Unified Robot Description Format

What is Unified Robot Description Format (URDF)

The Unified Robot Description Format (URDF) is an XML-based format used to describe the physical and kinematic properties of a robot. It is widely used in ROS (Robot Operating System) to define a robot’s structure so that it can be visualized, simulated, and controlled.

Definitions

<robot name="Qmini">
    <mujoco>
        <compiler meshdir="meshes" discardvisual="false"/>
    </mujoco>
    <!-- [CAUTION] uncomment when convert to mujoco -->
    <!-- <link name="world"></link>
    <joint name="floating_base_joint" type="floating">
      <parent link="world"/>
      <child link="base_link"/>
    </joint> -->
    <link name="base_link">
        <inertial>
            <origin xyz="-0.014456 5.6E-05 -0.041502" rpy="0 0 0"/>
            <mass value="4.7754"/>
            <inertia ixx="0.026652" ixy="-6E-06" ixz="-0.006659" iyy="0.04973" iyz="-9E-06" izz="0.049037"/>
        </inertial>
        <visual>
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <geometry>
                <mesh filename="meshes/base_link.STL"/>
            </geometry>
            <material name="">
                <color rgba="1 1 1 1"/>
            </material>
        </visual>
        <collision>
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <geometry>
                <mesh filename="meshes/base_link.STL"/>
            </geometry>
        </collision>
    </link>
    <link name="LL_hip_yaw">
        <inertial>
            <origin xyz="0.001558 0.000796 -0.10656" rpy="0 0 0"/>
            <mass value="0.73407"/>
            <inertia ixx="0.001096" ixy="1E-06" ixz="7E-06" iyy="0.000691" iyz="4E-06" izz="0.000544"/>
        </inertial>
        <visual>
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <geometry>
                <mesh filename="meshes/LL_hip_yaw.STL"/>
            </geometry>
            <material name="">
                <color rgba="1 1 1 1"/>
            </material>
        </visual>
        <!-- <collision>
          <origin xyz="0 0 0" rpy="0 0 0"/>
          <geometry>
            <mesh filename="meshes/LL_hip_yaw.STL"/>
          </geometry>
        </collision> -->
    </link>
    <joint name="LL-joint1" type="revolute">
        <origin xyz="0 0.055 0" rpy="0 0 0"/>
        <parent link="base_link"/>
        <child link="LL_hip_yaw"/>
        <axis xyz="0 0 1"/>
        <limit lower="-0.349" upper="0.525" effort="20" velocity="1"/>
    </joint>
</robot>