ros仿真练习代码

<?xml version="1.0"?>
<robot name="mbot" xmlns:xacro="http://www.ros.org/wiki/xacro">

    <!-- PROPERTY LIST -->
    <xacro:property name="M_PI" value="3.1415926"/>
    <xacro:property name="base_mass"   value="20" /> 
    <xacro:property name="base_radius" value="0.20"/>
    <xacro:property name="base_length" value="0.16"/>

    <xacro:property name="wheel_mass"   value="2" />
    <xacro:property name="wheel_radius" value="0.06"/>
    <xacro:property name="wheel_length" value="0.025"/>
    <xacro:property name="wheel_joint_x" value="0.25"/>
    <xacro:property name="wheel_joint_y" value="0.19"/>
    <xacro:property name="wheel_joint_z" value="0.05"/>

    <xacro:property name="caster_mass"    value="0.5" /> 
    <xacro:property name="caster_radius"  value="0.015"/> <!-- wheel_radius - ( base_length/2 - wheel_joint_z) -->
    <xacro:property name="caster_joint_x" value="0.18"/>

    <!-- Defining the colors used in this robot -->
    <material name="yellow">
        <color rgba="1 0.4 0 1"/>
    </material>
    <material name="black">
        <color rgba="0 0 0 0.95"/>
    </material>
    <material name="gray">
        <color rgba="0.75 0.75 0.75 1"/>
    </material>
    
    <!-- Macro for inertia matrix -->
    <xacro:macro name="sphere_inertial_matrix" params="m r">
        <inertial>
            <mass value="${m}" />
            <inertia ixx="${2*m*r*r/5}" ixy="0" ixz="0"
                iyy="${2*m*r*r/5}" iyz="0" 
                izz="${2*m*r*r/5}" />
        </inertial>
    </xacro:macro>

    <xacro:macro name="cylinder_inertial_matrix" params="m r h">
        <inertial>
            <mass value="${m}" />
            <inertia ixx="${m*(3*r*r+h*h)/12}" ixy = "0" ixz = "0"
                iyy="${m*(3*r*r+h*h)/12}" iyz = "0"
                izz="${m*r*r/2}" /> 
        </inertial>
    </xacro:macro>

    <!-- Macro for robot wheel -->
    <xacro:macro name="wheel" params="prefix reflect">
        <joint name="${prefix}_wheel_joint" type="continuous">
            <origin xyz="${reflect*wheel_joint_x} ${reflect*wheel_joint_y} ${-wheel_joint_z}" rpy="0 0 0"/>
            <parent link="base_link"/>
            <child link="${prefix}_wheel_link"/>
            <axis xyz="0 1 0"/>
        </joint>

        <link name="${prefix}_wheel_link">
            <visual>
                <origin xyz="0 0 0" rpy="${M_PI/2} 0 0" />
                <geometry>
                    <cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
                </geometry>
                <material name="gray" />
            </visual>
            <collision>
                <origin xyz="0 0 0" rpy="${M_PI/2} 0 0" />
                <geometry>
                    <cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
                </geometry>
            </collision>
            <cylinder_inertial_matrix  m="${wheel_mass}" r="${wheel_radius}" h="${wheel_length}" />
        </link>

        <gazebo reference="${prefix}_wheel_link">
            <material>Gazebo/Gray</material>
        </gazebo>

        <!-- Transmission is important to link the joints and the controller -->
        <transmission name="${prefix}_wheel_joint_trans">
            <type>transmission_interface/SimpleTransmission</type>
            <joint name="${prefix}_wheel_joint" >
                <hardwareInterface>hardware_interface/VelocityJointInterface</hardwareInterface>
            </joint>
            <actuator name="${prefix}_wheel_joint_motor">
                <hardwareInterface>hardware_interface/VelocityJointInterface</hardwareInterface>
                <mechanicalReduction>1</mechanicalReduction>
            </actuator>
        </transmission>
    </xacro:macro>

    <!-- Macro for robot caster -->
    <xacro:macro name="caster" params="prefix reflect">
        <joint name="${prefix}_caster_joint" type="continuous">
            <origin xyz="${reflect*caster_joint_x} 0 ${-(base_length/2 + caster_radius)}" rpy="0 0 0"/>
            <parent link="base_link"/>
            <child link="${prefix}_caster_link"/>
            <axis xyz="0 1 0"/>
        </joint>

        <link name="${prefix}_caster_link">
            <visual>
                <origin xyz="0 0 0" rpy="0 0 0"/>
                <geometry>
                    <sphere radius="${caster_radius}" />
                </geometry>
                <material name="black" />
            </visual>
            <collision>
                <origin xyz="0 0 0" rpy="0 0 0"/>
                <geometry>
                    <sphere radius="${caster_radius}" />
                </geometry>
            </collision>      
            <sphere_inertial_matrix  m="${caster_mass}" r="${caster_radius}" />
        </link>

        <gazebo reference="${prefix}_caster_link">
            <material>Gazebo/Black</material>
        </gazebo>
    </xacro:macro>

    <xacro:macro name="mbot_base_gazebo">
        <link name="base_footprint">
            <visual>
                <origin xyz="0 0 0" rpy="0 0 0" />
                <geometry>
                    <box size="0.001 0.001 0.001" />
                </geometry>
            </visual>
        </link>
        <gazebo reference="base_footprint">
            <turnGravityOff>false</turnGravityOff>
        </gazebo>

        <joint name="base_footprint_joint" type="fixed">
            <origin xyz="0 0 ${base_length/2 + caster_radius*2}" rpy="0 0 0" />        
            <parent link="base_footprint"/>
            <child link="base_link" />
        </joint>

        <link name="base_link">
            <visual>
                <origin xyz=" 0 0 0" rpy="0 0 0" />
                <geometry>
                    <box length="0.6 0.4 0.2"/>
                </geometry>
                <material name="yellow" />
            </visual>
            <collision>
                <origin xyz=" 0 0 0" rpy="0 0 0" />
                <geometry>
                    <cylinder length="${base_length}" radius="${base_radius}"/>
                </geometry>
            </collision>   
            <cylinder_inertial_matrix  m="${base_mass}" r="${base_radius}" h="${base_length}" />
        </link>

        <gazebo reference="base_link">
            <material>Gazebo/Blue</material>
        </gazebo>

        <wheel prefix="leftfront"  reflect="-1"/>
        <wheel prefix="rightfront" reflect="1"/>
        <wheel prefix="righthidden" reflect="1"/>
        <wheel prefix="lefthidden"  reflect="-1"/>

        <caster prefix="front" reflect="-1"/>
        <caster prefix="back"  reflect="1"/>

        <!-- 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>left_wheel_joint</leftJoint>
                <rightJoint>right_wheel_joint</rightJoint>
                <wheelSeparation>${wheel_joint_y*2}</wheelSeparation>
                <wheelDiameter>${2*wheel_radius}</wheelDiameter>
                <broadcastTF>1</broadcastTF>
                <wheelTorque>30</wheelTorque>
                <wheelAcceleration>1.8</wheelAcceleration>
                <commandTopic>cmd_vel</commandTopic>
                <odometryFrame>odom</odometryFrame> 
                <odometryTopic>odom</odometryTopic> 
                <robotBaseFrame>base_footprint</robotBaseFrame>
            </plugin>
        </gazebo> 
    </xacro:macro>

</robot>

<gazebo>
 <plugin name="skid_steer_drive_controller" filename="libgazebo_ros_skid_steer_drive.so">
    <alwaysOn>true</alwaysOn>
    <updateRate>${update_rate}</updateRate>
    <leftFrontJoint>${base_link_wheel1_joint}</leftFrontJoint>
    <rightFrontJoint>${base_link_wheel2_joint}</rightFrontJoint>
   <leftRearJoint>${base_link_wheel3_joint}</leftRearJoint>
    <rightRearJoint>${base_link_wheel4_joint}</rightRearJoint> 
    <wheelSeparation>0.100</wheelSeparation> 
    <wheelDiameter>0.040</wheelDiameter>
    <torque>20</torque>
    <commandTopic>cmd_vel</commandTopic>
    <odometryTopic>odom</odometryTopic>
    <odometryFrame>odom</odometryFrame>
    <robotBaseFrame>${base_link}</robotBaseFrame>
    <broadcastTF>1</broadcastTF>
  </plugin>
</gazebo>

<launch>

    <!-- 设置launch文件的参数 -->
    <arg name="world_name" value="$(find mbot_gazebo)/worlds/playground.world"/>
    <arg name="paused" default="false"/>
    <arg name="use_sim_time" default="true"/>
    <arg name="gui" default="true"/>
    <arg name="headless" default="false"/>
    <arg name="debug" default="false"/>

    <!-- 运行gazebo仿真环境 -->
    <include file="$(find gazebo_ros)/launch/empty_world.launch">
        <arg name="world_name" value="$(arg world_name)" />
        <arg name="debug" value="$(arg debug)" />
        <arg name="gui" value="$(arg gui)" />
        <arg name="paused" value="$(arg paused)"/>
        <arg name="use_sim_time" value="$(arg use_sim_time)"/>
        <arg name="headless" value="$(arg headless)"/>
    </include>

    <!-- 加载机器人模型描述参数 -->
    <param name="robot_description" command="$(find xacro)/xacro --inorder '$(find mbot_description)/urdf/xacro/gazebo/mbot_with_laser_gazebo.xacro'" /> 

    <!-- 运行joint_state_publisher节点，发布机器人的关节状态  -->
    <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher" ></node> 

    <!-- 运行robot_state_publisher节点，发布tf  -->
    <node name="robot_state_publisher" pkg="robot_state_publisher" type="robot_state_publisher"  output="screen" >
        <param name="publish_frequency" type="double" value="50.0" />
    </node>

    <!-- 在gazebo中加载机器人模型-->
    <node name="urdf_spawner" pkg="gazebo_ros" type="spawn_model" respawn="false" output="screen"
          args="-urdf -model mrobot -param robot_description"/> 

</launch>