Robotiq 3f gripper problem

asked 2019-03-21 09:59:45 -0500

pmuthu2s gravatar image

updated 2019-03-22 03:32:45 -0500

Hey guys,

I'm using ur10 robot and trying to connect Robotiq 3f gripper. The problem is that the gripper vibrates/shakes too much. I tried adding kp, kd, mu1 and mu2 parameters but still the gripper is shaking. What should I be doing?

I also created a ros_controller of type: position_controllers/JointTrajectoryController

Thanks !

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Did you tune the pid parameters of the controller?

kumpakri gravatar imagekumpakri ( 2019-03-21 11:29:12 -0500 )edit

Yes, I tried tuning the values, but I was not able to find a good result !

pmuthu2s gravatar imagepmuthu2s ( 2019-03-21 15:14:54 -0500 )edit

Did you observe a difference in the said gripper behavior? Might that be caused by the suboptimal PID values? It sounds to me like this is the case. Did you have any systematic approach while tuning the PID or just trying randomly? I imagine the shaking might be caused by too big P value or too low D value. You can also try omitting some of the parameters and see how the behavior change (making PI controller for example). Also see the limits for force you defined for the joints.

kumpakri gravatar imagekumpakri ( 2019-03-22 02:41:30 -0500 )edit

I tried dynamically re-configuring the PID values, not systematic though. It was not a successful approach.

pmuthu2s gravatar imagepmuthu2s ( 2019-03-22 06:43:24 -0500 )edit

Have you tried with no PID values? For our 3-Finger grippers, Gazebo 7.0.0 with position_controllers does something reasonable with no gains set, although it complains a lot:

[ERROR] [/gazebo::Pid::init]: No p gain specified for pid.  Namespace: /gazebo_ros_control/pid_gains/victor_right_gripper_fingerA_joint_2
arprice gravatar imagearprice ( 2019-03-26 13:17:19 -0500 )edit

Hey, sorry for the late response, Yeah, even that also did not work out.

pmuthu2s gravatar imagepmuthu2s ( 2019-04-03 08:09:10 -0500 )edit