get data from sensor - willinum/SPEC21 GitHub Wiki

• add plugin to your sensor in your sensors .sdf file eg.: for a 'ray' sensor add 'libgazebo_ros_ray_sensor.so' from the gazebo_ros_pkgs package. make sure to select the fitting branch (eg branch foxy if you use ros2 foxy)

• the following parameters can be tweaked:

  SDF parameters: <output_type>: Optional. The message type of the plugin's output. Can be any of the following:

  • sensor_msgs/PointCloud2: 3D cloud of points, Default
  • sensor_msgs/PointCloud: 3D cloud of points
  • sensor_msgs/LaserScan: 2D scan, uses center vertical ray if there are multiple
  • sensor_msgs/Range: Single distance value, minimum of all ray ranges of parent sensor

  <frame_name>: TF Frame id of output header. If not set, frame id will be name of sensor's parent link

  <min_intensity>: Clip intensity values for output to this value. Default: 0.0

  <radiation_type>: The radiation type to publish when the output type is sensor_msgs/Range. Can be either "infrared" or "ultrasonic". Default: "infrared".

• for this example you would add the following lines of code to your .sdf file(like this):

   <sensor type="ray" name="sensor">
   ...
   some sensor related stuff
   ...
   <plugin name="my_ray_sensor_plugin" filename="libgazebo_ros_ray_sensor.so">
      <ros>
    <!-- Configure namespace and remap to publish to /ray/range -->
    <namespace>/ray</namespace>
    <remapping>~/out:=range</remapping>
      </ros>
      <!-- Output as a Range, see aplugin sepcs for other types -->
      <output_type>sensor_msgs/Range</output_type>
      <!-- Clip intensity values so all are above 100, optional -->
      <min_intensity>100.0</min_intensity>
      <!-- Frame id for header of output, defaults to sensor's parent link name -->
       <frame_name>ray_link</frame_name>   <!-- -->
    </plugin> 
    </sensor>
  

• this publishes the range data from the sensor to the ros2 topic /ray/range (ros2 topic list)

• to print data to screen input following into terminal: ros2 topic echo /ray/range

• visualize in rviz2:

  • run in terminal ros2 run tf2_ros static_transform_publisher 0 0 0 0 0 0 map <frame_name (eg. ray_link)> (changes fixed frame in rviz2 to eg. ray_link)
  • start rviz2 via terminal command (rviz2)
    • 1 change fixed frame to your frame_name
    • 2 in bottom left corner of rviz2 interface select 'add' and choose according type eg. Range
    • 3 click in column besides topic and select desired topic

In the picture below you can see the simulation with the iris_clone2 drone running in gazebo and the visualization of the range data of the sensor in rviz2