ROS 2 Migration: Tricycle drive

Overview

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

Summary

• All SDF parameters are now snake_cased
• Use remapping argument to change default topics (cmd_vel, odom, joint_states)

SDF parameters

ROS 1	ROS 2
actuatedWheelDiameter	actuated_wheel_diameter
encoderWheelDiameter	encoder_wheel_diameter
wheelTorque	max_wheel_torque
odometryFrame	odometry_frame
robotBaseFrame	robot_base_frame
updateRate	update_rate
wheelAcceleration	max_wheel_acceleration
wheelDeceleration	max_wheel_deceleration
wheelSpeedTolerance	max_wheel_speed_tolerance
steeringSpeed	max_steering_speed
steeringAngleTolerance	max_steering_angle_tolerance
encoderWheelSeparation	wheel_separation
publishWheelTF	publish_wheel_tf
publishWheelJointState	publish_wheel_joint_state
steeringJoint	steering_joint
actuatedWheelJoint	actuated_wheel_joint
encoderWheelLeftJoint	encoder_wheel_left_joint
encoderWheelRightJoint	encoder_wheel_right_joint
odometrySource	odometry_source
commandTopic	<ros><remapping>cmd_vel:=custom_cmd_vel</remapping></ros>
odometryTopic	<ros><remapping>odom:=custom_odom</remapping></ros>

Example Migration

ROS1

    <model name='tricycle'>
      ...

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

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

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

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

      <plugin name="tricycle_drive_controller" filename="libgazebo_ros_tricycle_drive.so">
        <robotNamespace>demo</robotNamespace>
        <commandTopic>cmd_demo</commandTopic>
        <odometryTopic>odom_demo</odometryTopic>

        <updateRate>10.0</updateRate>

        <!-- joints -->
        <steeringJoint>front_steering_joint</steeringJoint>
        <actuatedWheelJoint>front_wheel_joint</actuatedWheelJoint>
        <encoderWheelLeftJoint>left_wheel_joint</encoderWheelLeftJoint>
        <encoderWheelRightJoint>right_wheel_joint</encoderWheelRightJoint>

        <publishWheelTF>false</publishWheelTF>
        <publishWheelJointState>true</publishWheelJointState>

        <!-- kinematics -->
        <actuatedWheelDiameter>0.135</actuatedWheelDiameter>
        <encoderWheelDiameter>0.135</encoderWheelDiameter>
        <encoderWheelSeparation>0.548</encoderWheelSeparation>

        <odometryFrame>odom</odometryFrame>
        <odometrySource>encoder</odometrySource>
        <robotBaseFrame>base_link</robotBaseFrame>

        <!-- limits -->
        <wheelAcceleration>1.8</wheelAcceleration>
        <wheelDeceleration>5.0</wheelDeceleration>
        <wheelSpeedTolerance>0.05</wheelSpeedTolerance>
        <wheelTorque>20</wheelTorque>
        <steeringSpeed>0.4</steeringSpeed>
        <steeringAngleTolerance>0.02</steeringAngleTolerance>

      </plugin>

    </model>

ROS2

    <model name='tricycle'>
      ...

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

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

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

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

      <plugin name='tricycle_drive_controller' filename='libgazebo_ros_tricycle_drive.so'>
        <ros>
          <!-- Set namespace -->
          <namespace>/demo</namespace>

          <!-- Remap default topics -->
          <remapping>cmd_vel:=cmd_demo</remapping>
          <remapping>odom:=odom_demo</remapping>
          <remapping>joint_states:=joints_demo</remapping>
        </ros>

        <update_rate>10.0</update_rate>

        <!-- Joints -->
        <steering_joint>front_steering_joint</steering_joint>
        <actuated_wheel_joint>front_wheel_joint</actuated_wheel_joint>
        <encoder_wheel_left_joint>left_wheel_joint</encoder_wheel_left_joint>
        <encoder_wheel_right_joint>right_wheel_joint</encoder_wheel_right_joint>

        <publish_wheel_tf>false</publish_wheel_tf>
        <publish_wheel_joint_state>true</publish_wheel_joint_state>

        <!-- kinematics -->
        <actuated_wheel_diameter>0.135</actuated_wheel_diameter>
        <encoder_wheel_diameter>0.135</encoder_wheel_diameter>
        <wheel_separation>0.548</wheel_separation>

        <odometry_source>0</odometry_source>
        <odometry_frame>odom</odometry_frame>
        <robot_base_frame>base_link</robot_base_frame>

        <!-- limits -->
        <max_wheel_acceleration>1.8</max_wheel_acceleration>
        <max_wheel_deceleration>5.0</max_wheel_deceleration>
        <max_wheel_speed_tolerance>0.05</max_wheel_speed_tolerance>
        <max_wheel_torque>20</max_wheel_torque>
        <max_steering_speed>0.4</max_steering_speed>
        <max_steering_angle_tolerance>0.02</max_steering_angle_tolerance>

      </plugin>

    </model>