cps_loki_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">

    <!-- Constants for robot dimensions -->
    <xacro:property name="PI" value="3.1415926535897931" />
    <xacro:property name="base_mass" value="0.3" /> <!-- arbitrary value for base mass -->
    <xacro:property name="base_width" value="0.25" /> <!-- Updated wheel spacing to 25cm -->
    <xacro:property name="base_length" value="0.34" />
    <xacro:property name="base_height" value="0.1" />
    <xacro:property name="wheel_mass" value="0.3" /> <!-- arbitrary value for wheel mass -->
    <xacro:property name="wheel_len" value="0.020" />
    <xacro:property name="wheel_radius" value="0.0625" />
    <xacro:property name="caster_wheel_mass" value="0.1" /> <!-- arbitrary value for caster wheel
    mass -->
    <xacro:property name="caster_wheel_radius" value="0.04" />
    <xacro:property name="z_offset" value="-${base_height/2}" /> <!-- Space btw top of beam and the
    each joint -->

    <!-- dummy link - used for ros2 control so it stops complaining? -->
    <link name="${prefix}dummy">
    </link>

    <joint name="${prefix}dummy_joint" type="fixed">
      <parent link="${prefix}dummy" />
      <child link="${prefix}base_link" />
    </joint>

    <!-- Base Link -->
    <link name="${prefix}base_link">
      <collision>
        <origin xyz="0 0 0" rpy="0 0 0" />
        <geometry>
          <box size="${base_length} ${base_width} ${base_height}" /> <!-- Updated base dimensions -->
        </geometry>
      </collision>

      <visual>
        <origin xyz="0 0 ${base_height/2}" rpy="0 0 0" />
        <geometry>
          <box size="${base_length} ${base_width} ${base_height}" /> <!-- Updated base dimensions -->
        </geometry>
        <material name="orange" />
      </visual>

      <inertial>
        <origin xyz="0 0 0" rpy="0 0 0" />
        <mass value="${base_mass}" />
        <inertia
          ixx="${base_mass / 12.0 * (base_length*base_length + base_height*base_height)}" ixy="0.0"
          ixz="0.0"
          iyy="${base_mass / 12.0 * (base_height*base_height + base_width*base_width)}" iyz="0.0"
          izz="${base_mass / 12.0 * (base_width*base_width + base_length*base_length)}" />
      </inertial>
    </link>

    <joint name="${prefix}left_wheel_joint" type="continuous">
      <parent link="${prefix}base_link" />
      <child link="${prefix}left_wheel" />
      <origin xyz="${base_length/2} 0 ${z_offset}" rpy="0 0 0" /> <!-- Updated wheel position -->
      <axis xyz="0 1 0" />
      <dynamics damping="0.2" />
    </joint>

    <!-- BASE_FOOTPRINT LINK (Used for SLAM: Should be oin the ground beneath the robo like the
    shadow) -->
    <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>

    <!-- left wheel Link -->
    <link name="${prefix}left_wheel">
      <collision>
        <origin xyz="0 0 0" rpy="${PI/2} 0 0" />
        <geometry>
          <cylinder length="${wheel_len}" radius="${wheel_radius}" />
        </geometry>
      </collision>

      <visual>
        <origin xyz="0 0 0" rpy="${PI/2} 0 0" />
        <geometry>
          <cylinder length="${wheel_len}" radius="${wheel_radius}" />
        </geometry>
        <material name="black" />
      </visual>

      <inertial>
        <origin xyz="0 0 0" rpy="${PI/2} 0 0" />
        <mass value="${wheel_mass}" />
        <inertia
          ixx="${wheel_mass / 12.0 * (3*wheel_radius + wheel_len*wheel_len)}" ixy="0.0" ixz="0.0"
          iyy="${wheel_mass / 12.0 * wheel_radius*wheel_radius}" iyz="0.0"
          izz="${wheel_mass / 12.0 * wheel_radius*wheel_radius}" />
      </inertial>
    </link>

    <joint name="${prefix}right_wheel_joint" type="continuous">
      <parent link="${prefix}base_link" />
      <child link="${prefix}right_wheel" />
      <origin xyz="${base_length/2} 0 ${z_offset}" rpy="0 0 0" /> <!-- Updated wheel position -->
      <axis xyz="0 -1 0" />
      <dynamics damping="0.2" />
    </joint>

    <!-- right wheel Link -->
    <link name="${prefix}right_wheel">
      <collision>
        <origin xyz="0 0 0" rpy="${PI/2} 0 0" />
        <geometry>
          <cylinder length="${wheel_len}" radius="${wheel_radius}" />
        </geometry>
      </collision>

      <visual>
        <origin xyz="0 0 0" rpy="${PI/2} 0 0" />
        <geometry>
          <cylinder length="${wheel_len}" radius="${wheel_radius}" />
        </geometry>
        <material name="black" />
      </visual>

      <inertial>
        <origin xyz="0 0 0" rpy="${PI/2} 0 0" />
        <mass value="${wheel_mass}" />
        <inertia
          ixx="${wheel_mass / 12.0 * (3*wheel_radius + wheel_len*wheel_len)}" ixy="0.0" ixz="0.0"
          iyy="${wheel_mass / 12.0 * wheel_radius*wheel_radius}" iyz="0.0"
          izz="${wheel_mass / 12.0 * wheel_radius*wheel_radius}" />
      </inertial>
    </link>

    <joint name="${prefix}caster_wheel_joint" type="fixed">
      <parent link="${prefix}base_link" />
      <child link="${prefix}caster_wheel" />
      <origin xyz="${-base_length/2} 0 ${z_offset}" rpy="0 0 0" /> <!-- Updated caster wheel position -->
    </joint>

    <!-- caster wheel Link -->
    <link name="${prefix}caster_wheel">
      <collision>
        <origin xyz="0 0 0" rpy="0 0 0" />
        <geometry>
          <sphere radius="${caster_wheel_radius}" />
        </geometry>
      </collision>

      <visual>
        <origin xyz="0 0 0" rpy="0 0 0" />
        <geometry>
          <sphere radius="${caster_wheel_radius}" />
        </geometry>
        <material name="white" />
      </visual>

      <inertial>
        <origin xyz="0 0 0" rpy="0 0 0" />
        <mass value="${caster_wheel_mass}" />
        <inertia
          ixx="${2.0/5.0 * caster_wheel_mass * caster_wheel_radius * caster_wheel_radius}"
          ixy="0.0" ixz="0.0"
          iyy="${2.0/5.0 * caster_wheel_mass * caster_wheel_radius * caster_wheel_radius}"
          iyz="0.0"
          izz="${2.0/5.0 * caster_wheel_mass * caster_wheel_radius * caster_wheel_radius}" />
      </inertial>
    </link>

    <!-- laser_link -->
    <link name="${prefix}laser_link">
      <collision>
        <origin xyz="${base_length/2} 0 ${base_height}" rpy="0 0 0" />
        <geometry>
          <box size="0.1 0.1 0.1" />
        </geometry>
      </collision>

      <visual>
        <origin xyz="${base_length/2} 0 ${base_height}" rpy="0 0 0" />
        <geometry>
          <box size="0.1 0.1 0.1" />
        </geometry>
        <material name="green" />
      </visual>

      <inertial>
        <origin xyz="${base_length/2} 0 ${base_height}" rpy="0 0 0" />
        <mass value="0.1" />
        <inertia
          ixx="0.001" ixy="0.0" ixz="0.0"
          iyy="0.001" iyz="0.0"
          izz="0.001" />
      </inertial>
    </link>

    <!-- camera_link -->
    <link name="${prefix}camera_link">
      <collision>
        <origin xyz="${base_length/2} 0 0" rpy="0 0 0" />
        <geometry>
          <box size="0.1 0.1 0.1" />
        </geometry>
      </collision>

      <visual>
        <origin xyz="${base_length/2} 0 0" rpy="0 0 0" />
        <geometry>
          <box size="0.1 0.1 0.1" />
        </geometry>
        <material name="blue" />
      </visual>

      <inertial>
        <origin xyz="${base_length/2} 0 0" rpy="0 0 0" />
        <mass value="0.1" />
        <inertia
          ixx="0.001" ixy="0.0" ixz="0.0"
          iyy="0.001" iyz="0.0"
          izz="0.001" />
      </inertial>
    </link>

    <!-- Base Joint -->
    <joint name="${prefix}base_joint" type="fixed">
      <parent link="${prefix}base_link" />
      <child link="${prefix}laser_link" />
      <origin xyz="0 0 ${base_height}" rpy="0 0 0" />
    </joint>

    <!-- Front Joint -->
    <joint name="${prefix}front_joint" type="fixed">
      <parent link="${prefix}laser_link" />
      <child link="${prefix}camera_link" />
      <origin xyz="${base_length/2} 0 ${base_height}" rpy="0 0 0" />
    </joint>

  </xacro:macro>
</robot>