Gazebo control example

Movement control implementation process

roslaunch urdf02_gazebo demo03_env.launch

start-up gazebo Simulation environment demo03_env.launch

launch file

<launch>
    <!-- 1.  It needs to be loaded in the parameter server  urdf -->
    <param name = "robot_description" command = "$(find xacro)/xacro $(find urdf02_gazebo)/urdf/car.urdf.xacro" />
    <!-- 2.  start-up Gazebo Simulation environment  roslaunch gazebo_ros empty_world.launch-->
    <include file = "$(find gazebo_ros)/launch/empty_world.launch">
        <arg name = "world_name" value = "$(find urdf02_gazebo)/worlds/box_house.world" />
    </include>
    <!-- 3.  stay Gazebo Add robot model in  -->
    <!-- rosrun gazebo_ros spawn_model -urdf -model mycar -param robot_description ,  here mycar yes robot name-->
    <node pkg = "gazebo_ros" type = "spawn_model" name = "spawn_model" args = "-urdf -model mycar -param robot_description"/>
</launch>

Add drives and controllers move.xacro

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

    <!--  Transmission realization : Used to connect the controller to the joint  -->
    <xacro:macro name="joint_trans" params="joint_name">
        <!-- Transmission is important to link the joints and the controller -->
        <transmission name="${joint_name}_trans">
            <type>transmission_interface/SimpleTransmission</type>
            <joint name="${joint_name}">
                <hardwareInterface>hardware_interface/VelocityJointInterface</hardwareInterface>
            </joint>
            <actuator name="${joint_name}_motor">
                <hardwareInterface>hardware_interface/VelocityJointInterface</hardwareInterface>
                <mechanicalReduction>1</mechanicalReduction>
            </actuator>
        </transmission>
    </xacro:macro>

    <!--  Each driving wheel needs to be equipped with a transmission device  -->
    <xacro:joint_trans joint_name="left2link" />
    <xacro:joint_trans joint_name="right2link" />

    <!--  controller  -->
    <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>left2ink</leftJoint> <!--  Left wheel  -->
            <rightJoint>right2link</rightJoint> <!--  Right wheel  -->
            <wheelSeparation>${base_radius * 2}</wheelSeparation> <!--  Wheel spacing  -->
            <wheelDiameter>${wheel_radius * 2}</wheelDiameter> <!--  Wheel diameter  -->
            <broadcastTF>1</broadcastTF>
            <wheelTorque>30</wheelTorque>
            <wheelAcceleration>1.8</wheelAcceleration>
            <commandTopic>cmd_vel</commandTopic> <!--  Motion control topics  -->
            <odometryFrame>odom</odometryFrame> <!--  Coordinate system of odometer  -->
            <odometryTopic>odom</odometryTopic> <!--  Odometer topic  -->
            <robotBaseFrame>base_footprint</robotBaseFrame> <!--  Root coordinate system  -->
        </plugin>
    </gazebo>
</robot>

add to xacro Integrated file car.urdf.xacro

<robot name="mycar" xmlns:xacro="http://wiki.ros.org/xacro">
    <!--  Contains inertia matrix files  -->
    <xacro:include filename = "head.xacro" />
    <!--  Including chassis 、 camera 、 Radar xacro file  -->
    <xacro:include filename = "demo02_car_base.urdf.xacro" />
    <xacro:include filename = "demo03_car_camera.urdf.xacro" />
    <xacro:include filename = "demo04_car_laser.urdf.xacro" />
    <!--  Motion control  -->
    <xacro:include filename = "gazebo/move.xacro" />
</robot>

Rviz Check odometer messages

Odometer : The pose state of the robot relative to the starting point coordinate system (X coordinate Y coordinate Z Coordinates and orientation )

start-up Rviz demo04_sensor.launch

<launch>
    <!--  start-up rviz -->
    <node pkg = "rviz" type = "rviz" name = "rviz" args = "-d $(find urdf01_rviz)/config/show_mycar.rviz"/>

    <!--  Add joint status publishing node  -->
    <node pkg = "joint_state_publisher" type = "joint_state_publisher" name = "joint_state_publisher" />

    <!--  Add robot status publishing node  -->
    <node pkg = "robot_state_publisher" type = "robot_state_publisher" name = "robot_state_publisher" />

</launch>

source ./devel/setup.bash
roslaunch urdf02_gazebo demo03_env.launch
roslaunch urdf02_gazebo demo04_sensor.launch

Add the component

radar laser.xacro

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

  <!--  radar  -->
  <gazebo reference="laser"><!-- reference  The name should match demo04_car_laser The radar inside has the same name -->
    <sensor type="ray" name="rplidar">
      <pose>0 0 0 0 0 0</pose><!-- x y z  Euler Angle  -->
      <visualize>true</visualize>
      <update_rate>5.5</update_rate>
      <ray>
        <scan>
          <horizontal>
            <samples>360</samples> <!-- The radar rotates for one cycle to collect 360 A little bit -->
            <resolution>1</resolution><!-- Each line will have a ranging ,2 It means that there will be one ranging for each two lines -->>
            <min_angle>-3</min_angle><!--  The unit is radians   turn right 3 A radian   Clockwise -->
            <max_angle>3</max_angle>
          </horizontal>
        </scan>
        <range>
          <min>0.10</min><!-- Radar sampling distance -->
          <max>30.0</max>
          <resolution>0.01</resolution><!-- accuracy -->
        </range>
        <noise>
          <type>gaussian</type><!-- Gauss noise   For simulation   Simulation error  -->
          <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><!-- The name should match demo04_car_laser The radar inside has the same name -->
      </plugin>
    </sensor>
  </gazebo>
</robot>

camera camera.xacro

<robot name="my_sensors" xmlns:xacro="http://wiki.ros.org/xacro">
  <!--  Quoted link -->
  <gazebo reference="camera">
    <!--  The type is set to  camara -->
    <sensor type="camera" name="camera_node">
      <update_rate>30.0</update_rate> <!--  The update frequency  -->
      <!--  Camera basic information settings  -->
      <camera name="head">
        <horizontal_fov>1.3962634</horizontal_fov>
        <image>
          <width>1280</width>
          <height>720</height>
          <format>R8G8B8</format>
        </image>
        <clip>
          <near>0.02</near>
          <far>300</far>
        </clip>
        <noise>
          <type>gaussian</type>
          <mean>0.0</mean>
          <stddev>0.007</stddev>
        </noise>
      </camera>
      <!--  Core plug-ins  -->
      <plugin name="gazebo_camera" filename="libgazebo_ros_camera.so">
        <alwaysOn>true</alwaysOn>
        <updateRate>0.0</updateRate>
        <cameraName>/camera</cameraName>
        <imageTopicName>image_raw</imageTopicName>
        <cameraInfoTopicName>camera_info</cameraInfoTopicName>
        <frameName>camera</frameName>
        <hackBaseline>0.07</hackBaseline>
        <distortionK1>0.0</distortionK1>
        <distortionK2>0.0</distortionK2>
        <distortionK3>0.0</distortionK3>
        <distortionT1>0.0</distortionT1>
        <distortionT2>0.0</distortionT2>
      </plugin>
    </sensor>
  </gazebo>
</robot>

rostopic pub -r 10 /cmd_vel  Set parameters to make the robot rotate