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Cartesian velocity control of robot arm

asked 2015-02-01 20:23:05 -0500

rand gravatar image

I have a 6DOF robot arm, and would like to start driving the end effector around with a joystick. I think the most natural way to do this would be to map my joystick axes to Cartesian velocities of the end effector. I have tried executing very small paths in the desired directions using MoveGroupCommander.compute_cartesian_path(), but I end up getting very jumpy results. Are there any facilities built into MoveIt or otherwise to help me do this?

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answered 2015-02-02 18:21:25 -0500

rand gravatar image

I actually found a good solution to this in the code for pr2_teleop_general. The basic idea is to:

  1. Grab the current robot state using RobotCommander.get_current_state()
  2. Call the GetPositionFK service of your move_group to get the the end effector position using this state as input.
  3. Scale your Cartesian velocity by a constant and add it onto this position. Call the GetPositionIK service of your move_group to get an inverse kinematics solution for this.
  4. Subtract your current joint angles from the IK joint angles, and multiply by some constant to get a velocity for every joint.
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rand, did this method worked for you or did you find something else? I am trying to do the same thing with my 7DOF robot. Thanks

sangfuu gravatar image sangfuu  ( 2015-04-07 15:28:08 -0500 )edit

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Asked: 2015-02-01 20:23:05 -0500

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Last updated: Feb 02 '15