Trip Kinematics

[Ibidu]

We need a kinematic node for the Triped visualisation in Rviz.
This node should take in the ROS topics for the joint states : /leg_i/swing/left(right)/joint/joint_states/ .
Then read the position of the joint state message.
From there the Kinematics of the Triped should be calculated.
The node should output the topics /tf_static and /tf.
Both publish geometrymsgs/TransformStamped[], the elements are geometrymsgs/TransformStamped, with:

• a child_frame_id: string, with the name of the respective Link in the urdf model. e.g. chassis for the chassis link in the /tf_static topic, or leg_1_open in /tf.

• a header: stdmsgs/header with
  -- frame_id: string name of the parent link, e.g. base_link for the chassis link
  -- seq: stamp, 0
  -- stamp: time

• a transform: geometrymsgs/Transform, with
  --rotation: Quaternion
  --translation: Vector3

the /tf_static contains only the chassis link, and the /tf topic contains all other links of the urdf, excluding the base_link.
See also: http://wiki.ros.org/robot_state_publisher

[Ibidu]

see also: http://docs.ros.org/en/api/geometry_msgs/html/msg/TransformStamped.html