sam_bot_description.urdf

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

  <!-- Define robot constants -->
  <xacro:property name="base_width" value="0.31"/>
  <xacro:property name="base_length" value="0.42"/>
  <xacro:property name="base_height" value="0.18"/>

  <xacro:property name="wheel_radius" value="0.10"/>
  <xacro:property name="wheel_width" value="0.04"/>
  <xacro:property name="wheel_ygap" value="0.025"/>
  <xacro:property name="wheel_zoff" value="0.05"/>
  <xacro:property name="wheel_xoff" value="0.12"/>

  <xacro:property name="caster_xoff" value="0.14"/>

  <!-- Define some commonly used intertial properties  -->
  <xacro:macro name="box_inertia" params="m w h d">
    <inertial>
      <origin xyz="0 0 0" rpy="${pi/2} 0 ${pi/2}"/>
      <mass value="${m}"/>
      <inertia ixx="${(m/12) * (h*h + d*d)}" ixy="0.0" ixz="0.0" iyy="${(m/12) * (w*w + d*d)}" iyz="0.0" izz="${(m/12) * (w*w + h*h)}"/>
    </inertial>
  </xacro:macro>

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

  <xacro:macro name="sphere_inertia" params="m r">
    <inertial>
      <mass value="${m}"/>
      <inertia ixx="${(2/5) * m * (r*r)}" ixy="0.0" ixz="0.0" iyy="${(2/5) * m * (r*r)}" iyz="0.0" izz="${(2/5) * m * (r*r)}"/>
    </inertial>
  </xacro:macro>

  <!-- Robot Base -->
  <link name="base_link">
    <visual>
      <geometry>
        <box size="${base_length} ${base_width} ${base_height}"/>
      </geometry>
      <material name="DarkBlue">
        <color rgba="0.09 0.30 0.46 1.0"/>
      </material>
    </visual>

    <collision>
      <geometry>
        <box size="${base_length} ${base_width} ${base_height}"/>
      </geometry>
    </collision>

    <xacro:box_inertia m="1" w="${base_width}" d="${base_length}" h="${base_height}"/>
  </link>

  <!-- Robot Footprint -->
  <link name="base_footprint">
    <xacro:box_inertia m="0" w="0" d="0" h="0"/>
  </link>

  <joint name="base_joint" type="fixed">
    <parent link="base_link"/>
    <child link="base_footprint"/>
    <origin xyz="0.0 0.0 ${-(wheel_radius+wheel_zoff)}" rpy="0 0 0"/>
  </joint>

  <!-- Wheels -->
  <xacro:macro name="wheel" params="prefix x_reflect y_reflect">
    <link name="${prefix}_link">
      <visual>
        <origin xyz="0 0 0" rpy="${pi/2} 0 0"/>
        <geometry>
          <cylinder radius="${wheel_radius}" length="${wheel_width}"/>
        </geometry>
        <material name="LightBlue">
          <color rgba="0.11 0.37 0.56 1.0"/>
        </material>
      </visual>

      <collision>
        <origin xyz="0 0 0" rpy="${pi/2} 0 0"/>
        <geometry>
          <cylinder radius="${wheel_radius}" length="${wheel_width}"/>
        </geometry>
      </collision>

      <xacro:cylinder_inertia m="2.5" r="${wheel_radius}" h="${wheel_width}"/>
    </link>

    <joint name="${prefix}_joint" type="continuous">
      <parent link="base_link"/>
      <child link="${prefix}_link"/>
      <origin xyz="${x_reflect*wheel_xoff} ${y_reflect*(base_width/2+wheel_ygap)} ${-wheel_zoff}" rpy="0 0 0"/>
      <axis xyz="0 1 0"/>
      <dynamics damping="0.2"/>
    </joint>
  </xacro:macro>

  <xacro:wheel prefix="drivewhl_l" x_reflect="-1" y_reflect="1" />
  <xacro:wheel prefix="drivewhl_r" x_reflect="-1" y_reflect="-1" />

  <link name="front_caster">
    <visual>
      <geometry>
        <sphere radius="${(wheel_radius+wheel_zoff-(base_height/2))}"/>
      </geometry>
      <material name="DarkBlue">
        <color rgba="0.09 0.30 0.46 1.0"/>
      </material>
    </visual>

    <collision>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <sphere radius="${(wheel_radius+wheel_zoff-(base_height/2))}"/>
      </geometry>
    </collision>

    <xacro:sphere_inertia m="0.005" r="${(wheel_radius+wheel_zoff-(base_height/2))}"/>
  </link>

  <joint name="caster_joint" type="fixed">
    <parent link="base_link"/>
    <child link="front_caster"/>
    <origin xyz="${caster_xoff} 0.0 ${-(base_height/2)}" rpy="0 0 0"/>
  </joint>

  <link name="imu_link">
    <visual>
      <geometry>
        <box size="0.1 0.1 0.1"/>
      </geometry>
    </visual>

    <collision>
      <geometry>
        <box size="0.1 0.1 0.1"/>
      </geometry>
    </collision>

    <xacro:box_inertia m="0.001" w="0.1" d="0.1" h="0.1"/>
  </link>

  <gazebo reference="imu_link">
    <sensor name="imu_sensor" type="imu">
      <ignition_frame_id>imu_link</ignition_frame_id>
      <plugin filename="ignition-gazebo-imu-system" name="ignition::gazebo::systems::Imu">
      </plugin>

      <topic>imu</topic>
      <always_on>true</always_on>
      <update_rate>100</update_rate>
      <visualize>true</visualize>
      <imu>
        <angular_velocity>
          <x>
            <noise type="gaussian">
              <mean>0.0</mean>
              <stddev>2e-4</stddev>
              <bias_mean>0.0000075</bias_mean>
              <bias_stddev>0.0000008</bias_stddev>
            </noise>
          </x>
          <y>
            <noise type="gaussian">
              <mean>0.0</mean>
              <stddev>2e-4</stddev>
              <bias_mean>0.0000075</bias_mean>
              <bias_stddev>0.0000008</bias_stddev>
            </noise>
          </y>
          <z>
            <noise type="gaussian">
              <mean>0.0</mean>
              <stddev>2e-4</stddev>
              <bias_mean>0.0000075</bias_mean>
              <bias_stddev>0.0000008</bias_stddev>
            </noise>
          </z>
        </angular_velocity>
        <linear_acceleration>
          <x>
            <noise type="gaussian">
              <mean>0.0</mean>
              <stddev>1.7e-2</stddev>
              <bias_mean>0.1</bias_mean>
              <bias_stddev>0.001</bias_stddev>
            </noise>
          </x>
          <y>
            <noise type="gaussian">
              <mean>0.0</mean>
              <stddev>1.7e-2</stddev>
              <bias_mean>0.1</bias_mean>
              <bias_stddev>0.001</bias_stddev>
            </noise>
          </y>
          <z>
            <noise type="gaussian">
              <mean>0.0</mean>
              <stddev>1.7e-2</stddev>
              <bias_mean>0.1</bias_mean>
              <bias_stddev>0.001</bias_stddev>
            </noise>
          </z>
        </linear_acceleration>
      </imu>
    </sensor>
  </gazebo>

  <joint name="imu_joint" type="fixed">
    <parent link="base_link"/>
    <child link="imu_link"/>
    <origin xyz="0 0 0.01"/>
  </joint>

  <ros2_control name="IgnitionSystem" type="system">
    <hardware>
      <plugin>ign_ros2_control/IgnitionSystem</plugin>
    </hardware>
    <joint name="drivewhl_l_joint">
      <command_interface name="velocity">
        <param name="min">-1</param>
        <param name="max">1</param>
      </command_interface>
      <state_interface name="position"/>
      <state_interface name="velocity"/>
    </joint>
    <joint name="drivewhl_r_joint">
      <command_interface name="velocity">
        <param name="min">-1</param>
        <param name="max">1</param>
      </command_interface>
      <state_interface name="position"/>
      <state_interface name="velocity"/>
    </joint>
  </ros2_control>


  <gazebo>
    <plugin filename="ign_ros2_control-system" name="ign_ros2_control::IgnitionROS2ControlPlugin">
      <parameters>$(find sam_bot_nav2_gz)/config/diff_drive_controller_velocity.yaml</parameters>
    </plugin>
  </gazebo>

  <link name="lidar_link">
    <inertial>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <mass value="0.125"/>
      <inertia ixx="0.001" ixy="0" ixz="0" iyy="0.001" iyz="0" izz="0.001" />
    </inertial>

    <collision>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <cylinder radius="0.0508" length="0.055"/>
      </geometry>
    </collision>

    <visual>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <cylinder radius="0.0508" length="0.055"/>
      </geometry>
      <material name="LightBlue">
        <color rgba="0.11 0.37 0.56 1.0"/>
      </material>
    </visual>
  </link>

  <joint name="lidar_joint" type="fixed">
    <parent link="base_link"/>
    <child link="lidar_link"/>
    <origin xyz="0 0 0.12" rpy="0 0 0"/>
  </joint>

  <gazebo reference="lidar_link">
    <sensor name="lidar" type="gpu_lidar">
      <ignition_frame_id>lidar_link</ignition_frame_id>
      <topic>scan</topic>
      <always_on>true</always_on>
      <visualize>true</visualize>
      <update_rate>5</update_rate>
      <ray>
        <scan>
          <horizontal>
            <samples>360</samples>
            <resolution>1.000000</resolution>
            <min_angle>0.000000</min_angle>
            <max_angle>6.280000</max_angle>
          </horizontal>
        </scan>
        <range>
          <min>0.120000</min>
          <max>3.5</max>
          <resolution>0.015000</resolution>
        </range>
        <noise>
          <type>gaussian</type>
          <mean>0.0</mean>
          <stddev>0.01</stddev>
        </noise>
      </ray>
    </sensor>
  </gazebo>


  <link name="camera_link">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <box size="0.015 0.130 0.022"/>
      </geometry>
      <material name="LightBlue">
        <color rgba="0.11 0.37 0.56 1.0"/>
      </material>
    </visual>

    <collision>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <box size="0.015 0.130 0.022"/>
      </geometry>
    </collision>

    <inertial>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <mass value="0.035"/>
      <inertia ixx="0.001" ixy="0" ixz="0" iyy="0.001" iyz="0" izz="0.001" />
    </inertial>
  </link>

  <joint name="camera_joint" type="fixed">
    <parent link="base_link"/>
    <child link="camera_link"/>
    <origin xyz="0.215 0 0.05" rpy="0 0 0"/>
  </joint>

  <link name="camera_frame"/>

  <joint name="camera_frame_joint" type="fixed">
    <origin xyz="0 0 0" rpy="${-pi/2} 0 ${-pi/2}"/>
    <parent link="camera_link"/>
    <child link="camera_frame"/>
  </joint>

  <gazebo reference="camera_link">
    <sensor name="robot_cam" type="camera">
      <camera>
        <horizontal_fov>1.047</horizontal_fov>
        <image>
          <width>320</width>
          <height>240</height>
        </image>
        <clip>
          <near>0.1</near>
          <far>100</far>
        </clip>
      </camera>
      <always_on>1</always_on>
      <update_rate>30</update_rate>
      <visualize>true</visualize>
      <topic>robot_cam</topic>
      <enable_metrics>true</enable_metrics>
    </sensor>
  </gazebo>
</robot>