LISA Hand: Indirect self-adaptive robotic hand for robust grasping and simplicity

Abstract

Humanoid robotic hand is one of most impressive research focus in robotics. There are two important requirements in robotic hands: on the one hand, a hand has a good humanoid appearance and sizes and can grasp almost all of common objects, on the other hand, the same hand is very simple in structure, very easy in control and very low in cost. Most of present dexterous robotic hands could not balance above two aspects. In searching for simple architecture and effective grasp at once, a novel under-actuated robotic hand is designed and manufactured and could achieve the above requirements perfectly, which is called Linkage Indirectly Self-Adaptive Under-actuated Hand, LISA Hand. The key of the LISA Hand is special and simple structure of its fingers. The indirectly under-actuated LISA finger can utilize the inverse forces from objects grasped to realize action of the next joint without any motor. Each of LISA fingers is composed of multiple-class block-linkage-slot transmission mechanisms, multiple springs and only one motor with a reducer. The LISA Hand has 5 fingers, 14 joint DOFs and only 5 motors. All fingers in the LISA Hand are similar. The thumb has two joints, and each of the other four fingers has three joints. Self-adaptation for good grasping performance is designed as the main function of the LISA finger. The grasping principle, process and force analysis of LISA Hands are given. Force analysis shows that the LISA Hand is valid and could be regarded as an end-effecter of humanoid robots.