UR5 Servoing

[adnan-saood]

Greetings all.
I am trying to control a UR5 robot using ROS2. The goal is to follow a polygon path with end-effector velocity control. The velocity of the end-effector needs to be controlled precisely (the task is similar to painting or welding but on a very small scale (area 2cmx2cm).

I started by using the moveit2 move group interface in C++, the problem is there seems to be no way to control the velocity of the end-effector, only timestamp it, and the results are not smooth.

I then started using moveit2-servo. I wrote a code for pose tracking, where the end-effector follows a frame published on a topic. The ros2_controller was (JointTrajectoryController). I was able to control the velocity and position of the end-effector using this method in simulation, but when I tried it on the real UR5 robot, the robot experienced rough vibrations. I understand that this behavior is expected from the JointTrajectoryController controller.

I tried to control the robot using the jointGroupVelocityController (link), but with no result. I am a bit confused if this is at all possible using the UR-ROBOTS-ROS2-Driver, as I found the plugin definition for the position, but without a mention of velocity interface. (link)

I feel I am missing something. Any suggestions would be appreciated. Thank you for your time.

[fmauch]

What do you mean with not mentioning the velocity interface? How about here or here just to pick two examples.

Did you try to change the controller using ros2 control switch_controllers --start forward_velocity_controller --stop scaled_joint_trajectory_controller?

[adnan-saood]

Hello,
Thanks for your reply and for the answer here, I was able to use moveit_servo with the UR5 robot via the URSim simulator.