Analysis Of The Electromechanical Coupling Facts About Precise Mechanical Transmission In Servo System

In the last several decades, servo technique has been applied to almost all over the society accompany with the new technique revolution, especially with the micro-electronics technique and calculators developing at very fast speed. Servo system plays an important role in defence construction, industrial production, communications and transport even family life.The thesis analyzed the electromechanical coupling facts about the mechanical transmission in servo system, after the process of coupling analysis of the electromechanical system. First, the electromechanical coupling facts about the mechanical transmission in servo system had been put forward. Then the precision of the mechanical transmission is analyzed and the model of the typical servo feed system is build based on the coupling facts. Finally, the simulation results of the coupling model are studied with Matlab/Simulink.The following research results are obtained:①Three modes of electromechanical coupling facts in servo system are summarized. They are the strong electromagnetism field of drive coupling with mechanical transmission, the parameters of armature circuit coupling with main motion of mechanical transmission and drive system coupling by workpiece. Among them, the coupling types of mechanical transmission are weak coupling between the parameters of control circuit and dynamic parameters and the harmonic current derived from electromagnetism field acting on main motion, leading to the vibration of mechanical transmission.②The coupling factors of mechanical transmission have been put forward, which include stiffness, driving error, hysterisis error, rotary inertia, structure resonance frequency and friction moment. The coupling relationship between those and the parameters of control circuit is analyzed.③The calculation method of drive error of mechanical transmission on the forward direction in closed loop servo system is deduced. By this method, only the drive error, the frequency out of the open loop bandwidth is need calculated in servo system.④The influences of drive error, hysterisis error and stiffness of the planetary gear, harmonic gear and lead screw on the performance of the servo system are discussed and the calculation methods have been put forward respectively.⑤The matrix model of servo system is build with coupling parameters according to the structure principle of electromechanical system.⑥The electro-mechanical coupling model was simulated with Matlab/Simulink. Simulation results show that if the value of stiffness is higher, the overshoot of the system is bigger; if the value of stiffness is lower, the response time to the set value is longer; transmission error with low frequency in dynamic transmitted chains doesn't influence on output and precision in servo system, but that with high frequency will influence on laden motion.