Study On Sliding Mode Control Of Silicon-based Anti-ferroelectric Bridge Micromirror Based On Hysteresis Inverse Compensation

Laser communications have advantages of fast transmission speed and large amount of information,which makes laser communications play an important role in space communications.In the existing domestic and foreign field,beam deflection microstructures have problems of slow response,large volume,high power consumption,complicated control and low precision.Therefore,a field-induced strain effect was studied based on?Pb,La??Zr,Ti?O₃?PLZT for short?silicon-based anti-ferroelectric materials.A micromirror component of the laser beam deflection was proposed based on the PLZT anti-ferroelectric bridge structure,and the design and control were studied on the anti-ferroelectric bridge micromirror.First,the deflection and stress of PLZT anti-ferroelectric bridge micromirror with different structural parameters?length,width,thickness?were analyzed by ANSYS Workbench finite element simulation software.The relationship between the deflection,stress variation and voltage,structural parameters of the anti-ferroelectric bridge micromirror driven by an external electric field was verified.Through the orthogonal experiment,the structural optimization was carried out to achieve the maximum center displacement within the fatigue characteristics of the micromirror component.It was 5000?m in length,200?m in width and10?m in thickness.Secondly,the discretized Preisach model was established by studying the hysteresis of PLZT anti-ferroelectric materials.On this basis,the random forest algorithm was proposed for nonlinear fitting,because the discretized Preisach model did not have erasure feature.Then,an improved model for the discretized Preisach with strict erasure was derived.At last,based on the inverse model of random forest improvement model,two schemes of hysteresis inverse compensation control and compound control were established.The simulation results showed that the compound control based on hysteresis inverse compensation and adaptive sliding mode control was able to control the absolute error under0.2?m?angle 0.08mrad?.Relative error can be controlled below 1.05%.The expected input had a good linear relationship with the actual output,and the correlation coefficient was R²=0.9996.Therefore,it could meet the requirement of precision tracking control of PLZT anti-ferroelectric bridge micromirror in beam deflection technology.To sum up,the paper verified from the theoretical basis that the proposed PLZT anti-ferroelectric bridge micromirror could achieve precision tracking control in beam deflection.And the combination control of hysteresis inverse compensation and adaptive sliding mode control was designed to improve tracking control accuracy.All these provided a theoretical basis for the design and development of micro-volume,fast response,and high precision tracking control beam deflection microstructures in laser communication systems.