Robot simulation in Gazebo

[atajafari]

Hi,

I would like to simulate a Yaskawa robot (let us say GP12) in Gazebo. My goal is to mount a camera on its end-effector, so that the robot can react to its surroundings.

The final goal is to transfer the generated trajectory to the real robot.

As the goal of the robot is to perform tasks in the task space, I am willing to implement a Cartesian controller, ideally this one.

I know that Motoros2 is not supporting simulation, and if I understood correctly it is also not compatible with ros2_control (as it says in the FAQ section).

That is why I would appreciate if anyone with experience could help me on this, or give me some tips.

Thank you in advance.

[gavanderhoorn]

To simulate a GP12 in Gazebo, you don't really need anything from MotoROS2, nor is the fact it's not compatible with ros2_control very important.

Gazebo does not simulate a controller (ie: a YRC1000 or DX200), and you would not need, nor use MotoROS2 with Gazebo.

What you would need to do:

• find/create a URDF or .xacro for the robot you intend to simulate in Gazebo (for the GP12, this could come from here)
• you might also need to add (dummy) elements for inertia and mass
• if you intend to use ros2_control (and it seems you do): extend the .xacro with the required ros2_control elements (describing the command and state interfaces and the system to simulate). Note: I'd recommend not modifying the original file directly, as that would make keeping it up to date with upstream changes harder (ie: if/when we release an update). XACRO supports include-ing other files, so composition would be preferred
• spawn the extended/modified .xacro in Gazebo
• load & activate the desired ros2_control controller

provided you have ros2_control, the Gazebo ros2_control plugins and your desired controller plugins installed, this should be enough to simulate the robot with Gazebo.

But note:

• the dynamic behaviour of the robot will not be representative of the real GP12
• you would not be using the same control interfaces (ie: MotoROS2 is not compatible with ros2_control)

[atajafari]

Thank you very much for your detailed reply.
I have successfully included the ros2_control plugins and I can now move the GP12 in the Gazebo environment.
Our goal is to create a trajectory using a vision sensor which will be used to retrieve information from the environment and finally generate a trajectory. The motion commands will be sent to the controller in task space (Cartesian) coordinates, as it will make the process much simpler.
To transfer the generated trajectory to a real robot: Since ros2_control is (still) not compatible, I guess a good option will be to record the joint states during a full trajectory motion in Gazebo, and then transfer it to the real robot controller with FollowJointTrajectory.
If I understood correctly, there is still no task space (Cartesian) motion possible with Motoros2, correct?

[gavanderhoorn]

there is still no task space (Cartesian) motion possible with Motoros2, correct?

Cartesian interfaces are still on the roadmap.