diff

<gazebo>
<plugin name="skid_steer_drive_controller" filename="libgazebo_ros_skid_steer_drive.so">
      <alwaysOn>true</alwaysOn>
      <updateRate>100.0</updateRate>
      <leftFrontJoint>left_front_wheel_joint</leftFrontJoint>
      <rightFrontJoint>right_front_wheel_joint</rightFrontJoint>
      <leftRearJoint>left_back_wheel_joint</leftRearJoint>
      <rightRearJoint>right_back_wheel_joint</rightRearJoint>
      <wheelSeparation>0.4</wheelSeparation>
      <wheelDiameter>0.07</wheelDiameter>
      <torque>10</torque>
      <commandTopic>cmd_vel</commandTopic>
      <topicName>cmd_vel</topicName>
      <odometryTopic>odom</odometryTopic>
      <odometryFrame>odom</odometryFrame>
      <robotBaseFrame>base_footprint</robotBaseFrame>
      <broadcastTF>false</broadcastTF>
  </plugin>
</gazebo>