Research on the Stiffness Performance for Robot Machining Systems

Abstract

Industrial robot is widely used in aviation manufacturing for its high precision,high efficiency and good expansibility.However,the low stiffness of a serial structure has been a primary factor affecting the end positioning accuracy and dynamic properties.This paper studies the stiffness property optimization for a redundant robot with an extra 7th axis.First,the joint stiffness values are obtained by experiment identification based on a conventional stiffness model.Then a genetic algorithm is employed to conduct the posture optimization under a given position and orientation constraint so as to allow the length of the semiaxis of the stiffness ellipsoid to reach its maximum along the normal direction of the workpiece.Finally,contrast experiments are carried out and the results show that the optimization method is of great significance for enhancing the positioning precision and improving machining properties.