| In order to achieve the requirement of high speed and high precision,the double wafer stage lithography adopts macro micro drive way.As the executing agency of macro table,permanent magnet synchronous linear motor,mainly responsible for the linear motion of large trip,its positioning accuracy is required to achieve micron level. However due to the characteristics of the linear motor,the main problems in the control are:the obvious model uncertainty,parameter uncertainty,and the influence of various nonlinear disturbance force. For the sake of neeting the control performance’s requirement,it must be to solve the above problems.Therefore adaptive robust control method is proposed in this paper,and then its control effect is verified by simulation,the system tracking performance and disturbance resistance are improved.Firstly,the basic structure and working principle of linear motor are analyzed,and the nonlinear interference force due to the opening structure is also brought forward.Then the mathematical model of the dq axis is derived,and the thrust equation is obtained,so the control of the motor can be realized by controlling the current.Then the nonlinear locating force are analyzed,the mathematical model is ideal.At last,the mathematical model of linear motor is established on the basic of the above.Secondly,in view of the linear motor parameters uncertainty problems of selecting the adaptive control method,so the parameters of the controller is not fixed,parameter adaptive law can be used for online identification of unknown parameters so as to update the controller.Because of the relative order of the motor model is greater than 1,the idea of backstepping method is needed.So first of all,this paper describes the design of backstepping method,and then analyzes the basic principle of adaptive control,combined with the backsteeping method to get the design process of the adaptive backstepping method.Finally,the control design and simulation verification are carried out for the actual model.Thirdly,aiming at the deficiency of adaptive control,this paper expounds the idea of deterministic robust control,and carries out the MATLAB simulation,which can effectively restrain the existence of all kinds of interference.In order to integrated the advantages of the above two control methods,adaptive robust control method is proposed,which is applied to the linear motor,the simulation can get the tracking performance and disturbance resistance are improved.Finally,in view of the practical application due to the presence of measurement noise on the controller parameter adaptive law in part model and adaptive compensation,which affect the control effect of the controller.Therefore,the desired compensation adaptive robust control thought,with the desired trajectory as a feedback regressor,the rest partment is the same with the adaptive robust controller.At last,the simulation is carried out to verify the effectiveness of the proposed method. |
