Study On Compensataion And Restraining Method Of Linear Motor Thrust Fluctuation

Since the 21 st century,the integrated circuit(IC)industry has become more and more important to the country's lifeline and people's lives.However,China's IC manufacturing industry has been severely constrained by Western developed countries in order to resolve the country's “the pain of without core”,it is our top priority to develop a lithography machine capable of processing and producing integrated circuits.This subject takes the dual-substrate stage lithography system as the research background,taking the lithography machine macroactuator-linear motor as the research object,to deeply study the compensation and control method of the thrust fluctuation that has great influence on the linear motor control performance.First of all,this article carries on the frequency sweep analysis to the linear motor,obtains the mathematical model of the linear motor.Then,a linear motor feedback controller is designed to prepare for the future work.At the same time,this paper will analyze the cause of the thrust fluctuation of the linear motor,establish a mathematical model of the positioning force,analyze the data acquisition method of the positioning force,and lay the foundation for subsequent compensation and control of the positioning force.Secondly,considering the mathematical form of the positioning force,this paper proposes two methods for identifying the positioning force—the singular value least squares method and the adaptive parameter identification method.This method can realize the full parameter identification of multi-sine signals and identify the positioning force.The method provides a way of thinking.At the same time,compared with the singular value least square method,the adaptive parameter identification method has a faster convergence speed.Then,this paper adopts feedforward control for the identified positioning force and conducts experimental verification.Thirdly,this paper aims at the off-line compensation effect of positioning force,combined with the excellent performance of adaptive control in systems with time-varying parameters,proposes an adaptive feedforward control algorithm to prove the stability of the algorithm.The simulation and experimental results show that the adaptive feedforward control algorithm has a good suppression effect on the thrust ripple of the linear motor,but there is a shortcoming of large control error in the early stage of the adaptive control.At the same time,the change of the motion status will also cause the fluctuation of the parameter,making The tracking error becomes larger.Finally,in this paper,the problems of adaptive feedforward control methods are combined with the motion characteristics of the linear motor in the lithography machine,and an iterative feedforward tuning control algorithm is used.Through simulation and experiment,it is proved that the method has a good positioning performance throughout the tracking process,and further improve the control accuracy.