Hi. I am trying to place a Velodyne Lidar Puck 16 on the top of a Turtlebot model in Gazebo. [ROS Kinetic - Gazebo 7.0]. All is good, until i apply a force/torque to the turtlebot: the robot moves, the lidar does not.

Where is the error?

In order to attatch the lidar to the turtlebot i modified the sdf model in this way:

model://velodyneVLP16 0 0 0.45 0 0 0 <joint name="VLP16joint" type="fixed"> VLP16::base_footprint create::base

The sdf file of the lidar is:

<?xml version='1.0'?> false <!-- 0 0 1 0 0 0 --> <!-- 0 0 0 0 0 0 --> 0 0 0 0 0 0 3.23643 0.0156863 0.065702 3.35996 -0.00821275 3.32745 2

    <collision name='base_footprint_collision_1'>
      <pose frame=''>0 0 -0.00185 0 0 0</pose>
      <geometry>
        <cylinder>
          <length>0.0717</length>
          <radius>0.0516</radius>
        </cylinder>
      </geometry>
      <surface>
        <contact>
          <ode/>
        </contact>
        <friction>
          <ode/>
          <torsional>
            <ode/>
          </torsional>
        </friction>
        <bounce/>
      </surface>
      <max_contacts>10</max_contacts>
    </collision>
    <visual name='base_footprint_visual_1'>
      <pose frame=''>0 0 -0.0377 0 0 0</pose>
      <geometry>
        <mesh>
          <scale>1 1 1</scale>
          <uri>model://velodyne_VLP16/meshes/VLP16_base_1.dae</uri>
        </mesh>
      </geometry>
      <material>
        <script>
          <uri>__default__</uri>
          <name>__default__</name>
        </script>
      </material>
    </visual>
    <visual name='base_footprint_visual_2'>
      <pose frame=''>0 0 -0.0377 0 0 0</pose>
      <geometry>
        <mesh>
          <scale>1 1 1</scale>
          <uri>model://velodyne_VLP16/meshes/VLP16_base_2.dae</uri>
        </mesh>
      </geometry>
      <material>
        <script>
          <uri>__default__</uri>
          <name>__default__</name>
        </script>
      </material>
    </visual>
    <visual name='base_footprint_visual_3'>
      <pose frame=''>0 0 -0.0377 0 0 0</pose>
      <geometry>
        <mesh>
          <scale>1 1 1</scale>
          <uri>model://velodyne_VLP16/meshes/VLP16_scan.dae</uri>
        </mesh>
      </geometry>
      <material>
        <script>
          <uri>__default__</uri>
          <name>__default__</name>
        </script>
      </material>
    </visual>

    <sensor name='velodyne-VLP16' type='ray'>
      <visualize>0</visualize>
      <update_rate>10</update_rate>
      <ray>
        <scan>
          <horizontal>
            <samples>1875</samples>
            <resolution>1</resolution>
            <min_angle>-3.14159</min_angle>
            <max_angle>3.14159</max_angle>
          </horizontal>
          <vertical>
            <samples>16</samples>
            <resolution>1</resolution>
            <min_angle>-0.261799</min_angle>
            <max_angle>0.261799</max_angle>
          </vertical>
        </scan>
        <range>
          <min>0.055</min>
          <max>140</max>
          <resolution>0.001</resolution>
        </range>
        <noise>
          <type>gaussian</type>
          <mean>0</mean>
          <stddev>0</stddev>
        </noise>
      </ray>
      <plugin name='gazebo_ros_laser_controller' filename='libgazebo_ros_velodyne_laser.so'>
        <topicName>/velodyne_points</topicName>
        <frameName>/velodyne</frameName>
        <min_range>0.8</min_range>
        <max_range>130.0</max_range>
        <gaussianNoise>0.008</gaussianNoise>
        <robotNamespace>/</robotNamespace>
      </plugin>
      <pose frame=''>0 0 0 0 0 0</pose>
    </sensor>
    <gravity>0</gravity>
    <self_collide>0</self_collide>
    <kinematic>0</kinematic>
  </link>
</model>