urdf

This package contains a C++ parser for the Unified Robot Description Format (URDF), which is an XML format for representing a robot model. The code API of the parser has been through our review process and will remain backwards compatible in future releases.

Homepage: http://wiki.ros.org/urdf

urdf::Model is a class containing robot model data structure. Every Robot Description File (URDF) can be described as a list of Links (urdf::Model::links_) and Joints (urdf::Model::joints_). The connection between links(nodes) and joints(edges) should define a tree (i.e. 1 parent link, 0+ children links).

Here is an example Robot Description Describing a Parent Link 'P', a Child Link 'C', and a Joint 'J'

  <joint name="J" type="revolute">
    <dynamics damping="1" friction="0"/>
    <limit lower="0.9" upper="2.1" effort="1000" velocity="1"/>
    <safety_controller soft_lower_limit="0.7" soft_upper_limit="2.1" k_position="1" k_velocity="1" />
    <calibration reference_position="0.7" />
    <mimic joint="J100" offset="0" multiplier="0.7" />

    <!-- origin: origin of the joint in the parent frame -->
    <!-- child link frame is the joint frame -->
    <!-- axis is in the joint frame -->
    <origin xyz="0 0 0" rpy="0 0 0"/> 
    <axis xyz="0 1 0"/> 
    <parent link="P"/>
    <child link="C"/>
  </joint>

  <link name="C">
    <inertial>
      <mass value="10"/>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <inertia ixx="1" ixy="0" ixz="0" iyy="1" iyz="0" izz="1"/>
    </inertial>

    <visual>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <box size="1 1 1"/>
      </geometry>
      <material name="Green"/>
    </visual>

    <collision>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <box size="1.01 1.01 1.01"/>
      </geometry>
      <contact_coefficient mu="0"  resitution="0"  k_p="0"  k_d="0" />
    </collision>
  </link>

  <material name="Green">
    <texture filename="...texture file..." />
    <!--color rgb="255 255 255" /-->
  </material>

Code API

The URDF parser API contains the following methods:

Parse and build tree from XML: urdf::Model::initXml
Parse and build tree from File: urdf::Model::initFile
Parse and build tree from String: urdf::Model::initString
Get Root Link: urdf::Model::getRoot
Get Link by name urdf::Model::getLink
Get all Link's urdf::Model::getLinks
Get Joint by name urdf::Model::getJoint