ROS 2 Migration: Body Wrench and Joint Effort

Overview

In ROS 1, services for applying wrenches on links and efforts on joints in simulation were provided by the gazebo_ros_api_plugin. In ROS 2, this feature is provided by the gazebo_ros_force_system plugin.

Read more about the migration of gazebo_ros_api_plugin at ROS 2 Migration: gazebo_ros_api_plugin.

Summary

• Usage of body in services have been replaced by link to match the gazebo specs.
• clear_joint_forces has been renamed to clear_joint_efforts to match the rest of the API.

	ROS 1	ROS 2
Service names	apply_body_wrench	apply_link_wrench
	clear_body_wrenches	clear_link_wrenches
	apply_joint_effort	apply_joint_effort
	clear_joint_forces	clear_joint_efforts
Service types	gazebo_msgs/ApplyBodyWrench	gazebo_msgs/ApplyLinkWrench
	gazebo_msgs/BodyRequest	gazebo_msgs/LinkRequest
	gazebo_msgs/ApplyJointEffort	gazebo_msgs/ApplyJointEffort
	gazebo_msgs/JointRequest	gazebo_msgs/JointRequest

Example usage

First, run Gazebo with the plugin:

gazebo --verbose -s libgazebo_ros_force_system.so

Apply Link Wrench

Now call the apply_link_wrench service from the command line, for example:

ros2 service call /apply_link_wrench gazebo_msgs/srv/ApplyLinkWrench '{link_name: "box::link", reference_frame: "", reference_point: { x: 100, y: 0, z: 0 }, wrench: { force: { x: 10, y: 0, z: 0 }, torque: { x: 0, y: 0, z: 0 } }, start_time: {sec: 0, nanosec: 0}, duration: {sec: -1, nanosec: 0} }'

Clear Link Wrenches

Call the clear_link_wrenches service from the command line, for example:

ros2 service call /clear_link_wrenches gazebo_msgs/srv/LinkRequest '{link_name: "box::link"}'

Apply Joint Effort

Call the apply_joint_effort service from the command line, for example:

ros2 service call /apply_joint_effort gazebo_msgs/srv/ApplyJointEffort '{joint_name: "joint", effort: -1.0, start_time: {sec: 0, nanosec: 0}, duration: {sec: 2000, nanosec: 0} }'

Clear Joint Efforts

Call the clear_joint_efforts service from the command line, for example:

ros2 service call /clear_joint_efforts gazebo_msgs/srv/JointRequest '{joint_name: "joint"}'