A reconfigurable compliant robotic gripper based on flexible scissors mechanism

Abstract

Traditional robotic grippers are constrained by their fixed structures and limited grasping range, which poses difficulties when handling objects of various shapes and sizes. In contrast, reconfigurable grippers can flexibly adjust their grasping mode and configuration based on object properties, enabling them to accommodate a wider range of geometries. However, existing reconfigurable grippers face challenges in achieving structural consistency, large-scale continuous deformation, and ease of manufacturing and operation. To overcome these limitations, this study proposes a reconfigurable compliant robotic gripper (RCRG) based on a flexible scissor mechanism finger (FSMF). The FSMF incorporates an anisotropic scissor unit design that decouples extension and bending motions, achieving up to 4.5 times continuous finger length adjustment. Multiple FSMF modules can be mounted on a rigid scissor mechanism base to form either a two-fingered or three-fingered RCRG, depending on task requirements. With this configuration, the RCRGs can transition from a compact, retracted form to a significantly expanded state by deforming both the base and the FSMFs, thereby reconfiguring the grasping space to accommodate objects of various sizes, shapes, and orientations for diverse tasks. Theoretical modelling and experimental validation were conducted to analyse the mechanical performance of the FSMF under different extension ratios. Various grasping tests results demonstrate that the proposed RCRGs design efficiently and stably handles various objects, with a grasping envelope variation of up to 64 times, showcasing high adaptability and flexibility.