sudo apt-get install ros-indigo-urdfdom-py

#! /usr/bin/env python

# Load the urdf_parser_py manifest, you use your own package
# name on the condition but in this case, you need to depend on
# urdf_parser_py.
import roslib; roslib.load_manifest('urdfdom_py')
import rospy

# Import the module

from urdf_parser_py.urdf import URDF

# 1. Parse a string containing the robot description in URDF.
# Pro: no need to have a roscore running.
# Cons: n/a
# Note: it is rare to receive the robot model as a string.
robot = URDF.from_xml_string("<robot name='myrobot'></robot>")

# - OR -

# 2. Load the module from a file.
# Pro: no need to have a roscore running.
# Cons: using hardcoded file location is not portable.
robot = URDF.from_xml_file()

# - OR -

# 3. Load the module from the parameter server.
# Pro: automatic, no arguments are needed, consistent
#      with other ROS nodes.
# Cons: need roscore to be running and the parameter to
#      to be set beforehand (through a roslaunch file for
#      instance).
robot = URDF.from_parameter_server()

# Print the robot
print(robot)

<robot name="test_robot">
    <link name="link0" />
    <link name="link1" />
    <link name="link2" />
    <link name="link3" />

    <joint name="joint1" type="continuous">
        <parent link="link0"/>
        <child link="link1"/>
        <origin xyz="0 0 0" rpy="0 0 0" />
        <axis xyz="1 0 0" />
    </joint>

    <joint name="joint2" type="continuous">
        <parent link="link1"/>
        <child link="link2"/>
        <origin xyz="0 0 1" rpy="0 0 0" />
        <axis xyz="1 0 0" />
    </joint>

    <joint name="joint3" type="continuous">
        <parent link="link2"/>
        <child link="link3"/>
        <origin xyz="0 0 1" rpy="0 0 0" />
        <axis xyz="1 0 0" />
    </joint>

</robot>

rosrun pykdl_utils kdl_parser.py [robot.xml]
rosrun pykdl_utils kdl_kinematics.py [robot.xml]
rosrun pykdl_utils joint_kinematics.py [robot.xml]

rosrun pykdl_utils kdl_parser.py `rospack find test`/robot.urdf

#! /usr/bin/env python

# Import the module
from urdf_parser_py.urdf import URDF
from pykdl_utils.kdl_parser import kdl_tree_from_urdf_model
from pykdl_utils.kdl_kinematics import KDLKinematics

robot = URDF.from_xml_file("/home/sc/catkin_ws/src/test/robot.urdf")

tree = kdl_tree_from_urdf_model(robot)
print tree.getNrOfSegments()

chain = tree.getChain("link0", "link3")
print chain.getNrOfJoints()

# forwawrd kinematics
kdl_kin = KDLKinematics(robot, "link0", "link3")
q = [0, 0, 0]
pose = kdl_kin.forward(q) # forward kinematics (returns homogeneous 4x4 matrix)
print pose 

q_ik = kdl_kin.inverse(pose) # inverse kinematics
print q_ik

if q_ik is not None:
    pose_sol = kdl_kin.forward(q_ik) # should equal pose
print pose_sol

J = kdl_kin.jacobian(q)
print 'J:', J

def pykdl_utils.kdl_kinematics.KDLKinematics.__init__    (self, urdf, base_link, end_link, kdl_tree = None)        

# Parameters:
# urdf    URDF object of robot.
# base_link    Name of the root link of the kinematic chain.
# end_link    Name of the end link of the kinematic chain.
# kdl_tree    Optional KDL.Tree object to use. If None, one will be generated from the URDF.

# Inverse kinematics for a given pose, returning the joint angles required to obtain the target pose.
def pykdl_utils.kdl_kinematics.KDLKinematics.inverse(self, pose, q_guess = None, min_joints = None, max_joints = None )  
      
# Parameters:
# pose    Pose-like object represeting the target pose of the end effector.
# q_guess    List of joint angles to seed the IK search.
# min_joints    List of joint angles to lower bound the angles on the IK search. If None, the safety limits are used.
# max_joints    List of joint angles to upper bound the angles on the IK search. If None, the safety limits are used.

  <package>
    ...
    <build_depend package="kdl_parser" />
    ...
    <run_depend package="kdl_parser" />
    ...
  </package>

#include <kdl_parser/kdl_parser.hpp>

   KDL::Tree my_tree;
   if (!kdl_parser::treeFromFile("filename", my_tree)){
      ROS_ERROR("Failed to construct kdl tree");
      return false;
   }

  KDL::Tree my_tree;
   ros::NodeHandle node;
   std::string robot_desc_string;
   node.param("robot_description", robot_desc_string, std::string());
   if (!kdl_parser::treeFromString(robot_desc_string, my_tree)){
      ROS_ERROR("Failed to construct kdl tree");
      return false;
   }

  KDL::Tree my_tree;
   TiXmlDocument xml_doc;
   xml_doc.Parse(xml_string.c_str());
   xml_root = xml_doc.FirstChildElement("robot");
   if (!xml_root){
      ROS_ERROR("Failed to get robot from xml document");
      return false;
   }
   if (!kdl_parser::treeFromXml(xml_root, my_tree)){
      ROS_ERROR("Failed to construct kdl tree");
      return false;
   }

   KDL::Tree my_tree;
   urdf::Model my_model;
   if (!my_model.initXml(....)){
      ROS_ERROR("Failed to parse urdf robot model");
      return false;
   }
   if (!kdl_parser::treeFromUrdfModel(my_model, my_tree)){
      ROS_ERROR("Failed to construct kdl tree");
      return false;
   }