Interval Type-2 Fuzzy Neural Network Control For H-type Stage Driven By Dual Linear Motors

This subject comes from National Natural Science Foundation of China(51175349)and Liaoning Provincial Natural Science Foundation(2015020151).H-type precision motion platform is composed of three permanent magnet linear synchronous motors which have identical structure and parameters.In this structure,two permanent magnet linear synchronous motors in Y axis are installed on the two parallel guide rails to move along the direction of Y level,a permanent magnet linear synchronous motor is installed on X axis to move along the direction of X level.Although the exactly same control method is used in Y axes,uncertainties caused by the variation of parameters in motors,the disturbance of friction and load will lead the motion of both sides cannot be synchronous.The positon synchronous error is exist because of these.This synchronous error will affect the quality of workpieces,even lead to a stop of the working process due to the over current protection.Therefore,the purpose of this thesis is to design a controller to ensure the high-precision motion of single axis,and on this basis,it is necessary to design a compensator to reduce the position synchronous error of H-type precision motion platform.Firstly,this thesis introduces the development of H-type precision motion platform at home and abroad and the research status of control strategies.The movement accuracy will be reduced because of the position synchronous error between the two axes,so on the basis of considering the influence of the X axis motion on the twisting force in the two parallel axis of the Y direction,accroding to principle and mathematical model of permanent magnet linear synchronous motor,the mathematical model of H-type precision motion platform can be derived.Then,based on the mathematical model of H-type precise motion platform,a sliding mode robust control method based on HJI(Hamilton-Jacobi Inequality)theory is proposed focus on the single axis motion performance.This control method firstly designed a sliding mode control law for the control system,then projected a Lyapunov function,finally based on the HJI theory,proved the robust condition can be guaranteed.A cross-coupling synchronous compensator is designed in order to reduce the position synchronous error between two axes.MATLAB/Simulink is used to model and simulate the controller.Compared proposed control method and ordinary sliding mode control method,the simuliation results show that the proposed method can reduce the single axis position tracking error,moreover,the cross-coupling compensator improves the synchronous performance.Finally,based on the reliability of the singal motion controller for H-type precision motion platform,an interval type-2 fuzzy neural network compensator is presented in order to improve the accuracy of position synchronous error between two axes.Interval type-2 fuzzy logic is extended from type-1 fuzzy logic to better deal with nonlinear and uncertain systems,futhermore,the computational method is simpler than type-2 fuzzy logic.MATLAB/Simulink is used to model and simulate the proposed compensator.