Study On Control Method And Technique Of Piezoelectrically Actuated Micro-displacement Scanning Platform

With the development of nanotechnology,precision positioning technology has become the common basis for many modern industrial fields and cutting-edge science and technology research.Piezoelectrically actuated micro-displacement actuators are characterized by their small size,high displacement resolution,high frequency response,and large bearing capacity.They generate micro-displacements under input voltage and have nanometer resolution.They are now widely used in precision positioning.However,due to the complex hysteresis nonlinearity of the actuator driven by piezoelectricity,the precise and precise positioning of the control system is very limited.On the other hand,in most cases,the piezoelectric actuator cannot be used directly on the micro-drive platform.Through the flexible hinge mechanism to achieve the movement,energy transfer and conversion.In general,the piezoelectric actuator has a high resonance frequency,which can satisfy the rapid positioning of the platform and the flexible hinge mechanism is similar to the mass spring damping system,which causes resonance when the micro-scanning platform is quickly positioned.Therefore,in the rapid positioning process,the piezoelectrically actuated micro-displacement scanning platform generally exhibits vibration and hysteresis characteristics.In this dissertation,the piezoelectrically actuated micro-displacement scanning platform system is used as a controlled object.The dynamic response characteristics and the resonance characteristics of the piezoelectrically actuated micro-displacement scanning platform control system are analyzed in depth,and the micro-displacement to improve piezoelectric actuation is studied.The method and theory for the control of the scanning platform in the resonant state improve its application in the field of high-precision motion control.The main research contents are as follows:(1)Modeling and analysis of micro-displacement scanning platform system based on piezoelectric actuation.Firstly,the mathematical model of the micro-displacement scanning system was analyzed and set up using the theory of system modeling.The output signal of the system was measured by Gaussian white noise excitation piezoelectric actuated micro-displacement scanning platform system,and was identified by MATLAB system identification toolbox.Unknown parameters in the established mathematical model.(2)Theoretical analysis of time delayed position feedback control method.For the main problem we need to solve,the vibration state of the piezoelectrically actuated micro-displacement scanning platform in the resonance state is combined with the existing control strategies.In this paper,firstly,the time-delay position feedback controller algorithm is theoretically analyzed,and then the corresponding simulation experiment is performed.Due to the uncertainties in system modeling and the effects of environmental disturbances and ceramic hysteresis nonlinearity,creep and other non-linear effects,the model reference adaptive control method is used in this paper to improve the performance of the control system.(3)Experimental testing and analysis of piezoelectrically actuated microdisplacement scanning platforms.Aiming at the control algorithm proposed in this paper,the experimental analysis was carried out,and an experimental platform was set up.Experimental tests were performed on the experimental platform of Doppler vibrometer and dSPACE.Under the condition of stable external environment,through the given input signal,the bandwidth of the control system is tested,and the signal is traced to verify the feasibility of the algorithm.The experimental results show that the control algorithm proposed in this paper can well compensate the errors caused by the external environment and the inaccuracy of the modeling and improve the resonance state of the system.