diff --git a/examples/pybullet/gym/pybullet_data/xarm/xarm6.urdf b/examples/pybullet/gym/pybullet_data/xarm/xarm6.urdf
deleted file mode 100644
index f7ad51d9f..000000000
--- a/examples/pybullet/gym/pybullet_data/xarm/xarm6.urdf
+++ /dev/null
@@ -1,314 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- =================================================================================== -->
-<!-- |    This document was autogenerated by xacro from src/xarm_ros/xarm_description/urdf/xarm6_robot.urdf.xacro | -->
-<!-- |    EDITING THIS FILE BY HAND IS NOT RECOMMENDED                                 | -->
-<!-- =================================================================================== -->
-<robot name="xarm6" xmlns:xacro="http://ros.org/wiki/xacro">
-  <!--
-  Author: Jason Peng <jason@ufactory.cc>
-  Contributers:
--->
-  <gazebo>
-    <plugin filename="libgazebo_ros_control.so" name="gazebo_ros_control">
-      <robotNamespace>/xarm</robotNamespace>
-      <!-- <controlPeriod>0.0001</controlPeriod> -->
-      <robotSimType>gazebo_ros_control/DefaultRobotHWSim</robotSimType>
-      <legacyModeNS>true</legacyModeNS>
-    </plugin>
-  </gazebo>
-  <link name="base"/>
-  <joint name="base_joint" type="fixed">
-    <parent link="base"/>
-    <child link="link_base"/>
-    <origin rpy="0 0 0" xyz="0 0 0"/>
-  </joint>
-    <!-- added tool0 to comply with ROS industrial-->
-  <link name="tool0"/>
-  <joint name="tool_joint" type="fixed">
-    <parent link="link6"/>
-    <child link="tool0"/>
-    <origin rpy="0 0 0" xyz="0 0 0"/>
-  </joint>
-  <material name="Black">
-    <color rgba="0.0 0.0 0.0 1.0"/>
-  </material>
-  <material name="Red">
-    <color rgba="0.8 0.0 0.0 1.0"/>
-  </material>
-  <material name="White">
-    <color rgba="1.0 1.0 1.0 1.0"/>
-  </material>
-  <material name="Silver">
-    <color rgba="0.753 0.753 0.753 1.0"/>
-  </material>
-  <link name="link_base">
-    <visual>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/base.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-      <material name="White"/>
-    </visual>
-    <collision>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/base.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-    </collision>
-    <inertial>
-      <origin rpy="0 0 0" xyz="0.0 0.0 0.09103"/>
-      <mass value="2.7"/>
-      <inertia ixx="0.00494875" ixy="-3.5E-06" ixz="1.25E-05" iyy="0.00494174" iyz="1.67E-06" izz="0.002219"/>
-    </inertial>
-  </link>
-  <link name="link1">
-    <visual>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link1.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-      <material name="White"/>
-    </visual>
-    <collision>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link1.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-    </collision>
-    <inertial>
-      <origin rpy="0 0 0" xyz="-0.002 0.02692 -0.01332"/>
-      <mass value="2.16"/>
-      <inertia ixx="0.00539427" ixy="1.095E-05" ixz="1.635E-06" iyy="0.0048979" iyz="0.000793" izz="0.00311573"/>
-    </inertial>
-  </link>
-  <joint name="joint1" type="revolute">
-    <parent link="link_base"/>
-    <child link="link1"/>
-    <origin rpy="0 0 0" xyz="0 0 0.267"/>
-    <axis xyz="0 0 1"/>
-    <limit effort="50.0" lower="-6.28318530718" upper="6.28318530718" velocity="3.14"/>
-    <dynamics damping="1.0" friction="1.0"/>
-  </joint>
-  <link name="link2">
-    <visual>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link2.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-      <material name="White"/>
-    </visual>
-    <collision>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link2.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-    </collision>
-    <inertial>
-      <origin rpy="0 0 0" xyz="0.03531 -0.21398 0.03386"/>
-      <mass value="1.71"/>
-      <inertia ixx="0.0248674" ixy="-0.00430651" ixz="-0.00067797" iyy="0.00485548" iyz="0.00457245" izz="0.02387827"/>
-    </inertial>
-  </link>
-  <joint name="joint2" type="revolute">
-    <parent link="link1"/>
-    <child link="link2"/>
-    <origin rpy="-1.5708 0 0" xyz="0 0 0"/>
-    <axis xyz="0 0 1"/>
-    <limit effort="50.0" lower="-2.18" upper="2.18" velocity="3.14"/>
-    <dynamics damping="1.0" friction="1.0"/>
-  </joint>
-  <link name="link3">
-    <visual>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link3.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-      <material name="White"/>
-    </visual>
-    <collision>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link3.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-    </collision>
-    <inertial>
-      <origin rpy="0 0 0" xyz="0.06781 0.10749 0.01457"/>
-      <mass value="1.384"/>
-      <inertia ixx="0.0053694" ixy="0.0014185" ixz="-0.00092094" iyy="0.0032423" iyz="-0.00169178" izz="0.00501731"/>
-    </inertial>
-  </link>
-  <joint name="joint3" type="revolute">
-    <parent link="link2"/>
-    <child link="link3"/>
-    <origin rpy="0 0 0" xyz="0.0535 -0.2845 0"/>
-    <axis xyz="0 0 1"/>
-    <limit effort="32.0" lower="-4.01" upper="0.11" velocity="3.14"/>
-    <dynamics damping="1.0" friction="1.0"/>
-  </joint>
-  <link name="link4">
-    <visual>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link4.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-      <material name="White"/>
-    </visual>
-    <collision>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link4.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-    </collision>
-    <inertial>
-      <origin rpy="0 0 0" xyz="-0.00021 0.02578 -0.02538"/>
-      <mass value="1.115"/>
-      <inertia ixx="0.00439263" ixy="5.028E-05" ixz="1.374E-05" iyy="0.0040077" iyz="0.00045338" izz="0.00110321"/>
-    </inertial>
-  </link>
-  <joint name="joint4" type="revolute">
-    <parent link="link3"/>
-    <child link="link4"/>
-    <origin rpy="-1.5708 0 0" xyz="0.0775 0.3425 0"/>
-    <axis xyz="0 0 1"/>
-    <limit effort="32.0" lower="-6.28318530718" upper="6.28318530718" velocity="3.14"/>
-    <dynamics damping="1.0" friction="1.0"/>
-  </joint>
-  <link name="link5">
-    <visual>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link5.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-      <material name="White"/>
-    </visual>
-    <collision>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link5.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-    </collision>
-    <inertial>
-      <origin rpy="0 0 0" xyz="0.05428 0.01781 0.00543"/>
-      <mass value="1.275"/>
-      <inertia ixx="0.001202758" ixy="0.000492428" ixz="-0.00039147" iyy="0.0022876" iyz="-1.235E-04" izz="0.0026866"/>
-    </inertial>
-  </link>
-  <joint name="joint5" type="revolute">
-    <parent link="link4"/>
-    <child link="link5"/>
-    <origin rpy="1.5708 0 0" xyz="0 0 0"/>
-    <axis xyz="0 0 1"/>
-    <limit effort="32.0" lower="-1.75" upper="3.14159265359" velocity="3.14"/>
-    <dynamics damping="1.0" friction="1.0"/>
-  </joint>
-  <link name="link6">
-    <visual>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link6.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-      <material name="Silver"/>
-    </visual>
-    <collision>
-      <geometry>
-        <mesh filename="meshes/xarm6/visual/link6.stl"/>
-      </geometry>
-      <origin rpy="0 0 0" xyz="0 0 0"/>
-    </collision>
-    <inertial>
-      <origin rpy="0 0 0" xyz="0 0.00064 -0.00952"/>
-      <mass value="0.1096"/>
-      <inertia ixx="4.5293E-05" ixy="0" ixz="0" iyy="4.8111E-05" iyz="0" izz="7.9715E-05"/>
-    </inertial>
-  </link>
-  <joint name="joint6" type="revolute">
-    <parent link="link5"/>
-    <child link="link6"/>
-    <origin rpy="-1.5708 0 0" xyz="0.076 0.097 0"/>
-    <axis xyz="0 0 1"/>
-    <limit effort="20.0" lower="-6.28318530718" upper="6.28318530718" velocity="3.14"/>
-    <dynamics damping="1.0" friction="1.0"/>
-  </joint>
-  <transmission name="tran1">
-    <type>transmission_interface/SimpleTransmission</type>
-    <joint name="joint1">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-    </joint>
-    <actuator name="motor1">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-      <mechanicalReduction>100</mechanicalReduction>
-    </actuator>
-  </transmission>
-  <transmission name="tran2">
-    <type>transmission_interface/SimpleTransmission</type>
-    <joint name="joint2">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-    </joint>
-    <actuator name="motor2">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-      <mechanicalReduction>reduction</mechanicalReduction>
-    </actuator>
-  </transmission>
-  <transmission name="tran3">
-    <type>transmission_interface/SimpleTransmission</type>
-    <joint name="joint3">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-    </joint>
-    <actuator name="motor3">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-      <mechanicalReduction>reduction</mechanicalReduction>
-    </actuator>
-  </transmission>
-  <transmission name="tran4">
-    <type>transmission_interface/SimpleTransmission</type>
-    <joint name="joint4">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-    </joint>
-    <actuator name="motor3">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-      <mechanicalReduction>reduction</mechanicalReduction>
-    </actuator>
-  </transmission>
-  <transmission name="tran5">
-    <type>transmission_interface/SimpleTransmission</type>
-    <joint name="joint5">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-    </joint>
-    <actuator name="motor5">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-      <mechanicalReduction>reduction</mechanicalReduction>
-    </actuator>
-  </transmission>
-  <transmission name="tran6">
-    <type>transmission_interface/SimpleTransmission</type>
-    <joint name="joint6">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-    </joint>
-    <actuator name="motor6">
-      <hardwareInterface>hardware_interface/PositionJointInterface</hardwareInterface>
-      <mechanicalReduction>reduction</mechanicalReduction>
-    </actuator>
-  </transmission>
-  <gazebo reference="link_base">
-    <selfCollide>true</selfCollide>
-  </gazebo>
-  <gazebo reference="link1">
-    <selfCollide>true</selfCollide>
-  </gazebo>
-  <gazebo reference="link2">
-    <selfCollide>true</selfCollide>
-  </gazebo>
-  <gazebo reference="link3">
-    <selfCollide>true</selfCollide>
-  </gazebo>
-  <gazebo reference="link4">
-    <selfCollide>true</selfCollide>
-  </gazebo>
-  <gazebo reference="link5">
-    <selfCollide>true</selfCollide>
-  </gazebo>
-  <gazebo reference="link6">
-    <selfCollide>true</selfCollide>
-  </gazebo>
-</robot>
-