Research On Model-free Control Methods Of MEMS Electromagetic Scanning Micromirrors

As a kind of micro-optical device,MEMS scanning micromirror has gradually gained extensive attention of researchers in the development of MEMS(Micro Electro Mechanical System)technologies.It has many excellent characteristics such as small size,low cost,lower power consumption,higher sensitivity,and so on.Therefore,it has very broad applications in highdefinition projection display,modern optical communications,and next-generation lidar and other fields.In recent years,a large number of researchers in the world have hot interests in MEMS scanning micromirrors.The performances of the micromirrors have been improved to a certain degree by control methods.In this paper,electromagnetically driven MEMS scanning micromirror is regarded as the research object.Based on the research and analysis of the existed control methods,appropriate model-free controllers for the micromirror system are designed.And the main work of this paper is listed as follows:Firstly,the basic theory of the model-free control method is introduced,and the model-free adaptive control is applied in the control of MEMS electromagnetic micromirror system.If the micro-mirror system is influenced by uncertain factors such as external disturbances and system noise,the traditional model-free control system may have bad performances.Therefore,a model-free control algorithm with error correction items is designed to improve the robust properties of the control system.Moreover,the boundedness of the control error in the control system is proved.Finally,the simulated and experimental results show that the proposed method is better than the traditional model-free control algorithm.In proposed model-free control algorithm above,the search direction is still estimated by the pseudo partial derivative of the objective function,which may be have larger estimated errors.Thus,estimated method is proposed to estimate the search direction of the objective function.Moreover,the boundedness of the estimated partial derivative and the control error are proved,respectively.Finally,the validation of the improved control method is verified by the micro-mirror system experiment results and simulated results.