Foot and Leg Trajectory Testing Procedure

(Notes on How to run a test on the Stanford climbing wall)

Getting Started

  • Power up the RHex stack
  • Log into the stack
    • See note on power supply for login & passwords
  • OR
  • Log into a Unix machine with SSH authentication and open a terminal window
    • To do a remote login use: ssh username@hostname:folder (ie. ssh will log in and default to the rhex user home directory)
    • Type exit to logout

Creating a .RC file (This text file holds all the trajectory settings)

  • This file should be securly copied to bailorgana, so its easiest to use Matlab on the Linux machines
  • Open Matlab and find a copy of the profile generating code
    • The latest versions are stored on chewie at /users/Software/LegTestCode/
    • See below for the specifics about various tests
  • Copy the .RC file to bailorgana
    • Use the scp command to securely copy the .RC file to bailorgana
      • Usage: scp {filename} {username}@{hostname}:{folder}
      • Eg. scp profile_gait.rc rhex@bailorgana:users/amcclung/LegTestCode01
      • Edit the script to automate the process and copy specific files
  • Note: If necessary use emacs or vi to edit the .RC

Start the test

  • Go to the directory with the test code on bailorgana
    • This is currently /home/rhex/users/amcclung/LegTestCode01
  • Switch users to the root user
    • To switch users, use su root or just su and then enter the password, type exit when you're done
  • Execute the program from the current directory (ie. ./poscontrol_test2)
  • After everything has been initialized (& calibrated) for the test, the progam PAUSES until the user presses a key.
  • The test profile is executed (looped) for the length specified by the related .RC file
  • ALERT! NOTE: Press Ctrl-C to stop the test at any time
    • Additions: Faster, manual calibration routine; wing step input program; manual control program

Calibration Routine

HOW IT WORKS: As soon as the program starts, the calibration routine sequentially applies a specified (small) constant voltage to the motors and uses the encoders to detect motor stall (once a hard stop is reached). After the 2 stops are reached, the motors then move to the starting test position, defined by two angular offsets. Once at the start position, the program pauses for the user to press a key and begin the test. If the encoders do not detect a stall, a timeout occurs (and the calibration continues from the timeout position).
  • Variables :
    • calib_posStartTime - how long it takes the motors move to the start position, at the end of calibration [Units: seconds]
    • calib_posStallTime - the timeout period for the hard stop (stall) search [Units: seconds]
    • calib_smallVoltage0 - the (small) motor voltage on the crank (4-bar drive motor) [Units: volts]
    • calib_smallVoltage3 - the (small) motor voltage on the wing (tilt motor) [Units: volts]
    • calib_offset0 - crank rotation to start position from hard stop [Units: degrees]
    • calib_offset3 - wing rotation to start position from hard stop [Units: degrees]
  • ALERT! Notes :
    • The motor voltages must be large enough to rotate the motors, otherwise a stall is instantly detected. 1.0V seems to be a reasonable amount.

Getting the data

Please see Emily for questions on data acquisition!
  1. Log in as administrator on princessleia and start LabVIEW.
  2. Open the following file from the OPEN pulldown menu: C:\Program Files\ATI DAQ FT\ATIDAQ Software CD\Samples\LabVIEW\ This will always be the most recent and updated VI available.
  3. Click on the top left hand corner arrow to start the interface.
  4. Click Bias/Tear button to zero/calibrate the sensors.
  5. Enter the filename for data to be saved in. For sequential files, we haven't automated the process quite yet so you'll have to keep track of this yourself!
  6. To manually take data, make sure you choose on the pulldown menu below the graph manual trigger instead of digital trigger. This will let you do a test run and check that you are taking data by pressing the manual trigger button.
  7. Most often, you will leave the default data acquisition by digital trigger. There is a separate line that comes from RHex stack that starts the data acquisition as the test-track starts moving and stops after a predefined amount of time. If you kill the RHex stack halfway through, it won't kill the digital trigger so you'll probably have to restart the VI.
  8. The digital marker is another digital line from the RHex stack that allows us to synchronize and reference time intervals.
  9. To see your saved data, go to MATLAB and use plot_results.m OR FTplot.m in F:/users/LV_data/ to plot data (on princessleia) .
  • ALERT! Notes :
    • The RED line on the RHex stack rainbow ribbon cable is the digital trigger
    • The YELLOW line on the RHex stack rainbow ribbon cable is the digital marker toggle
    • The RED line from the green terminal block is GROUND
    • The red and black twisted pair of LabView-RHex connecting wires are extended by a white and black twisted pair with masking tape that has blue markings
    • If in doubt, use a multimeter or oscilliscope to determine GND, trigger and marker lines

ALERT! General Notes:

  • Make sure encoders are connected well (w/o encoder signals, or wrong signals, the PD control causes the motors to spin at FULL speed!)
  • You MUST be the root user to execute the code properly
  • See Trey if you have questions

Please add notes as the testing procedure evolves

-- AMcClung? - 28 Feb 2004

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