<?xml version="1.0" ?>

<!-- adapted from Daniel Mellinger, Nathan Michael, Vijay Kumar, "Trajectory Generation and Control for Precise Aggressive Maneuvers with Quadrotors" -->

<robot xmlns="http://drake.mit.edu"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://drake.mit.edu ../../../../pods/drake/doc/drakeURDF.xsd" name="quadrotor">
  <link name="base_link">
    <inertial>
      <mass value="0.5"/>
      <origin xyz="0 0 0"/>
      <inertia ixx="0.0023" ixy="0.0" ixz="0.0" iyy="0.0023" iyz="0.0" izz="0.004"/>
    </inertial>
    <visual>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <mesh filename="quadrotor_base.obj" scale=".1 .1 .1"/>
      </geometry>
    </visual>
    <!-- note: the original hector quadrotor urdf had a (simplified, but still complex) collision mesh, too -->
    <collision>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <geometry>
        <cylinder radius=".3" length=".1"/>
      </geometry>
    </collision>      
  </link>
  <frame link="base_link" name="body" rpy="0 0 0" xyz="0 0 0" />
  <force_element name="prop1">
    <propellor lower_limit="0" upper_limit="10" scale_factor_thrust="1.0" scale_factor_moment="0.0245">
      <parent link="base_link"/>
      <origin xyz=".1750 0 0"/>
      <axis xyz="0 0 1"/>
    </propellor>
  </force_element>

  <force_element name="prop2">
    <propellor lower_limit="0" upper_limit="10" scale_factor_thrust="1.0" scale_factor_moment="-0.0245">
      <parent link="base_link"/>
      <origin xyz="0 .1750 0 "/>
      <axis xyz="0 0 1"/>
    </propellor>
  </force_element>
  
  <force_element name="prop3">
    <propellor lower_limit="0" upper_limit="10" scale_factor_thrust="1.0" scale_factor_moment="0.0245">
      <parent link="base_link"/>
      <origin xyz="-.1750 0 0"/>
      <axis xyz="0 0 1"/>
    </propellor>
  </force_element>
  
  <force_element name="prop4">
    <propellor lower_limit="0" upper_limit="10" scale_factor_thrust="1.0" scale_factor_moment="-0.0245">
      <parent link="base_link"/>
      <origin xyz="0 -.1750 0"/>
      <axis xyz="0 0 1"/>
    </propellor>
  </force_element>
  
</robot>

