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    阿克曼urdf模型构建错误

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    ROS2机器人开发：从入门到实践
    gazebo urdf配置
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    • 27616077292
      赤诚
      最后由 编辑

      阿克曼urdf模型在构建的时候，同时加入左前轮和右前轮的转动连杆时，模型就显示错误，不加的话可以显示，但是无法正常控制使用，在gazebo设置中的wheels
      <left_steering_joint>fr_left_steer_joint</left_steering_joint>
      <right_steering_joint>fr_right_steer_joint</right_steering_joint>
      这两句代码，加与不加的效果如下
      8947b1c2-cda6-479f-91a5-8fa8a781d284-image.png 这是不加的效果
      47d6a261-29c6-41fd-a7ff-7f4aca1e1565-image.png 这是加了的效果

      下面是完整的urdf代码

      <!-- 底盘实现 -->
      <robot xmlns:xacro="http://www.ros.org/wiki/xacro" name="car">
      <!-- 1、需要声明变量-->
      <!-- PI值 -->
      <xacro:property name="PI" value="3.1415927"/>
      <!-- 底盘尺寸质量 -->
      <xacro:property name="car_length" value="0.27"/>
      <xacro:property name="car_width" value="0.185"/>
      <xacro:property name="car_height" value="0.055"/>
      <xacro:property name="car_mass" value="20"/>

      <!-- 轮胎尺寸质量连杆质量 -->
<xacro:property name="wheel_radius" value="0.0375"/>
<xacro:property name="wheel_length" value="0.03"/>
<xacro:property name="wheel_mass" value="2"/>
<xacro:property name="steering_mass" value="0.01" />
<!-- 轮胎关节平移量 -->
<xacro:property name="wheel_joint_x" value="0.085"/>
<xacro:property name="wheel_joint_y" value="0.09"/>
<xacro:property name="wheel_joint_z" value="${-(car_height/2 + distance - wheel_radius)}"/>
<!-- 雷达属性 -->
<xacro:property name="laser_radius" value="0.03"/>
<xacro:property name="laser_length" value="0.03"/>
<!-- 雷达关节偏移量 -->
<xacro:property name="laser_joint_x" value="0.04"/>
<xacro:property name="laser_joint_y" value="0.0"/>
<xacro:property name="laser_joint_z" value="${car_height/2 + laser_length/2}"/>
<!-- 离地间距 --> 
<xacro:property name="distance" value="0.07"/>
<!-- 抽取颜色 -->
<material name="black">
   <color rgba="0.0 0.0 0.0 1.0"/>
</material>
<material name="white">
   <color rgba="1.0 1.0 1.0 1.0"/>
</material>
<material name="blue">
    <color rgba="0.0 0.0 0.4 1.0"/>
</material>


<!-- 2、设置base_footprint -->
<link name="base_footprint">
    <!-- <visual>
        <geometry>
                <sphere radius="0.001"/>
        </geometry>
    </visual> -->
    <origin xyz="0 0 0" rpy="0 0 0" />
</link>
 <!-- 3、设置base_link -->
 <link name="base_link">
    <visual>
        <geometry>
            <box size="${car_length} ${car_width} ${car_height}"/>
        </geometry>
        <origin xyz="0 0 0 " rpy="0 0 0"/>
        <material name="white"/>
    </visual>
    <!-- 3-1、设置碰撞参数 -->
    <collision>
        <geometry>
            <box size="${car_length} ${car_width} ${car_height}"/>
        </geometry>
        <origin xyz="0 0 0 " rpy="0 0 0"/>
    </collision>
    <!-- 3-2、设置惯性矩阵 -->
    <inertial>
        <mass value="${car_mass}" />
        <inertia ixx="${car_mass/12 * (car_width*car_width + car_height*car_height)}"
            ixy="0" ixz="0"
            iyy="${car_mass/12 * (car_length*car_length + car_height*car_height)}" iyz="0"
            izz="${car_mass/12 * (car_width*car_width + car_length*car_length)}" />
    </inertial>   
</link>
<!-- 3-3 gazebo设置颜色 -->
<gazebo reference="base_link">
    <material>Gazebo/White</material>
</gazebo>
<!-- 3-4、使用joint将二者关联 -->
<joint name="base_joint" type="fixed">
    <parent link="base_footprint"/>
    <child link="base_link"/>
    <origin xyz="0.0 0.0 ${car_height/2 + distance}"/>
</joint>

<!-- 4、左前轮 -->
<!-- 4-1、左前轮转动杆 -->
<link name="fr_left_steer_link">
    <inertial>
        <mass value="${steering_mass}" />
        <inertia
            ixx="${steering_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            ixy="0" ixz="0"
            iyy="${steering_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            iyz="0" izz="${steering_mass/2 * wheel_radius*wheel_radius}" />
    </inertial>
</link>
<!-- 4-2、将转动连杆与车体连接 -->
<joint name="fr_left_steer_joint" type="revolute">
    <origin xyz="${wheel_joint_x} ${wheel_joint_y} 0" rpy="0 0 0" />
    <parent link="base_link" />
    <child link="fr_left_steer_link" />
    <axis xyz="0 0 1" />
    <limit upper="0.6" lower="-0.6" effort="-1.0" velocity="-1.0" />
</joint>
<!-- 4-3、设置左前车轮 -->
<link name="fr_left_wheel">
    <visual>
        <origin xyz="0 0 0" rpy="1.5707963 0 0" />
        <geometry>
            <cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
        </geometry>
        <material name="black"/>
    </visual>
    <!-- 4-4 设置碰撞参数 -->
    <collision>
        <origin xyz="0 0 0" rpy="1.5707963 0 0" />
        <geometry>
            <cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
        </geometry>
    </collision>
    <!-- 4-5 设置惯性矩阵 -->
    <inertial>
        <mass value="${wheel_mass}" />
        <inertia
            ixx="${wheel_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            ixy="0" ixz="0"
            iyy="${wheel_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            iyz="0" izz="${wheel_mass/2 * wheel_radius*wheel_radius}" />
    </inertial>
</link>
<!-- 4-6、gazebo有自己的颜色设置标签 -->
<gazebo reference="fr_left_wheel">
    <material>Gazebo/Black</material>
</gazebo>
<!-- 4-7、与转动连杆连接起来 -->
<joint name="fr_left_wheel_joint" type="continuous">
    <origin xyz="0 0 ${wheel_joint_z}" />
    <parent link="fr_left_steer_link" />
    <child link="fr_left_wheel" />
    <axis xyz="0 0 -1" />
    <dynamics friction="0.8" damping="0.5" />
    <limit lower="-3.14159" upper="3.14159" effort="200" velocity="-1" />
</joint>

<!-- 5、右前轮 -->
<!-- 5-1、右前轮转动杆 -->
<link name="fr_right_steer_link">
    <inertial>
        <mass value="${steering_mass}" />
        <inertia
            ixx="${steering_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            ixy="0" ixz="0"
            iyy="${steering_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            iyz="0" izz="${steering_mass/2 * wheel_radius*wheel_radius}" />
    </inertial>
</link>
<!-- 5-2、将转动连杆与车体连接 -->
<joint name="fr_right_steer_joint" type="revolute">
    <origin xyz="${wheel_joint_x} -${wheel_joint_y} 0" rpy="0 0 0" />
    <parent link="base_link" />
    <child link="fr_right_steer_link" />
    <axis xyz="0 0 1" />
    <limit upper="0.6" lower="-0.6" effort="-1.0" velocity="-1.0" />
</joint>
<!-- 5-3、设置右前车轮 -->
<link name="fr_right_wheel">
    <visual>
        <origin xyz="0 0 0" rpy="1.5707963 0 0" />
        <geometry>
            <cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
        </geometry>
        <material name="black"/>
    </visual>
    <!-- 5-4 设置碰撞参数 -->
    <collision>
        <origin xyz="0 0 0" rpy="1.5707963 0 0" />
        <geometry>
            <cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
        </geometry>
    </collision>
    <!-- 5-5 设置惯性矩阵 -->
    <inertial>
        <mass value="${wheel_mass}" />
        <inertia
            ixx="${wheel_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            ixy="0" ixz="0"
            iyy="${wheel_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            iyz="0" izz="${wheel_mass/2 * wheel_radius*wheel_radius}" />
    </inertial>
</link>
<!-- 5-6、gazebo有自己的颜色设置标签 -->
<gazebo reference="fr_right_wheel">
    <material>Gazebo/Black</material>
</gazebo>
<!-- 5-7、与转动连杆连接起来 -->
<joint name="fr_right_wheel_joint" type="continuous">
    <origin xyz="0 0 ${wheel_joint_z}" />
    <parent link="fr_right_steer_link" />
    <child link="fr_right_wheel" />
    <axis xyz="0 0 1" />
    <dynamics friction="0.8" damping="0.5" />
    <limit lower="-3.14159" upper="3.14159" effort="200" velocity="-1" />
</joint>

<!-- 6、左后轮 -->
<!-- 6-1、设置左后车轮 -->
<link name="re_left_wheel">
    <visual>
        <origin xyz="0 0 0" rpy="1.5707963 0 0" />
        <geometry>
            <cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
        </geometry>
        <material name="black"/>
    </visual>
    <!-- 6-2 设置碰撞参数 -->
    <collision>
        <origin xyz="0 0 0" rpy="1.5707963 0 0" />
        <geometry>
            <cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
        </geometry>
    </collision>
    <!-- 6-3 设置惯性矩阵 -->
    <inertial>
        <mass value="${wheel_mass}" />
        <inertia
            ixx="${wheel_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            ixy="0" ixz="0"
            iyy="${wheel_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            iyz="0" izz="${wheel_mass/2 * wheel_radius*wheel_radius}" />
    </inertial>
</link>
<!-- 6-4、gazebo有自己的颜色设置标签 -->
<gazebo reference="re_left_wheel">
    <material>Gazebo/Black</material>
</gazebo>
<!-- 6-5、与车体连接起来 -->
<joint name="re_left_wheel_joint" type="continuous">
    <origin xyz="-${wheel_joint_x} ${wheel_joint_y} ${wheel_joint_z}" />
    <parent link="base_link" />
    <child link="re_left_wheel" />
    <axis xyz="0 0 1" />
    <dynamics friction="0.8" damping="0.5" />
    <limit lower="-3.14159" upper="3.14159" effort="200" velocity="-1" />
</joint>

<!-- 7、右后轮 -->
<!-- 7-1、设置右后车轮 -->
<link name="re_right_wheel">
    <visual>
        <origin xyz="0 0 0" rpy="1.5707963 0 0" />
        <geometry>
            <cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
        </geometry>
        <material name="black"/>
    </visual>
    <!-- 7-2 设置碰撞参数 -->
    <collision>
        <origin xyz="0 0 0" rpy="1.5707963 0 0" />
        <geometry>
            <cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
        </geometry>
    </collision>
    <!-- 7-3 设置惯性矩阵 -->
    <inertial>
        <mass value="${wheel_mass}" />
        <inertia
            ixx="${wheel_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            ixy="0" ixz="0"
            iyy="${wheel_mass/12*(3*wheel_radius*wheel_radius + wheel_length*wheel_length)}"
            iyz="0" izz="${wheel_mass/2 * wheel_radius*wheel_radius}" />
    </inertial>
</link>
<!-- 7-4、gazebo有自己的颜色设置标签 -->
<gazebo reference="re_right_wheel">
    <material>Gazebo/Black</material>
</gazebo>
<!-- 7-5、与车体连接起来 -->
<joint name="re_right_wheel_joint" type="continuous">
    <origin xyz="-${wheel_joint_x} -${wheel_joint_y} ${wheel_joint_z}" />
    <parent link="base_link" />
    <child link="re_right_wheel" />
    <axis xyz="0 0 1" />
    <dynamics friction="0.8" damping="0.5" />
    <limit lower="-3.14159" upper="3.14159" effort="200" velocity="-1" />
</joint>

<!-- 8、虚拟方向盘 -->
<link name="virtual_steer_link">
    <visual>
        <origin xyz="0.0 0.0 0.0" rpy="0.0 0.0 0.0" />
        <geometry>
            <box size="0.01 0.01 0.01" />
        </geometry>
        <material name="steer">
            <color rgba="1.0 1.0 0.0 1" />
        </material>
    </visual>
    <inertial>  <!-- Gazebo won't show this link without this inertial mass -->
        <origin xyz="0.0 0.0 0.0" rpy="0.0 0.0 0.0" />
        <mass value="0.001" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0" />
    </inertial>
</link>
<joint name="virtual_steering_wheel_joint" type="revolute">
    <origin xyz="-${wheel_joint_x} 0.0 0.0" rpy="0.0 0.0 0.0" />
    <parent link="base_link" />
    <child link="virtual_steer_link" />
    <axis xyz="-1 0 0" />
    <limit lower="-3" upper="3" effort="200" velocity="20" />
</joint>


<!-- 给上面的一些属性添加物理因素 -->
<gazebo reference="base_link">
    <material>Gazebo/White</material>
    <mu1>0.5</mu1>   <!-- 静摩擦系数 -->
    <mu2>0.5</mu2>   <!-- 滑动摩擦系数 -->
</gazebo>
<gazebo reference="fr_left_wheel">
    <material>Gazebo/Black</material>
    <mu1>1.0</mu1>
    <mu2>1.0</mu2>
</gazebo>
<gazebo reference="fr_right_wheel">
    <material>Gazebo/Black</material>
    <mu1>1.0</mu1>
    <mu2>1.0</mu2>
</gazebo>
<gazebo reference="re_left_wheel">
    <material>Gazebo/Black</material>
    <mu1>1.0</mu1>
    <mu2>1.0</mu2>
</gazebo>
<gazebo reference="re_right_wheel">
    <material>Gazebo/Black</material>
    <mu1>1.0</mu1>
    <mu2>1.0</mu2>
</gazebo>
<!-- 虚拟方向盘 -->
<gazebo reference="virtual_steer_link">
    <material>Gazebo/Yellow</material>
</gazebo>

<!-- 发布机器人的关节状态 (joint_states)，并通过 ROS 2 系统与机器人状态发布器 (robot_state_publisher) -->
<!-- Here's an example message to publish to test it:
        ros2 topic pub -1 /set_joint_trajectory trajectory_msgs/msg/JointTrajectory  '{header: {frame_id:
world}, joint_names: [slider_joint, arm_joint], points: [  {positions: {0.8,0.6}} ]}' -->
<gazebo>
    <plugin name="gazebo_ros_joint_state_publisher"
        filename="libgazebo_ros_joint_state_publisher.so">
        <update_rate>100</update_rate>
        <joint_name>fr_right_steer_joint</joint_name>
        <joint_name>fr_right_wheel_joint</joint_name>
        <joint_name>fr_left_steer_joint</joint_name>
        <joint_name>fr_left_wheel_joint</joint_name>
        <joint_name>re_right_wheel_joint</joint_name>
        <joint_name>re_left_wheel_joint</joint_name>
        <joint_name>virtual_steering_wheel_joint</joint_name>
    </plugin>
</gazebo>

<!-- 插件从 ROS 话题 /set_joint_trajectory 接收 JointTrajectory 消息并控制机器人关节运动。 -->
<gazebo>
    <plugin name="gazebo_ros_joint_pose_trajectory"
        filename="libgazebo_ros_joint_pose_trajectory.so">
        <update_rate>2</update_rate>
    </plugin>
</gazebo>


<!-- 阿克曼Gazebo插件 -->
<gazebo>
    <plugin name='gazebo_ackermann_drive' filename='libgazebo_ros_ackermann_drive.so'>
        <ros>
            <!-- <namespace>ugv_gazebo_ackermann</namespace> -->
            <remapping>cmd_vel:=cmd_vel</remapping>
            <remapping>odom:=odom</remapping>
            <remapping>distance:=distance</remapping>
        </ros>

        <update_rate>100.0</update_rate>

        <!-- wheels -->
        <front_left_joint>fr_left_wheel_joint</front_left_joint>
        <front_right_joint>fr_right_wheel_joint</front_right_joint>
        <rear_left_joint>re_left_wheel_joint</rear_left_joint>
        <rear_right_joint>re_right_wheel_joint</rear_right_joint>
        <left_steering_joint>fr_left_steer_joint</left_steering_joint>
        <!-- <right_steering_joint>fr_right_steer_joint</right_steering_joint> -->
        <steering_wheel_joint>virtual_steering_wheel_joint</steering_wheel_joint>

        <!-- 车轮最大转向角 -->
        <max_steer>0.383972</max_steer>

        <!-- 方向盘最大转向角 -->
        <max_steering_angle>1.570796</max_steering_angle>

        <!-- 车辆最大线速度 m/s -->
        <max_speed>5</max_speed>

        <!-- PID 参数 -->
        <left_steering_pid_gain>1500 0 1</left_steering_pid_gain>
        <left_steering_i_range>0 0</left_steering_i_range>
        <right_steering_pid_gain>1500 0 1</right_steering_pid_gain>
        <right_steering_i_range>0 0</right_steering_i_range>
        <linear_velocity_pid_gain>1500 0 1</linear_velocity_pid_gain>
        <linear_velocity_i_range>0 0</linear_velocity_i_range>

        <!-- output -->
        <publish_odom>true</publish_odom>
        <publish_odom_tf>true</publish_odom_tf>     <!-- Don't pubslish this when using robot
        localization -->
        <publish_wheel_tf>false</publish_wheel_tf>  <!-- Don't publish this. It will override all
        wheel frames to robot_base_frame parameter below.-->
        <publish_distance>true</publish_distance>

        <odometry_frame>odom</odometry_frame>
        <robot_base_frame>base_footprint</robot_base_frame>

    </plugin>
</gazebo>

      </robot>

      小鱼小 1 条回复 最后回复 回复 引用 0
      • 小鱼小
        小鱼 技术大佬 @2761607729
        最后由 编辑

        @2761607729 看看有没有什么插件报错，不行可以用ros2-control

        新书配套视频：https://www.bilibili.com/video/BV1GW42197Ck/

        27616077292 1 条回复 最后回复 回复 引用 0
        • 27616077292
          赤诚 @小鱼
          最后由 编辑

          @小鱼 插件没有报错，这也是从github上面搬下来的，我自己又重写了一个，感觉像逻辑问题，但是搞了好久也没找见是那个问题

          1 条回复 最后回复 回复 引用 0
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