Design, modeling, and manipulability evaluation of a novel four-DOF parallel gripper for dexterous in-hand manipulation

This study presents a novel four-degrees-of-freedom parallel gripper with potential application to industrial automation. The gripper adopts a parallel grasping mode on objects and can independently complete in-plane horizontal and vertical motions and in-hand twisting motion. Kinematic and dynamic models of the gripper-object system are developed. The controllable internal force acting on the object is calculated to obtain the minimum driving force/torque. An energy-based manipulability index is developed on the basis of the derived solutions. The numerical simulation includes a comparison between the MATLAB model and the ADAMS model to verify the motion forms of the parallel gripper and the rationality of analytical modeling studies. Manipulability performance is evaluated along the transportation path of the object. Results indicate that the gripper can achieve horizontal transmission to supplement the workspace of a robotic arm, and it exhibits relatively better performance in in-hand manipulation and in-plane vertical transmission.