====== DLR/HIT hand cartesian library ======

The hand cartesian library enables the DLR/HIT hand to:

  * Calculate current cartesian position of finger tips.
  * Calculate current forces at finger tips.
  * Run different types of controllers for each finger.
  * Close loop inverse kinematics controller.
  * Velocity inverse kinematics.

===== Installation instructions =====

  * Get the code from oid5 repository
  * Compile patched version of orocos-kdl
  * Compile yarp

===== Prerequisite: Run the DLR/HIT server =====

  * Run the server for the DLR/HIT hand in the computer where the hand is connected:

  cd oid5/robots/kimp/hand/sahand_api
  ./sahand_yarp.py -n

===== Usage =====

  * Creating the hand object:

  import hand as h
  hand=h.Hand(handedness="left",sahand_number=1,portprefix="",sahand_port_name_prefix="/sahand")

Use the values adequate for your configuration. 
sahand_number indicates the port where the hand was connected to the PCI card.
sahand_port_name_prefix indicates the prefix used by the DLR/HIT server.
handedness is used for selecting the correct kinematic description.
portprefix is used to add a prefix to the client port names.

  * Getting data from the hand:

  hand.update_sensor_data()
  first=hand.fingers[1]
  print first.cur_joint_pos

This prints the current joint position of the finger.
The finger class has a lot of more members that contain data or functions to calculate.

  * To get access to the kinematics members of the finger just look into fingerobject.kinematics.*
  * To get access to the controller members of the finger just look into fingerobject.controller.*
  * To control the hand. First select the controller for each finger that you want to use:

  hand.set_controller(Finger_controller_sahand_joint_pos,finger_list=[1])

First argument is a controller class in this case Finger_controller_sahand_joint_pos is the controller that only relays information to the hand directly. There are other controllers like a close loop inverse kinematics one.
The second argument is a list of fingers which will have this controller.

  * To command a finger to move to a joint position:

  from numpy import pi
  hand.set_refs(1,[0,10*pi/180,0])
  hand.update_controller_refs()

Angles are in radians. Any other units are the standard metric scale (meters, seconds,Nm, etc)
To know what the refs are, please take a look in the set_refs member in the selected controller class.
The joint order is: first in the list corresponds to the first joint of the kinematic chain starting from the base of the chain.

  * One can also change the controller parameters in the same than the references using hand.set_params(finger,params_list) and then hand.update_controller_params()