Research On Driving Characteristics Of Optoelectronic-piezoelectric Composite Actuator For Optical Path Selectio

In the rapid development of optical fiber communication technology,the exchange of information can be completed directly by optical switching,where the actuator used for optical path selection is an important component of the optical switching mechanism.Common driving methods of micro-actuator include piezoelectric drive,electromagnetic drive,electrostatic drive,electrothermal drive and other forms.However,these driving methods all require electrical or magnetic excitation devices,so their electromagnetic compatibility is poor.In this dissertation,a photovoltaic-piezoelectric hybrid actuator based on the anomalous photovoltaic effect of lanthanum-doped lead zirconate titanate（PLZT）ceramic was proposed,combining the photoelectric conversion characteristics of PLZT ceramic with the advantages of fast response of piezoelectric film to realize a remote contactless optical control drive,avoiding electromagnetic interference and providing a choice and reference basis for the optical control actuators used for optical path selection.The principle of photogenerated voltage was explained based on the anomalous photovoltaic effect,the pyroelectric effect and the positive piezoelectric effect in combination with the light-electricity-thermal-force multi-physical field coupling relationship of PLZT ceramic under high-energy light excitation,then a mathematical model in the illumination and light-off phase was established.Experimental tests on the voltage and surface temperature of PLZT ceramics at different light intensities were carried out to verify the correctness of the mathematical model of photovoltaic voltage,and to point out that the temperature change caused by illumination has a non-negligible influence on the photoelectric properties,and that the temperature rise is the main reason for the decrease of photovoltaic voltage during the illumination phase.Based on the photoelectric conversion function of PLZT ceramic,a photovoltaic-piezoelectric hybrid actuator with PLZT ceramic and PVDF film laminated fixed-fixed beam structure was proposed.Based on the study of the driving principle of this actuator,the mathematical model of the photovoltaic-piezoelectric hybrid driving method was established.Numerical analysis and finite element method were used to simulate the driving displacement of the actuator to verify the correctness of the mathematical model and determine the maximum displacement output point.At a driving voltage of 900V,the actuator can output a displacement about 160×10^-6m,the relative error between theoretical value and simulated value of the driving displacement is 0.63%.The driving characteristics of the proposed photovoltaic-piezoelectric hybrid actuator were studied.Combined with the mathematical model of driving displacement,a theoretical analysis of the influence of each dimensional parameter of the piezoelectric film laminated fixed-fixed beam structure on the output displacement of the actuator under a constant driving voltage was carried out.Experimental measurements of the photogenerated voltage of PLZT ceramic when driving different sizes of PVDF films were carried out.On this basis,combined with finite element simulation method,the analysis of the influence of PVDF film length,thickness and light intensity on the driving characteristics of the photovoltaic-piezoelectric hybrid actuator was carried out.Based on the ON-OFF control strategy of the excitation light source,the closed-loop control model of the photovoltaic-piezoelectric hybrid actuator was established.The closed-loop control simulations of the photovoltaic-piezoelectric hybrid driving voltage and the PLZT ceramic photovoltage without load were carried out to verify the feasibility of the closed-loop control strategy.Then closed-loop control was explored for the situation where two PLZT ceramics provide bidirectional photovoltage.The optical multi-physics properties of PLZT ceramic provide the basis for the optical control of voltage,force,displacement and other output properties of photovoltaic hybrid actuators based on PLZT ceramics.The study of the driving characteristics of the photovoltaic-piezoelectric hybrid actuator for optical path selection carried out not only provides a reference and basis for the study of other types of photovoltaic hybrid actuators,but also expands the engineering applications of PLZT ceramic.