Modeling And Motion Control For Rigid-Flexible Coupling Motion Stage Based On Frequency Domain

As the pillar of modern information technology,integrated circuit is of great significance to national production,national defense science and technology and other fields.As an interdisciplinary discipline,it cannot be separated from the support of precision electronic manufacturing and precision electronic processing technology.Precision moving platform,as the core part of precision machining and manufacturing,needs to meet the requirements of high speed and precision positioning.As a new type of platform structure,the rigid-flexible coupling platform can compensate the friction dead zone through the flexure hinge,improve the positioning accuracy of the system,and meet the requirements of high acceleration at the same time,so it is an ideal platform structure.The targeted research on the control strategy of the platform is helpful to improve the performance of the platform,which is the only way to achieve high-speed and high-precision motion positioning.(1)Based on the structure and working principle of the rigid-flexible coupled motion platform,the platform is equivalent to a two-degree-of-freedom double-inertia spring damping system.Based on this,mathematical modeling is carried out to obtain its transfer function.On this basis,the frequency domain characteristics of the system are analyzed in this paper,which lays a foundation for the following system identification and controller design.Through frequency domain analysis,it can be seen that the resonance phenomenon,equivalent stiffness,mass ratio and friction of the system will affect the frequency domain characteristics of the system,which should be considered in the design of the controller.(2)In this paper,a system identification method is designed to complete the frequencydomain modeling of the rigid-flexible coupled motion platform.In frequency domain identification,this paper mainly considers the following three points: system identification structure,excitation signal and signal processing and analysis.In order to simplify the design of identification system,open-loop identification is chosen.In terms of incentive signals,this paper compares several kinds of incentive signals,and according to theoretical analysis and simulation,finally uses CHIRP signal as the incentive signal of system identification.In the signal processing and analysis,this paper uses the correlation analysis method with anti-noise to process the input and output data,so as to avoid the influence of measurement noise on the identification accuracy.After the frequency domain characteristics of the system are obtained,the frequency domain characteristics are fitted to transfer function based on genetic algorithm,so as to facilitate the following controller design.Finally,the simulation experiment is carried out to verify the identification method,and the accuracy of the identification method is illustrated.(3)According to the model obtained,the control structure of "cascade P/PI controller +filter" is designed in this paper.The speed loop is controlled by proportional integral,and a low-pass filter and a notch filter are added according to the system's frequency domain characteristics.The position loop is controlled by proportion.Then,according to the sensitivity function and other frequency domain indexes,the parameters of the controller are adjusted to make the system meet the requirements of stability and disturbance immunity.Finally,the simulation experiment is carried out to verify the controller structure and the effect of parameter tuning.(4)The rigid-flexible coupled motion platform control system is built in this paper,and the identification and controller design experiments are carried out on the real system to verify the feasibility of the above methods in the real system.In order to make the actual system meet both the frequency domain index and the time domain requirement,the coarse-fine parameter tuning method is adopted in this paper.In the parameters satisfying the frequency domain index,the controller parameters are fine-tuned according to the time domain index.The experimental results show that the rigid-flexible coupled motion platform has a setting time of 12 ms and a positioning accuracy of 0.1?m.The high speed and high precision motion positioning effect is realized,which demonstrates the superiority of the identification and controller design method.