Gazebo 控制实例

运动控制实现流程

roslaunch urdf02_gazebo demo03_env.launch

启动gazebo仿真环境 demo03_env.launch

launch文件

<launch>
    <!-- 1. 需要再参数服务器中载入 urdf -->
    <param name = "robot_description" command = "$(find xacro)/xacro $(find urdf02_gazebo)/urdf/car.urdf.xacro" />
    <!-- 2. 启动Gazebo仿真环境 roslaunch gazebo_ros empty_world.launch-->
    <include file = "$(find gazebo_ros)/launch/empty_world.launch">
        <arg name = "world_name" value = "$(find urdf02_gazebo)/worlds/box_house.world" />
    </include>
    <!-- 3. 在Gazebo中添加机器人模型 -->
    <!-- rosrun gazebo_ros spawn_model -urdf -model mycar -param robot_description , 这里mycar是robot name-->
    <node pkg = "gazebo_ros" type = "spawn_model" name = "spawn_model" args = "-urdf -model mycar -param robot_description"/>
</launch>

添加传动装置及控制器 move.xacro

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

    <!-- 传动实现:用于连接控制器与关节 -->
    <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>

    <!-- 每一个驱动轮都需要配置传动装置 -->
    <xacro:joint_trans joint_name="left2link" />
    <xacro:joint_trans joint_name="right2link" />

    <!-- 控制器 -->
    <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> <!-- 左轮 -->
            <rightJoint>right2link</rightJoint> <!-- 右轮 -->
            <wheelSeparation>${base_radius * 2}</wheelSeparation> <!-- 车轮间距 -->
            <wheelDiameter>${wheel_radius * 2}</wheelDiameter> <!-- 车轮直径 -->
            <broadcastTF>1</broadcastTF>
            <wheelTorque>30</wheelTorque>
            <wheelAcceleration>1.8</wheelAcceleration>
            <commandTopic>cmd_vel</commandTopic> <!-- 运动控制话题 -->
            <odometryFrame>odom</odometryFrame> <!-- 里程计的坐标系 -->
            <odometryTopic>odom</odometryTopic> <!-- 里程计话题 -->
            <robotBaseFrame>base_footprint</robotBaseFrame> <!-- 根坐标系 -->
        </plugin>
    </gazebo>
</robot>

添加xacro集成文件 car.urdf.xacro

<robot name="mycar" xmlns:xacro="http://wiki.ros.org/xacro">
    <!-- 包含惯性矩阵文件 -->
    <xacro:include filename = "head.xacro" />
    <!-- 包含底盘、摄像头、雷达的xacro文件 -->
    <xacro:include filename = "demo02_car_base.urdf.xacro" />
    <xacro:include filename = "demo03_car_camera.urdf.xacro" />
    <xacro:include filename = "demo04_car_laser.urdf.xacro" />
    <!-- 运动控制 -->
    <xacro:include filename = "gazebo/move.xacro" />
</robot>

Rviz 查看里程计消息

里程计: 机器人相对出发点坐标系的位姿状态(X 坐标 Y 坐标 Z坐标以及朝向)

启动Rviz demo04_sensor.launch

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

    <!-- 添加关节状态发布节点 -->
    <node pkg = "joint_state_publisher" type = "joint_state_publisher" name = "joint_state_publisher" />

    <!-- 添加机器人状态发布节点 -->
    <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

添加组件

雷达 laser.xacro

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

  <!-- 雷达 -->
  <gazebo reference="laser"><!-- reference 名字要与demo04_car_laser里面雷达名字相同-->
    <sensor type="ray" name="rplidar">
      <pose>0 0 0 0 0 0</pose><!-- x y z 欧拉角 -->
      <visualize>true</visualize>
      <update_rate>5.5</update_rate>
      <ray>
        <scan>
          <horizontal>
            <samples>360</samples> <!--雷达旋转一周采集360个点-->
            <resolution>1</resolution><!--每一个线会有一根测距，2表示每两根线会有一根测距-->>
            <min_angle>-3</min_angle><!-- 单位是弧度 向右转3个弧度 顺时针-->
            <max_angle>3</max_angle>
          </horizontal>
        </scan>
        <range>
          <min>0.10</min><!--雷达采样距离-->
          <max>30.0</max>
          <resolution>0.01</resolution><!--精确度-->
        </range>
        <noise>
          <type>gaussian</type><!--高斯噪音 用于仿真 模拟误差 -->
          <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><!--名字要与demo04_car_laser里面雷达名字相同-->
      </plugin>
    </sensor>
  </gazebo>
</robot>

摄像头 camera.xacro

<robot name="my_sensors" xmlns:xacro="http://wiki.ros.org/xacro">
  <!-- 被引用的link -->
  <gazebo reference="camera">
    <!-- 类型设置为 camara -->
    <sensor type="camera" name="camera_node">
      <update_rate>30.0</update_rate> <!-- 更新频率 -->
      <!-- 摄像头基本信息设置 -->
      <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>
      <!-- 核心插件 -->
      <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 设置参数让机器人转动