Research On Multi-stage Modified Dynamic PIM Odel And Accuracy Control Of Piezoelectric Actuators

In recent years,nanoscience and nanotechnology have flourished,and micro-nano precision positioning systems have became a research hotspot.Positioning accuracy is an important index for micro-nano positioning systems,and the performance of driving devices in positioning systems has a great influence on positioning accuracy.Among many driving devices5piezoelectric ceramic actuators have the advantages of small size,large bearing capacity,high resolution,no noise,no heat,and are widely used in micro positioning systems.However,thevoltage displacement oulput characteristics of Piezoelectric ceramic actuators has a complex nonlinear relationship,which makes it difficult to accurately position under open loop conditions.Based on this,the paper takes the piezoelectric ceramic actuator as the research object On the basis of studying the nonlinear characteristics of hysteresis,based on the weighted superposition of basic operators to achieve the PI model of fitting the hysteresis curve,a multi-stage improved dynamic PI is established.The model is used to verify the fitting degree of the model with the experimental data through MATLAB simulation.The inverse model of the design model is used as the feedforward controller to compensate the hysteresis of the piezoelectric ceramic driver,and the sinusoidal signal tracking effect at different frequencies is analyzed by simulation.The accuracy control effect of the feedforward controller is verified.The specific research content of this paper is as follows:(1)A multi-segment PI model was designed.Based on the variation law of the hysteresis curve of the piezoelectric ceramic actuator,the model was segmented and identified to establish an improved PI model,and the traditional PI model was compared by MATLAB simulation to verify the accuracy of the model.(2)A new type of operator(OSP operator)related to the input frequency and the input frequency derivative was designed.For the piezoelectric ceramic driver,as the input frequency increases,the hysteresis loop becomes "wide" The OSP operator was used to replace the basic operator in the multi-segment PI model,so that the new model can more accurately fit the new input frequency change.Hysteresis curve,the accuracy of the model was verified by MATLAB simulation.(3)A feedforward controller was designed to compensate the hysteresis of the piezoelectric ceramic driver.Based on the designed multi-stage improved dynamic PI inverse model,the piezoceramic actuator was output with ideal displacement through feedforward control,and the sinusoidal signal tracking effect at different frequencies was simulated and verified to verify the effectiveness of the controller.In this thesis,a multi-segment improved dynamic PI model was designed for the piezoelectric ceramic actuator and the corresponding feedforward controller was designed based on its inverse model.The validity of the model and the accuracy of the controller was verified by simulation.