CN-122015625-A - Piezoelectric actuator displacement self-sensing device and method based on total charge

CN122015625ACN 122015625 ACN122015625 ACN 122015625ACN-122015625-A

Abstract

The invention discloses a piezoelectric actuator displacement self-sensing device and method based on total charge, and belongs to the field of micro-nano positioning and intelligent sensing. The device comprises a driving circuit, a protection circuit and a measuring circuit, adopts a capacitive voltage division structure and a coupled charge amplifier, realizes displacement sensing by measuring total charge flowing to a piezoelectric actuator, and obviously reduces cost while ensuring measurement accuracy when capacitance parameters meet Cc < < Cp < < Cr. The method provides an extended piezoelectric constitutive equation, establishes a displacement self-sensing model with clear structure and controllable parameters, supports model simplification according to precision requirements, and realizes high-precision and high-timeliness real-time displacement estimation. The method solves the problems of complex model, large calculated amount, high charge measurement cost and easy drifting in the prior art, and is suitable for the fields of micro-nano manipulation, precise positioning, vibration suppression and the like.

Inventors

ZHANG DUANQIN
Zhu Huihao
DING JING
CHEN YAOYAO
ZHANG DEHAI

Assignees

郑州轻工业大学

Dates

Publication Date: 20260512
Application Date: 20260214

Claims (10)

1. A piezoelectric actuator displacement self-sensing device based on total charge is characterized by comprising The driving circuit is used for providing excitation voltage for the piezoelectric actuator and comprises a voltage type driving power supply, the piezoelectric actuator and a reference capacitor C r which is connected in series between the negative electrode or the ground wire of the driving power supply and the piezoelectric actuator; The circuit comprises a reference capacitor C r , a protection circuit unit, a displacement self-sensing device, a voltage self-sensing device and a voltage self-sensing device, wherein the input end of the protection circuit unit is connected to the two ends of the reference capacitor C r and is used for receiving and clamping voltage signals at the two ends of the reference capacitor C r ; The measuring circuit unit comprises a charge amplifier, wherein the input end of the charge amplifier is electrically connected with the output end of the protection circuit unit through a coupling capacitor C c , and the charge amplifier consists of a high-impedance operational amplifier, a feedback capacitor C f and a feedback resistor R f which are connected between the output end and the inverting input end of the operational amplifier in parallel; The operational amplifier output voltage V o and the voltage V r (t) at the two ends of the reference capacitor C r satisfy the following relationship: 。
2. The piezoelectric actuator displacement self-sensing device based on total charge as set forth in claim 1, wherein said protection circuit unit is omitted when said drive circuit has an overvoltage/overcurrent protection function.
3. The piezoelectric actuator displacement self-sensing device based on total charge of claim 1, wherein said charge amplifier is a quasi-static charge amplifier having an output voltage V o and a total charge Q flowing to the piezoelectric actuator satisfying the relationship: 。
4. The piezoelectric driver displacement self-sensing device based on total charge as set forth in claim 3, further comprising means for compensating for measurement errors caused by said charge amplifier input bias current I b and input offset voltage V os , the compensated total charge 。
5. A piezoelectric driver displacement self-sensing method based on total charge, which is characterized by comprising the following steps: step 1, establishing an extended piezoelectric constitutive equation to decompose the electric displacement into pure dielectric electric displacement Piezoelectric coupling electrodisplacive And piezoelectric induced electrical displacement Decomposing strain into pure elastic strain Piezoelectric coupling strain And piezoelectrically induced strain And establish piezoelectric coupling electric displacement And piezoelectrically induced strain Piezoelectric coupling strain With piezoelectric induced electrical displacement A synchronous ratio constraint relationship between the two; Step 2, constructing a displacement self-sensing model describing the dynamic relationship among the output displacement x of the piezoelectric actuator, the driving voltage V in and the total charge Q based on the extended piezoelectric constitutive equation; Step 3, using the device of any one of claims 1-4, collecting time sequence data of the driving voltage V in , the output displacement x and the output voltage V o ; step 4, based on the model in the step 2 and the data in the step 3, carrying out parameter identification by adopting a physical model and data driving hybrid method to obtain an accurate displacement self-sensing model; step 5, converting the displacement self-perception model with the completed parameter identification into a displacement estimated value with the driving voltage V in and the output voltage V o as inputs In the working process of the piezoelectric actuator, the driving voltage V in and the output voltage V o which are measured in real time are input into the displacement reconstruction model, and the estimated value of the output displacement is obtained by real-time calculation 。
6. The method of self-sensing displacement of a piezoelectric actuator based on total charge as claimed in claim 5, wherein: the extended piezoelectric constitutive equation is: , wherein, Is the dielectric constant of the piezoelectric coupling, Is the piezoelectric coupling elastic compliance constant, and d is the piezoelectric coefficient.
7. The method for self-sensing displacement of a piezoelectric actuator based on total charge as set forth in claim 5, wherein said self-sensing displacement model comprises a compensation term for rate-dependent energy loss and rate-independent energy loss during conversion of electrical energy to mechanical energy, and wherein said self-sensing displacement model has a complete structural form of: wherein n, L, A respectively represent the number of layers, the total thickness and the cross-sectional area of the piezoelectric stack, Representing the excitation voltage actually applied to the piezoelectric actuator, , Representing the total charge of the charge pump, The output displacement is indicated as such, For the parameters to be identified, the unit is the same as the capacitance, As a function of the time constant, , M is a parameter to be identified; Is the dielectric constant of the piezoelectric coupling, Is the piezoelectric coupling elastic compliance constant and d is the piezoelectric coefficient, wherein the second formula represents the incorporation of the charge loss corresponding to all rate dependent energy loss into the calculated pure dielectric free charge term Wherein the third equation represents the charge loss corresponding to the rate independent loss.
8. The method of claim 7, wherein the displacement self-sensing model is simplified to a simplified form without considering any loss and charge measurement error , The displacement self-perception model can be further simplified into 。
9. The method of self-sensing displacement of piezoelectric actuator based on total charge as set forth in claim 7, wherein said self-sensing displacement model is simplified to a term of charge loss corresponding to a pure dielectric free charge dynamic model and a rate-independent loss taking into account rate-dependent loss for the purpose of simplifying calculation 。
10. The method of claim 5, wherein the number of parameters of the displacement self-sensing model is 3 to 9, and the simplification is supported by neglecting loss terms to adapt to different real-time and precision requirements.

Description

Piezoelectric actuator displacement self-sensing device and method based on total charge Technical Field The invention relates to the field of micro-nano positioning and intelligent sensing, in particular to a piezoelectric actuator displacement self-sensing device and method based on total charge. Background The piezoelectric actuator has the advantages of high displacement resolution, high response speed and the like, is an indispensable core component for executing physical movement in micro-nano scale mechanisms and precise control equipment, and is generally used in the micro-nano positioning and operating fields of micro-galvanometers, micro-nano operating robots, micro-servo valves and the like which need precise positioning. However, there are nonlinear characteristics such as hysteresis and creep between the displacement response and the excitation voltage of the piezoelectric actuator, and in applications such as biomedical and ultra-precise manufacturing, there are often extremely high requirements for positioning accuracy and control of the interaction state with the environment. Thus, achieving accurate measurement and control of its end displacement is a critical technical challenge. The accurate measurement of the displacement of the piezoelectric actuator has two technical schemes, namely an external high-precision displacement sensor is adopted, the defects of the external high-precision displacement sensor are mainly high cost and occupied space, and the displacement measurement is indirectly realized by measuring an electric signal related to the output displacement and an applicable displacement self-sensing model by utilizing the property of coexistence of the piezoelectric effect and the piezoelectric inverse effect. The second technical scheme, namely the displacement self-sensing technology, is particularly suitable for the application occasions with limited space such as micro-nano operation or vibration suppression. The displacement self-sensing based on charge measurement is the mainstream technology at present, but has some core bottleneck problems that (1) a displacement self-sensing theoretical model for describing nonlinear dynamics behaviors among output displacement, charge and excitation voltage has inherent contradiction between the simplification degree and sensing precision, the complex model has large calculated amount and influences the timeliness of online sensing, and the displacement sensing precision is difficult to ensure after excessive simplification. 2) The charge measurement related in the self-sensing technology has measurement errors such as charge drift and the like, particularly has larger measurement errors under the quasi-static excitation working condition, and in industrial application, the problem of compensation of the measurement errors under the condition of limited charge measurement cost is urgently needed to be solved. Disclosure of Invention The invention aims at solving the technical problems that the existing self-sensing model has the defects of complex structure and large calculated amount, and is difficult to meet the real-time displacement sensing requirement, and meanwhile, the measurement bandwidth of the charge amplifying circuit for charge measurement is limited by the frequency response characteristic of an integration network, and the integration drift easily causes charge measurement errors, so that the low-frequency performance and stability of the displacement self-sensing are further restricted. In order to solve the above problems, a piezoelectric actuator displacement self-sensing device and a method based on total charge are provided. The object of the invention is achieved in the following way: A piezoelectric actuator displacement self-sensing device based on total charge comprises The driving circuit is used for providing excitation voltage for the piezoelectric actuator and comprises a voltage type driving power supply, the piezoelectric actuator and a reference capacitor C r which is connected in series between the negative electrode or the ground wire of the driving power supply and the piezoelectric actuator; The circuit comprises a reference capacitor C r, a protection circuit unit, a displacement self-sensing device, a voltage self-sensing device and a voltage self-sensing device, wherein the input end of the protection circuit unit is connected to the two ends of the reference capacitor C r and is used for receiving and clamping voltage signals at the two ends of the reference capacitor C r; The measuring circuit unit comprises a charge amplifier, wherein the input end of the charge amplifier is electrically connected with the output end of the protection circuit unit through a coupling capacitor C c, and the charge amplifier consists of a high-impedance operational amplifier, a feedback capacitor C f and a feedback resistor R f which are connected between the output end and the inverting input end of the operationa