sadbot.urdf

<robot name="sadbot" xmlns:xacro="http://ros.org/wiki/xacro">

  <link name="base_link">
    <inertial>
      <mass value="1"/>
      <inertia ixx="1" ixy="0" ixz="0" iyy="1" iyz="0" izz="1"/>
    </inertial>
  </link>

  <joint name="joint_1" type="revolute">
    <child link="base_link"/>
    <parent link="link_1"/>
    <axis xyz="0 0 1"/>
    <limit effort="1" lower="-1" upper="1" velocity="1"/>
    <dynamics damping="1"/>
  </joint>

  <link name="link_1">
    <inertial>
      <mass value="1"/>
      <inertia ixx="1" ixy="0" ixz="0" iyy="1" iyz="0" izz="1"/>
    </inertial>
  </link>

  <gazebo reference="joint_1">
    <provideFeedback>true</provideFeedback>
    <sensor name="gzft_sensor" type="force_torque">
      <always_on>1</always_on>
      <update_rate>100.0</update_rate>
      <visualize>1</visualize>
      <force_torque>
        <frame>child</frame>
      </force_torque>
    </sensor>
  </gazebo>
</robot>