Sensor based control for the execution of regrasping primitives on a multifingered robot hand

We demonstrate the robust execution of two regrasping primitives, rotation and pivoting on a four-fingered hand, based on the real-time sensors data based control. We indicate frequently occurring grasp errors and faults during execution of the two regrasping primitives. The sensors data is obtained from two sources. One is force-torque sensors mounted on the finger tips of the four fingers. The other is a laser range sensor mounted on the palm of the hand. The grasp information acquired through these two sources is useful for both sensing the errors and controlling the fingers. The paper proposes strategies to recover or prevent faulty grasps during manipulation, which may lead to unwanted object movements or grasp failures. The object to be manipulated is a polygonal prism, the model of which is known a priori.