Issues with Motoman HC20 Joint Movement Stopping Midway Through GoalPosition in Rviz MotionPlanning

[yuutayuuta50]

I've encountered an issue where, when attempting to move the joint_1_s axis alone, the robot unexpectedly stops before reaching the designated GoalPosition.

To provide some context, I've noticed that adjusting the max_velocity in the joint_limits.yaml file to 0.14 prevents the robot from stopping mid-movement, but this speed is not practical for our applications. I am seeking advice on how to address and potentially resolve this issue to achieve a more practical operating speed without the robot halting unexpectedly.

Here are some additional details that might help with diagnosing the problem:

The issue only occurs when operating the actual robot using the robot_interface_streaming_hc20.launch file. This problem does not manifest in simulations.
When manually controlling the robot using the touch panel for jog operations, the robot moves at a much faster pace without any issues.
While I have only observed this issue with the joint_1_s axis so far, it might also affect other axes, but I have not verified this yet.

[ted-miller]

This issue is most likely a case of the Functional Safety Unit limiting the motion. The FSU can impose speed limits and even completely stop robot motion if specific conditions are met. (This is especially prevalent on the HC robots.)

I recommend contacting your local Yaskawa office for assistance with adjusting the FSU settings for your particular application.

[yuutayuuta50]

Thank you for your advice. I will reach out to Yaskawa for assistance with adjusting the FSU settings.

[EricMarcil]

The HC20 is a collaborative robot with PFL (Power Force Limiting) and PFL (Functional Safety Unit). Most system have a PFL Speed Limit during playback when the PFL function is enabled to limit the robot speed and keep the robot motion to a safe speed to operate in proximity of humans.

The Speed Limit will remove exceeding speed command and slow down the robot but ROS will not be aware of it, which causes the robot to stop short of its target position.

There was a recent merge request that was done to help handle this issue: #542
It was merge so should be in the latest release version 1.9.11. This should enable the MotoRos driver to account for the SpeedLimit but there still no feedback to Ros, so the ROS side might complain about the robot failling too far back behind the command.

[yuutayuuta50]

Thank you for the detailed explanation.We'll update to the latest version (1.9.11) and see how it affects the robot's behavior in our experiments.

[yuutayuuta50]

Thank you for your response. We have conducted the experiments.

The setting for "speed limit for collaborative op" in the photo was set at 250mm/s, and when we changed it to 500mm/s, the robot started moving faster. It's possible that we misunderstood and thought that only updating the motoman_driver would suffice as another solution. Should we also have updated the controller's MotoRosYRC1_1912.out file?

[EricMarcil]

Yes, you should update to the MotoRosYRC_1912.out as it is the part that was changed to handle the speed reduction.

[yuutayuuta50]

Thank you for your response. I'll go ahead and implement that update and then test to see how it performs.