Design and Analysis of an Adaptive Grasping Device Based on Parallelogram Mechanism

Abstract. Aiming at the defects of traditional rigid grippers, such as poor environmental adaptability, easy damage to fragile and flexible objects, cumbersome structure and high driving redundancy, an adaptive grasping device based on the parallelogram mechanism is designed in this paper. Based on the traditional parallelogram mechanism, an adaptive parallelogram mechanism is improved and constructed, which realizes passive adaptive grasping relying on the elastic deformation of springs, and can effectively adapt to objects of different sizes and protect the integrity of grasped workpieces. A 2-RRR planar parallel mechanism is adopted as the driving mechanism of the gripper unit. The degree of freedom and constraint characteristics of the mechanism are analyzed through screw theory and kinematic model. Meanwhile, a linkage transmission structure with bevel gear sets is applied to optimize the traditional six-motor driving scheme into a dual-motor driving mode, which significantly reduces driving redundancy and overall control cost. The analysis of grasping conditions for objects with different sizes verifies that the device possesses excellent dimensional adaptability and grasping stability. The research results can provide a reliable theoretical basis and technical reference for the innovative optimization of traditional mechanical mechanisms and the design and engineering application of flexible adaptive grasping equipment.