A binary coded digital self-sensing piezoelectric stack device and working method
By using a digital self-induced piezoelectric stacking device with binary encoding in stacked piezoelectric materials, the problem of poor reliability and insufficient anti-interference ability of stacked piezoelectric materials in the prior art is solved, and output displacement adjustment with high reliability and accuracy is achieved.
Patent Information
- Application Number
- CN202210167766.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-02-23
- Publication Date
- 2025-05-16
- Estimated Expiration
- 2042-02-23
AI Technical Summary
The series structure of existing stacked piezoelectric materials and their simulated driving methods have problems such as poor reliability, severe heat generation, poor anti-interference ability, and hysteresis nonlinearity in the input and output, which limits their application in aerospace and other fields.
The digital self-induced piezoelectric stacking device adopts binary encoding to realize continuous stepwise adjustment of the output displacement of the stacked piezoelectric material through digital driving signals. Combined with the self-induced unit, compensation unit and digital control unit, closed-loop control and accuracy compensation are realized, eliminating hysteresis, and enhancing anti-interference ability.
High reliability, continuous adjustment and accuracy compensation of the output displacement of stacked piezoelectric materials are realized, which enhances the anti-interference ability and solves the problems of poor reliability and insufficient anti-interference ability in the prior art.
Smart Images
Figure CN114637195B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of smart material actuators, and in particular to a binary-coded digital self-inductive piezoelectric stack device and a working method. Background Art
[0002] As a bridge connecting its electrical components and hydraulic mechanical components, the motor converter is one of the key components of the electro-hydraulic servo valve and even the hydraulic control system. The performance of the electro-mechanical converter is directly related to the performance indicators of the electro-hydraulic control system. Stacked piezoelectric materials are a type of motor conversion intelligent material that can output linear displacement under the action of an electric field. Compared with other forms of intelligent materials such as magnetostrictive materials and shape memory alloys, stacked piezoelectric materials have the advantages of small size, fast response, large output force, and simple driving method. Therefore, they are widely used in various electromechanical systems.
[0003] However, in terms of driving mode, existing stacked piezoelectric materials all adopt a series structure, where piezoelectric sheets of equal thickness are axially stacked, and excitation voltage is applied at the same time, and they are driven at the same time. The disadvantage of simultaneous driving is poor reliability. If a layer of piezoelectric material in the stack breaks down during operation, the entire piezoelectric stack will fail, and it will generate severe heat during operation.
[0004] As far as the driving signal is concerned, the existing stacked piezoelectric materials all use analog signals. The disadvantages of analog driving signals are serious hysteresis nonlinearity and poor anti-interference ability. In order to overcome the electromagnetic interference of the working environment, a complex control strategy needs to be designed. In the series structure, the maximum output displacement of the stacked piezoelectric material is adjusted by increasing the number of radially stacked piezoelectric sheets. Under the driving mode of analog signals, the output displacement amplitude of the stacked piezoelectric material is controlled by adjusting the voltage amplitude of the driving signal.
[0005] Since there is an inherent hysteresis nonlinearity between the driving signal and the output displacement of piezoelectric materials, scholars at home and abroad have proposed various feedforward control strategies in order to obtain linear output displacement.
[0006] Reference 1: Fang Chu, Guo Jin, Xu Xinxing, Jiang Zhenhua, Wang Tingfeng. Piezoelectric ceramic hysteresis nonlinear feedforward compensator [J]. Optics and Precision Engineering, 2016, 24(09): 2217-2223. In this paper, an improved PI model based on the stop operator is proposed, and the compensation effect of the improved PI model on hysteresis nonlinearity is verified by experimental methods. The results show that the hysteresis nonlinearity of the piezoelectric stack output can be effectively suppressed by feedforward compensation.
[0007] Reference 2: Zhu Bin, Zhu Yuchuan, Li Yuyang, et al. Research on hysteresis modeling and feedforward compensation of piezoelectric stack actuator [J]. Piezoelectrics and Acoustooptics, 2018, 40(1): 38-41, 46. A feedforward compensator based on an inverse model was designed for the dynamic hysteresis characteristics of the input voltage and output displacement of the piezoelectric stack actuator. The experimental results show that after compensation using the constructed hysteresis inverse model, the hysteresis loop of the piezoelectric stack actuator is reduced, but the nonlinearity of the output displacement decreases by only 3%.
[0008] In summary, although the series structure of the existing stacked piezoelectric materials and their analog driving method have the advantages of simple structure, convenient driving, high output accuracy, etc., their input and output have hysteresis nonlinearity, poor working reliability, severe heat generation, poor anti-interference ability and other disadvantages, which seriously limit the practical application of stacked piezoelectric materials, especially in fields such as aerospace that have high requirements on the reliability and anti-interference ability of motor converters. Summary of the invention
[0009] Purpose of the invention: In view of the above shortcomings, the present invention provides a binary-coded digital self-sensing piezoelectric stack device, which can realize continuous step-by-step adjustment of the output displacement of the stacked piezoelectric material through a digital driving signal, and has strong working reliability; it can realize closed-loop control and precision compensation of the piezoelectric stack, eliminate hysteresis, and has strong anti-interference ability. At the same time, the present invention also provides a working method of a binary-coded digital self-sensing piezoelectric stack device, and provides a working method of a piezoelectric stack device with strong reliability and anti-interference ability.
[0010] Technical solution: To solve the above problems, the present invention adopts a binary-coded digital self-sensing piezoelectric stack device, including: a self-sensing unit, a compensation unit, a digital driving unit and a digital control unit;
[0011] The digital drive unit includes multiple pieces of axially stacked third piezoelectric materials, which are divided into n levels, where n is an integer; used to output displacement; the compensation unit includes a single piece of second piezoelectric material, and the self-sensing unit includes a single piece of first piezoelectric material; the digital drive unit is installed on the compensation unit, and the compensation unit is installed on the self-sensing unit; the compensation unit is used to perform precision compensation on the output displacement of the digital drive unit according to the precision compensation signal; the self-sensing unit is used to sense the output displacement of the digital drive unit; the digital control unit outputs a binary-coded digital drive signal to drive the digital drive unit to output displacement; the digital control unit collects the output of the self-sensing unit and generates a binary-coded digital control signal and a precision compensation signal in combination with a reference displacement signal; the digital control unit transmits the precision compensation signal to the compensation unit; the digital control unit outputs a digital control signal to the digital drive unit to realize closed-loop control.
[0012] Furthermore, the number of the third piezoelectric materials in each stage of the digital drive unit is 2 n-1 piece, that is, increasing step by step according to the binary arrangement, so as to realize the continuous step-by-step adjustment of the output displacement of the stacked piezoelectric material.
[0013] Furthermore, the positive and negative electrodes of each level of the third piezoelectric material are connected to form a series connection; and the levels are radially superimposed to form a parallel drive.
[0014] Furthermore, the digital control unit specifically includes an acquisition module, a digital output module, and a motion control module; the acquisition module is used to acquire the voltage signal output by the induction unit, convert it into actual displacement and compare it with the reference displacement signal to obtain the error; the motion control module is used to perform logical judgment and calculation based on the error to generate a binary-coded digital control signal and a precision compensation signal; the digital output module is used to output the digital control signal and the precision compensation signal.
[0015] Furthermore, the number of output ports of the digital output module is the same as the number of digital drive unit levels.
[0016] Furthermore, the compensation unit has two working modes, working mode 1 is used to perform accuracy compensation on the output displacement of the digital drive unit according to the accuracy compensation signal, and working mode 2 is used to replace the faulty piezoelectric material in the digital drive unit; the digital control unit also includes a fault diagnosis module, which is used to judge the working state of the stacked piezoelectric material in the digital drive unit in real time. If the stacked piezoelectric material fails, the compensation unit is switched to working mode 2.
[0017] Furthermore, the thickness of the self-sensing unit and the compensation unit can be adjusted according to actual working conditions.
[0018] In addition, the present invention provides a working method of a binary-coded digital self-inductive piezoelectric stack device, characterized in that it comprises the following steps:
[0019] (1) Given a reference displacement signal, the digital control unit outputs a binary-coded digital drive signal according to the reference displacement signal, driving the digital drive unit to output displacement;
[0020] (2) The self-sensing unit is squeezed by the digital driving unit, and an induced electric field is generated due to the positive piezoelectric effect to output an induced voltage;
[0021] (3) The digital control unit collects the voltage signal output by the sensing unit, converts it into actual displacement and compares it with the given reference displacement signal to obtain the error; the motion control module performs logical judgment and operation based on the error to generate a binary-coded digital control signal and a precision compensation signal; the digital output module outputs the digital control signal to the digital drive unit to realize the closed-loop control of the device; the motion control module outputs the precision compensation signal to the compensation unit, and the compensation unit performs precision compensation on the displacement output by the digital drive unit.
[0022] Furthermore, step (3) also includes determining the working state of the piezoelectric material in the stack in real time through a fault diagnosis module of the digital control unit. If a fault occurs in the piezoelectric material in the stack, the compensation unit is switched to working mode 2, and the compensation unit replaces the faulty piezoelectric sheet.
[0023] Beneficial effects: Compared with the prior art, the binary-coded digital self-sensing piezoelectric stack device described in the present invention has the following significant advantages: displacement output is achieved by setting an n-level binary piezoelectric stack structure of a digital driving unit; precision compensation of output displacement is achieved by setting a single-piece piezoelectric material of a compensation unit, and the faulty piezoelectric sheet works in the event of a digital piezoelectric stack failure; the output displacement of the piezoelectric stack is sensed by setting a single-piece piezoelectric material of a self-sensing unit; and finally, binary-coded step-by-step regulation, closed-loop control, precision compensation and fault diagnosis of the piezoelectric stack output displacement are achieved by a digital control unit, thereby obtaining a piezoelectric stack device with strong working reliability and strong anti-interference ability. Compared with the prior art, the working method of the binary-coded digital self-sensing piezoelectric stack device described in the present invention provides a working method of a piezoelectric stack device with strong reliability and anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 Shown is a schematic diagram of a binary-coded digital self-sensing piezoelectric stack and its digital control system;
[0025] Figure 2 Shown is the schematic diagram of digital piezoelectric stack displacement output;
[0026] Figure 3 Shown is a digital piezoelectric stack displacement-control signal diagram;
[0027] Figure 4 This is a schematic diagram of the generation of digital control signals and precision compensation signals in this embodiment. DETAILED DESCRIPTION
[0028] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.
[0029] like Figure 1 As shown, the present invention adopts a binary-coded digital self-sensing piezoelectric stack device, which includes: a self-sensing unit 1, a compensation unit 2, a digital driving unit 3 and a digital control unit 4.
[0030] The digital drive unit 3 is composed of n-level sheet-shaped third piezoelectric materials stacked axially, and the number of sheet-shaped third piezoelectric materials stacked in each level is 2 n -1 piece, that is, increasing step by step according to the binary arrangement. Figure 2As shown, the positive and negative electrodes of each level of the sheet-shaped third piezoelectric material are connected to each other to form a series connection, and the radial overlap between each level constitutes a parallel drive. The digital drive unit 3 outputs displacement under the drive of the digital control unit 4 outputting a binary-coded digital drive signal.
[0031] The compensation unit 2 is composed of a single piece of second piezoelectric material, and its thickness can be adjusted according to the actual working conditions; the digital drive unit 3 is installed on the compensation unit 2. The compensation unit 2 has two working modes: working mode 1 and working mode 2. Among them, working mode 1: the compensation unit 2 works under the drive of the precision compensation signal output by the digital control unit 4, and performs precision compensation on the output displacement of the digital drive unit 3 to improve the output precision of the digital piezoelectric stack displacement; working mode 2: replace the faulty piezoelectric material in the digital drive unit 3, and work under the drive of the digital control signal output by the digital controller 4 to ensure the reliability of the digital piezoelectric stack displacement output.
[0032] The self-sensing unit 1 is composed of a single piece of first piezoelectric material, and its thickness is adjustable according to actual working conditions; the compensation unit 2 is installed on the self-sensing unit 1. The self-sensing unit 1 is used to sense the output displacement of the digital driving unit 3.
[0033] The digital control unit 4 is connected to the digital drive unit 3, the compensation unit 2, and the self-sensing unit 1 through the I / O port. The digital control unit 4 specifically includes an acquisition module, a digital output module, and a motion control module. The number of output ports in the digital output module is n, which is determined by the number of levels of the digital drive unit 3, and one output port is corresponding to one level of piezoelectric material.
[0034] The working method of a binary-coded digital self-inductive piezoelectric stack device described in the present invention specifically comprises the following steps:
[0035] (1) Piezoelectric stack displacement output: Given a reference displacement signal; based on the reference displacement signal, the digital control unit outputs a binary-coded digital drive signal; the digital drive unit turns on the drive switches of each level of the piezoelectric stack, and the drive voltage acts on the positive and negative poles of the piezoelectric material of the stack to form a drive electric field, and the digital drive unit outputs the displacement;
[0036] (2) Displacement amplitude self-sensing: The self-sensing unit is squeezed by the digital drive unit, and the positive piezoelectric effect generates an induced electric field and outputs an induced voltage;
[0037] (3) Closed-loop control and precision compensation: The digital control unit collects the voltage signal output by the sensing unit, converts it into actual displacement and compares it with the given reference displacement signal to obtain the error; the motion control module performs logical judgment and operation based on the error to generate a binary-coded digital control signal and a precision compensation signal; the digital output module outputs the digital control signal to the digital drive unit to achieve closed-loop control of the device; the motion control module outputs the precision compensation signal to the compensation unit, and the compensation unit performs precision compensation on the displacement output by the digital drive unit.
[0038] like Figure 3 and Figure 4 As shown, for the four-level binary piezoelectric stack structure, the given reference displacement signal is ε r =14.3δ, initially, the actual displacement is 0, and the error is 14.3δ after comparison; the digital output module outputs a digital control signal 14δ to the digital drive unit, enters the controller, and outputs a digital control signal 0111, which opens the switches of bit 2, bit 3, and bit 4 for binary coding step adjustment; if the output precision compensation signal is an analog voltage, the compensation unit 2 is controlled to output a displacement of 0.3δ, so that the total displacement reaches 14.3δ and reaches the specified position. When vibration occurs, the self-sensing unit senses that the actual displacement is 12δ and the error is 2.3δ. The digital output module outputs a digital control signal 2δ to the digital drive unit, and outputs a digital control signal 0100, which opens bit 2 for binary coding step adjustment; the compensation unit is controlled to output a displacement of 0.3δ and reaches the specified position again. Fault diagnosis and troubleshooting: The fault diagnosis module of the digital control unit is used to judge the working state of the stacked piezoelectric material in the digital drive unit in real time. If the stacked piezoelectric material fails, the compensation unit is switched to working mode 2, and the compensation unit replaces the faulty piezoelectric sheet to work.
Claims
1. A binary-coded digital self-inductive piezoelectric stack device, characterized in that: include: A self-sensing unit (1), a compensation unit (2), a digital driving unit (3) and a digital control unit (4); The digital driving unit (3) comprises a plurality of pieces of third piezoelectric materials stacked axially, divided into n levels, where n is a positive integer, and is used to output displacement; The compensation unit (2) includes a single piece of second piezoelectric material, and the self-sensing unit (1) includes a single piece of first piezoelectric material; the digital drive unit (3) is mounted on the compensation unit (2), and the compensation unit (2) is mounted on the self-sensing unit (1); the self-sensing unit (1) is used to sense the output displacement of the digital drive unit (3); the compensation unit (2) has two working modes, working mode 1 is used to perform precision compensation on the output displacement of the digital drive unit (3) according to the precision compensation signal, and working mode 2 is used to replace the faulty piezoelectric material in the digital drive unit (3); The digital control unit (4) outputs a binary-coded digital drive signal to drive the digital drive unit (3) to output displacement; the digital control unit (4) collects the output of the self-sensing unit (1) and generates a binary-coded digital control signal and a precision compensation signal in combination with a reference displacement signal; the digital control unit (4) transmits the precision compensation signal to the compensation unit (2); the digital control unit (4) outputs the digital control signal to the digital drive unit (3) to implement closed-loop control; the digital control unit (4) specifically comprises a collection module, a digital output module, and a motion control module; the collection module is used to collect the electric output of the self-sensing unit (1); A pressure signal is converted into an actual displacement and compared with a reference displacement signal to obtain an error; a motion control module is used to perform logical judgment and operation according to the error to generate a binary-coded digital control signal and a precision compensation signal; a digital output module is used to output the digital control signal and the precision compensation signal; the number of output ports of the digital output module is the same as the number of levels of the digital drive unit (3); and the digital control unit (4) further comprises a fault diagnosis module, which is used to determine in real time the working state of the stacked piezoelectric material in the digital drive unit (3); if a fault occurs in the stacked piezoelectric material, the compensation unit (2) is switched to working mode 2.
2. The binary-coded digital self-inductive piezoelectric stack device according to claim 1, characterized in that: The number of third piezoelectric materials in each stage of the digital drive unit (3) is 2 n -1 tablet.
3. The binary-coded digital self-inductive piezoelectric stack device according to claim 2, characterized in that: The positive and negative electrodes of the third piezoelectric material of each stage are connected to form a series connection; and the radial superposition between each stage forms a parallel drive.
4. The binary-coded digital self-inductive piezoelectric stack device according to claim 1, characterized in that: The thickness of the self-sensing unit (1) and the compensation unit (2) can be adjusted according to actual working conditions.
5. A method for operating a binary-coded digital self-inductive piezoelectric stack device according to claim 1, characterized in that: The following steps are involved: (1) Given a reference displacement signal, the digital control unit outputs a binary-coded digital drive signal according to the reference displacement signal to drive the digital drive unit to output displacement; (2) The self-sensing unit is squeezed by the digital driving unit, and an induced electric field is generated due to the positive piezoelectric effect to output an induced voltage; (3) The digital control unit collects the voltage signal output by the sensing unit, converts it into actual displacement and compares it with the given reference displacement signal to obtain the error; the motion control module performs logical judgment and operation based on the error to generate a binary-coded digital control signal and a precision compensation signal; the digital output module outputs the digital control signal to the digital drive unit to realize the closed-loop control of the device; the motion control module outputs the precision compensation signal to the compensation unit, and the compensation unit performs precision compensation on the displacement output by the digital drive unit.
6. The working method of the binary-coded digital self-inductive piezoelectric stack device according to claim 5, characterized in that: Step (3) also includes determining the working state of the piezoelectric material in the stack in real time through the fault diagnosis module of the digital control unit. If a fault occurs in the piezoelectric material in the stack, the compensation unit is switched to working mode 2, and the compensation unit replaces the faulty piezoelectric sheet.
Citation Information
Patent Citations
Active digital crystal oscillator anti-vibration compensation device and method
CN110829999A
Anti-vibration crystal oscillator
CN111010089A