<?xml version="1.0"?>
<robot name="SimpleDoublePendulum">
  <link name="base">
    <inertial>
      <origin xyz="0 0.0 0" rpy="0 0 0"/>
      <mass value="1"/>
      <inertia ixx="0" ixy="0" ixz="0" iyy="0" iyz="0" izz="0"/>
    </inertial>
  </link>
  <link name="link1">
    <inertial>
      <origin xyz="0 -0.5 0" rpy="0 0 0"/>
      <mass value="1"/>
      <inertia ixx="0" ixy="0" ixz="0" iyy="0" iyz="0" izz="0"/>
    </inertial>
  </link>
  <link name="link2">
    <inertial>
      <origin xyz="0 -0.5 0" rpy="0 0 0"/>
      <mass value="1"/>
      <inertia ixx="0" ixy="0" ixz="0" iyy="0" iyz="0" izz="0"/>
    </inertial>
  </link>
  <joint name="shaft1" type="continuous">
    <parent link="base"/>
    <child link="link1"/>
    <origin xyz="0 0.0 0" rpy="0 0 0"/>
    <axis xyz="0 0 1"/>
    <dynamics damping="0.1"/>
  </joint>
  <transmission type="SimpleTransmission" name="shaft1_trans">
    <actuator name="shaft1" />
    <joint name="shaft1" />
    <mechanicalReduction>1</mechanicalReduction>
  </transmission>
  <joint name="shaft2" type="continuous">
    <parent link="link1"/>
    <child link="link2"/>
    <origin xyz="0 -1.0 0" rpy="0 0 0"/>
    <axis xyz="0 0 1"/>
    <dynamics damping="0.1"/>
  </joint>
  <transmission type="SimpleTransmission" name="shaft2_trans">
    <actuator name="shaft2" />
    <joint name="shaft2" />
    <mechanicalReduction>1</mechanicalReduction>
  </transmission>
  <frame link="link1" name="frame_on_link1" rpy="-1 0.1 0.2" xyz="0.8 -0.2 0.3"/>
  <frame link="link2" name="frame_on_link2" rpy="-1 0.1 0.2" xyz="0.8 -0.2 0.3"/>
  <!-- Frames located at the COM of each link. -->
  <frame link="link1" name="link1_com" rpy="0 0 0" xyz="0 -0.5 0"/>
  <frame link="link2" name="link2_com" rpy="0 0 0" xyz="0 -0.5 0"/>
</robot>
