How can use effort controller in ros2_kortex (ActuatorConfig)

[odj3460]

We are modifying hardware_interface based on the API torque-control example.
I want to be able to give torque input at low-level, i.e. switch to the ros-controller's effort controller.
As of now, I have set it that way, but the following error occurs.

---

[ros2_control_node-1] terminate called after throwing an instance of 'Kinova::Api::KDetailedException'
[ros2_control_node-1] what(): Server protocol error, Error sub type=UNSUPPORTED_SERVICE => <srv: 10, fct: 7, msgType: 3>
[ros2_control_node-1] description: Service not registered for service id: 10
[ros2_control_node-1]
[ros2_control_node-1] Stack trace (most recent call last) in thread 339292:
[ros2_control_node-1] #17 Object "", at 0xffffffffffffffff, in

However, even if I check the API-related documentation, I cannot find what 'service id:10' means.
Maybe, I think that this problem is on ''k_api::ActuatorConfig::ActuatorConfigClient''.

In the basic hardware_interface.cpp, it was stated that ros2_kortex is not provided for effort input.
But even if I modify the source file, is it currently not possible?

I would like to use a controller other than the default joint-trajectory-controller and twist-controller.

To be precise, it is a position-controller or effort-controller.
However, there are situations in which both of these low-level controls are not working well.
Are there any examples or guidelines for how to do this?

[smoya23]

Hi @odj3460,

It's not impossible to implement low-level effort controller inside the current hardware_interface, it was just not part of our defined supported feature set. Our example in the Kortex repo is a good starting point in order to get it to work inside our current hardware interface. Please note that you will also need to add the effort controller inside the ros2_controllers.yaml file of your arm description package (for a 6dof, it's located in here) . Regarding the error you're getting, is it possible for you to provide a code snippet of what is causing the error to happen? I can try and guide you from there.

Best,
Santiago

[odj3460]

Thank you for the answer.

Actually, this problem was already solved.
But, I have one more question.

When I run the hardware_interface, I can get the topic for joint_states from ros2_controller. The topic is '/joint_states'.
The problem is the configuration of the joint values.

From the topic, /joint_states is configured as [joint1 joint2 joint4 joint5 joint3 joint6]. Joint configuration order for joint 3-5 is wrong.
What's the reason for this problem?