An Underactuated Gripper with Pulley-Link Mechanisms for Pinching and Lifting in Environmental Constraints

Abstract

This paper presents an underactuated gripper (PLP Gripper) capable of achieving stable pinching operations under various environmental constraints. The fingertip of the gripper can adapt to unstructured environments and realize a gripping-lifting effect on lightweight objects. The mechanical gripper consists of two finger phalanxes, integrating dual-parallelogram mechanisms and pulley-link mechanisms. The dual-parallelogram linkages ensure that the fingertip maintains a fixed vertical posture relative to the base, while the pulley-linkage mechanisms provide the device with adaptability to object surfaces and a lifting effect. By incorporating elastic elements and limit blocks, the system preserves the initial posture of the finger, preventing deviations in the initial grasping position caused by finger deformation in non-operational states and thereby ensuring the stability of the grasping process. Experimental results verify the gripper's exceptional adaptive and gripping-lifting performance, demonstrating its broad application potential in complex dynamic environments.