Bidirectional stick-slip piezoelectric linear driving device and control method

Abstract

The invention discloses a bidirectional stick-slip piezoelectric linear driving device and a driving, modeling and control method thereof, and belongs to the technical field of micro-nano precision driving and positioning. The device is composed of an L-shaped fixed base, a piezoelectric stack, a carbon fiber friction rod, a stainless steel sliding block and the like, is compact in structure and has forward and reverse stick-slip motion capacity. And sawtooth wave voltages with different symmetry are applied to drive the piezoelectric stack, so that high-resolution bidirectional displacement of the stainless steel sliding block is realized. In order to solve the problem that a traditional model is difficult to represent reverse motion, a unified modeling method fusing a LuGre friction model and a Bouc-Wen hysteresis model is provided, and the description precision of nonlinear dynamic behaviors is improved. And on the control strategy, a fuzzy PID algorithm is introduced, forward and reverse bidirectional set point tracking control in a single period is realized, and the stability and response performance of the system under multiple working conditions are effectively enhanced. The method is suitable for high-precision positioning, bidirectional driving and micro-operation control in a complex environment, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The application relates to a bidirectional stick-slip piezoelectric linear driving device and a control method, and belongs to the technical field of micro-nano precision driving and positioning. BACKGROUND

[0002] The piezoelectric linear driving device is widely applied to precision occasions such as biomedical engineering, semiconductor manufacturing, optical focusing and atomic force microscopy due to its compact structure, large output force, fast response and high positioning precision. According to the working principle, the piezoelectric linear driving device can be divided into ultrasonic type, direct driving type, inchworm type and stick-slip type and the like. The stick-slip type driving device has a wide application prospect in the micro-nano positioning field due to its simple structure and large stroke. The traditional stick-slip type driving device is usually based on the inverse piezoelectric effect of the piezoelectric stack and realizes the propulsion of the stainless steel slider through asymmetric motion. However, the structure generally has problems such as single motion direction, asymmetric friction characteristics and insufficient reverse motion precision, and is difficult to meet the needs of high-performance bidirectional driving applications.

[0003] In the aspect of modeling, early researches are mostly focused on one-way driving mechanism and cannot effectively consider the friction hysteresis and nonlinear coupling effect in the reverse motion, and lack a unified modeling framework to describe the dynamic characteristics and asymmetry in the bidirectional motion process. In the aspect of control method, although the traditional PID controller has a simple structure, it has limitations in dealing with system nonlinearity and parameter variation. Although the method such as sliding mode control improves the robustness of the system, it is difficult to adapt to the demand of multi-mode switching. At present, there is still a lack of an intelligent control strategy that can balance the bidirectional driving precision and mode adaptive ability.

[0004] To solve the above problems, it is urgent to design a piezoelectric driving system and a control method with high precision, bidirectional symmetric driving ability and adaptability to dynamic changes in multiple working conditions. SUMMARY

[0005] To solve the technical problems such as insufficient controllability of stick-slip behavior, high-resolution positioning and bidirectional stable motion control of the traditional piezoelectric linear driving device, the application discloses a bidirectional stick-slip piezoelectric linear driving device and a control method.

[0006] The technical scheme adopted by the application is:

[0007] The piezoelectric linear driving device with bidirectional stick-slip motion is characterized in that the driving device is mainly composed of a fixed base, a piezoelectric stack, a carbon fiber friction rod, a stainless steel slider and a fixed screw and the like.

[0008] The fixed base is in an L-shaped structure, is installed on the shock isolation table through a fixing screw, the shock isolation table is provided with a plurality of pre-set fixing holes, the fixed base is fixed through the fixing screw and the fixing hole group, and the fixing holes are used for multi-point fixing to enhance the installation stability and operation reliability of the whole device.

[0009] The piezoelectric stack is adhered to the vertical side of the fixed base through epoxy resin and is embedded in the groove provided on the fixed base, the cross-sectional area of the groove is greater than that of the piezoelectric stack, and the groove is used for limiting and assisting positioning, so that the adhesion firmness and assembly consistency are improved.

[0010] The lead wire of the piezoelectric stack is led out through the guide hole provided on the side wall of the fixed base and is connected with an external power supply device. The guide hole can effectively constrain the running track of the lead wire, reduce the swing and interference of the lead wire in the working process of the driving device, and help to improve the electrical connection reliability and structural safety of the system.

[0011] The front end of the piezoelectric stack is firmly connected with the carbon fiber friction rod through epoxy resin glue, and a driving force transmission channel is formed. The stainless steel sliding block is in a hollow cylindrical structure, the inner diameter of the stainless steel sliding block is greater than the outer diameter of the carbon fiber friction rod, so that the stainless steel sliding block can be sleeved on the outside of the friction rod and relatively slides in the axial direction. By means of the periodic expansion and contraction movement of the piezoelectric stack, the stainless steel sliding block realizes controllable stick-slip displacement in the forward and reverse directions.

[0012] The application also provides a driving method of the piezoelectric linear driving device for bidirectional stick-slip movement, which comprises the following steps: S1. applying a forward or reverse sawtooth wave voltage signal to the piezoelectric stack; S2. when the forward sawtooth wave voltage signal is applied, the driver realizes the net displacement of the stainless steel sliding block in the forward direction through periodic stick-slip movement in multiple reciprocating motions; S3. when the reverse sawtooth wave voltage signal is applied, the driver realizes the net displacement of the stainless steel sliding block in the reverse direction through periodic stick-slip movement in multiple reciprocating motions, and the displacement and the movement direction are accurately controlled by adjusting the amplitude, frequency and slope parameters of the voltage waveform.

[0013] Further, the forward sawtooth wave is a slow-rising fast-falling waveform, and the reverse sawtooth wave is a fast-rising slow-falling waveform.

[0014] In the piezoelectric linear driving device, the piezoelectric stack is used to drive the stainless steel sliding block to realize forward or reverse movement. Specifically, when a forward sawtooth wave voltage signal meeting the set parameter condition is applied to the piezoelectric stack, the stainless steel sliding block generates forward displacement; when a reverse sawtooth wave voltage signal meeting the set parameter condition is applied, the stainless steel sliding block generates reverse displacement. By adjusting the amplitude, frequency and rising or falling slope of the sawtooth wave voltage, the movement direction and displacement of the stainless steel sliding block can be accurately controlled, and high-resolution forward and reverse stick-slip movement is realized.

[0015] The application also provides a modeling and control method for a piezoelectric linear drive device for bidirectional stick-slip motion.

[0016] In the modeling, a LuGre friction model is introduced to describe the nonlinear friction between the stainless steel slider and the carbon fiber friction rod, and a Bouc-Wen hysteresis model is introduced to represent the hysteresis nonlinearity of the piezoelectric stack. The models are used to describe the dynamic behavior of the device in forward and reverse stick-slip motion.

[0017] Further, in the modeling method, the dynamic characteristics of the stick-slip piezoelectric linear drive device are described by a second-order system containing mass, damping and stiffness, and the mass, damping and stiffness parameters of the piezoelectric stack, carbon fiber friction rod and stainless steel slider are considered together. The hysteresis characteristics of the piezoelectric stack are represented by the Bouc-Wen model, and the piezoelectric response is constructed by the nonlinear relationship between the hysteresis variable and the driving voltage. The friction characteristics are modeled by the LuGre model, which describes the nonlinear relationship between the friction force and the relative speed through parameters such as contact surface stiffness, damping, viscous friction, etc. The trend of friction force change is compensated by combining the Stribeck effect, and finally the nonlinear dynamics of the piezoelectric drive device in the stick-slip motion process is accurately described.

[0018] The proposed modeling method can represent the dynamic behavior of the piezoelectric linear drive device in forward and reverse stick-slip motion, and the LuGre friction model and Bouc-Wen hysteresis model are introduced into the model, thereby effectively improving the description accuracy of the nonlinear characteristics of the system.

[0019] The control method generates a control signal based on a fuzzy PID controller to control the piezoelectric stack to drive the stainless steel slider to achieve the target displacement. The controller supports dual-mode switching: step drive waveform is used for coarse positioning, and fuzzy PID adjustment waveform is used for fine positioning. The fuzzy PID controller uses a Mamdani type structure, and the inputs include error, error rate and historical control output.

[0020] The current control output is adjusted in real time by the gain provided by the fuzzy PID controller, and the control parameters are updated at each sampling time, thereby realizing online adaptive adjustment. The fuzzy PID control algorithm is as follows:

[0021]

[0022] e(t)=x d (t)-x(t)

[0023] The fuzzy PID controller dynamically adjusts the proportional gain K p , the integral gain K i and the differential gain K dTo achieve online adaptive adjustment.

[0024] The proposed control method has strong robustness and can adapt to dynamic changes in external environment, and is especially suitable for high-precision control requirements under complex stick-slip motion conditions, thereby significantly enhancing the stability and adaptability of the system.

[0025] The present application has the following beneficial effects:

[0026] The present application realizes the controllability of the piezoelectric driving device in the positive and negative directions through the structure optimization and control strategy collaborative design, and significantly improves the performance of the piezoelectric driving device in high-resolution positioning and bidirectional stable motion control. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 Fig. 1 shows the structure of a piezoelectric driving device for bidirectional stick-slip motion according to the present application;

[0028] Figure 2 Fig. 2 shows the driving principle of a piezoelectric linear driving device for realizing forward stick-slip motion according to the present application;

[0029] Figure 3 Fig. 3 shows the driving principle of a piezoelectric linear driving device for realizing reverse stick-slip motion according to the present application;

[0030] Figure 4 Fig. 4 shows the dynamic modeling structure of a piezoelectric linear driving device for realizing bidirectional stick-slip motion according to the present application;

[0031] Figure 5 Fig. 5 shows the control method of a piezoelectric linear driving device for realizing bidirectional stick-slip motion according to the present application;

[0032] Figure 6 Fig. 6 shows the model accuracy effect diagram of a piezoelectric linear driving device for realizing forward stick-slip motion when the voltage is changed according to the present application;

[0033] Figure 7 Fig. 7 shows the model accuracy effect diagram of a piezoelectric linear driving device for realizing reverse stick-slip motion when the voltage is changed according to the present application;

[0034] Figure 8 Fig. 8 shows the model accuracy effect diagram of a piezoelectric linear driving device for realizing forward stick-slip motion when the mass of the stainless steel slider is changed according to the present application;

[0035] Figure 9The model accurate effect diagram of the piezoelectric linear driving device for changing the reverse stick-slip motion of the stainless steel slider mass is shown;

[0036] Figure 10 The PID control and fuzzy PID control effect comparison diagram of the piezoelectric linear driving device forward stick-slip motion control is shown;

[0037] Figure 11 The piezoelectric linear driving device forward and reverse stick-slip motion control diagram realized by the fuzzy PID control method is shown; DETAILED DESCRIPTION

[0038] The specific embodiments of the present application will be described in detail below in conjunction with the accompanying drawings and examples. It should be noted that the drawings and examples are only used to illustrate the principles and technical solutions of the present application and cannot be regarded as a limitation on the scope of protection of the present patent. The following is an explanation of the reference numerals in the drawings: 1, fixed base; 2, lead wire on piezoelectric stack; 3, shock isolation table; 4, piezoelectric stack; 5, fixed screw; 6, groove on fixed base; 7, lead wire guide hole; 8, stainless steel slider; 9, carbon fiber friction rod.

[0039] First, the structure of the present application is introduced.

[0040] As shown in Figure 1 The piezoelectric driving device for realizing forward and reverse stick-slip motion, according to the present application, mainly includes two functional modules: one is a fixed module composed of a fixed base 1, a shock isolation table 3 and a fixed screw 5; the other is a driving module composed of a piezoelectric stack 4, a stainless steel slider 8 and a carbon fiber friction rod 9.

[0041] Among them, the fixed base 1 adopts an "L" type structure, which is firmly installed on the upper surface of the shock isolation table 3 through the fixed screw 5. In order to enhance the positioning accuracy and installation stability of the structure, the shock isolation table 3 is pre-provided with a plurality of fixed holes, and the fixed base 1 is fastened by the fixed hole group to ensure that the driving device does not shift or loosen during operation.

[0042] In terms of the driving module, the piezoelectric stack 4 is adhered to the vertical side of the fixed base 1 by epoxy resin, and the bottom is embedded in the groove 6 on the fixed base, the size of the groove 6 is larger than the cross section of the piezoelectric stack 4, which plays a limiting and auxiliary positioning role, thereby improving the adhesion and assembly consistency.

[0043] The lead wire 2 of the piezoelectric stack 4 is used to connect the piezoelectric stack with the external power supply device, and the lead wire is led out along the guide hole 7 on the fixed base 1. The guide hole is arranged at the side wall position of the fixed base 1, which can ensure the reliability of electrical connection while reducing the swing and interference of the lead wire during device operation, thereby improving the system stability and assembly safety.

[0044] The front end of the piezoelectric stack 4 is connected to the carbon fiber friction rod 9 by epoxy adhesive to form a transmission path of driving force. The stainless steel slider 8 is designed as a hollow cylindrical structure, and its inner diameter is larger than the outer diameter of the carbon fiber friction rod 9, so that it can be sleeved outside the carbon fiber friction rod and relatively slide along the axial direction, so as to cooperate with the expansion and contraction movement of the piezoelectric stack, and realize the stick-slip displacement of the stainless steel slider in the positive and negative directions.

[0045] As shown in Figure 2 and Figure 3 , the application also provides a driving method of a piezoelectric driving device for realizing forward and reverse stick-slip movement. In the piezoelectric driving device, the piezoelectric stack is driven to realize expansion and contraction movement, so as to drive the stainless steel slider to produce forward or reverse displacement.

[0046] Figure 2 As shown in the driving mode for realizing the forward movement of the stainless steel slider, when a sawtooth wave voltage signal with symmetry greater than 50% is applied to the piezoelectric driving device, it includes a slow rising stage t0-t1 and a rapid falling stage t1-t2. Specifically, in the slow rising stage, the voltage slowly rises, the piezoelectric stack slowly extends, and since the output force F PES of this stage is less than the static friction force f s between the stainless steel slider and the carbon fiber friction rod, the stainless steel slider and the carbon fiber friction rod remain in the adhered state and move forward synchronously with the carbon fiber friction rod, producing a segment of forward displacement d f . In the rapid falling stage, the voltage rapidly falls, the piezoelectric stack rapidly contracts, and the carbon fiber friction rod rapidly resets. Since the stainless steel slider has inertia, the force acting on it exceeds the static friction force threshold, and relative movement occurs, producing a segment of backward displacement d r . In this stage, sliding friction is dominant. In a complete cycle, since the forward displacement d f is greater than the backward displacement d r , the stainless steel slider as a whole realizes the movement of the net forward displacement. With the repetition of the cycle, the stainless steel slider continuously realizes the forward stick-slip movement.

[0047] Figure 3 As shown in the driving mode for realizing the reverse movement of the stainless steel slider, when a sawtooth wave voltage signal with symmetry less than 50% is applied, it includes a rapid rising stage t0-t1 and a slow falling stage t1-t2. In the rapid rising stage, the voltage rapidly rises, the piezoelectric stack rapidly elongates, and the carbon fiber friction rod moves forward, and the stainless steel slider produces a small segment of forward displacement d f . In the slow falling stage, the voltage slowly falls, the carbon fiber friction rod slowly resets, and the stainless steel slider cannot overcome the static friction force due to insufficient driving force and remains in the adhered state with the carbon fiber friction rod and moves reversely with it for a segment of displacement d r, thus realizing the reverse driving. In this mode, due to the reverse displacement d r greater than the forward displacement d f , the stainless steel slider generates a reverse net displacement in each cycle, forming a continuous reverse stick-slip motion.

[0048] As shown in Figure 4 and Figure 5 , the application also provides a modeling and control method for a piezoelectric driving device realizing forward and reverse stick-slip motion. The proposed modeling method can simultaneously represent the dynamic behavior of the piezoelectric driving device in forward and reverse stick-slip motion, and the LuGre friction model and Bouc-Wen hysteresis model are introduced into the model, thereby effectively improving the description accuracy of the nonlinear characteristics of the system. The proposed control method has strong robustness and can adapt to dynamically changing external environment, especially suitable for high-precision control requirements under complex stick-slip motion conditions, significantly enhancing the stability and adaptability of the system.

[0049] As shown in Figure 4 , the coupled electromechanical dynamics of the piezoelectric driving device can be approximated as a second-order system, and since the carbon fiber friction rod and the piezoelectric stack have similar masses, their inertia cannot be ignored. To simplify the analysis process, the modeling framework treats the piezoelectric stack and the carbon fiber friction rod as a whole structure, thereby effectively simplifying the physical configuration and retaining key dynamic characteristics. The mathematical expression of the piezoelectric driving device is as follows:

[0050]

[0051] where m PES , m f and m s represent the mass of the piezoelectric stack, the carbon fiber friction rod and the stainless steel slider respectively; c PES and c f represent the damping coefficients of the piezoelectric stack and the carbon fiber friction rod, k PES and k f represent their respective stiffness; U(t) is the linear output of the applied driving voltage on the piezoelectric stack; x(t), and represent the displacement, velocity and acceleration of the piezoelectric stack respectively; f represents the friction force between the carbon fiber friction rod and the stainless steel slider.

[0052] The mathematical expression of the Bouc-Wen hysteresis model of the piezoelectric stack is as follows:

[0053]

[0054] where α, β and γ are constants used to determine the shape of the hysteresis loop, and u(t) is the voltage applied to the piezoelectric stack.

[0055] Therefore, in the formula, the Bouc-Wen model is adopted to replace the linear output U(t). U(t) can be expressed as:

[0056] U(t) = k PES (du-h) (3)

[0057] Wherein, the LuGre friction model is widely used in the modeling of stick-slip type piezoelectric actuators. According to the LuGre friction model, the friction force f between the output end of the carbon fiber friction rod and the stainless steel slider can be expressed as:

[0058] f = σ0z + σ1dz / dt + σ2v (4)

[0059] dz / dt = v - |v|z / g(v) (5)

[0060]

[0061] Wherein, σ0 represents the stiffness coefficient of the contact pair, σ1 represents the damping coefficient of the contact pair, σ2 represents the viscous friction coefficient, z is the average offset of the contact surface burr, v is the relative speed between the stainless steel slider and the contact surface of the carbon fiber friction rod, v s is the Stribeck speed, f s is the static friction, f c is the Coulomb friction.

[0062] Under the action of the friction force f, the motion of the stainless steel slider satisfies the following dynamic equation:

[0063]

[0064] As Figure 5 shown, it is a block diagram of the switching set point control system. The whole control system is divided into two working modes: step mode (rough motion) and scanning mode (precise motion). The desired position is set as x d . After applying the voltage, the piezoelectric stack starts to elongate, driving the stainless steel slider to displace, and the displacement is recorded as x. When the error e(t) exceeds the set threshold value, the system first enters the step mode, at which time the stainless steel slider moves with a large step length, and the driving waveform is a sawtooth wave; when the displacement x exceeds the threshold value, the system switches to the scanning mode, and the stainless steel slider starts to move with small precision. In this mode, the driving waveform is generated by the fuzzy PID controller, so as to realize high-precision displacement control.

[0065] The expression of the threshold value is as follows:

[0066]

[0067] wherein, Δd represents the net displacement of the stainless steel slider, threshold is the x d The remainder part of the net displacement Δd, i.e., x d The modulo operation result of Δd.

[0068] The present application introduces a fuzzy PID control architecture with adaptive compensation mechanism, aiming to ensure the system transient stability while realizing asymptotic tracking performance. The controller adopts online intelligent gain scheduling strategy, realizing the dynamic optimization of proportional gain K p Integral gain K i And differential gain K d Through the rule-based reasoning engine and the triangular membership function.

[0069] The current control output is adjusted in real time by the gain provided by the fuzzy PID controller, and the control parameters are updated at each sampling time, so as to realize online adaptive adjustment. The fuzzy PID control algorithm is as follows:

[0070]

[0071] e(t)=x d (t)-x(t) (10)

[0072] Wherein, u(t) represents the output of the fuzzy PID controller at time t, K p Is the proportional gain, e(t) is the error at the current time, K i Is the integral gain, T is the sampling period, K d Is the differential gain, e(t-1) is the error at the previous time. Parameters ΔK p , ΔK i And ΔK d Respectively represent the real-time adjustment of proportional, integral and differential gain obtained by fuzzy logic reasoning. In order to improve the interpretability and adaptability of the controller, the designed fuzzy PID control system adopts Mamdani type reasoning structure, which has three input variables: tracking error e(t), error change rate And historical adjustment output Δu Controller output is the adjusted PID gain value ΔK p , ΔK i And ΔK d . The fuzzy logic module runs in the predefined input / output domain. Specifically, the input variable e(t) is normalized to the domain range of [-1, 1], which covers the error interval that may occur under typical working conditions of the system. The output of the control gain is also mapped to the corresponding scaling interval: ΔK p ∈[0,10]、ΔK i ∈[0,5]、ΔK d∈ [0, 0.0001], which are obtained by experimental tuning to match the dynamic response range of the system.

[0073] Figures 6-9 is the experimental data for the actual output displacement of the piezoelectric linear drive device for realizing the forward and reverse stick-slip motion and the relationship curve between the experimental data and the modeling method simulation.

[0074] Figure 6 The net displacement of the stainless steel slider under different driving voltages is shown. The designed linear driver maintains good stability during operation and exhibits regular periodic forward stepping characteristics in each excitation cycle. Experimental results show that the single-step displacement amplitude is highly sensitive to the driving voltage, and as the voltage increases, the single-step displacement increases significantly, thereby achieving greater cumulative displacement under higher voltage input. At the same time, the model simulation results (dotted line) are highly consistent with the experimental curves (solid line), verifying that the constructed model has good tracking accuracy and simulation ability for forward displacement under varying driving voltage conditions.

[0075] Figure 7 Further shows the evolution characteristics of the reverse displacement with time, which has similar motion law as the forward motion and also shows significant voltage dependence. The driver also maintains stability during reverse motion and achieves regular backward stepping in each excitation cycle. It is worth noting that the minimum root mean square error of the modeling reaches 0.053 μm, indicating that the constructed model also has high simulation accuracy for reverse displacement under varying voltage conditions.

[0076] Figure 8 The displacement response curves of the stainless steel slider under different loading mass conditions are given. Experiments show that the slider displacement shows obvious dependence on the loading mass: when the loading mass is 1.5 g, the displacement is the smallest; while under the conditions of 3.0 g and 3.8 g, the displacement amplitudes are similar. Especially under the conditions of 3.0 g and 4.5 g mass, the system achieves the maximum displacement output, revealing a non-monotonic nonlinear relationship between the slider mass and the driving performance. The simulation results are highly consistent with the experimental curves, further verifying that the constructed model has good tracking accuracy and prediction ability for forward displacement under varying mass conditions.

[0077] Figure 9 The displacement response characteristics under reverse motion are shown, which have consistent mass dependence behavior as forward motion, and both have good symmetry and proportional consistency in amplitude and trend. Under all experimental conditions, the maximum root mean square error of the system is 0.1548 μm, fully indicating that the constructed model also has high simulation accuracy for reverse displacement under different mass configurations.

[0078] Figure 10The figure shows the comparison of PID control and fuzzy PID control effects of the forward stick-slip motion control of the piezoelectric linear driving device proposed in the application. In the forward motion process, the traditional PID and fuzzy PID controller both show quite good positioning accuracy and dynamic response performance. However, under the steady state condition, the maximum error of the traditional PID control is 0.215 μm, and the maximum error of the fuzzy PID control is 0.11 μm, and the error reduction rate is 49%, which shows a significant improvement in accuracy.

[0079] Figure 11 The figure shows the piezoelectric linear driving device forward and reverse stick-slip motion control diagram realized by the fuzzy PID control method proposed in the application. The double-mode control architecture of the proposed fuzzy PID regulation significantly improves the positioning performance by integrating the bidirectional driving mechanism in the piezoelectric linear driving device proposed in the application. In this experiment, the driver sequentially tracks two different displacement targets: first moves to the set point 1 (40 μm), and then switches to the set point 2 (20 μm). The experimental results show that the driver achieves stable tracking with high accuracy, low steady-state error and small overshoot at both target positions, and the enlarged view further highlights the tracking accuracy.

[0080] The piezoelectric linear driving device proposed in the application can complete bidirectional precise positioning between multiple reference positions in one operation cycle, marking a significant breakthrough in control performance. By combining the fuzzy logic adaptive adjustment mechanism with the nonlinear stick-slip control method, the system has stronger flexibility and response capability compared with the traditional single-point control scheme.

Claims

1. A bidirectional stick-slip piezoelectric linear drive device, characterized in that: include: A fixed base (1), the fixed base (1) is an "L"-shaped structure and is mounted on the vibration isolation platform (3) by screws; A piezoelectric stack (4), the piezoelectric stack (4) is bonded to the vertical side of the fixed base (1) by epoxy resin glue, and the bottom of the piezoelectric stack (4) is embedded in a groove (6) provided on the fixed base, so as to improve the structural stability; a carbon fiber friction rod (9), one end of the carbon fiber friction rod (9) being bonded to the piezoelectric stack (4) by epoxy resin glue; A stainless steel slider (8) is a hollow cylindrical structure, the inner diameter of which is larger than the outer diameter of the carbon fiber friction rod (9), so that the stainless steel slider (8) is fitted over and slides along the axial direction of the carbon fiber friction rod; The wire (2) is led out from the piezoelectric stack through the guide hole (7) and connected to an external power supply.

2. The bidirectional stick-slip piezoelectric linear drive device according to claim 1, characterized in that: The vibration isolation platform (3) is provided with a plurality of fixing holes for realizing multi-point fastening of the fixing base (1).

3. The bidirectional stick-slip piezoelectric linear drive device according to claim 1, characterized in that: The cross-sectional area of ​​the groove (6) on the fixed base (1) is larger than the cross-sectional area of ​​the piezoelectric stack (4), and is used for limiting position and improving bonding stability.

4. The bidirectional stick-slip piezoelectric linear drive device according to claim 1, characterized in that: A guide hole (7) is provided on the side wall of the fixed base (1), and the piezoelectric stack lead wire (2) is connected to an external power supply through the guide hole, so as to improve the stability of the wire layout and the connection reliability.

5. The driving method of the bidirectional stick-slip piezoelectric linear drive device according to claims 1-4, characterized in that: The following steps are involved: S1. Apply a forward or reverse sawtooth voltage signal to the piezoelectric stack; S2. When a positive sawtooth wave voltage signal is applied, the driver performs periodic stick-slip motion, causing the stainless steel slider to achieve an overall net forward displacement in multiple reciprocating motions. S3. When a reverse sawtooth wave voltage signal is applied, the driver performs periodic stick-slip motion, causing the stainless steel slider to achieve an overall net backward displacement in multiple reciprocating motions. By adjusting the amplitude, frequency, and slope parameters of the voltage waveform, precise control of the displacement and movement direction can be achieved.

6. The driving method according to claim 5, wherein: The forward sawtooth wave is a waveform that rises slowly and falls quickly, and the reverse sawtooth wave is a waveform that rises quickly and falls slowly.

7. A modeling method for a bidirectional stick-slip piezoelectric linear drive device according to any one of claims 1 to 4, characterized in that: The LuGre friction model is introduced into the modeling to describe the nonlinear friction between the stainless steel slider and the carbon fiber friction rod; The Bouc-Wen hysteresis model is also introduced to characterize the hysteresis nonlinearity of the piezoelectric stack; the model is used to describe the dynamic behavior of the device in forward and reverse stick-slip motions.

8. The modeling method according to claim 7, characterized in that: In the modeling method, the dynamic characteristics of the stick-slip piezoelectric linear drive device are described by a second-order system including mass, damping, and stiffness, and the mass, damping, and stiffness parameters of the piezoelectric stack, carbon fiber friction rod, and stainless steel slider are taken into account. The model characterizes the hysteresis characteristics of the piezoelectric stack using the Bouc-Wen model, and constructs the piezoelectric response through the nonlinear relationship between the hysteresis variable and the driving voltage. The friction characteristics are modeled using the LuGre model, and the nonlinear relationship between the friction force and the relative velocity is described through parameters such as the contact surface stiffness, damping, and viscous friction. The friction force variation trend is compensated by combining the Stribeck effect, ultimately achieving an accurate description of the nonlinear dynamics of the piezoelectric drive device during the stick-slip motion process.

9. A control method for a bidirectional stick-slip piezoelectric linear drive device according to any one of claims 1 to 4, characterized in that: A control signal is generated based on a fuzzy PID controller to control the piezoelectric stack to drive the stainless steel slider to achieve the target displacement. The controller supports dual-mode switching: coarse positioning uses a stepper drive waveform, and fine positioning uses a fuzzy PID adjustment waveform. The fuzzy PID controller adopts a Mamdani-type structure, and its inputs include error, error change rate, and historical control output.

10. A control method according to claim 9, characterized in that: The current control output is adjusted in real time by the gain provided by the fuzzy PID controller. The control parameters are updated at each sampling moment to achieve online adaptive adjustment. The fuzzy PID control algorithm is as follows: e(t)=x d (t)-x(t) The fuzzy PID controller dynamically adjusts the proportional gain K during the control cycle p , integral gain K i and differential gain K d , in order to achieve online adaptive adjustment.

Images