dialog smallscale ClickSmallscal e and click a plot to set vertical axis scaling to include the maximum and minimum points of all data traces plotted in the right column plot Zoom In Click Zoom I n to decrease the
2. There are a few items that are not provided that you will need to purchase separately prior to setting up your system 1 One MoCap camera support frame as specified by the LittleDog Government Project Team Please purchase the correct frame so that your MoCap system closely matches the government test facility 2 Six BOGEN Manfrotto Super Clamp with 3025 Head mounts readily available at most major online photo amp video supply stores the following part number is valid online at B amp H Photo http www bhphotovideo com a PN BO2910 BOGEN Manfrotto Super Clamp with 3025 Head 3 Two surge protected power strips 4 Black cloth for masking items from the motion capture system 12 LittleDog Robot 1 0 User Guide You will need a lab space that is about 12 ft by 15 ft with 8 5 ft ceilings and enough additional room to have a desk near by To set up your system we recommend you perform steps in the following order 1 The first step is to ensure you are in possession of all of the equipment listed in Packing List Section 1 3 1 as well as the additional equipment listed above 2 Set up your MoCap system For instructions on setting up your MoCap system see Section S 3 Unpack the HOST and MoCap computers as well as the Monitor KVM switch wireless bridge and Ethernet switch Place both computers in a safe location near the intended MoCap tracking volume The HOST computer can be identified by the remova
3. 22 LittteDog Robot 1 0 User Guide TAN MW 1 MM gll Figure 9 MoCap Frame Assembly 23 LittleDog Robot 1 0 User Guide 2 1 2 Vicon System Configuration 2 1 2 1 Realtime Engine Parameters The Vicon realtime engine has a number of parameters which can be tuned to change marker reconstruction marker labeling and kinematic fitting of the LittleDog model A realtime engine parameter settings file rtp has been included with your LittleDog system Load the settings file by first going into setup mode by pressing the Setup tab on the upper left hand side Select RealTime Engine RealTime Engine Parameters Load RealTime Options and select the parameters file 2 1 2 2 Vicon Skeleton Files For MoCap system operation you must have the Vicon skeleton vsk files located in the session directory you are currently operating in To check which session you re currently in press the Data Management tab at the top left hand side of the window The Vicon system has the capability to record and post process motion but this is not required for real time motion capture which will be the primary use of the system If you change capture sessions just copy the Vicon skeleton files over to the new session directory located within CAMOCAP_DATA Three Vicon skeleton files have been included with your LittleDog system littledog vsk terrainA vsk and terrainB vsk Copy these files over to your current session directory when setting up y
4. Vicon MoCap System Host Computer Vicon Computer Robot State Estimator Ethernet e User Network BDI Apps LittleDog API Ethernet LittleDog Servo Loop Comms 500 Hz 100 Hz Figure 1 LittleDog System Schematic Ethernet Wireless Hub 802 11B The LittleDog System is comprised of a LittleDog Robot a Host Computer a MoCap Computer and a Vicon MoCap System Figure 1 illustrates how these components are connected together This manual describes how to set up the LittleDog Robot system and how to get started using it The LittleDog system comes pre configured with regard to communications The robot communicates with the Host computer over a private wireless Ethernet network The Vicon motion capture system communicates with the Host computer via a wired connection The Host computer has a second wired Ethernet port that can be used to connect the Host computer to the outside world Getting all that networking to perform correctly at high rates is a challenge We encourage you to leave the network settings as pre configured with the exception of the Host computer s external network interface which you can set as you please Robot control applications run on the Host computer and communicate with both the robot and motion capture system at 100Hz collecting a current snapshot of the system state and issuing commands to the robot every 10ms Joint level servo controllers are provided on the LittleDog
5. dat containing a full record of all the information collected from the robot and motion capture system as well as commands sent to the robot during the previous trial This data is logged at a rate of approximately 100Hz and every data entry is time stamped both by the robot when the data is acquired and by the host when it is received from the robot robot is frozen Flag indicating that low level robot software has frozen robot motion robot is undervoltage Flag indicating the battery voltage is low robot killswitch Flag indicating the kill switch is active not present in the Learning Locomotion project robot watchdog Flag indicating the robot watchdog has timed out battery voltage Battery voltage in Volts battery current Battery current in Amps imu orientation rz rx ry IMU orientation in Yaw Roll Pitch Euler coordinates mi rates x y z IMU angular rates 39 LittleDog Robot 1 0 User Guide feg joint q_d PD joint position command rad mocap body orientation rz rx ry mocap body age Age in frames of body data terrain k age Age in frames of terrain data 40 LittleDog Robot 1 0 User Guide 4 Working with BDIPlot BDIP1ot is a tool for viewing and analyzing numerical data sets generated by the Boston Dynamics software delivered with LittleDog BDIP1ot is based on Matlab but can run stand alone If more advanced mathematical analysis or plotting routines are needed than BDIP1ot provides Lit
6. 0 0365 00 Postion wih respect to Body Frame FLHP Rv RED 00 00302 00 Postion wih respect to Hip X Frame FL KNEE AY PURPLE 00 00 0 0751 Postion wih respect to Hip Y Frame FL_FOOT sue oom 00 Lage FRHIPRX ORANGE 0401 0 0365 00 Poston with respect to Body Frame mme Bue oo 00 0 1027 Poston wih respect to Knee Frame num ORANGE 0 101 0 0385 00 Postion wih respect to Body Frame nun RED oo 0 0302 00 Postion wih respect to Hip X Frame HL KNEE RY PURPLE oo 00 0 0751_ Postion wih respect to Hip Y Frame HLFOOT cur ooz1 00 LA Poston wih respect to Knee Frame HR HIP RX ORANGE 0 101 0065 0 0 Postion with respect to Body Frame HR HIP AY RED oo 00802 00 Postion wih respect to Hip X Frame HR KNEE RY PURPLE oo 00 0 0751 Postion wih respect to Hip Y Frame HRFOOT u 002 oo LA Poston wih respect to Knee Frame Table 2 Joint Limits Property Min Unt Description FLKNEE RY 31 10 Rad Kneelimt FL_HIP_RX Rad Hip RX Limit FL_HIP_RY Rad Hip RY Limit ee NEL ES FRHPRX o6 06 Rad HipRXLmi 4 Rad Hip RY Limit HL KNEE RY 10 31 Rad _ Hip RY Limi HLHP RX os ose Rad Hip RY Limi 5 Rad Hip RY Limit HR KNEE RY 10 31 Rad Kneelimi HRHP RX oe ose Rad Hp RX Limi HR_HIP_RY Rao Hip RY Limit 29 L ittleDog R
7. IMPLIED OR OTHERWISE INCLUDING WITHOUT LIMITATION ANY WARRANTY OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE OR WITH RESPECT TO INTELLECTUAL PROPERTY OWNERSHIP NO ORAL OR WRITTEN INFORMATION OR ADVICE GIVEN BY ANY Boston Dynamics EMPLOYEE REPRESENTATIVE OR DISTRIBUTOR WILL CREATE A WARRANTY FOR THE SOFTWARE AND LICENSEE MAY NOT RELY ON ANY SUCH INFORMATION OR ADVICE 11 Limited Warranty on Media Boston Dynamics warrants the media on which SOFTWARE is recorded and provided to LICENSEE under this Agreement to be free from defects in materials and workmanship under normal use for a period of ninety 90 days after the date of the original delivery of SOFTWARE to LICENSEE Such warranty is solely for LICENSEE s benefit and LICENSEE has no authority to assign pass through or transfer this warranty to any other person or entity If LICENSEE greater than the rights expressly stated in the body of th returns any defective media to Boston Dynamics or an authorized Boston Dynamics representative during the warranty period with proof of purchase Boston Dynamics will at its sole option either replace such defective media or refund the purchase price for such media This warranty will not apply to any media that has been damaged by abuse accident or misuse The foregoing warranty sets forth Boston Dynamics s entire liability and LICENSEE s exclusive remedy for any defects in any media and is in lieu of and Boston Dynamics disclaims a
8. If you accidentally short the wires the battery must be placed 1n a safe area for observation for approximately 15 minutes Additionally if a short occurs and contact 15 made with metal such as rings on your hand severe injuries may occur due to the conductibility of electric current 7 A battery can still ignite even after 10 minutes 8 In the event of a crash you must remove battery for observation and place in a safe open area away from any combustible material for approximately 15 minutes 9 Ifforany reason you need to cut the terminal wires it will be necessary to cut each wire separately ensuring the wires to not touch each other or a short may occur potentially causing a fire 10 To solder a connector Remove insulating tape of Red wire and solder to positive terminal of a connector then remove insulating tape of Black wire and solder to the negative terminal of connector Be careful not to short the wire lead If you accidentally cause the battery to short place it in a safe open space and observe the battery for approximately 15 minutes A battery may swell or even possibly catch fire after a short time 11 Never store or charge battery pack inside your car in extreme temperatures since extreme temperature could ignite fire Charging Process 1 Never charge batteries unattended 2 Charge in an isolated area away from other flammable materials 3 Let battery cool down to ambient temperature before charging 4 Do not charg
9. Learning locomotion program to facilitate testing This example allows a user to control the initialization and execution of robot control software through the interface in order to execute a number of experimental walking trials with the robot Commands Current System State Mocap Initialized Battery Voltage Calibrate Robot Ron Taal Robot Calibrated CPU Temp Data Timestamp Battery Current Bu i i i 1 D i I i I D i I i f 1 I H i I D d J Successfully connected to robot Starting calibration done Shut Down amp Quit Figure 7 LittleDog walk example GUI 19 LittleDog Robot 1 0 User Guide First we will build the walk example Change directory to LI TTLEDOG exampl es walk Use qmake walk pro make to build the example application again check for any errors and resolve them before proceeding You can now start the interface by executing Wal k The program will display a GUI that allows you to manually sequence through the process of connecting to both the motion capture system and the robot calibrating the robot and controlling a trial The text display area at the bottom of the window reports status and error messages from the robot and robot interface software u
10. buver assumes all risks associated with lithium batteries If vou do not agree with these conditions return the battery immediately before use General Guidelines and Warnings 1 Use specific Lithium Polymer charger only Do not use a NiMH or NiCd charger Failure to do so may a cause fire which may result in personal injury and property damage 2 Never charge batteries unattended When charging LiPo batteries you should always remain in constant observation to monitor the charging process and react to potential problems that may occur 3 Some LiPo chargers on the market may have technical deficiencies that may cause it to charge the LiPo batteries incorrectly or at an improper rate It 1s your responsibility solely to assure the charger you purchased works properly Always monitor charging process to assure batteries are being charged properly Failure to do so may result in fire 4 Ifat any time you witness a battery starting to balloon or swell up discontinue charging process immediately disconnect the battery and observe it in a safe place for approximately 15 minutes This may cause the battery to leak and the reaction with air may cause the chemicals to 1gnite resulting 1n fire 5 Since delayed chemical reaction can occur 1t 15 best to observe the battery as a safety precaution Battery observation should occur in a safe area outside of any building or vehicle and away from any combustible material 6 Wire lead shorts can cause fire
11. i 36 3 4 BUILDING YOUR FIRST LITTLEDOG BEHAVIOR aaa aaa kaaa kaaa kaaa 39 3 5 CONTENTS OF A LITTLEDOG DATA ET 39 4 WORKING WITH BDIPLOT rrrererrnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 41 LittleDog Robot 1 0 User Guide ZU VENN 41 42 RUNNING BDIPLOT cri di 41 42 1 Variable List Allee dE 43 A A 43 423 GOMMAnd Nida oc 44 4 3 THE BOSTON DYNAMICS MATLAB TOOLBOX eese kakaa 48 4 3 1 Installing and Running the Matlab Toolbox ccccocoonncnncccconccnncnononcnncnnnanonnnnos 48 4 3 2 Manipulating Data in Matlab cccconncncononcnnoconnncononnncononcnnnnnncnnoonanoncnnanennnnnnens 49 4 3 3 Accessing Variable Names And Values kaaa kaaa kaaa 49 234 sample Matlab SCD EE 50 5 MAINTAINING YOUR LITTLEDOG esennnvnnnennnnnnnnnnnnnennnnsnnnnnnnnnnnnnnnnnnnnnnnnnnnennnnsnnnnnnnnnnenne 51 5L HOWTOCHANGE BATTERIES EE 51 0 2 iMOMWJIOINSPECTYOURABOBO Fiscales ld 53 9 9 GEET eebe 53 SAL MENA PAN aS 53 9 3 2 External Power SUpDply ici dis 57 5 4 MOCAP MARKER MAINTANENCE see 57 ob TNE DOSANDDON Sane 57 6 REFERENCE nn EE 59 7 TROUBLE SHOOTING iii a dA 60 Teli ERROR MESSAGES casacas 60 Fl TEA MESSE REL Emm 60 E EEDOOdES A s i o i da A a 60 7 2 FREQUENTLY ASKED QUESTIONS sessoosseeeannnnnnenenirernossernnnnnrrrrereeosssennnnnnnrrrrrrereeno 61 LittleDog Robot 1 0 User Guide List of Figures Figure 1 LittleDog System Schematic c
12. of model associated with the data B BDI t Vector of time values synchronized with data readings DI data Data array containing runtime data The size of the array is BDI rows xBDI cols Number of readings for each variable BDI cols Number of variables in data file Names and units of all variables stored in the BDI data array 4 3 3 Accessing Variable Names And Values Variable names and units are stored in the BDI data array BDI vars varnamel varname2 varnamen The name of the n variable can be obtained by entering BDl vars n name Data corresponding to this variable can be assessed by entering BDI data n 49 LittleDog Robot 1 0 User Guide 4 3 4 Sample Matlab Script Below is a sample Matlab script see sample m that asks the user for a valid data file prints key file statistics and plots a random variable from the file This example illustrates usage of the Boston Dynamics Matlab toolbox file pathname uigetfile data Select Data File if file 0 return end Read the file S BDI read file strcat pathname file II Print statistics ALSDE Spr ink VELTE statistics V A disp sprintf name file disp sprintf model name s S model disp sprintf ol varsi d Samo Mae y Jy disp sprintf of samples d S rows disp sprintf average dt d n S dt Pick a random variable nx comet maxt 1 floor ra
13. shown below We have consistently been able to get mostly excellent results if you have less than this you may want to try calibration again Status Report g Place the L Frame from your calibration toolkit into the workspace This will define your world origin so it may make some sense to align it with the orientation of one of the terrain boards h Click the Track Frame and then the Gang buttons If the world is inverted for some reason in the 3D workspace window repeat this step i Calibration is now complete Change into capture mode by pressing the button at the top of the Vicon window j Press the 38 Active biects X tab on the right hand side and make sure that the LittleDog model and any terrain board models you have in the workspace are check marked as shown below If the models are not fitting the reconstructed markers well try unloading and reloading the models by toggling the check mark Available Objects check box to make active 27 LittleDog Robot 1 0 User Guide 2 3 Kinematics Definitions and Coordinate Conventions 2 3 1 Body Coordinates X HR FR Figure 10 Body Coordinates 2 3 2 Hip and Leg Coordinate Frames Z HR HP RY X HR KNEE RY HR FOOT Figure 11 Hip Wing Coordinates Figure 12 Leg Crank Coordinates 28 LittleDog Robot 1 0 User Guide Table 1 Joint Offsets Frame Name Color Code xim Yim Zim Description FL HP AX ORANGE 0401
14. the SOFTWARE and accompanying materials and any proprietary information contained in the media are proprietary in nature and contain valuable confidential information developed or acquired at great expense You agree not to disclose to others or utilize such trade secrets or proprietary information except as provide herein 7 Enforcement of Terms If LICENSEE fails to fulfill any of its obligations under this Agreement Boston Dynamics and or its licensors may pursue all available legal remedies to enforce this Agreement and Boston Dynamics may at any time after LICENSEE s default of this Agreement terminate this Agreement and all licenses and rights granted under this Agreement LICENSEE agrees that Boston Dynamics s licensors referenced in the SOFTWARE are third party beneficiaries of this Agreement and may enforce this Agreement as it relates to their intellectual property LICENSEE further agrees that if Boston Dynamics terminates this Agreement for default LICENSEE will within ten 10 days after any such termination deliver to Boston Dynamics or render unusable all SOFTWARE originally provided hereunder and any copies thereof embodied in any medium 8 Governing Law This Agreement shall be governed by and interpreted in accordance with the laws of the Commonwealth of Massachusetts excluding its choice of law rules 9 U S GOVERNMENT PURCHASES If SOFTWARE is acquired for or on behalf of the U S Government then Lit
15. LittleDog Robot 1 0 S SOK A LA TET Boston Dynamics 4 i im LittleDog Robot 1 0 User Guide LittleDog Robot 1 0 User Guide Part No LittleDog Robot 1 0 2 User Guide Copyright 2006 Boston Dynamics LittleDog is a trademark of Boston Dynamics Boston Dynamics 515 Massachusetts Avenue Cambridge MA 02139 Telephone 617 868 5600 Fax 617 868 5907 www BostonDynamics com LittleDog Robot 1 0 User Guide LittleDog Robot 1 0 User Guide LittleDog Software License Agreement This is a legally binding agreement between you LICENSEE and Boston Dynamics with its principal place of business at 515 Massachusetts Avenue Cambridge MA Boston Dynamics By breaking the seal on the package containing the LittleDog software and or by installing and or using the software regardless of its form or the method of the recording the SOFTWARE LICENSEE is agreeing to be bound by the terms and conditions of this agreement including the software license and disclaimer of software warranty below Please read this document carefully before opening the package and or using the SOFTWARE If LICENSEE does not agree with the terms and conditions of this agreement LICENSEE should promptly return the unopened package and the SOFTWARE to the place where it was obtained and LICENSEE will be given a full refund of any license fee that LICENSEE paid 1 Grant of License Subject to the terms and conditions of this Agreemen
16. an assess performance after a trial is completed rather than watching these displayed values in real time Be aware that if the host loses communications with the robot at any point the majority of buttons will become inactive and the status display will indicate that the host is ABORTING CONNECTION This is a fatal error and the user should recover by exiting the UI via the Shut Down amp Quit button and restart the application This is an indication that the host and robot were unable to communicate for an extended period of time and that the connection between them has been terminated to force the robot into a safe state the robot eyes will turn Red 21 LittleDog Robot 1 0 User Guide 2 MoCap System The high resolution motion capture system MoCap is based on the Vicon MX system Each system consists of 6 camera like devices that are mounted around the terrain board Each camera has a strobed light source and an array sensor The robot will be instrumented with retroreflectors mounted on its body legs and feet Data from all six cameras are integrated by a tracking control unit that correlates and transforms the data and makes them available to the control system of the LittleDog robots This section will discuss the MoCap system as it applies to the LittleDog System For further information about specific components of the Vicon system including hardware and software please see the Vicon User Manual included with your s
17. ange of 13 to 20VDC Note that if the supply voltage is below 18VDC batteries in the robot will be discharged It is worth noting that desktop development of robot behaviors robot in the air on a stand can be done with an 18 VDC supply at 2 A assuming no significant external load is applied to the legs 5 4 MoCap Marker Maintanence The retroreflective markers on the body of the robot are prone to damage It is required that they protrude from the body to improve visibility to the MoCap system This means that they are often the first things to make contact with the ground during a fall resulting in damage to the marker In order to keep your MoCap system working you MUST ensure that damaged markers are replaced or repaired The markers can be repaired using small pieces if retroreflective tape if the damage is small If the marker is damaged beyond repair it will need to be replaced Extra markers were included in a small kit with your initial delivery The markers are glued on with a soft glue that can be removed simply un screw the marker from its post If you are unsure about what type of glue to use please contact Boston Dynamics When the retroreflective tape is scraped off any portion of the sphere the marker is considered damaged 5 5 The Do s and Don ts e Domake LittleDog walk over really difficult obstacles e Do inspect your robot frequently to catch minor problems before they become major ones e Do not hesitate to contact Bos
18. arge below 2 1 Amps 7800 mAh Charge below 7 8 Amps 8000 mAh Charge below at 8 Amps First Discharge Keep the flight time to 6 minute sessions with 15 minute breaks Storage amp Transportation 1 Store battery at room temperature between 40 and 80 degrees F for best results 2 Do not expose battery pack to direct sunlight heat for extended periods 3 When transporting or temporarily storing in a vehicle temperature range should be greater than 20 degrees F but no more than 150 degrees F 4 Storing battery at temperatures greater than 170 degrees F for extended periods of time more than 2 hours may cause damage to battery and possible fire Canng for Battery 1 Charge battery with good quality Lithium Polymer charger A poor quality charger can be dangerous 2 Set voltage and current correctly failure to do so can cause fire 3 Please check cell voltage after the first charge Example 1 Cell 4 2V 4 15 to 4 22 2 Cell 8 4V 8 32 to 8 44 3 Cell 12 6V 12 48 to 12 66 4 Cell 16 8V 16 64 to 16 88 5 Cell 18 5V 18 30 to 18 60 4 Do not discharge battery to a level below 3V per cell under load Deep discharge below 3V per cell can deteriorate battery performance 5 Use caution to avoid puncture of the cell Puncture of cells may cause a fire Operating Temperature Charge 32 to 113 degrees F Discharge 32 to 140 degrees F 1 Let battery cool down to an ambient temperature before charging 2 During discharge and handlin
19. ations with the robot instruct the robot to calibrate itself and finally it will sweep the joints through sinusoidal motions until the user interrupts the program by pressing control C This program does not interact with the user at all after being started so to begin with you must ensure that the robot is positioned safely on its stand Begin by placing the robot on its stand with the front legs extended forward and hind legs extended backward Be sure not to force motion of any of the joints see Figure 5 Make sure that the robot is secure and that there is clearance around the robot for the legs to swing freely Eye LEDs Figure 5 Calibration posture CAUTION Although the motions produced by this example will execute safely when the robot is on the stand most motions will not be safely executed on the stand In general it is advised that you hold the robot by its handle when initiating motion Power your LittleDog on so that the red LED in the power switch illuminates After approximately 45 seconds the eyes of the robot will turn red This indicates that the embedded software on the robot has started and that it is waiting for a connection from the host computer The LED eyes on the robot indicate status of the onboard software DARK robot off or trial running RED waiting for connection ORANGE connected to host but not calibrated GREEN calibrating or calibrated see Table 6 LittleDog Robot 1 0 User Guide At this po
20. bers of your group should be able to do with ease With very little practice you will be able to start and calibrate your system in only a few minutes by following the steps outlined below 1 Starting the System a Turn on the MoCap computer and the Vicon MX Net system the switch is on the back b On the MoCap computer start the Vicon 1Q 2 0 Software During program startup the red LED rings surrounding the camera lenses should turn off and on again after about a second c Change into setup mode by clicking the button on the upper left hand side of the Vicon 1Q window d Click the hardware configurations tab El Hardware on the right hand side and make sure that cameras 1 6 are listed on the right hand side as shown below If they are not check to make sure the system is connected properly and restart the Vicon software Device Setup Frame Rate id IP Address Reorder Cameras Heprogram Mat oam Mut om 2 Mut om 3 Mu am 4 Mu am 5 Mu amb 25 LittleDog Robot 1 0 User Guide Connect to the Vicon system by clicking the 4 icon If the system connects properly the green and blue boxes next to the camera names will turn a lighter color and the system status bar on the bottom of the Vicon window should show you have now connected If there was a problem connecting to any of the cameras the color of the boxes next to their name will not change If this happens try restarting the Vicon iQ software and cycling
21. ble hard drive accessible in the drive bay Additionally the MoCap PC is marked with a Windows XP sticker near the bottom left of the case 4 The next step is to connect it all together Place the two computers side by side with the wireless bridge and Ethernet switch stacked on top as shown in Figure 4 Using the short BLUE Ethernet patch cable connect the wireless bridge to the number 1 position on the Ethernet switch Connect the RED three foot patch from the PCI Ethernet card in the MoCap PC to position 2 on the Ethernet switch Connect the PADAKA three foot patch from the PCI Ethernet card in the Host PC to position 3 on the Ethernet switch The built in Ethernet port on the MoCap PC goes to the Vicon MXnet box the port is found on the back of the MXnet The built in Ethernet port on the Host PC goes to the outside world LittleDog Robot 1 0 User Guide 3 A E ok Vicon MXnet P 9 6 u 4 y m i Dn Figure 4 Setting up your system Next plug the KVM switch to both machines The KVM inputs go to the Monitor via the provided DVI to VGA adapters two USB ports the sound and mic located on the back of each computer The output of the KVM goes to the mouse keyboard and monitor Hook up all the power cords 5 Unpacking your Robot Please note how we have packed the robot so you can pack it the same way in the unlikely event you need to ship the robot back to us Each kit sh
22. ccccccccocccnnccnnncccconononncnnnnononnnnnnnnnnnnnnnnnannnnnnnnnnnnnnnncnnns 9 Figure 2 The LittleDog Platform E 10 Figure 3 Electrical System Lay OU stories i 11 Figure 4 Setting up your gvglem nennen nennen nnn nnns nnn nennen nnns 14 Figure 5 Calibration posture ea kaaa kaaa 17 Figure 6 Robot Zero Configuration Rostton kakaa 18 Figure 7 LittleDog walk example GU 19 Figure 8 MoCap Frame CGomponents nennen kaaa 22 Figure 9 MoCap Frame Assembly 0aaaa aaa nnne nnne nnns nn na nnne nnns 23 Figure 10 Body Coordina Susana patet a nter t jeans edad idas 28 Figure 11 Hip Wing Coordinates aaa aaa aaa 28 Figure 12 Leg Crank Cord varer eee 28 Figure 13 Body Parameters kakaa kakaa 30 Figure 14 Leg Parameters E 31 Figure 15 LittleDog API state diagram eese 33 FETE PPT VV NAG OWS santino arado eones 42 Figure 17 Battery Compartments ooooonnccnnnccccononcnnnnncnnononannnnnnnnonononnnnennnnnnnonnnannnnnnnnonenanecnnns 51 Figure 18 Battery Installation sees 52 List of Tables TENNE 29 FE JENTE 29 Table 3 Body Harameierg kaaa kaaa naka kaaa aaa kakaa kaaa aaa kakaa kaaa 30 Table A Beg Pr mii a ne 31 Table 5 Motor E an Lurer eie 59 TE ENDE 60 LittleDog Robot 1 0 User Guide LittleDog Robot 1 0 User Guide 1 LittleDog System LittleDog is a small quadruped robot for research applications LittleDog was designed to explore the fundamental relationships among motor learning dynamic co
23. d method of calibration is for the user to hold the robot by its handle when executing the calibration procedure this will ensure that the legs to not inadvertently make contact with either the stand or any other objects during the calibration process After termination of the basic program you will find a dataset file data containing the full record of robot state and commands that were sent to the robot during this trial There are three ways you can access the information contained in this file you can use BDIPlot as described in Section 4 of this manual you can use the bduDataSetFil e utility classes provided with the development kit and documented in the electronic API reference manual included with your kit see LI TTLEDOG doc ht ml index ht ml or you can load the file directly into MatLab using the tools provided in the wi n32 directory of your development kit see LI TTLEDOG wi n32 1 4 3 Running the WALK Example While the basic example provides a convenient method to verify basic functionality of LittleDog it does not afford much interaction or provide any operator feedback The walk example included with the development kit includes a graphical user interface GUI and provides a more complete example of how LittleDog can be operated This example makes use of the LittleDog reference UI this user interface system must be used with all application programs submitted for evaluation by the government test team as part of the
24. e located in LI TTLEDOG doc html index htm 7 1 2 LED Codes The LittleDog platform has two status LEDs located near the top of the robot at the front end appear as eyes as shown in The following combinations of status LEDs can provide useful information about your platforms status Table 6 Status LED Codes RIGHT Eye LEFT Eye OFF Bootine OR Trial running with no errors EAN E rr 60 LittleDog Robot 1 0 User Guide 7 2 Frequently Asked Questions At times machines do not operate the way we would like If the LittleDog System is not performing properly review possible problems and their resolutions as described below If these do not solve the problem contact Boston Dynamics through the contact information provided with your LittleDog system Can I paint or modify my robot gt No gt You may not have the same robot throughout the entire program Please insure any markings such as university stickers are non permanent I read the whole manual and I still need help gt The first place you should go is the official project website where you will find useful posting and contact instructions for reaching the correct person at Boston Dynamics LittleDog will not turn on gt Check to see if battery is charged power tether is attached gt Cycle the power switch When I cycle the power on my LittleDog sometimes it does not turn on Every now and then the power boa
25. e batteries packs in series Charge each battery pack individually Failure to do so may result in incorrect battery recognition and charging functions Overcharging may occur and fire may be the result 5 When selecting the cell count or voltage for charging purposes select the cell count and voltage as 1t appears on the battery label As a safety precaution please confirm the information printed on the battery is correct a Example The label on a 2 Cell battery pack in series will read Charge as 2 Cell 7 4V or may cause fire You must select 2 Cell for charging b Example The label on a 3 Cell battery pack in series will read Charge as 3 Cell 11 1V or may cause fire You must select 3 Cell for charging 6 Selecting a cell count other than the one printed on the battery always confirm label 15 correct can cause fire 55 LittleDog Robot 1 0 User Guide T You must check the pack voltage before charging Do not attempt to charge any pack 1f open voltage per cell is less than 3 3v Example Do not charge a 2 cell pack if below 6 6v Do not charge a 3 cell pack if below 9 9v 8 You must select the charge rate current that does not to exceed IC one times the capacity of the battery A higher setting may cause fire The below chart 15 calculated at 1 x capacity of pack Example 730 mAh Charge below 730 mA 860 mAh Charge below 860 mA 1320 mAh Charge below 1 32 Amps 1900 mAh Charge below 1 9 Amps 2100 mAh Ch
26. e first time time through printf updateControl Initializing all joints to use PD servos n float k 30 0 30 0 30 0 7 float dT e 995 106 0 6 F for int 120 I NUM LEGS I for int j 0 NUM JOI NTS j I result setJointServoType Leglndex l Jointindex j SERVO PD handle result setJointServoType result true result setjointPDServoGai ns Legl ndex l Joi ntl ndex j k j blj handle result set ointPDServoGains result true Do control for this particular timestamp float t getDataTimestamp amp t blat GAL 02 Simi SALS E o s float qu2 8 0 2 009 HA TET OZ Post q d3 SLET SNE prose gs for int 120 NUM LEGS lot Xd 9 2 qul if 1 1 1 3 xd 1 result setJointPDServoSetPoints Legl ndex l HIP RX x d handle result setJointPDServoPoints result false setJointPDServoSetPoints Leglndex l HIP RY 4 q d2 1 57 2 0 handle result setJointPDServoPoints result false setJointPDServoSetPoints Leglndex l KNEE RY 2 q d3 handle result setJointPDServoPoints result false virtual void uninitControl void FINE URI GORE OL Ceann UP sud Ap p 3 LittleDog Robot 1 0 User Guide This derived class makes use of the i ni t Control method to initialize its internal state to indicate when the first call to updateControl is made It is important to note that the ini tControl method is not allowed to co
27. ed for over which to integrate the variable By default these bounds cover the entire duration of the data Once time bounds have been entered a new variable containing the integral of the chosen variable is added to the end of the variable list Gain Click Gai n and click a variable Enter a scale factor A new variable is created Offset Click Of f set and click a variable to shift a variable up or down Enter an offset A new variable is appended to the end of the variable list Click Avg and click a variable A new variable containing the average of all values of the clicked variable is appended to the end of the variable list Abs Click Abs and click a variable to calculate the absolute value of a variable A new variable is appended to the end of the variable list Click Mag and click either two 2D or three 3D variables to calculate the magnitude of the variables The magnitude is the square root of the sum of the squares of the variables 47 LittleDog Robot 1 0 User Guide 4 3 The Boston Dynamics Matlab Toolbox If there are advanced data analysis or presentation needs that go beyond the capabilities of BDIP1ot there is a Boston Dynamics toolbox for use in Matlab This toolbox allows access to data from Boston Dynamics data files Note that Matlab and a Matlab license are required to use this toolbox 4 3 1 Installing and Running the Matlab Toolbox Install the LittleDog win32 tools as described under section 5 1 T
28. ems charging the pack You should always charge and discharge your batteries in pairs as marked 53 LittleDog Robot 1 0 User Guide CAUTION When one of these LiPol batteries fails it will swell up If a battery pack feels or looks swollen DO NOT recharge it Recharging a swollen battery pack can catch fire Contact manufacturer for proper disposal instructions Thunder Power Batteries 4720 West University Ave Las Vegas NV 89103 Phone 702 228 8883 Fax 702 228 8885 www thunderpower batteries com 5 3 1 1 Battery Safety Instructions and Warnings The following two pages contain a reference copy of the original safety and warning sheet authored and provided by Thunder Power Batteries It is identical to the one provided with your original shipment This warning sheet can also be found at http www thunderpower batteries com images THPSafetyWarnings pdf 94 LittleDog Robot 1 0 User Guide WARNING Please read before charging or using battery IMPORTANT SAFETY INSTRUCTIONS AND WARNINGS You must read these safety instructions and warnings before using or charging your batteries Lithium Polymer batteries are volatile Failure to read and follow the below instructions may result in fire personal injury and damage to property if charged or used improperly Thunder Power its distributors or retailers assume no liability for failures to comply with these warnings and safety guidelines By purchasing this battery the
29. etimes needs to be manipulated mathematically The Math controls provide this functionality Math Ops kAult Dn Add Sub erint Gain ofset Abs Mag 46 LittleDog Robot 1 0 User Guide Mathematical operations can be divided into two groups operations between two variables and operations on a single variable Mul t Di v and Add Sub both take two variables as input These functions multiply divide add and subtract one variable from another Der i v nt Gai n Offset Avg and Abs on the other hand require only a single input variable NOTE When new variables are created double check variable name before pressing Enter There is currently no way to delete a variable once it has been created Math Controls Mul t Di v Click Mul t Di v and then click two variables Select multiply or divide in the dialog The function is performed and a new variable is appended to the end of the list The default variable name is created by concatenating the two variable names separated by or Add Sub Click Add Sub and then click two variables Select add or subtract in the dialog The function is performed and a new variable is appended to the end of the list The default variable name is created by concatenating the two variable names separated by a or Deriv Int ClickDeri v I nt and click a variable Select differentiate or integrate in the dialog If Integrate is selected minimum and maximum times are ask
30. g of batteries do not exceed 160 degrees F Battery Lite Batteries that lose 20 of their capacity must be removed from service and disposed of properly Discharge the battery to 3V Cell making sure output wires are insulated then wrap battery in a bag for disposal Product Warranty Product warranty 15 limited to original defects in material and workmanship Warranty does not cover collateral damage Due to the nature and use of this product there 1s no term warranty Misuse abuse incorrect charging and other inappropriate use of this product are not covered under warranty Thunder Power Batteries 4720 West University Ave Las Vegas NV 89103 Phone 702 228 8883 Fax 702 228 8885 www thunderpower batteries com 56 LittleDog Robot 1 0 User Guide 5 3 2 External Power Supply LittleDog can be powered from an external power supply through the 16 foot power tether provided The tether can often be a time saving feature during development as it removes the time associated with charging batteries The tether can be connected or disconnected with internal battery packs installed That means if you have a fresh set of batteries in the robot and you want to do a tether less test you can simply unplug the tether without shutting down the robot The external power supply must be able to provide a nominal voltage of 18 VDC at 6 A continuous to exercise the full capabilities of the platform The robot will operate with an external supply r
31. h all future trials LD ERROR CODE initializeRobot void Initiate the communication with the robot LD ERROR CODE calibrate bool force false Initiate the robot calibration procedure Calibrate will cause the robot to move and will not return until the calibration procedure has succeeded or detected a failure If the process was successful it will be possible to now call r unTri al however if the calibration process failed it must be attempted again Unless the optional f or ce argument is set to true calibrate will return immediately if the robot has already been calibrated Iff or ce is true then calibrate will force a recalibration of the robot LD ERROR CODE runTrial void This function begins a robot trial run during which user control functions will be called and data will be collected The function will block until the trial is either stopped by calling 34 LittleDog Robot 1 0 User Guide stopRobot oraborted by calling abort Connecti on as such it is recommended that runTrial be called from a thread separate from any UI thread so that the trial can be stopped or aborted if necessary Trials can be stopped asynchronously by calling stopRobot orabortConnection WheneverrunTrial returns a new data file will be produced in the current directory that contains all the information collected during the previous trial the file includes a date stamp and performer identification in the name to uniquely indicate when
32. his will also install the Boston Dynamics Matlab toolbox in the C V Li ttl eDog mat I ab directory If LittleDog is installed in a different directory substitute the directory for C V Li ttl eDog To access the toolbox from Matlab add the C NLittleDogNmatlab directory to the Matlab path This may be done from the main Matlab window by clickingFile Set Path oratthe Matlab command prompt by entering path path C 1LittleDogl matlab It should now be possible to test the Boston Dynamics Matlab toolbox by typing sample at the Matlab prompt This will run a small program that will ask for a data file and plot a random variable from the file Open the following file C 1LittleDoglmatlablexample data BostonDynamics LittleDog data The sample script listed in Section 4 3 4 below serves as a good example of how to use the toolbox As with all Matlab functions type help scriptname to get detailed instructions on how to use the toolboxes functions All Boston Dynamics functions are prefixed by the acronym BDI A good starting point is to look at the toolboxes two key functions BDI read file and BDI get var 48 LittleDog Robot 1 0 User Guide 4 3 2 Manipulating Data in Matlab When BDIPlot opens a data file it creates a global Matlab data structure for that data file Key fields in this data structure are described below Boston Dynamics Matlab Data Structure Elements BDI fname Name of open data file BDI mode Name
33. iated with the most recent run and returns the software system to the Robot Calibrated state From this state you can safely begin another trial or exit from the example by using the Shutdown and Quit button located at the lower right corner of the window Note that the eyes will be dark during execution of a trial to avoid interference with the motion capture system 20 LittleDog Robot 1 0 User Guide 1 4 4 Notes about LittleDog operation The status displays located on the upper right side of the UI window provide a real time assessment of robot status These displays include battery voltage battery current CPU temperature and a data timestamp Battery voltage and CPU Temperature will both change color to warn the operator of critical situations over temperature for the CPU or low battery voltage The battery current allows the user to assess overall performance typical hotel load from the electronics is approximately 0 5A typical operation will draw 3 4A the absolute maximum draw for the platform is 12 5A and should not be seen in operation The timestamp provides a crude indication of communications status between the robot and host When the two are communicating the timestamp will increase regularly if communications are dropped the timestamp may freeze and jump forward as communications are recovered Note that all of these values are recorded in the data set associated with a trial whenever a trial is running so users c
34. int you can execute basi c on the host computer to cause LittleDog to run through the basic motion sequence The sequence of execution for this program is as follows e Host connects to the Vicon motion capture system e Host connects to LittleDog eyes turn yellow orange e Host calibrates the joints of the robot eyes turn green l 2 35 4 knees fold up hips rx rotate down hips ry rotate up the robot unfolds itself to its zero configuration with the legs extended straight down below the robot with both the upper and lower legs perpendicular to the ground see Figure 6 e The host commands sinusoidal motion to all the joints on LittleDog eyes go dark Figure 6 Robot Zero Configuration Position This program can be terminated at any time by pressing control C on the host computer eyes turn red again indicating that the robot is waiting for a new connection If the basic example encounters any errors it will display an error message and if the error prevents further operation the program will exit Typical errors include incorrect IP address settings in your bdi rt cfg file or problems with calibration due to the robot being unable to complete motions It is important that the legs be free of any obstacles during the calibration process as the robot detects 18 LittleDog Robot 1 0 User Guide motor stall in order to align the encoders and any external obstacles may cause this process to fail The preferre
35. ion or exclusion of liability for incidental or consequential damages or allow the exclusion of implied warranties so the limitation and exclusion above may not apply to LICENSEE and LICENSEE may have other rights that vary from state territory or principality to state territory or principality LittleDog Robot 1 0 User Guide Table of Contents 1 UTILEDOG SYSTEM curia 8 FEE ES EEE 9 1 2 PLATFORM SPECIFICATIONS src 10 1 21 MEGA OVE oeste ido 10 1 2 2 Electrical Overview ooccccccconccnnccoconnonncnononnonnnnonnnnnnnononnnnnnnononnnnnnnnnnnnrnnnnnnnanennnnss 10 LS GEMTNESTARJED andina 11 CS FACING LIS pe a 11 1 3 2 Setting Up the System aeri ninni ace io oce intro Fendt serius 12 1 4 RUNNING THE ROBOT FOR THE FIRST TIME 16 1 4 1 Installing LittleDog Software kakaa 16 1 4 2 Running the BASIC Exvample esses 17 1 4 8 Running the WALK Evampie aa 19 1 4 4 Notes about LittleDog operaton aaa aaa aaa 21 2 MOCAP SYSTEM sosa 2 oo jede je EE 22 est SETE 22 CN E METTE red 22 2 1 2 Vicon System Configuration saciar 24 ze CT Ne Na i o adi E E ee E o 24 2 2 1 Quick and Dirty System Startup amp CGalbraton kakaa 25 2 3 KINEMATICS DEFINITIONS AND COORDINATE CONVENTIONS aaa nakaaa kaaa kaaa 28 Body Coordinates TEE ITE A 28 2 3 2 Hip and Leg Coordinate Frames kaaa 28 3 SOFTWARE sre esa UU C 32 Sul WORKING WITH THE AP ponete nda 32 22 SEE ep o iju ada godinom 34 So TREBASICEXAMPLE eens eee nae osle a skih elek se i
36. ll other warranties express implied or otherwise including without limitation any warranty of merchantability or fitness for a particular purpose 12 LIMITATION OF LIABILITY IN NO EVENT SHALL Boston Dynamics OR ITS LICENSORS BE LIABLE TO LICENSEE FOR ANY SPECIAL CONSEQUENTIAL INCIDENTAL OR INDIRECT DAMAGES OF ANY KIND INCLUDING WITHOUT LIMITATION THE COST OF COVER DAMAGES ARISING FROM LOSS OF DATA USE PROFITS OR GOODWILL OR PROPERTY DAMAGE WHETHER OR NOT BOSTON DYNAMICS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH LOSS HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY ARISING OUT OF THIS AGREEMENT THESE LIMITATIONS SHALL APPLY NOTWITHSTANDING THE FAILURE OF ESSENTIAL PURPOSE OF ANY LIMITED REMEDY BOSTON DYNAMICS s LIABILITY ARISING OUT OF THIS SOFTWARE LICENSE AGREEMENT AND OR LICENSEE S USE OR POSSESSION OF THE SOFTWARE INCLUDING WITHOUT LIMITATION ANY AND ALL CLAIMS COMBINED WILL NOT EXCEED THE AMOUNT OF THE LICENSE FEE LICENSEE PAID FOR THE SOFTWARE PROVIDED UNDER THIS AGREEMENT 13 Laws Governing Warranties and Liability The law s of a jurisdiction may define the scope of warranty to be provided for products or the manner in which a supplier s liability may be limited and such law s shall govern this Agreement only to the extent a party protected by such law s cannot waive the protection thereof by contract In the U S and other countries some states territories or other principalities do not allow the limitat
37. lt true i static void handle result const char func LD ERROR CODE result bool exit on error l if an error occurs print it out and optionally exit if result LD OKAY return printf An error occurred calling s nitError was s n func dog getErrorCodeString result if exit_on_error exit EXI T_FAILURE 38 LittleDog Robot 1 0 User Guide 3 4 Building Your First LittleDog Behavior A skeleton application for controlling LittleDog has been provided as part of the development kit Under LI TTLEDOG examples there is a directory named mi ni mum ui example This directory contains a system that uses the same interface as the walk example discussed in Section 1 4 3 but issues no commands to the robot To facilitate testing and system control by the government testing group all performers in the Learning Locomotion program will be required to use an interface that includes this basic functionality so we strongly suggest that you begin developing all applications using this skeleton Simple behaviors can quickly be developed by copying this entire directory and editing the MyLi tt eDog cpp file to issue the desired commands to the robot Note that included with the example is a README t xt file which explains the key components of the system 3 5 Contents of a LittleDog Data Set Whenever a trial is terminated typically by a call tostopTrial the LittleDog system will save a data set file
38. lumn of plots shows data for the entire simulation The right column shows close ups of portions of the same data Plots can be vertically scaled depending on the level of detail required The left and right plots in a single row are always shown with the same scale Several variables may be plotted concurrently in the same row The vertical red line shown in all the plots referred to as the Data Cursor indicates the current location in the data The current value of all traces at the cursor position is always displayed on the top left of each plot Note on plotting variables from multiple files of different lengths If more than one data file at a time is open and one of the data files 1s shorter than the other the last value of every variable in the shorter file is used for any comparisons with later data in the longer file 43 LittleDog Robot 1 0 User Guide 4 2 3 Command Window The Command Window displays controls that are used to alter the view of data plotted in the Data window A menu at the top of the Command Window provides access to file and window functions Functions are grouped into three categories Plot View and Math Several plot features can be controlled by using the buttons in the View and Plot sections in the Command Window This includes adding and removing plots clearing plots scaling plots and zooming in and out Time and tick index number corresponding to the cursor position are shown below the control buttons
39. m Finally you must edit your performer specific configuration file To do this change directory to LITTLEDOG config then copy bdi rt DEFAULT cfg to bdi rt cfg and open bdi rt cfg inan editor You must ensure that the IP address for the robot is set correctly in this file it will be of the form 10 66 68 xxx where xxx is the number indicated on the back of your robots CF disk and that your performer id as specified by the Government test group is set correctly in the performer field near the bottom of this file 16 LittleDog Robot 1 0 User Guide 1 4 2 Running the BASIC Example If your motion capture system is available for use we suggest that you perform the calibration and setup procedures associated with it prior to running this example Performing the calibration and setup will give you experience with the entire LittleDog system through this example and will generate data files that include motion capture information Refer to Section 2 2 for instruction on setup and calibration of the motion capture system With your LittleDog developers kit installed as described above you can now change directory to LI TTLEDOG examples basi c You can build the basic example by executing gmake basi c pro and then make Confirm that both commands complete and that there are no errors reported by either The entire program for this example is contained in mai n cpp This program will connect to the motion capture system initiate communic
40. mity Sta EE CORE686 Leg x4 Sialis Touchdown Sensor bl LEDs Force Measurment VGA RS232 Analog Keyboard LEGEND y USB Digital 1 0 Ethernet User Accesable Figure 3 Electrical System Layout 1 3 Getting Started 1 3 1 Packing List e One HOST PC with Linux installed e One MoCap PC with Windows XP installed this box also includes o One KVM keyboard video and mouse switch o One Keyboard o One Mouse o Fourcolor coded Ethernet cables o Linksys Wireless Bridge o Linksys Ethernet Switch e One LCD Monitor LittleDog Robot 1 0 User Guide e One Vicon MoCap System including o Six Vicon MX40 4Mpixel Cameras with strobes and lenses o Six 50m camera cables o One Vicon MXNet interface box o One calibration kit o One sample general purpose marker kit not used in the LittleDog System o Software already installed on your computer license dongles and Vicon manual e One LittleDog Robot Shipping Case o One LittleDog robot o Two sets of battery chargers with power supplies o Six LiPol battery packs o One robot stand o One small spare kit 2 MoCap markers 1 thumb screw spare antenna o One User Manual 1 3 2 Setting Up the System Please take the time to carefully read the instructions provided on how to unpack assemble and run your LittleDog Robot System It may take several hours to set up and up to four people during parts of the MoCap frame assembly as described later in Section 2 1 1 1
41. nd S n_ vars Se vers name horzcat S vars inx name If we don t know the index we can search by name i data BDI get var S name Otherwise we can just grab the data by index DE Sete STN LE Add some labels xlabel t J ylabel name title sprintf t vs s name 50 LittleDog Robot 1 0 User Guide 5 Maintaining Your LittleDog The key to keeping your LittleDog happy is to pay attention to wear and tear The sooner you catch problems or wearing components the more likely it can be repaired with minimum down time The following section covers some of the major maintenance items Recognizing when your LittleDog s behavior changes is the best way to catch problems Section 5 2 covers the basic things to watch for such as sloppy or stiff Joints loose fasteners etc 5 1 How to change batteries There are two battery compartments in each LittleDog robot They are located on the right and left side of the body as shown in Figure 17 The door on the battery compartment can be removed by loosening the thumb screw and tilting the door up starting at the bottom of the robot The following page describes the sequence used to exchange the batteries Figure 17 Battery Compartments CAUTION Do not over tighten the thumb screw as this may damage the insert in the plastic shell and prevent installing the battery door in the future 91 LittleDog Robot 1 0 User Guide Removing the Batte
42. ntrol perception of the environment and rough terrain locomotion LittleDog has four legs each powered by three electric motors The legs have a large range of motion and workspace The motors are strong enough for dynamic locomotion including climbing There is an onboard computer that performs sensing actuator control and communications tasks LittleDog s sensors measure joint angles body orientation and foot ground contact Onboard lithium polymer batteries allow for approximately 30 minutes of continuous operation without recharging Tethered power operation is available to extend operation time during development LittleDog comes with a set of software control utilities that are accessed through the LittleDog API User developed control programs run on the Host computer and communicate with the robot over a wireless link to support remote operation and analysis A motion tracking system provides real time measurement of the robot s body and limb locations in the test environment The motion tracking system is based on a high precision Vicon motion capture MoCap system The MoCap system uses specialized cameras special light sources and retroreflective markers on the robot to report accurate positions of the robot and terrain This information is then processed into parameters such as joint angles body posture and terrain location and made available to the user through the Robot API LittleDog Robot 1 0 User Guide 1 1 System Overview
43. ntrol settings or parameters on the robot thus it is the responsibility of the updat eControl method to make these settings the first time it is called As you can see UupdateControl deals with these first time issues then goes on to issue commands to the robot In this example all the joints are set to perform PD control with moderate gain settings and the PD servos associated with each joint are sent sinusoidal position commands as time progresses Finally the example program includes a signal handler and error handler that are shown below The signal handler is used to catch Sl GI NT generated by a user pressing control C and to call the stopRobot method of the MyLittleDog object which causes motion to stop and runTrial to return The error handler simply prints the appropriate text error message associated with a returned error code and exits or returns static void signal handler int printf Stopping control process n fflush stdout this will stop initializeRobot calibrate or runTrial ll in their tracks not immediately but quickly this won t affect initializeMocap but abortConnection would stopRobot and abortConnection can be called nearly anywhere and return immediately Do not delete dog right here One could delete it after initializeRobot calibrate or runTrial returns however LD ERROR CODE result result dog gt stopRobot handle result stopRobot resu
44. obot 1 0 User Guide Table 3 Body Parameters Property Value Unit Description o Mass 2240 g Body massw Batey gt Length Total body length 304 Total body length 116 180 Total body width body plus hips Total body height Hip separation width symmetrical about center Luip XZ CG Width Lup Wu Length Figure 13 Body Parameters 30 LittleDog Robot 1 0 User Guide Table 4 Leg Parameters Property Value Unit Description Mass 1190 g Leg Mass 177 8 mm Total leg length Upper Leg Length Xorrser 21 mm Lower leg length 102 7 mm Lower Leg Length FSperecnon 2 mm Max Force Sensor Deflection Extended Zero Position Retracted Lup XorrsET Figure 14 Leg Parameters 31 LittleDog Robot 1 0 User Guide 3 Software Control of LittleDog is divided between an embedded computer in the robot and software running on the Host computer The LittleDog onboard computer performs the following functions e reads calibrates and filters the robot s sensors e writes to actuators e servos individual joints e communicates with the host computers The onboard software is divided into two layers The servo layer samples and filters data for each sensor and performs joint level servo functions every 2 millisecond 500 hz The communication layer supports communications between LittleDog and the Host computer reporting sensor
45. ould contain the items listed in the Packing List Section 1 3 1 LittleDog Robot 1 0 User Guide 6 Install a fresh set of batteries or connect the external power tether For information on how to charge and install your batteries see Section 5 OPTIONAL setting up an external power supply see Section 5 3 2 7 You are ready to install the Robot API and power up your system Please read Section 1 4 to get started using your system LittleDog Robot 1 0 User Guide 1 4 Running the Robot for the First Time Prior to operating your LittleDog robot for the first time there are administrative tasks you must perform to properly configure your robot system We suggest that you change the root password on your host computer system from the default value it was shipped with After changing your root password you must contact both Boston Dynamics at littledog BostonDynamics com and the Learning Locomotion Government test group to inform them of your new root password This is critical for testing that will be performed by the test group and will allow Boston Dynamics remote access to your host computer to provide remote diagnosis and support if you encounter any problems with your system Next create a new user account using us er add on your Host computer linux that you will use for doing LittleDog software development Finally you should log in to the host computer using this newly created account 1 4 1 Installing LittleDog Softwa
46. our system In the directory SLITTLEDOQG vicon files on the host computer there are four files that must be copied to the Vicon motion capture PC The files and where they should be copied to are e littledog vsk e terrainA vsk e terrainB vsk e RTEparams 001 rtp 2 2 Calibration A detailed description of how to calibrate your MoCap system can be found in the Vicon documentation located in C Program Files Vicon Documentation Books Foundation Guides Vicon Manual preparation_v1_2 pdf Groups should calibrate typically at least once every day they are using the motion capture system Additionally if the motion capture frame is jarred or hit by persons or objects the cameras may move slightly and your system performance will suffer if the system is not recalibrated The motion capture workspace is small and calibrating takes less than 5 minutes so groups should calibrate whenever necessary to maintain peak system performance 24 LittleDog Robot 1 0 User Guide When should you recalibrate the system 1 Atthe beginning of every test day 2 If markers oscillate in the Vicon 3D workspace window 3 Ifa particular camera has a large percentage of unassigned rays as shown by the white ray in the 3D workspace window 4 If there are multiple reconstructions of a single marker appearing in the 3D workspace window 2 2 1 Quick and Dirty System Startup amp Calibration System calibration is a quick and painless procedure that all mem
47. rd will latch off just try turning the switch to the off position and back again I own more than one LittleDog robot can I operate them simultaneously No your HOST machines have been configured to talk to one robot at a time LittleDog s onboard IMU accurately tracks body position and orientation at the beginning of an experimental run but after awhile the values drift why gt The IMU contains accelerometers which integrate acceleration to compute body position and orientation Over time small errors in the detected acceleration will accumulate and yield an inaccurate position reading The IMU data is only valid for short periods of time 61 R y A 1 515 Massachusetts Avenue Cambridge MA 02139 USA 617 868 5600 www BostonDynamics com
48. re Copy or download the LittleDog API software development kit to your home directory either from the CD provided with this manual or from the address given to you at the LittleDog training session Uncompress and untar the kit in your home directory this will create a directory named Littl eDogAPI 1 0 0 which contains all the software tools associated with operating and analyzing data from the robot A subdirectory titled Wi n 32 contains a zip file which includes a set of plotting and data analysis tools that you can install on a Windows PC see the README t xt file included there for details To successfully build and run the example applications for LittleDog you must set two environment variables LITTLEDOG LittleDogAPI 10 0 QTDIR usr lib qt 3 3 You can now change your working directory to LI TTLEDOG and finish configuring your Host control environment Optionally at this point you can also complete configuration of your Vicon motion capture system if it is currently set up To do this you should refer to the README t xt file contained in LI TTLEDOG vi con files as well as the instructions contained in Section 2 1 2 of this manual This directory contains the current Vicon models for the LittleDog robot and the currently deployed terrain boards and they must be placed on the motion capture control PC as described in Section 2 of this manual in order for the motion capture system to function with the LittleDog control syste
49. robot and initiate a trial The listing for this procedure follows static MyLittleDog dog NULL int main int argc char argv signal SIGINT signal handler MyLittleDog dog 61 bool forced false l pass in f if you want to force calibration always if farge 2 amp amp strcmp argv 1 f forced true LD ERROR CODE result printf Connecting to Mocap n result l initializeMocap handle result initializeMocap result false ANETT Cannet trng FE RODOVE xe ys result TpnitiabrzeRoboti handle result initializeRobot result true printf s calibration of robot n forced Forced Non forced result l calibrate forced handle result calibrate result true DLIDEDU Starting us el CONE FO coli I result l runfrial handle result runtrial result true printf Exiting main n fflush stdout return 0 36 LittleDog Robot 1 0 User Guide The heart of the control for this example is contained in the updat eControl method of the derived My Li t t I eDog object class MyLittleDog public LittleDog public bool first ti me virtual bool initControl void printf initControl called n first time true return true tells the caller that we are ok virtual void updateControl void LD ERROR CODE result one time only if first time first time false Initialize the PD servos th
50. robot and operate at a sampling frequency of 500Hz A complete log of all robot state motion capture data and robot commands is collected on the Host computer whenever an experimental trial is performed with the LittleDog system LittleDog Robot 1 0 User Guide 1 2 Platform Specifications 1 2 1 Mechanical Overview Body Dimensions 340 x 180 x 143 mm Ground Clearance 120 mm Leg Length 180 mm Total Weight 3 kg LittleDog has twelve actuated degrees of freedom each powered by an electric motor with position sensing encoder Each leg also has a single axis force sensor in the lower leg capable of detecting touchdown events and measuring approximate lower leg axial forces Detailed parameters and kinematics information can be found in Section 2 3 Figure 2 The LittleDog Platform 1 2 2 Electrical Overview LittleDog s electronics includes the following e x86 architecture 266 MHz CPU with 128MB RAM e Mini PCI bus hosting onboard 802 11b wireless Ethernet card e Platform I O Support Power MEMS IMU angles rates linear accelerations Proximity Sensor e Power Source 2 1 Ah 14 8V LiPol 4 cells in series Optional external tethered power LittleDog Robot 1 0 User Guide Battery Packs 2 Battery Motor 1 o 14 8V Protection External Power Supply 18V Motor 12 Proxi
51. ry 1 Once the battery compartment is open you can lift the battery out of the compartment 2 To disconnect press on the connectors release tab and the white connectors will separate as shown in Figure 18 A WARNING Do not pull on the connectors without releasing the latch Installing the Battery 1 Connect the two mating connectors before installing battery Place the battery in the compartment insuring the leads coming from the battery pack are pointing down as shown in Figure 18 B Insert the battery door ensure the tabs engage at the top of the compartment Tilt the battery door down as shown in Figure 18 C insuring the red and black battery wires do not get pinched under the edge of the door A C Figure 18 Battery Installation 92 LittleDog Robot 1 0 User Guide 5 2 How to inspect your robot There are several items that should be checked on a regular basis to ensure the healthy operation of your LittleDog e Check to ensure the CF disk is properly seated e Check the MoCap markers for damage see Section 5 4 for more information e Check the battery connectors and wires on both the robot and battery packs for wear e Check the condition of the tether to ensure there is no wear that could cause a short and damage the system e Check the measurement range of the leg force sensors e Check the wear of the rubber feet These can be replaced as required by simply cu
52. sers can use the utility class bduLog to report messages to this text box To operate the example begin by pressing the button labeled Connect to Mocap System This is an optional step but will enable you to collect information from the motion capture system during your trial presuming that the motion capture system is properly set up and running Next you can press the Connect to Robot button this will initiate communications between the robot and the host computer Note both how the central display indicators change to indicate the current state of the robot system and that after connecting to the robot the status displays on the right side of the window actively report the health of the robot as shown in Figure 7 At this point the robots eyes should have changed from Red to Orange indicating that the host is successfully connected to and communicating with the robot Much like what happened automatically in the previous example we can now go through the calibration process Calibrate the robot by pressing the Calibrate Robot button This will present you with a small dialog box asking you to confirm the current posture of the robot adjust the robot to match the posture shown in the picture front legs stretched forward rear legs stretched backwards If you are using the stand be sure that the robot is positioned squarely on its stand and press OK to initiate joint calibration of the robot During the calibration proce
53. ss the robots eyes change from Orange to Green to indicate that calibration is in process At the end of the calibration process the eyes will stay Green to indicate successful calibration or return to orange to indicate that calibration failed NOTE If you have previously calibrated the robot since powering it on calibration is optional as the robot will remember the prior joint calibration parameters At this point you should note the state of the system as reported by the middle section of the UI indicates that the robot is calibrated You should also visually confirm that the robot is in a standing zero configuration posture all four legs extended perpendicular to the ground if this is not the case you should reposition the legs to be outstretched and execute the calibration procedure again You can now lift the robot by the handle and press the button labeled Run Trial to initiate a trial Be aware that there is no active control of the robot joints prior to pressing Run Trial so the robot will be limp when you pick it up off of the stand As soon as the trial begins execution the robot will begin performing a kinematic walk behavior At any time while LittleDog is moving either during a trial or during calibration the large red Stop Robot button is active and can be pressed to stop motion of LittleDog Using the Stop button during a trial results in the LittleDog software finalizing the data sets assoc
54. st window does not appear until a data file is opened 41 LittleDog Robot 1 0 User Guide BDIPlot Variable List back_angle_start ankle offset ankle offset r toe clearance in start lean k knee lean k ankle lean b ankle lean set knee lean set ankle freefall k knee freefall b knee freefall k ankle freefall b ankle h base f a base pelvis f x h base f a base pelvis f y b base f a base pelvis f z h base fa base pelvis t x h base f a base pelvis t y b base f a base pelvis t z h base f a base pelvis poa h base f a base pelvis poa b base f a base pelvis poa a back torso zb base ff y a back torso a back torso a back torso a back torso a back torso a back torso h base fif x h base fif z b base fit x h base fit y h base fit z b base f poa x Fb bose basene r rg ket r poa z 0250 a back torso b base f poa y pna e a back torso hb base f poa z sweep span left sweep span right sweep time left sweep time right sweep rate left zi a back torso h base fifa b base f a back torso f x h base f a back torsozf y h base f a back torso f z b hase_fa back_torso t_x h base fia back torso t y h base f a back torso t z F2 pbech hane b bata Fd QUOD sweep rate right v b base f a back torso poa X Close File Close File Variable List Window Data Window BDIPlot Command E OE x File Window View Autoscale Hescale Smallscale Zoom In oom Ou
55. t Plot Clear Clear Last Clear All Phase Po Add Delete Math Ops Mult Di Add Sub D ernv lnt Gain Offset Abs Mag Simalass Controls localhost Connect 000005 Cycle Speed time 2 0370 tick 2037 step 10 Command Window Figure 16 BDIPlot Windows 42 LittleDog Robot 1 0 User Guide 4 2 1 Variable List Window The Variable List window contains the list of recorded variables for each data file that is loaded This window does not appear until a data file is opened A data file can be opened by using the Command window s Fi e Open menu item see the Command Window section below The orange bar at the top of the Variable List window displays the name s of the open data file s Along the bottom of the Variable List window are three buttons Close File Closes the data file associated with the Variable List Load Plot Loads a saved list of plots Save Plot Saves the current plots including scales and number of plots This can save plots from only a single data file at a time To plot a variable in the Data window 1 Click a variable in the Variable List 2 Click a plot row in the Data window There is currently no way to delete variables 4 2 2 Data Window The Data window displays plots of variables against time Time is on the horizontal axis and variable values are on the vertical axis By default there are five plots in the Data window The left co
56. t Boston Dynamics hereby grants to LICENSEE a non transferable and non exclusive right to use and execute the SOFTWARE on a single computer system at one time LICENSEE agrees that it will not reverse engineer decompile or disassemble any portion of the SOFTWARE nor extract data of any kind from the SOFTWARE f LICENSEE disposes of any media or apparatus containing SOFTWARE LICENSEE will ensure that it has completely erased or otherwise destroyed any SOFTWARE contained on such media or stored in such apparatus LICENSEE may not distribute lease transfer export loan or otherwise convey the SOFTWARE or any portion thereof to anyone 2 Copying Restrictions In order to effect LICENSEE s license rights hereunder it may install the SOFTWARE by copying it onto the hard disk drive or into the CPU memory of a computer system for use thereon and may make full or partial copies of the SOFTWARE but only as necessary for backup or archival purposes LICENSEE agrees that i LICENSEE s use and possession of such copies shall be solely under the terms and conditions of this Agreement and ii LICENSEE shall place the same proprietary and copyright notices and legends on all such copies as included by Boston Dynamics on the media containing the authorized copy of the SOFTWARE originally provided by Boston Dynamics 3 Ownership LICENSEE agrees and acknowledges that Boston Dynamics transfers no ownership interest in the SOFTWARE in the intellec
57. the power to the Vicon MX Net system Ma System HealTime Connected Connected 2 Calibrating the System a Change into calibration mode my by clicking the button on the upper left hand side of the Vicon window On the right hand side of the Vicon window make sure the 120 mm Wand and the Ergo_9mm_LFrame are selected for the Wand and LFrame respectively Click the sa tab at the top of the Vicon window and select cameras 1 6 while pressing the Ctrl key You should see the output of each of the six cameras in the center of the Vicon window Make sure there are no reflective objects in the motion capture workspace Remove the robot and cover any terrain board markers with a dark piece of fabric Press the SetwanaWaw JN button on the upper right hand side and begin the wand wave It is important to cover the entire motion capture space a few times with wand Make an effort to keep out of the view of the cameras when waving the wand While waving the wand a rainbow pattern signifying the wand will appear in the each of the six camera views Make sure to get good coverage in each of the six cameras as shown below Camera 1 MXA 26 LittleDog Robot 1 0 User Guide f Press the button to start the camera position fitting iterations this should take about a minute and you will see the status on the bottom of Vicon window When calibration is finished the quality of calibration is displayed in the status window as
58. the trial was performed Multiple trials can be run during a session that is to say runTrial can be called multiple times before the LittleDog object is destroyed LD ERROR CODE stopRobot void Stop current operation being performed on robot This is valid either when the robot is in the process of calibrating or if a trial is currently being run on the robot Calling st opRobot either from within a users updateControl method or from some other thread is the preferred way to stop robot operation There are three virtual methods defined in the LittleDog base class A derived class that intends to control the robot must implement the updat eControl method and may optionally implement both initControl and uninitControl When a trial is executing in response to runTrial having been called a users updateControl method will be invoked approximately every 10 msec in response to the host computer receiving state information from the robot The users implementation of updat eControl has complete access to this information as well as information from the motion capture system through the variety of get set methods provided by the LittleDog base class and may make use of all of those functions to implement behavior on the robot Programmers are advised to be sensitive to the amount of time it takes for them to return from acalltoupdateControl ll as if it takes longer than 10 msec to complete they will miss data from the robot altho
59. timespan displayed in the right hand column of the Data window Zoom Out Click Zoom Out to increase the timespan in the right hand column of the Data window 45 LittleDog Robot 1 0 User Guide 4 2 3 2 Using Plot Controls Plot controls perform general purpose plotting functions Plot Clear Clear Last Clear All Phase Plot Add Delete Clear Clear Last andClear All remove data traces from plots Phase Plot plots two variables against one another Add and Del et e increases or decreases the number of plots in the Data window Plot Controls Click Cl ear and click a plot to remove all variables Clear Last ClickClear Last andclick a plot from which to remove the most recently added plot variable If only one variable is being displayed Clear Last clears the plot Clear All Removes all variables from all plots Phase Plot ClickPhase Plot and then click two variables A figure is displayed that plots the variables with respect to each other The first variable is plotted along the horizontal axis and the second is plotted along the vertical axis To set the start and end points of both axes slide the control at the top of the Data window Add Click Add or Del ete to increase or decrease the number of plots Delete displayed Select whether you want the plot to be added to or removed from the top or the bottom of the Data window 4 2 3 3 Using Math Controls To perform data analysis data som
60. tleDog data can be imported directly into Matlab for customized analysis using the Boston Dynamics Matlab toolbox In BDIPlot data can be displayed in two ways e as graphs of variables over time and e as graphs of one variable plotted against another phase plots BDIP1ot can plot variables from multiple datafiles at the same time so that data from multiple trials can be compared side by side BDIP1ot supports data manipulation functions including multiplication division integration differentiation scaling and shifting functions 4 1 Installing BDIPlot To install BDIP1ot unzip the file LittleDog win32 tools zip located in the win32 directory of the LittleDog software distribution into an installation directory The rest of this document will assume that the installation directory is C Li ttl eDog If BDIPlot is installed in a different directory substitute the true installation directory for C Li ttl eDog in the rest of this document The directory bdi pl ot will contain the BDIP1ot program The directory mat ab will contain the Boston Dynamics Matlab toolbox which is described in section 5 3 4 2 Running BDIPlot To start BDIPlot go to the C LittleDog bdi plot directory and run the file BDIPlot Launch cmd This command script makes a number of settings to the environment before executing bdi pl ot exe BDIPlot has three windows a Variable List a Data window and a Command window Note that the Variable Li
61. tleDog Robot 1 0 User Guide a It is recognized and agreed that SOFTWARE contains commercial computer software as that term is used in FAR Parts 12 and 27 4 and any applicable agency supplements thereto and DFARS Parts 211 70 227 4 OCT 1988 227 71 JUN 1995 and 227 72 JUN 1995 b If this purchase is subject to FAR Part 27 and FAR 52 227 19 has been incorporated into the terms of this purchase the Government s rights in the SOFTWARE are no greater than RESTRICTED RIGHTS as specified in FAR 52 227 19 c If this purchase is subject to DFARS Part 227 OCT 1988 the Government s rights in the SOFTWARE are no greater than RESTRICTED RIGHTS as specified in DFARS 252 227 7013 c 1 i d The Government s rights in the SOFTWARE are no greater than the rights expressly stated in the body of this Standard Licensing Agreement if this purchase is subject to i FAR Part 12 ii FAR Part 27 and FAR 52 227 19 has not been incorporated into the terms of this purchase ili DFARS Part 211 70 iv DFARS Parts 227 71 and 227 72 JUN 1995 or v any other regulation or clause permitting the contractor to deliver commercial computer software under the contractor s standard commercial license e Any related technical data shall be delivered to the Government with no more than limited rights 10 DISCLAIMER OF SOFTWARE WARRANTY Boston Dynamics PROVIDES THE SOFTWARE TO LICENSEE AS 15 AND WITHOUT WARRANTY OF ANY KIND EXPRESS
62. ton Dynamics if you suspect something is wrong with your LittleDog system email littledog BostonDynamics com e Dobe careful with your robot When it breaks you may lose valuable research time e Do write all code that is to be delivered to the Government Test Team compatible with the provided UI e Don t drop your LittleDog or handle it roughly the joint stops are designed to handle forces generated by the motors e Don t force joints that feel jammed The human body is much stronger than the small motors and gears and you can break things with enough force Attempt to wiggle the joint back and forth until it moves smoothly again 57 LittleDog Robot 1 0 User Guide e Don t run LittleDog on its stand as the stand may inhibit the range of motion of the legs and the robot may damage itself 58 LittleDog Robot 1 0 User Guide 6 Reference Table 5 Motor Parameters Property Value Unit Description Hip Torque Const 1 703 Transmission Scaled Motor Constant Hip Motor Current Limit Maximum Motor Current Knee Torque Const 1 022 Transmission Scaled Motor Constant Knee Motor Current Limit ue A Maximum Motor Current 99 LittleDog Robot 1 0 User Guide 7 Trouble Shooting 7 1 Error Messages 7 1 1 Text Messages The text error messages that are returned by the API are fairly descriptive Additional information may be found in the electronic reference manual provided with the LittleDog softwar
63. tting off the old ones and gluing new ones on More feet can be obtained from Boston Dynamics e Inspect the antennas for wear They can get caught in legs or be damaged during a fall 5 3 Power Source The LittleDog platform can be powered either by a pair of internal batteries or an external power supply through a 16 foot tether The following two sections describe how to use the batteries or external power supply 5 3 1 Internal Batteries The internal batteries are 2100mAh LiPol batteries that can be charged with the chargers provided or any correctly configured LiPol capable battery charger Access to the batteries is in the midsection of the platform on the left and right sides as shown in Section 5 1 WARNING Read charging instructions provided with TP 425 charger and on the following two pages carefully prior to charging the batteries Please set up your charger to charge 2 cells This is done by pressing the CELL button until an LED is illuminated beside the 2CL mark on the charger You also need to set the current limit during recharge This is done by pressing the CURRENT button until an LED is illuminated beside the 2 0A mark on the charger This 2 0A charge rate is the highest recommended for these batteries It is very important to monitor the health of your battery packs From time to time prior to charging measure the voltage of each battery pack If the value is less than 6 25V under load you may have probl
64. ttleDog and the motion capture system and save it to a local file 32 LittleDog Robot 1 0 User Guide The primary interface between a user and the LittleDog API is through the Li ttl eDog class A control program must be subclassed from LittleDog and must implement an updateControl method Once an object of a Li ttl eDog subclass is created there is a specific progression of states the system must proceed through to run trials Developers should refer to the electronic reference manual included with the software distribution for a detailed description of the methods provided by this base class L TTLEDOG doc html index html Mocap Initialized Robot Initialized Calibrating Robot Calibrated Trial Running Figure 15 LittleDog API state diagram A typical session would proceed as follows e user creates My Li t t I eDog object e user optionally callsi ni ti al i zeMocap to setup host vicon communications e usercallsi niti al i zeRobot tosetup host robot communications e usercallscal i brate e usercallsrunTri al o LittleDog calls virtuali ni t Control once o LittleDog makes multiple calls to virtual updat eControl user calls stopRobot from within updateControl or in response to button click in UI thread o LittleDog calls virtual uni ni t Control once user destroys My Li t t I eDog object 33 LittleDog Robot 1 0 User Guide The call toi niti ali zeMocap is optional and onl
65. tual property in SOFTWARE nor in any SOFTWARE copy to LICENSEE under this Agreement or otherwise and that Boston Dynamics and its licensors reserve all rights not expressly granted hereunder After LICENSEE pays any applicable license fees LICENSEE will own the media on which the SOFTWARE was originally provided hereunder and on which LICENSEE subsequently copies the SOFTWARE but Boston Dynamics and its licensors shall retain ownership of all SOFTWARE and copies of the SOFTWARE or portions thereof embodied in or on any media 4 Transfer Restrictions LICENSEE may not sublicense transfer or assign this Agreement or any rights or obligations under this Agreement in whole or in part 5 Export Restrictions LICENSEE agrees not to export or re export directly or indirectly from the United States through any country or to any country of ultimate destination defined by the United States Government or any agency thereof as an Excluded Territory LICENSEE will not export directly or indirectly the Licensed Programs or Documentation to any country from which the United States Government or any agency thereof requires an export license or other governmental approval at the time of export without first obtaining such license or approval The U S Government s list of Excluded Territories is subject to change without notice and is therefore not included herein 6 Confidentiality By accepting this license you acknowledge that
66. ugh the LittleDog system will log the data and record that the data was missed by the program Programmers should consult the electronic LittleDog reference manual located in LI TTLEDOG doc html index html for a complete list of methods provided by the base class In addition to the functions provided by the LittleDog class there are a number of utility classes included with the development kit Of particular note are the functions provided in bduLog h for interacting with the Boston Dynamics message logging system used to send messages to the text display at the bottom of the window used in the example GUI applications and the Litt eDogDataSetFileReader Writer which provide access to the data sets produced by the LittleDog system and allow programmers to log internal information from their software in the same format as the LittleDog system uses for the automatically generated data sets 35 LittleDog Robot 1 0 User Guide 3 3 The BASIC Example To better understand how these functions interact with one another and the LittleDog robot we revisit the basic example that was used to first operate the robot in Section 1 4 2 The mai n defined by this program constructs a MyLi t t I eDog object that is derived from the LittleDog class provided with the development kit It then parses the one argument it takes f causes it to force recalibration and proceeds to initialize the motion capture system initialize the robot calibrate the
67. values and passing servo commands to the servo layer at a rate of 100Hz over an 802 11b wireless Ethernet link A control interface layer running on the host computer presents the LittleDog robot to the users for behavioral control and learning It formats data from both LittleDog s internal sensors and the motion capture system and presents a coherent interface for use on the host computer The API provided on the host computer allows users to perform a variety of control tasks on the robot in either robot joint coordinates or Cartesian coordinates relative to the robots body and provides reasonably synchronous access to data from both the robot and the motion capture system Furthermore during execution of a trial when a users control software has control of the robot all data received from and sent to the robot is automatically collected into a data set that can be analyzed with a number of tools 3 1 Working with the API The user s control software runs in an environment that is controlled by the LittleDog API and communicates with the LittleDog robot system via that same LittleDog C API At the highest level the API has functions to e initialize the robot and motion capture system e read robot sensors e write torques to robot actuators e select servo function e specify gains to the joint servos e specify setpoints to the joint servos e perform kinematic transformations e read motion capture data e collect data from both Li
68. y needs to be called if motion capture system will be used during the trial If a trial has been started without initializing the motion capture system the trial must be terminated and the host robot communications must be closed prior to calling initializeMocap This progression of states is shown in Figure 15 Users should refer to the electronic reference manual provided with the LittleDog software development kit for the specifics of using the LittleDog API The information provided in this section only provides an overview of the basic functions along with a brief explanation of the basic example program discussed in Section 1 4 2 3 2 Basic API functions The following methods of the LittleDog class allow a user program to control the overall operation of the robot State getState voi d Queries the system for current state of the API const char getPerformerName void Queries the system for the performer name as derived from bdi rt cfg const char getErrorCodeString LD ERROR CODE error code Convert an LD ERROR CODE toa string LD ERROR CODE abortConnection void Abort all communication with the robot Calling this function stops the robot and terminates all communication with both the robot and the motion capture system The system is returned to the UNI NI TI ALI ZED state LD ERROR CODE initializeMocap voi d Initiate communication with the mocap system Once initialized the motion capture system will be used wit
69. ystem 2 1 Setting Up Setting up the MoCap system involves assembling a large support structure for the cameras mounting and aiming the cameras connecting the cameras to the Vicon MX Net and finally setting up the camera hardware and software Once that is complete the system is ready for calibration 2 1 1 Mounting the Cameras 2 1 1 1 Building the Frame The MoCap frame Figure 9 C comes in several large pieces and needs to be assembled To do so you will need a few extra sets of hands Figure 8 shows a simplified view of the components that will come with the truss structures Assembly of the truss is relatively simple The four corner posts are bolted to the floor base as shown in Figure 9 A The upper structure forming a large rectangle as shown in Figure 9 C is pre assembled on the ground and lifted up onto the four corner posts The only tricky part to the assembly order is to ensure that you install one of the long support beams with two end pieces in place as the last step in assembling the top structure as shown in Figure 9 B 2 6m Truss Qty 4 1 0m Truss Qty 2 Once the upper structure is assembled you are ready 1 8m Truss Qty 4 to lift it into place The lift will require a minimum of five people four to support the top structure and Corner Truss Qty 4 one to place the corner legs more people makes the Base Plate Qty 4 job easier tall colleagues are the best Figure 8 MoCap Frame Components

LittleDog Robot 1.0 - Computational Learning and Motor Control Lab

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