Move the robot

First check the controllers’ state using ros2 control list_controllers, before running any commands. (Remember to install the ros2controlcli package).

  • Send goals to the Joint Trajectory Controller by using a demo node from ros2_controllers_test_nodes package by starting the following command in another terminal:

    $ ros2 launch ur_robot_driver test_scaled_joint_trajectory_controller.launch.py

    The robot should move, after a few seconds.

  • To test another controller, simply define it using initial_joint_controller argument, for example when using mock hardware:

    $ ros2 launch ur_robot_driver ur_control.launch.py ur_type:=ur5e \
  robot_ip:=yyy.yyy.yyy.yyy use_mock_hardware:=true \
  initial_joint_controller:=joint_trajectory_controller

    And send the command using demo node:

    $ ros2 launch ur_robot_driver test_joint_trajectory_controller.launch.py

    After a few seconds the robot should move(or jump when using emulation).

In case you want to write your own ROS node to move the robot, there is an example python node included that you can use as a start.

$ ros2 run ur_robot_driver example_move.py
[INFO] [1720623611.547903428] [jtc_client]: Waiting for action server on scaled_joint_trajectory_controller/follow_joint_trajectory
[INFO] [1720623611.548368095] [jtc_client]: Executing trajectory traj0
[INFO] [1720623620.530203889] [jtc_client]: Done with result: SUCCESSFUL
[INFO] [1720623622.530668700] [jtc_client]: Executing trajectory traj1
[INFO] [1720623630.582108072] [jtc_client]: Done with result: SUCCESSFUL
[INFO] [1720623632.582576444] [jtc_client]: Done with all trajectories
[INFO] [1720623632.582957452] [jtc_client]: Done

Warning

This is a very basic node that doesn’t have the same safety checks as the test nodes above. Look at the code and make sure that the robot is able to perform the motions safely before running this on a real robot!

Using MoveIt

MoveIt! support is built-in into this driver already.

To test the driver with the example MoveIt-setup, first start the driver as described above and then start the MoveIt! nodes using

ros2 launch ur_moveit_config ur_moveit.launch.py ur_type:=ur5e launch_rviz:=true

Now you should be able to use the MoveIt Plugin in rviz2 to plan and execute trajectories with the robot as explained here.

Note

The MoveIt configuration provided here has Trajectory Execution Monitoring (TEM) disabled, as the Scaled Joint Trajectory Controller may cause trajectories to be executed at a lower velocity than they were originally planned by MoveIt. MoveIt’s TEM however is not aware of this deliberate slow-down due to scaling and will in most cases unnecessarily (and unexpectedly) abort goals.

Until this incompatibility is resolved, the default value for execution_duration_monitoring is set to false. Users who wish to temporarily (re)enable TEM at runtime (for use with other, non-scaling controllers) can do so using the ROS 2 parameter services supported by MoveIt.

For more details, please see ur_moveit_config.