path planning exceeding velocity limits of ur5

Question

Hi,

I am using moveit for path planning of a ur5. After finding a valid path, I want to execute it to the real robot (which is connected and communicating properly) but I always receive an error message like:

[ERROR] [WallTime: 1412925263.358047] Received a goal with velocities that are higher than 2.000000

the controller reports:

[INFO][ ... ]: Received new trajectory execution service request...
[WARNING][ ... ]: Controller handle reports status FAILED
[INFO][ ... ]: Execution completed: FAILED

any ideas how to fix that ?

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Originally posted by psfa_fz on ROS Answers with karma: 36 on 2014-10-10

Post score: 0

Answer 1

[ERROR] [WallTime: 1412925263.358047] Received a goal with velocities that are higher than 2.000000

The error you are seeing is not caused by exceeding a real, actual velocity limit, but rather by a check in ur_driver that compares the requested velocities against a (private) parameter called max_velocity. The idea behind the check was most likely to be able to enforce a maximum velocity over a trajectory. This is currently not (very well) documented.

This parameter has a default of 2 rad/s (this is in joint space).

You can do two things:

1. add a max_velocity parameter to the ur_driver node element in ur_bringup/launch/ur_common.launch, like so:

   <node name="ur_driver" pkg="ur_driver" type="driver.py" args="...">
       <param name="max_velocity" type="double" value="YOUR_MAX_SPEED" />
   </node>
   

2. edit ur_driver/src/ur_driver/driver.py, and increase the default value for the max_velocity parameter.

For now, I'd recommend you use option 1 on a source checkout of the universal_robot repository. Option 2 is really not a good idea.

I'll open a ticket on the github repository asking for this to be documented better.

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Edit: for reference, see universal_robot/issues/124.

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Originally posted by gvdhoorn with karma: 86574 on 2014-10-10

This answer was ACCEPTED on the original site

Post score: 1