Design Of Multi Motor Synchronous Control System Based On Iterative Learning Control

In the development of lithography machine,the dual wafer stage change program is an essential part of the design.Multiple actuators are required to cooperate with each other in order to perform the change smoothly.And in the process of operation,the motor positioning accuracy and running speed are relatively high design requirements.Therefore,this paper makes a detailed research on the control of the revolution motor and the rotation motor which plays a key role in changing the wafer stage.Firstly,the system composition of lithography machine and the dual wafer stage is introduced.According to the structure,function and design idea of double stage platform,the specific program is planned.In order to ensure the validity and stability of the platform change,the S curve is designed as the input trajectory of the actuator.The positioning problem and synchronization requirement of each actuator during the whole stage change are analyzed.Secondly,the interference of the revolution motor and the rotating motor in the process of changing the station is analyzed carefully,and the periodic interference model is obtained.An iterative learning algorithm is adopted to design a single motor executive controller,and its control effect is analyzed by simulation,and the feasibility of the algorithm is verified.Using high-order iterative learning to improve the single motor controller,the purpose of faster convergence and anti periodic disturbance is achieved.Thirdly,considering the structure of the dual motor system,the advantages and disadvantages of different synchronization control strategies are analyzed.According to each synchronous control structure,a synchronous control system of dual motor is designed,and then verified by simulation analysis.Finally,the cross coupled master-slave control structure is more suitable for the synchronous control structure of the revolution and rotation system.The iterative learning algorithm is applied to the synchronous controller,and its synchronization control effect is verified by simulation.Finally,the synchronization control structure of the selected system is mainly based on the method,and the two order iterative learning algorithm is adopted to control the main motor to design an improved synchronous control system.The simulation analysis is compared with the iterative learning synchronization controller to show the advantages of the overall tracking er ror and the overall error of the system.The experiment system of changing platform is introduced.The control effect of iterative learning algorithm and double motor synchronous control strategy is verified on the experimental platform.The experimental results show that the error characteristics of the iterative learning algorithm and the master-slave synchronization structure are basically satisfied with the system performance index.