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Do I need PID gains for velocity_controllers?

asked 2022-05-27 04:21:56 -0500

CroCo
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updated 2022-06-11 10:39:21 -0500

lucasw

8729 ●137 ●239 ●256 https://github.com/lucasw

I would like to use velocity_controllers/JointGroupVelocityController. In ros_controllers, the controllers velocity_controllers/JointVelocityController and velocity_controllers/JointGroupVelocityController are forward command controller. My understanding is that the controller doesn't need pid gains; but if I compile my code, I get these errors

[ERROR] [1653642231.819643360, 0.195000000]: No p gain specified for pid.  Namespace: /rrbot/gazebo_ros_control/pid_gains/joint1
[ERROR] [1653642231.820926527, 0.195000000]: No p gain specified for pid.  Namespace: /rrbot/gazebo_ros_control/pid_gains/joint2

I'm using Gazebo 9 and melodic.

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answered 2022-05-27 13:15:53 -0500

Mike Scheutzow
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updated 2022-05-27 13:18:17 -0500

I have not used a velocity_controller, but I think the answer to your title question is "No".

As far as I know, that situation is not really an ERROR, and the log level should be more like INFO. #q293830 has more discussion of this.

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When I add gazebo_ros_control/pid_gains, the arms falls down but removing them, the arm doesn't fall down. Interesting. I'm not sure what Gazebo is doing with the pid gains so that velocity controller is not able to maintain the zero setpoint. But again, forward command controller doesn't need any internal controller to map its input.

CroCo ( 2022-05-28 11:25:47 -0500 )edit

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Asked: 2022-05-27 04:21:56 -0500

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Last updated: May 27 '22

Do I need PID gains for velocity_controllers? edit

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Do I need PID gains for velocity_controllers?