Position Control Of X-Y Precision Plane Motion Stage Based On Iterative Learning Control

X-Y precision plane motion table is widely used in precision motion control fields such as lithography machine workpiece table,CNC machine tool,shape contour laser measurement system,etc.,so it has high requirements for the contour control accuracy of the system.To achieve higher contour control accuracy,the position tracking control accuracy of each single axis must be improved.Then,on this basis,the two axes are dynamically adjusted in real time according to the desired trajectory and cooperate with each other to achieve the purpose of reducing the contour error.For this reason,this paper adopts Iterative Learning Control(ILC)as the single-axis position controller,improves the position tracking control accuracy of singleaxis through multiple iterations,and introduces Cross-coupling Control(CCC)to establish the relationship between the two axes.The coordination relationship can improve the contour control accuracy.Firstly,the basic structure of the X-Y precision plane motion table is analyzed,its mathematical model is obtained,and the basic control algorithm of the X-Y precision plane motion table is determined.On this basis,a visual co-simulation model of the X-Y precision plane motion table is established using Simulink and Solidwork,and the feasibility of the control scheme is preliminarily verified through simulation experiments.Then,the step scanning trajectory is designed with the S-shaped acceleration and deceleration curve as the target curve,which is used to verify the contour error of the X-Y precision plane motion table.In order to improve the single-axis position tracking accuracy of the XY precision plane motion stage,a control scheme combining PD type variable gain open and closed loop iterative learning control and PID feedback control is designed.The algorithm converges faster and effectively reduces the Iterative tracking error.However,it is found in the experiment that some high-frequency noise will affect the stability of the system after many iterations.In order to solve this problem,a low-pass filter is added to the PD-type variable gain open and closed loop iterative learning control,and the XY precision plane is moved.The above iterative learning controllers are compared and analyzed in the simulation model.In order to improve the dynamic coordination ability between the two axes of the X-Y precision plane motion table,CCC is added between the two axes.The contour error calculation model of any trajectory is designed,the components of contour error in each axis are calculated,and the PID controller is used to compensate.Through the cooperation between the crosscoupling controller and the iterative learning controller of each axis,the contour control accuracy of the X-Y precision plane motion table is improved.In order to further improve the stability of the X-Y precision plane motion stage,an Adaptive Iterative Learning Control(AILC)that can be adjusted in real time according to the system state is designed.And the control performance of the algorithm is analyzed through three different motion trajectories in the X-Y precision plane motion table simulation model.Finally,the control model of the X-Y precision motion platform is built in Simulink,and the position control of the X-Y precision motion platform is realized by using the rapid prototype control system in the laboratory.Based on this control system,the single-axis position tracking accuracy of X-axis and Y-axis under the control of different algorithms,and the dual-axis contour control accuracy under the AILC+CCC control scheme and the ILC+CCC control scheme under the input of three different trajectories are tested.The experimental results show that the control scheme of AILC+CCC has higher stability and higher control precision.