Simulation

Apart from being used with a real robot, the ROS driver can be used with ros2_control’s mock hardware or the URSim simulator (which is equivalent from the driver’s perspective).

Additionally, the robot can be simulated using Gazebo Classic or GZ Sim but that’s outside of this driver’s scope.

Usage with official UR simulator

The easiest way to use URSim is the Docker image provided by Universal Robots. There is an image for each software generation:

We have prepared a script to unify the startup of the simulator independent of the software platform version:

ros2 run ur_client_library start_ursim.sh -m <ur_type> -v <ursim_version>

If you skip the -v option, the script will use the latest version of the PolyScope 5 URSim image. If you skip the -m option, the robot model will default to a UR5(e) robot.

Example:

$ ros2 run ur_client_library start_ursim.sh -v 10.8.0 -m ur20
ROBOT_MODEL: ur20
ROBOT_SERIES: polyscopex
URSIM_VERSION: 10.8.0
5b140a83f8600c7ada0b7d75bc7a5808667adbeec77387e8c73b093f10fd2379
Starting URSim. Waiting for UrService to be up...................................
UrService is up
Installing URCapX /home/feex/.ursim/polyscopex/urcaps/external-control-0.1.0.urcapx


To access PolyScopeX, open the following URL in a web browser.


        http://192.168.56.101

To exit, press CTRL+C

Accessing the URSim GUI is done using a web browser. The script will print the URL to access the GUI. Depending on the PolyScope version, this is different.

Open http://192.168.56.101:6080/vnc.html in a web browser.

With this, we can spin up a driver using

ros2 launch ur_robot_driver ur_control.launch.py ur_type:=<ur_type> robot_ip:=192.168.56.101 launch_rviz:=true

When we now move the robot in Polyscope, the robot’s RViz visualization should move accordingly.

For details on the (PolyScopr 5 and CB3) Docker image, please see the more detailed guide here.

Mock hardware

The package can simulate hardware with the ros2_control MockSystem. This emulator enables an environment for testing of “piping” of hardware and controllers, as well as testing robot’s descriptions. For more details see ros2_control documentation for more details.

Note

Some driver functionalities currently don’t work with mock hardware:

  • The TCP pose broadcaster does not work.

  • The passthrough trajectory controller does not function when calling the follow joint trajectory action.

  • The force mode controller also does not respond when trying to start force mode.

  • The GPIO controller cannot verify that it has changed the state of an I/O pin, so it will report a failure when trying to set an I/O pin.