What is a ROS controller file

A ROS controller file includes all the information ROS requires to operate robots. In GRIP, such files are required when you integrate a robot with MoveIt!, or if you have implemented your own controller following this tutorial.

Note

If your robot is composed of both an arm and a robot hand (and integrated through MoveIt!), you must specify one ROS controller file for the arm and one for the hand.

Each controller file must follow this template: .. code-block:: yaml

<controller_name>:

type: “<controller_type>” joints:

• <joint_name_1>

• …

• <joint_name_n>

constraints:

goal_time: <goal_time> stopped_velocity_tolerance: <velocity_tolerance> <joint_name_1>: {trajectory: <value>, goal: <value>} <joint_name_2>: {trajectory: <value>, goal: <value>} … <joint_name_m>: {trajectory: <value>, goal: <value>}

stop_trajectory_duration: <trajectory_duration> state_publish_rate: <publish_rate> action_monitor_rate: <monitor_rate> allow_partial_joints_goal: <boolean>

If you create your own controller (i.e., derived from controller_interface::ControllerBase, see here) declared in a plugin, you must define it in this file as well. Please note that some of the options, such as constraints, stop_trajectory_duration or others may not be relevant, i.e. depends on the controller type and/or your implementation.

When using MoveIt!, please make sure that the controllers defined in such files match the same name as the MoveIt! controllers defined in controllers.yaml of your moveit configuration package. If you are using your own ROS controller, you don’t need to include it in the moveit config package.