bot_mini_description/urdf/diffbot_description.urdf.xacro

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

  <xacro:macro name="diffbot" params="prefix">
    <xacro:include filename="inertial_macros.xacro"/>

    <!-- Constants for robot dimensions -->
    <xacro:property name="PI" value="3.1415926535897931"/>

    <!-- new properties -->
    <xacro:property name="chassis_length" value="0.34"/>
    <xacro:property name="chassis_width" value="0.26"/>
    <xacro:property name="chassis_height" value="0.123"/>
    <xacro:property name="chassis_mass" value="3.0"/>
    <xacro:property name="wheel_radius" value="0.0625"/>
    <xacro:property name="wheel_thickness" value="0.020"/>
    <xacro:property name="wheel_mass" value="0.02"/>
    <xacro:property name="wheel_offset_x" value="0.285748"/>
    <xacro:property name="wheel_offset_y" value="0.13"/>
    <xacro:property name="wheel_offset_z" value="-0.035"/>
    <xacro:property name="caster_wheel_radius" value="0.04"/>
    <xacro:property name="caster_wheel_mass" value="0.01"/>
    <xacro:property name="caster_wheel_offset_x" value="0.075"/>
    <xacro:property name="caster_wheel_offset_z" value="${wheel_offset_z - wheel_radius + caster_wheel_radius}"/>
    <xacro:property name="chassis_offset" value="0.065"/>
    
    <!-- Base Link -->
    <link name="${prefix}base_link">
    </link>

    <!-- Adding base_footprint for mapping (Needed by slam toolbox) -->
    <joint name="${prefix}base_footprint_joint" type="fixed">
      <parent link="${prefix}base_link" />
      <child link="${prefix}base_footprint" />
      <origin xyz="0 0 0" rpy="0 0 0" />
    </joint>

     <link name="${prefix}base_footprint">
    </link>

    <!-- CHASSIS LINK -->

    <joint name="${prefix}chassis_joint" type="fixed">
        <parent link="${prefix}base_link"/>
        <child link="${prefix}chassis"/>
        <origin xyz="${-chassis_length/2 + chassis_offset} 0 ${wheel_radius - wheel_offset_z}"/>
    </joint>

    <link name="${prefix}chassis">
        <visual>
            <origin xyz="0 0 0"/>
            <geometry>
                <box size="${chassis_length} ${chassis_width} ${chassis_height}"/>
            </geometry>
            <material name="orange"/>
        </visual>
        <collision>
            <origin xyz="0 0 0"/>
            <geometry>
                <box size="${chassis_length} ${chassis_width} ${chassis_height}"/>
            </geometry>
        </collision>
        <xacro:inertial_box mass="0.5" x="${chassis_length}" y="${chassis_width}" z="${chassis_height}">
            <origin xyz="0 0 0" rpy="0 0 0"/>
        </xacro:inertial_box>
    </link>

    <gazebo reference="chassis">
        <material>Gazebo/Orange</material>
    </gazebo>

    <!-- RIGHT WHEEL -->
    <joint name="${prefix}right_wheel_joint" type="fixed">
        <parent link="${prefix}chassis"/>
        <child link="${prefix}right_wheel"/>
        <origin xyz="${chassis_length/2 - 0.075} -${wheel_offset_y + wheel_thickness/2} ${wheel_offset_z}" rpy="${pi/2} 0 0" />
        <axis xyz="0 0 -1"/>
        <limit effort="1" velocity="20" />
        <joint_properties friction="0.0"/>
    </joint>

    <link name="${prefix}right_wheel">
        <visual>
            <geometry>
                <cylinder radius="${wheel_radius}" length="${wheel_thickness}"/>
            </geometry>
            <material name="blue"/>
        </visual>
        <collision>
            <geometry>
                <sphere radius="${wheel_radius}"/>
            </geometry>
        </collision>
        <xacro:inertial_cylinder mass="${wheel_mass}" length="${wheel_thickness}" radius="${wheel_radius}">
            <origin xyz="0 0 0" rpy="0 0 0"/>
        </xacro:inertial_cylinder>
    </link>

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

    <!-- LEFT WHEEL -->
    <joint name="${prefix}left_wheel_joint" type="fixed">
        <parent link="${prefix}chassis"/>
        <child link="${prefix}left_wheel"/>
        <origin xyz="${chassis_length/2 - chassis_offset} ${wheel_offset_y + wheel_thickness/2} ${wheel_offset_z}" rpy="-${pi/2} 0 0" />
        <axis xyz="0 0 1"/>
    </joint>

    <link name="${prefix}left_wheel">
        <visual>
            <geometry>
                <cylinder radius="${wheel_radius}" length="${wheel_thickness}"/>
            </geometry>
            <material name="blue"/>
        </visual>
        <collision>
            <geometry>
                <sphere radius="${wheel_radius}"/>
            </geometry>
        </collision>
        <xacro:inertial_cylinder mass="${wheel_mass}" length="${wheel_thickness}" radius="${wheel_radius}">
            <origin xyz="0 0 0" rpy="0 0 0"/>
        </xacro:inertial_cylinder>
    </link>

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

    <!-- CASTER WHEEL -->
    <joint name="${prefix}caster_wheel_joint" type="fixed">
        <parent link="${prefix}chassis"/>
        <child link="${prefix}caster_wheel"/>
        <origin xyz="-${caster_wheel_offset_x*2} 0 ${caster_wheel_offset_z}"/>
    </joint>

    <link name="${prefix}caster_wheel">
        <visual>
            <geometry>
                <sphere radius="${caster_wheel_radius}"/>
            </geometry>
            <material name="white"/>
        </visual>
        <collision>
            <geometry>
                <sphere radius="${caster_wheel_radius}"/>
            </geometry>
        </collision>
        <xacro:inertial_sphere mass="${caster_wheel_mass}" radius="${caster_wheel_radius}">
            <origin xyz="0 0 0" rpy="0 0 0"/>
        </xacro:inertial_sphere>
    </link>

    <gazebo reference="caster_wheel">
        <material>Gazebo/White</material>
        <mu1 value="0.001"/>
        <mu2 value="0.001"/>
    </gazebo>

    <!-- LASER -->
    <!-- now rotated and mounted on the underside -->
    <joint name="${prefix}laser_joint" type="fixed">
        <parent link="${prefix}chassis"/>
        <child link="${prefix}laser_frame"/>
        <origin xyz="${chassis_length/2 -chassis_offset} 0 -0.07" rpy="${pi} 0 0"/>
    </joint>

    <link name="${prefix}laser_frame">
        <visual>
            <geometry>
                <cylinder radius="0.04" length="0.05"/>
            </geometry>
            <material name="black"/>
        </visual>
        <collision>
            <geometry>
                <sphere radius="${caster_wheel_radius}"/>
            </geometry>
        </collision>
        <xacro:inertial_sphere mass="${caster_wheel_mass}" radius="${caster_wheel_radius}">
            <origin xyz="0 0 0" rpy="0 0 0"/>
        </xacro:inertial_sphere>
    </link>

    <gazebo reference="laser_frame">
        <material>Gazebo/White</material>
    </gazebo>

    <!-- camera_link -->
    <link name="${prefix}camera_link">
      <visual>
        <origin xyz="0 0 0" rpy="0 -0 0" />
        <geometry>
          <mesh filename="package://cps_loki_description/mesh/camera_link_visual.stl"/>
        </geometry>
        <material name="camera_link_material">
          <color rgba="0.26274509803921569651 0.28235294117647058432 0.30196078431372547213 1.0"/>
        </material>
      </visual>
      <collision>
        <origin xyz="0 0 0" rpy="0 -0 0" />
        <geometry>
          <mesh filename="package://cps_loki_description/mesh/camera_link_collision.stl"/>
        </geometry>
      </collision>
      <inertial>
        <origin xyz="5.3378961738576549005e-07 0.0016484827975361887251 -0.020840554768345870285" rpy="0 0 0"/>
        <mass value="0.064008494238512375629" />
        <inertia ixx="1.7394518695567356026e-05" ixy="-4.87317899857206066e-10" ixz="-1.7982620680900958214e-11" iyy="3.2074360900148983727e-05" iyz="2.0892555595878115295e-06" izz="2.8321439372619354409e-05" />
      </inertial>
    </link>

    <!-- Camera Joint -->
    <joint name="${prefix}camera_joint" type="fixed">
      <origin xyz="${chassis_length / 2 - chassis_offset} 0 0" rpy="0 0 ${PI}" />
      <parent link="${prefix}base_link" />
      <child link="${prefix}camera_link" />
      <axis xyz="0 0 1"/>
      <limit effort="1" velocity="20" />
      <joint_properties friction="0.0"/>
    </joint>

  </xacro:macro>
</robot>