A new assembly error modeling and calculating method of complex multi-stage gear transmission system for a large space manipulator

In the design stage, there are difficulties to quantitatively estimate the transmission error of the complex multi-stage gear reducer for a large space manipulator and determine whether the tolerance design of the main parts is reasonable. In view of the above problems, a mathematical method for predicting transmission error of gear system based on design tolerances is proposed. Instead of considering tangential integrated errors of gears and geometric errors based on measurement, this paper comprehensively considers the machining and assembly errors of key components such as shafts, gears and housings, which satisfy the requirements of design tolerances. By tracing the assembly errors of gear system, the characterization of geometric errors is presented. Then, the formula of each error source is established, and an accurate mathematical model of the total transmission error is developed. Finally, a novel sensitivity method of gear transmission accuracy is developed to find out the critical parts and factors which affect the assembly performance of gear system. The numerical and experimental results agree well with each other, which verifies the validity of the methodology.