A stiffness matching-based deformation errors control strategy for dual-robot collaborative machining of thin-walled parts

Abstract

Thin-walled parts are widely used in aerospace industry. To reduce the deformation errors of such thin-walled parts in machining and also to achieve simultaneous machining of both sides, a novel dual-robot machining system is developed in this paper. In this system, the local rigidity of the thin-walled parts can be enhanced via mutual support between two robots on both sides of the parts, thus reducing the deformation error caused by the low rigidity of the parts effectively. Further, a new concept of dual-robot stiffness matching is introduced, and the deformation of thin-walled parts caused by stiffness mismatching between two robots is analyzed and given a close-form solution. On basis of this solution, a dual-robot posture optimization model, which can satisfy the stiffness matching constraint and improve the normal stiffness of two robots, is developed and then is solved efficiently using the proposed easy-execution sequential algorithm based on the directed node graph and Dijkstra searching, thus the deformation errors of thin-walled parts in machining can be ulteriorly controlled effectively. Finally, the computer simulation and experiments are performed and the results demonstrate that the developed dual-robot machining system and the stiffness matching-based deformation control strategy can effectively reduce the deformation of thin-walled parts in machining.