5 ROS simulation modeling (3-rviz+gazebo+ control simulation robot)

5.5 Give the model sensor information to control the simulation robot

5.5.1 Realization effect

Controlling robot movement through keyboard , At the same time, you can subscribe to radar information .

5.5.2 stay urdf File to add gazebo Sensor information

1、 Add information about the differential drive wheel

    <gazebo>
        <plugin name="differential_drive_controller" filename="libgazebo_ros_diff_drive.so">
            <rosDebugLevel>Debug</rosDebugLevel>
            <publishWheelTF>true</publishWheelTF>
            <robotNamespace>/</robotNamespace>
            <publishTf>1</publishTf>
            <publishWheelJointState>true</publishWheelJointState>
            <alwaysOn>true</alwaysOn>
            <updateRate>100.0</updateRate>
            <legacyMode>true</legacyMode>
            <leftJoint>base_l_wheel_joint</leftJoint> 
            <rightJoint>base_r_wheel_joint</rightJoint>
            <wheelSeparation>0.315</wheelSeparation> 
            <wheelDiameter>0.18</wheelDiameter>
            <broadcastTF>1</broadcastTF>
            <wheelTorque>30</wheelTorque>
            <wheelAcceleration>1.8</wheelAcceleration>
            <commandTopic>cmd_vel</commandTopic>
            <odometryFrame>odom</odometryFrame> 
            <odometryTopic>odom</odometryTopic>
            <robotBaseFrame>base_coordinate</robotBaseFrame>
        </plugin>
    </gazebo>

2、 Add lidar information

    <gazebo reference="laser">
    <sensor type="ray" name="rplidar">
      <pose>0 0 0 0 0 0</pose>
      <visualize>true</visualize>
      <update_rate>5.5</update_rate>
      <ray>
        <scan>
          <horizontal>
            <samples>360</samples>
            <resolution>1</resolution>
            <min_angle>-3</min_angle>
            <max_angle>3</max_angle>
          </horizontal>
        </scan>
        <range>
          <min>0.10</min>
          <max>30.0</max>
          <resolution>0.01</resolution>
        </range>
        <noise>
          <type>gaussian</type>
          <mean>0.0</mean>
          <stddev>0.01</stddev>
        </noise>
      </ray>
      <plugin name="gazebo_rplidar" filename="libgazebo_ros_laser.so">
        <topicName>/scan</topicName>
        <frameName>laser</frameName>
      </plugin>
    </sensor>
  </gazebo>

More sensor information , Refer to the official ：http://gazebosim.org/tutorials?tut=ros_gzplugins

3、launch The file does not need to be modified

4、 start-up launch The file in rviz Subscribe to radar topics
stay rviz Medium add add to LaserScan, Among them topic Internal subscription /scan topic of conversation , modify size The size makes the lidar scanning result clearer .

5、 Control robot motion
New terminal input rosrun teleop_twist_keyboard teleop_twist_keyboard.py Control the robot movement through the keyboard .

5.5.3 Existing problems

In the keyboard control robot movement , There may be situations ： There is no problem with the model , But the robot's forward motion is unnatural .
Subscribe to the robot at this time TF Coordinates and odometer information odometry Find out , default odom Direction to X The positive direction of the shaft is the forward direction , therefore urdf The wheel of the model needs to be considered to go around Y The shaft .

5.6 Reference content and resource connection

5.6.1 Reference content of simulation modeling

1、B standing ROS Introduction and practice ：【 Aote School Park 】ROS Introduction to Robotics 《ROS Theory and practice 》 Zero basic course
2、ROS-WIKI：https://wiki.ros.org/urdf/XML
3、gazebo official ：http://gazebosim.org/tutorials?tut=ros_gzplugins

5.6.2 Simulation scene resource connection

0 Integral resources

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