Geometrical design and experimental investigation of underactuated robotic hand for motion and grasp force augmentation

Abstract

The application of robotics in many areas is paving way for continuing research in robotics. However complex problems still exist in robot applications. One such problem is the manipulation of parts that are unstructured with respect to their portability by robot grippers. Researchers ever focus in the design of robotic grippers, the main part that does the important task of accomplishing the mission tasks like picking up sample soils, holding and manipulating parts like tools and assembly objects, etc. Human hand is one of the complex but versatile creations of nature. Hence the hand along with its fingers serves as an ideal mechanism which researchers attempt to mimic for their gripper design. The use of underactuation concept in gripper mechanism design has emerged as an important research area. Underactuation leads to employing a lesser number of actuators than the system degrees of freedom. Obviously, lesser number of actuators in robot grasping application means reduced gripper weight, lesser control difficulties and reduced cost of the gripper without compromising on the grasp function quality. The underactuated hands fall in between the simple two-fingered grippers that are used for robust grasping applications and the multi-finger, multi-sensor dexterous hand used for intricate and complex grasping functions. An underactuated gripper with two actuators, one for actuating the finger and another for orientation had been designed so far. However a gripper that can give motion and force augmentation has not been attempted. This work, hence, attempts in the design of such a gripper using a single actuator. newline