add JointControllerStateArray for group controllers

[Smilels]

No description provided.

[bmagyar]

Could you elaborate please?

[Smilels]

Could you elaborate please?

Yes.
JointControllerState is designed to present the current controller state of one joint.
But for most of the robot arms or multi-fingered robotic hands, we don't want to use 6 or 5 publishers or subscribers to publish or get the controller states, especially when people use group controllers, for example, JointGroupVelocityController on PR2 or JointGroupEffortController on Shadow hand.
Therefore, I think an array message will be helpful here.

[bmagyar]

This sounds very reasonable. Do you have a Pull Request on JointGroupVelocityController and friends that are already using this message? I would prefer to wait with merging this until there's a PR showing it working.

[Smilels]

This sounds very reasonable. Do you have a Pull Request on JointGroupVelocityController and friends that are already using this message? I would prefer to wait with merging this until there's a PR showing it working.

I am using PR2 but PR2 has its pr2_controllers. Therefore I only gave two pull requests for PR2.
PR2/pr2_controllers#400
PR2/pr2_robot#264

In this pull [request], I also built a new ros message (pr2_controllers_msgs/msg/JointControllerStateArray.msg).

I have verified that this JointGroupVelocityController works well on PR2. Please see this video https://www.youtube.com/watch?v=rAj2IWl2ezs.

I haven't tested JointGroupVelocityController on other robots. I am thinking to write a JointGroupEffortController interface for Shadow hand.

[v4hn]

@Smilels The identifier looks like a typo. I would expect controller_state ?

[Smilels]

thank you. I have updated the variable name to controller_state.