onebot.urdf.xacro

onebot.urdf.xacro

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

    <xacro:include filename="$(find onebot_description)/urdf/caster.urdf.xacro" />
    <xacro:include filename="$(find onebot_description)/urdf/wheel.urdf.xacro" />
   
    <xacro:arg name="mesh_enabled" default="true" />
    <xacro:arg name="robot_namespace" default="/"/> 
        
    <link   name = "base_link">
        <inertial>
            <origin xyz="-0.108 0 -0.02579" rpy="0 0 0"/>
            <mass value="3.978"/>
            <inertia ixx="0.021858680" ixy="0.0" ixz="0.010020353"
                    iyy="0.078572349" iyz="-0.0"
                    izz="0.091971324"/>
        </inertial>
        <visual>
            <xacro:if value="$(arg mesh_enabled)">
                <origin xyz="0 0 0" rpy="0 0 0" />
                <geometry>
                    <mesh filename="package://onebot_description/meshes/base_link.dae" />
                </geometry>
            </xacro:if>
            <xacro:unless value="$(arg mesh_enabled)">
                <origin xyz="-0.125 0 -0.01" rpy="0 0 0" />
                <geometry>
                    <box size="0.25 0.25 0.02" />
                </geometry>
                <material name="Blue" />    
            </xacro:unless>
        </visual>
        <collision>
            <origin xyz="-0.125 0 -0.01" rpy="0 0 0" />
            <geometry>
                <box size="0.25 0.25 0.02" />
            </geometry>
        </collision>
    </link>

    <link   name =  "base_footprint"/>
        
    <joint name = "base_joint"  type = "fixed">
        <parent link="base_footprint"/>
        <child link="base_link"/>
        <origin xyz="0.0 0.0 0.09188" rpy="0 0 0" />
        <axis xyz="0 1 0" rpy="0 0 0" />
    </joint>

    <xacro:caster caster_prefix="rear" parent_link="base_link" >
        <origin xyz="-0.20 0.0 -0.02533" rpy="0 0 0" />
    </xacro:caster>

    <xacro:wheel wheel_prefix="left" parent_link="base_link" >
        <origin xyz="-0.04 0.14 -0.045" rpy="0 0 0" />
    </xacro:wheel>

    <xacro:wheel wheel_prefix="right" parent_link="base_link" >
        <origin xyz="-0.04 -0.14 -0.045" rpy="0 0 0" />
    </xacro:wheel>

    <gazebo>
        <plugin name="gazebo_ros_control" filename="libgazebo_ros_control.so">
        <robotNamespace>$(arg robot_namespace)</robotNamespace>
        <legacyModeNS>true</legacyModeNS>
        </plugin>
    </gazebo>

</robot>

Then the xacro macros are used. First the caster is instantiated and the expected arguments are given. Also the wheels are instantiated with the wheel prefix being left and right.

In line 62, gazebo ros control plugin is attached. This enables the usage of ROS controllers with the URDF model.