bullet3/examples/pybullet/gym/pybullet_data/differential/diff_ring.urdf

<?xml version="1.0" ?>
<robot name="husky_robot" xmlns:xacro="http://ros.org/wiki/xacro">
  <material name="White">
    <color rgba="1.0 1.0 1.0 1.0"/>
  </material>
  <link name="world"/>
	<link name="diff_ring">
  	<contact>
      <lateral_friction value="1.0"/>
      <rolling_friction value="0.0"/>
      <stiffness value="30000"/>
      <damping value="1000"/>
    </contact>
    
    <inertial>
      <mass value="2.637"/>
      <origin xyz="0 0 0"/>
      <inertia ixx="0.02467" ixy="0" ixz="0" iyy="0.02467" iyz="0" izz="0.04411"/>
    </inertial>
    <visual>
      <origin rpy="1.57079632679 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh scale="0.001 0.001 0.001" filename="differential/diff_ring.stl"/>
      </geometry>
      <material name="DarkGrey"/>
    </visual>
     <visual>
      <origin rpy="1.57079632679 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh scale="0.001 0.001 0.001" filename="differential/diff_carrier.stl"/>
      </geometry>
      <material name="DarkGrey"/>
    </visual>
    <collision>
      <origin rpy="1.570795 0 0" xyz="0 0.025 0"/>
      <geometry>
        <cylinder length="0.01" radius="0.05"/>
      </geometry>
    </collision>
  </link>
  <joint name="diff_ring_world" type="continuous">
    <parent link="world"/>
    <child link="diff_ring"/>
    <origin rpy="0 0 0" xyz="0.256 0.2854 0.03282"/>
    <axis rpy="0 0 0" xyz="0 1 0"/>
  </joint>
  <link name="diff_spiderA">
  	<contact>
      <lateral_friction value="1.0"/>
      <rolling_friction value="0.0"/>
      <stiffness value="30000"/>
      <damping value="1000"/>
    </contact>
    
    <inertial>
      <mass value="2.637"/>
      <origin xyz="0 0 0"/>
      <inertia ixx="0.02467" ixy="0" ixz="0" iyy="0.02467" iyz="0" izz="0.04411"/>
    </inertial>
    <visual>
      <origin rpy="1.57079632679 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh scale="0.001 0.001 0.001" filename="differential/diff_spider.stl"/>
      </geometry>
      <material name="DarkGrey"/>
    </visual>
   
    
    
    
    <collision>
      <origin rpy="1.570795 0 0" xyz="0 0.01 0"/>
      <geometry>
        <cylinder length="0.01" radius="0.015"/>
      </geometry>
    </collision>
  </link>
  
  <joint name="diff_spiderA_ring" type="continuous">
    <parent link="diff_ring"/>
    <child link="diff_spiderA"/>
    <origin rpy="0 0 1.570795" xyz="0.0 0.0 0.0"/>
    <axis rpy="0 0 0" xyz="0 1 0"/>
  </joint>
 
 <link name="diff_spiderB">
  	<contact>
      <lateral_friction value="1.0"/>
      <rolling_friction value="0.0"/>
      <stiffness value="30000"/>
      <damping value="1000"/>
    </contact>
    
    <inertial>
      <mass value="2.637"/>
      <origin xyz="0 0 0"/>
      <inertia ixx="0.02467" ixy="0" ixz="0" iyy="0.02467" iyz="0" izz="0.04411"/>
    </inertial>
    <visual>
      <origin rpy="1.57079632679 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh scale="0.001 0.001 0.001" filename="differential/diff_spider.stl"/>
      </geometry>
      <material name="DarkGrey"/>
    </visual>
   
    
    
    
    <collision>
      <origin rpy="1.570795 0 0" xyz="0 0.01 0"/>
      <geometry>
        <cylinder length="0.01" radius="0.015"/>
      </geometry>
    </collision>
  </link>
  
  <joint name="diff_spiderB_ring" type="continuous">
    <parent link="diff_ring"/>
    <child link="diff_spiderB"/>
    <origin rpy="0 0 -1.570795" xyz="0.0 0.0 0.0"/>
    <axis rpy="0 0 0" xyz="0 1 0"/>
  </joint>
  
  
  <link name="diff_sideA">
  	<contact>
      <lateral_friction value="1.0"/>
      <rolling_friction value="0.0"/>
      <stiffness value="30000"/>
      <damping value="1000"/>
    </contact>
    
    <inertial>
      <mass value="2.637"/>
      <origin xyz="0 0 0"/>
      <inertia ixx="0.02467" ixy="0" ixz="0" iyy="0.02467" iyz="0" izz="0.04411"/>
    </inertial>
    <visual>
      <origin rpy="1.570795 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh scale="0.001 0.001 0.001" filename="differential/diff_side.stl"/>
      </geometry>
      <material name="DarkGrey"/>
    </visual>
    
    <collision>
      <origin rpy="1.570795 0 0" xyz="0 0.01 0"/>
      <geometry>
        <cylinder length="0.01" radius="0.015"/>
      </geometry>
    </collision>
  </link>
  
  <joint name="diff_sideA_ring" type="continuous">
    <parent link="diff_ring"/>
    <child link="diff_sideA"/>
    <origin rpy="0 0 0" xyz="0.0 0.0 0.0"/>
    <axis rpy="0 0 0" xyz="0 1 0"/>
  </joint>
  
   <link name="diff_sideB">
  	<contact>
      <lateral_friction value="1.0"/>
      <rolling_friction value="0.0"/>
      <stiffness value="30000"/>
      <damping value="1000"/>
    </contact>
    
    <inertial>
      <mass value="2.637"/>
      <origin xyz="0 0 0"/>
      <inertia ixx="0.02467" ixy="0" ixz="0" iyy="0.02467" iyz="0" izz="0.04411"/>
    </inertial>
    <visual>
      <origin rpy="-1.570795 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh scale="0.001 0.001 0.001" filename="differential/diff_side.stl"/>
      </geometry>
      <material name="DarkGrey"/>
    </visual>
    
    <collision>
      <origin rpy="-1.570795 0 0" xyz="0 -0.01 0"/>
      <geometry>
        <cylinder length="0.01" radius="0.015"/>
      </geometry>
    </collision>
  </link>
  
  <joint name="diff_sideB_ring" type="continuous">
    <parent link="diff_ring"/>
    <child link="diff_sideB"/>
    <origin rpy="0 0 0" xyz="0.0 0.0 0.0"/>
    <axis rpy="0 0 0" xyz="0 1 0"/>
  </joint>
</robot>