<?xml version="1.0"?>
<robot name="smartcar" xmlns:xacro="http://ros.org/wiki/xacro">
  <property name="M_PI" value="3.14159"/>

  <!-- Macro for SmartCar body. Including Gazebo extensions, but does not include Kinect -->
  <include filename="$(find smartcar_description)/urdf/gazebo.urdf.xacro"/>

  <property name="base_x" value="0.33" />
  <property name="base_y" value="0.33" />

  <xacro:macro name="smartcar_body">


	<link name="base_link">
	<inertial>
      <origin xyz="0 0 0.055"/>
      <mass value="1.0" />
      <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
    <visual>
      <geometry>
        <box size="0.25 .16 .05"/>
      </geometry>
	  <origin rpy="0 0 0" xyz="0 0 0.055"/>
      <material name="blue">
	  <color rgba="0 0 .8 1"/>
      </material>
   </visual>
   <collision>
      <origin rpy="0 0 0" xyz="0 0 0.055"/>
      <geometry>
        <box size="0.25 .16 .05" />
      </geometry>
    </collision>
  </link>


 <link name="left_front_wheel">
	<inertial>
      <origin  xyz="0.08 0.08 0.025"/>
      <mass value="0.1" />
       <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
    <visual>
      <geometry>
        <cylinder length=".02" radius="0.025"/>
      </geometry>
      <material name="black">
        <color rgba="0 0 0 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 1.57075 1.57075" xyz="0.08 0.08 0.025"/>
      <geometry>
         <cylinder length=".02" radius="0.025"/>
      </geometry>
    </collision>
  </link>

  <joint name="left_front_wheel_joint" type="continuous">
    <axis xyz="0 0 1"/>
    <parent link="base_link"/>
    <child link="left_front_wheel"/>
    <origin rpy="0 1.57075 1.57075" xyz="0.08 0.08 0.025"/>
    <limit effort="100" velocity="100"/>
    <joint_properties damping="0.0" friction="0.0"/>
  </joint>

  <link name="right_front_wheel">
	<inertial>
      <origin xyz="0.08 -0.08 0.025"/>
      <mass value="0.1" />
       <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
    <visual>
      <geometry>
        <cylinder length=".02" radius="0.025"/>
      </geometry>
      <material name="black">
        <color rgba="0 0 0 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 1.57075 1.57075" xyz="0.08 -0.08 0.025"/>
      <geometry>
         <cylinder length=".02" radius="0.025"/>
      </geometry>
    </collision>
  </link>

  <joint name="right_front_wheel_joint" type="continuous">
    <axis xyz="0 0 1"/>
    <parent link="base_link"/>
    <child link="right_front_wheel"/>
    <origin rpy="0 1.57075 1.57075" xyz="0.08 -0.08 0.025"/>
    <limit effort="100" velocity="100"/>
    <joint_properties damping="0.0" friction="0.0"/>
 </joint>

 <link name="left_back_wheel">
    <inertial>
      <origin xyz="-0.08 0.08 0.025"/>
      <mass value="0.1" />
       <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
    <visual>
      <geometry>
        <cylinder length=".02" radius="0.025"/>
      </geometry>
      <material name="black">
        <color rgba="0 0 0 1"/>
      </material>
   </visual>
   <collision>
       <origin rpy="0 1.57075 1.57075" xyz="-0.08 0.08 0.025"/>
      <geometry>
         <cylinder length=".02" radius="0.025"/>
      </geometry>
    </collision>
  </link>

  <joint name="left_back_wheel_joint" type="continuous">
    <axis xyz="0 0 1"/>
    <parent link="base_link"/>
    <child link="left_back_wheel"/>
    <origin rpy="0 1.57075 1.57075" xyz="-0.08 0.08 0.025"/>
    <limit effort="100" velocity="100"/>
    <joint_properties damping="0.0" friction="0.0"/>
  </joint>

  <link name="right_back_wheel">
	<inertial>
       <origin xyz="-0.08 -0.08 0.025"/>
       <mass value="0.1" />
       <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
    <visual>
      <geometry>
        <cylinder length=".02" radius="0.025"/>
      </geometry>
      <material name="black">
        <color rgba="0 0 0 1"/>
      </material>
   </visual>
   <collision>
      <origin rpy="0 1.57075 1.57075" xyz="-0.08 -0.08 0.025"/>
      <geometry>
         <cylinder length=".02" radius="0.025"/>
      </geometry>
    </collision>
  </link>


  <joint name="right_back_wheel_joint" type="continuous">
    <axis xyz="0 0 1"/>
    <parent link="base_link"/>
    <child link="right_back_wheel"/>
    <origin rpy="0 1.57075 1.57075" xyz="-0.08 -0.08 0.025"/>
    <limit effort="100" velocity="100"/>
    <joint_properties damping="0.0" friction="0.0"/>
  </joint>

  <link name="head">
	<inertial>
      <origin xyz="0.08 0 0.08"/>
      <mass value="0.1" />
      <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
    <visual>
      <geometry>
        <box size=".02 .03 .03"/>
      </geometry>
	  <material name="white">
		<color rgba="1 1 1 1"/>
	  </material>
     </visual>
     <collision>
      <origin xyz="0.08 0 0.08"/>
      <geometry>
         <cylinder length=".02" radius="0.025"/>
      </geometry>
    </collision>
  </link>

  <joint name="tobox" type="fixed">
    <parent link="base_link"/>
    <child link="head"/>
    <origin xyz="0.08 0 0.08"/>
  </joint>
  </xacro:macro>

</robot>
 

2、gazebo屬性部分