ROS 2 Migration: Diff drive

Overview

This pages describes the changes the diff drive plugin in gazebo_plugins for ROS 2, including a migration guide.

gazebo_ros_diff_drive

• <publishWheelJointState> has been removed. Use the gazebo_ros_joint_state_publisher plugin instead.

• All SDF parameters are now snake_cased:

  ROS 1	ROS 2
  leftJoint	left_joint
  rightJoint	right_joint
  wheelSeparation	wheel_separation
  wheelDiameter	wheel_diameter
  commandTopic	command_topic
  odometryTopic	odometry_topic
  odometryFrame	odometry_frame
  wheelTorque	max_wheel_torque

Example Migration

ROS1

    <model name='vehicle'>
      ...

      <joint name='left_wheel_joint' type='revolute'>
        ...
      </joint>

      <joint name='right_wheel_joint' type='revolute'>
        ...
      </joint>

      <plugin name='diff_drive' filename='libgazebo_ros_diff_drive.so'>
        <leftJoint>left_wheel_joint</leftJoint>
        <rightJoint>right_wheel_joint</rightJoint>
        <wheelSeparation>0.5380</wheelSeparation>
        <wheelDiameter>0.3</wheelDiameter>
        <wheelTorque>20</wheelTorque>
        <commandTopic>cmd_vel</commandTopic>
        <odometryTopic>odom</odometryTopic>
        <odometryFrame>odom</odometryFrame>
        <publishWheelJointState>true</publishWheelJointState>
      </plugin>

    </model>

ROS2

    <model name='vehicle'>
      ...

      <joint name='left_wheel_joint' type='revolute'>
        ...
      </joint>

      <joint name='right_wheel_joint' type='revolute'>
        ...
      </joint>

      <!-- Use gazebo_ros_joint_state_publisher instead of publishWheelJointState -->
      <plugin name="joint_states" filename="libgazebo_ros_joint_state_publisher.so">
        <joint_name>right_wheel_joint</joint_name>
        <joint_name>left_wheel_joint</joint_name>
      </plugin>


      <plugin name='diff_drive' filename='libgazebo_ros_diff_drive.so'>

        <!-- Replace camelCase elements with camel_case ones -->
        <left_joint>left_wheel_joint</left_joint>
        <right_joint>right_wheel_joint</right_joint>
        <wheel_separation>0.5380</wheel_separation>
        <wheel_diameter>0.3</wheel_diameter>
        <command_topic>cmd_vel</command_topic>
        <odometry_topic>odom</odometry_topic>
        <odometry_frame>odom</odometry_frame>

        <!-- wheelTorque is now max_wheel_torque -->
        <max_wheel_torque>20</max_wheel_torque>


      </plugin>

    </model>