LPSA underactuated mode of linearly parallel and self-adaptive grasping in the CLIS robot hand with Chebyshev linkage and idle stroke

Abstract

Traditional finger with parallel and self-adaptive grasping mode cannot perform a linear translation of its distal phalange. The linear translation of the distal phalange is useful in grasping typical objects put on a table without motion of manipulators. This paper presents an underactuated grasping mode of linearly parallel and self-adaptive grasping (LPSA grasping). The LPSA grasping mode involves two stages in grasping: 1) Linear pinching of the distal phalange; 2) Self-adaptive grasping of the distal phalange around the distal joint. This paper presents a novel underactuated robot hand (CLIS hand), which can achieve LPSA grasping mode. The CLIS hand has two symmetrical fingers driven by one motor. Each finger has Chebyshev four linkages to make linear motion of distal joint, gears for keeping parallel status, two springs and idle-stroke transmission mechanism for self-adaptation. Experimental results show that the CLIS hand is valid for LPSA grasping mode.