Arm Calibration

Revision as of 21:55, 30 November 2017 by Imcmahon (talk | contribs) (Robot Arm Calibration)
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Robot Arm Calibration

We recommend you run the arm calibration routine regularly, starting right after you have your workstation to Sawyer communication set up, and again roughly once per month to keep your robot's arms responding reliably.

These are calibrate_arm.py is located in the intera_sdk repo.

Before running the Calibration script, you must remove any grippers from the arms, level the robot using the feet on its base, and make sure that there are no obstructions within reach of its arms, as they will move through the most of their accessible range throughout the procedure, and collisions will result in a failed calibration.

Note: The recommended order of operations in calibration is:

  1. Run the calibrate_arm routine
  2. Then Reboot

After the reboot, the robot's arms will be fully calibrated.

Note: The Intera Manufacturing Mode UI will run through this entire routine for you by selecting Calibrate from the "System" menu.

Calibrate - calibrate_arm.py

First is our calibrate_arms.py script.

To run this, simply type in a properly initialized `intera.sh` shell:

$ ./intera.sh
$ rosrun intera_interface calibrate_arm.py
usage: calibrate_arm.py [-h]

optional arguments:
  -h, --help            show this help message and exit

What is this doing?

This is where we calibrate Sawyer's joint torque sensors. Because we know the mass and center off mass for each rigid segment of Sawyer's arm, we know what the torque due to gravity should be on each joint in any given arm pose. By sampling the torque sensor readings at a set of known poses, we can find the correct calibration values for the torque sensors.