bullet3/data/cartpole.urdf

<?xml version="1.0"?>
<robot name="physics">

    <link name="slideBar">
    <visual>
      <geometry>
        <box size="30 0.05 0.05"/>
      </geometry>
      <origin xyz="0 0 0"/>
      <material name="green">
        <color rgba="0 0.8 .8 1"/>
      </material>
    </visual>
    <inertial>
      <mass value="0"/>
      <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
  </link>

  <link name="cart">
    <visual>
      <geometry>
        <box size="0.5 0.5 0.2"/>
      </geometry>
      <origin xyz="0 0 0"/>
      <material name="blue">
        <color rgba="0 0 .8 1"/>
      </material>
    </visual>
    <collision>
      <geometry>
          <box size="0.5 0.5 0.2"/>
      </geometry>
      <origin xyz="0 0 0"/>
    </collision>
    <inertial>
      <mass value="1"/>
      <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
  </link>

  <joint name="slider_to_cart" type="prismatic">
    <axis xyz="1 0 0"/>
    <origin xyz="0.0 0.0 0.0"/>
    <parent link="slideBar"/>
    <child link="cart"/>
    <limit effort="1000.0" lower="-15" upper="15" velocity="5"/>
  </joint>

  <link name="pole">
    <visual>
      <geometry>
        <box size="0.05 0.05 1.0"/>	
      </geometry>
      <origin rpy="0 0 0" xyz="0 0 0.5"/>
      <material name="white">
        <color rgba="1 1 1 1"/>
      </material>
    </visual>
    <inertial>
    <origin xyz="0 0 0.5"/>
      <mass value="10"/>
      <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="1.0" iyz="0.0" izz="1.0"/>
    </inertial>
     <collision>
      <geometry>
        <box size="0.05 0.05 1.0"/>	
      </geometry>
      <origin rpy="0 0 0" xyz="0 0 0.5"/>
    </collision>
  </link>

  <joint name="cart_to_pole" type="continuous">
    <axis xyz="0 1 0"/>
    <origin xyz="0.0 0.0 0"/>
    <parent link="cart"/>
    <child link="pole"/>
  </joint>
  
</robot>