Design, Analysis and Validation of A Novel Tendon-driven Underactuated Gripper

A novel tendon-driven underactuated gripper is proposed in this paper. Compared with the traditional tendon-driven gripper, the novel one can achieve a much more stable grasping because of the stiffness retaining mechanism (SRM), which is fixed on the joint of two phalanges and can lock the joint passively when the tendon-tension is large enough. First, the configuration and movement sequence of SRM are designed. Then, some special parts and geometrical parameters of SRM are analyzed and optimized to achieve a smooth grab operation. At last, in order to validate the grasp performance of novel tendon-driven gripper with SRM, a prototype is manufactured by 3D printing, and some comparative grasp experiments have been done. Compared with the traditional gripper without SRM, the novel one can output four more times grasp force and maintain thirty more times grasp stiffness.