<?xml version="1.0" ?>
<robot name="movable_obstacle">
  <link name="block_link">
    <inertial>
      <origin rpy="0 0 0" xyz="0 0 0"/>
       <mass value="0"/>
       <inertia ixx="0" ixy="0" ixz="0" iyy="0" iyz="0" izz="0"/>
    </inertial>
  </link>
  <link name="sphere_link">
    <visual>
      <geometry>
        <sphere radius="0.1"/>
      </geometry>
      <origin xyz='0 0 0' rpy='0 0 0'/>
      <material name='block_color'>
        <color rgba="0 0 0 1"/>
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <sphere radius="0.1"/>
      </geometry>
    </collision>
    <inertial>
      <origin rpy="0 0 0" xyz="0 0 0"/>
       <mass value=".1"/>
       <inertia ixx="1" ixy="0" ixz="0" iyy="1" iyz="0" izz="1"/>
    </inertial>
  </link>
  <joint name="car_wheel" type="prismatic">
    <parent link="block_link"/>
    <child link="sphere_link"/>
    <origin xyz="0.5 0 0.62" rpy="0 0 0"/>
    <axis xyz="0 1 0"/>
    <limit  lower="-0.8" upper="0.8" />
  </joint>
</robot>