UR driver twist_controller not implemented?

edit

It's likely your ros_control configuration file does not contain any information on the twist_controller.

If that's the case, switch_controller cannot switch to it, as the controller_manager will not have loaded it.

I've added the following to the .ur5e_controllers.yaml file for my robot in the Universal_Robots_ROS_Driver/ur_robot_driver/config folder:

twist_controller:
   type:         cartesian_ros_controllers/TwistController

   # The controller uses this identifier to get the according command handle
   # from the hardware interface.
   frame_id:     "endpoint_to_control"

   joints:
   - joint1
   - joint2
   - joint3
   - joint4
   - joint5
   - joint6

This didn't really work so I tried also to load the controller using "/controller_manager/load_controller twist_controller" and I got the following error:

[ERROR] [1630403138.102246501]: Could not load controller 'twist_controller' because controller type 'cartesian_ros_controllers/TwistController' does not exist.
[ERROR] [1630403138.102345667]: Use 'rosservice call controller_manager/list_controller_types' to get the available types

Do I have to clone the following repository or is it not relevant? https://github.com/fzi-forschungszent...

You'll have to make sure to have installed the referenced controller, yes.

re: clone repository: on Noetic, you can install the controller using apt: status_page/ros_noetic_default.html?q=carte (green squares everywhere).

On Melodic you'll either have to enable the TestingRepository or build from source, as the package has been released, but Melodic has not seen any sync yet (note the blue square in the last column of the row for twist_controller).

Thanks! I've already cloned the said repository and changed the config .yaml file to:

twist_controller:
   type: cartesian_ros_controllers/TwistController

   # The controller uses this identifier to get the according command handle
   # from the hardware interface.
   frame_id: "endpoint_to_control"

   joints:
     - shoulder_pan_joint
     - shoulder_lift_joint
     - elbow_joint
     - wrist_1_joint
     - wrist_2_joint
     - wrist_3_joint

You mentioned that I can install the controller using apt, but how exactly do I do that? (I'm really new to ROS)

You don't need to do both. Either install using apt, or build it from source (where git clone is one step).

See #q252478 for a (high-level) overview of the workflow.

Just git clone-ing a repository is typically not sufficient.

Ok, did that. But I checked the controller list using "rosservice call controller_manager/list_controllers" and I don't see any twist_controller.

Moreover, when I tried loading again the twist_controller I got this new error:

[ERROR] [1630405521.163189747]: This controller requires a hardware interface of type 'cartesian_ros_control::TwistCommandInterface'. Make sure this is registered in the hardware_interface::RobotHW class.
[ERROR] [1630405521.163288661]: Initializing controller 'twist_controller' failed

Any clue what this means?

It tells you that the driver you're using does not expose the required resources for the controller to use.

You'll have to make sure that you're using the correct version of the driver.

If you're using the UR driver, the Cartesian interfaces were only added recently, so you may have to update and rebuild.

But I'd ask the maintainers / developers.