Kinematic Synthesis and Design of the Robust Closed Loop Articulated Minimally actuated (CLAM) Hand

The paper presents a comprehensive design process for the development of the minimally actuated Closed Loop Articulated Mechanical (CLAM) hand. Each of the fingers is designed as a planar one degree of freedom eight-bar linkage with an anthropomorphic backbone chain. The fingers movement is based on experimentally obtained physiological precision grasping task, with incorporated second-order task specifications, related to maintaining fingertip-body contact with a minimum number of fingers. Instead of actuating individual joints in each finger, the mechanism generates the desired anthropomorphic grasping trajectory using a single actuator in each finger. The paper offers not only details on multi-loop articulated hands design based on anthropometric data and physiological task with second-order effects for maintaining the object-fingertip contact, but also shows how this class of hands that have been considered mostly for adaptive grasping can be successfully utilized for precision grasping. The minimal number of fingers and actuators can simplify the control, resulting in a robust, lightweight, and cost-effective solution for the precision grasping of a variety of objects with different shapes and geometries.