Located at /root/catkin_ws/src/ros_lawn_tractor/lawn_tractor_sim/urdf/lawn_tractor.urdf.xacro

lawn_tractor.urdf.xacro

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

<!-- TODO:  collision link element to be added -->
<!-- TODO:  inertial link element to be added -->

<!-- define base link, center of rear axle for an ackermann vehicle -->
  <link name="base_link">
    <visual>
      <origin xyz='0.55 0 0' rpy='0 0 ${pi}' />
      <geometry>
        <mesh filename="package://lawn_tractor_sim/meshes/lawn_tractor.dae" scale='1 1 1'/>
      </geometry>
    </visual>
  </link>

<!-- define base footprint (virtual link) -->
  <link name="base_footprint" />


  <!-- define gps link -->
  <link name="gps">
    <visual>
      <origin xyz='0 0 0' rpy='0 0 0' />
      <geometry>
        <sphere radius='0.05' />
      </geometry>
      <material name='red'>
        <color rgba='1 0 0 0.5' />
      </material>
    </visual>
  </link>

  <!-- define camera link -->
  <link name="camera">
    <visual>
      <origin xyz='0 0 0' rpy='0 0 0' />
      <geometry>
        <sphere radius='0.05' />
      </geometry>
      <material name='red'>
        <color rgba='1 0 0 0.5' />
      </material>
    </visual>
  </link>

    <!-- xacro macro definition -->
    <!-- default inertia -->
    <xacro:macro name='default_inertia' params='mass x:=0 y:=0 z:=0'>
        <inertial>
            <origin xyz='${x} ${y} ${z}' />
            <mass value='${mass}' />
            <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0" />
        </inertial>
    </xacro:macro>



<!-- define base footprint joint -->
  <joint name="base_footprint_joint" type="fixed">
    <parent link="base_footprint"/>
    <child link="base_link"/>
    <origin xyz="0 0 0.25" rpy="0 0 0" />
  </joint>

<!-- define gps joint -->
  <!-- define gps joint -->
  <joint name="gps_joint" type="fixed">
    <parent link="base_link"/>
    <child link="gps"/>
    <origin xyz="1.25 0 1.0" rpy="0 0 0" />
  </joint>

<!-- define camera joint -->
  <joint name="camera_joint" type="fixed">
    <parent link="base_link"/>
    <child link="camera"/>
    <origin xyz="1.5 0 0.5" rpy="${-pi/2} 0 ${-pi/2}" />
  </joint>

  <!-- define ultrasonic sensor joint -->
  <joint name="range_joint" type="fixed">
    <parent link="base_link"/>
    <child link="base_laser_link"/>
    <origin xyz="1.5 0 0.75" rpy="0 0 0" />
  </joint>
</robot>