A kinematic algorithm for manipulating an irregular object with robotic fingers

The parallel jaw grippers have been in use in industrial manipulators as standard end-effectors for a long time. A simple ON-OFF controller is adequate for these grippers. They typically use pneumatic cylinders as actuators for opening and closing of its jaws. However, a gripper of this type is incapable of handling convex objects; and dexterous manipulations like unscrewing a flask is almost impossible. It is obvious that fingers instead of jaws are required to perform complex tasks. However, the control of such fingers is not simple ON-OFF events. This paper presents a computational frame work on the basis of constraints of a closed kinematic chain, in order to grasp and manipulate unknown objects. This approach does not depend on grasped objects geometry for articulating the fingers.