A quasi-zero stiffness flexible mechanism guided cross-scale piezoelectric turntable

Abstract

This invention discloses a cross-scale piezoelectric rotary stage guided by a quasi-zero stiffness flexible mechanism, belonging to the field of high-performance piezoelectric drive technology, and solving the speed fluctuation problem caused by the transmission dead zone of the guide structure. The cross-scale piezoelectric rotary stage of this invention includes a quasi-zero stiffness flexible rotary guide mechanism, a bending composite piezoelectric actuator, a stiffness adjustment component, and a sensing and detection component. The quasi-zero stiffness of the rotary guide mechanism is achieved through parallel matching of positive and negative stiffness flexible beams. The stiffness adjustment component can adjust the pre-deformation of the guide mechanism. The driving bending unit of the bending composite piezoelectric actuator drives the guide mechanism, and the clamping bending unit adjusts the contact force. Large-stroke, non-backward stepping motion is achieved by alternating stick-slip stepping and controlling the contact force during the stick-slip phase. High-precision motion is achieved using DC micro-drive. This invention has cross-scale smooth motion output capability and is suitable for process control fields such as micro-nano manufacturing and biological puncture.

Description

Technical Field

[0001] This invention belongs to the field of piezoelectric drive technology, specifically, it relates to a cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism. Background Technology

[0002] Precision actuation is a core technology for the development of high-end equipment towards advanced precision. With the advancement of precision manufacturing, optical equipment, and life sciences, precision actuators need to combine large stroke and high precision to meet the performance requirements of micro- and nano-manipulation in cross-scale processing and inspection. Benefiting from the advantages of piezoelectric actuation technology—high precision, fast response, and no electromagnetic interference—piezoelectric actuators are widely used in high-end equipment for precision actuation. Stepper piezoelectric actuators achieve large stroke motion output by accumulating tiny step distances. Unlike point-to-point control, process control requires maintaining smooth speed during motion. However, traditional stepper piezoelectric actuators exhibit backlash and step-like characteristics, resulting in significant force and velocity fluctuations during motion. Unstable force and velocity fluctuations can affect surface quality in micro- and nano-manufacturing processes and the morphology of organisms during medical punctures.

[0003] The motion guiding mechanism is a core component of a stepper piezoelectric actuator. Motion guiding devices, represented by guide rails, sliders, and ball bearings, inevitably suffer from dead zones between the guiding and stationary components during motion transmission due to unavoidable machining and assembly errors. Therefore, the backlash in the guiding mechanism is a major cause of speed fluctuations in the piezoelectric actuator, especially under commutation, low-speed, and light-load conditions. A backlash-free guiding mechanism can eliminate commutation idle time and reverse dead zones, avoiding stalling and sudden crawling phenomena. Therefore, eliminating the backlash between guiding components to achieve smooth and stable motion output has become an urgent technical requirement for expanding the application of piezoelectric actuators in process control. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism, which solves the speed fluctuation problem caused by the transmission dead zone of traditional stepper piezoelectric actuator guiding mechanisms.

[0005] The above-mentioned objective of this invention is achieved through the following technical solution: A cross-scale piezoelectric rotary stage guided by a quasi-zero stiffness flexible mechanism includes: a quasi-zero stiffness flexible rotary guide mechanism, a bending composite piezoelectric actuator, a stiffness adjustment component, and a sensing and detection component; The quasi-zero stiffness flexible rotary guide mechanism consists of an inner ring, an outer ring, and positive stiffness flexible beams and negative stiffness flexible beams arranged circumferentially between the inner and outer rings. At least two bending composite piezoelectric actuators are arranged circumferentially along the quasi-zero stiffness flexible rotary guide mechanism. The bending composite piezoelectric actuators are connected to the inner ring via a mounting base. The bending composite piezoelectric actuators bend circumferentially along the outer ring to drive the outer ring of the quasi-zero stiffness flexible rotary guide mechanism to produce an eccentric rotational deformation relative to the inner ring. The bending deformation of the bending composite piezoelectric actuators in the vertical direction of the outer ring is used to actively adjust the contact force between its driving foot and the outer ring of the quasi-zero stiffness flexible rotary guide mechanism.

[0006] The stiffness adjustment component is set in the rotational tangential direction of the quasi-zero stiffness flexible rotary guide mechanism and is used to adjust the pre-deformation of the guide mechanism. The sensing and detection component is mounted on the quasi-zero stiffness flexible rotary guide mechanism and is used to detect the motion information parameters of the inner ring relative to the outer ring.

[0007] Moreover, the mechanical characteristics of the positive stiffness flexible beam are that the elastic force is positively correlated with the rotation angle, and straight beam type flexible hinge, arc type flexible hinge or leaf type flexible hinge is used to provide positive stiffness bearing support in the direction of rotation. The mechanical characteristics of the negative stiffness flexible beam are that the elastic force is negatively correlated with the rotation angle. It adopts a buckling beam type flexible hinge, an inclined type flexible hinge, or a diaphragm type negative stiffness structure. The elastic deformation force is obtained through geometric nonlinearity and preload induction. The elastic deformation force promotes deformation and drives the structure to deviate from the initial equilibrium position, so as to provide negative stiffness bearing support in the rotation direction.

[0008] Furthermore, the piezoelectric element of the bending composite piezoelectric actuator adopts a four-section piezoelectric ceramic stack, which is connected in series between the mounting base and the base. The opposing sections of the four-section piezoelectric ceramic stack each produce elongation and shortening deformation, driving the base to produce composite bending deformation. Alternatively, the inner end of the base is fixedly connected to the base, and the piezoelectric element is fixedly connected around the base. The two piezoelectric elements on opposite sides each produce elongation and shortening deformation, driving the base to produce composite bending deformation. The composite bending deformation includes bending deformation along the driving direction and bending deformation along the clamping direction. The driving foot is fixedly set on the upper part of the outer end of the base and contacts the lower end face of the outer ring of the quasi-zero stiffness flexible rotary guide mechanism. The magnitude of the contact force is adjusted by the bending deformation of the base along the clamping direction.

[0009] Furthermore, the piezoelectric elements of the bending composite piezoelectric actuator are arranged in a sandwich or patch configuration.

[0010] Furthermore, the stiffness adjustment assembly includes a bolt mounting base and an axial preload bolt. The bolt mounting base is a fixing component, and a threaded hole is provided on the bolt mounting base along the rotational tangential direction of the quasi-zero stiffness flexible rotary guide mechanism. The axial preload bolt is connected in the threaded hole, and its end contacts the top pressure block fixed to the lower part of the outer ring of the quasi-zero stiffness flexible rotary guide mechanism. By adjusting the screwing amount of the circumferential preload bolt, the initial deformation of the negative stiffness flexible beam is adjusted, thereby realizing the adjustment of the rotational negative stiffness value of the negative stiffness flexible beam.

[0011] Moreover, the sensing and detection components include a circular grating and its reading unit coaxially mounted on the central axis of the outer ring, or detection units such as capacitive displacement sensors, laser displacement sensors, and laser interferometers arranged circumferentially, used to acquire the angular displacement signal of the piezoelectric turntable in real time and feed it back to the drive control unit of the piezoelectric turntable to realize closed-loop motion control.

[0012] Furthermore, the motion modes of the cross-scale piezoelectric turntable include: The piezoelectric element of the bending composite piezoelectric actuator along the driving direction achieves minute bending deformation by applying a DC driving signal, driving the outer ring of the quasi-zero stiffness flexible rotary guide mechanism to output high-precision rotary motion. The piezoelectric element of the bending composite piezoelectric actuator along the driving direction is driven by alternating dynamic and static friction by applying a sawtooth wave signal. When one group of bending composite piezoelectric actuators performs sliding motion, the other several groups of bending composite piezoelectric actuators 2 perform adhesive motion, balancing static friction and sliding friction, reducing displacement back, and sequentially alternating to achieve large-angle rotational motion. The piezoelectric element along the clamping direction of the bending composite piezoelectric actuator controls the contact force between the driving foot and the outer ring of the quasi-zero stiffness flexible rotary guide mechanism by applying a trapezoidal wave signal. This causes the outer ring of the quasi-zero stiffness flexible rotary guide mechanism to be clamped during the viscous motion phase and released during the sliding motion phase, thus suppressing back displacement and achieving smooth actuation.

[0013] The advantages and positive effects of this invention are as follows: 1. This invention employs a circumferentially arranged drive structure with multiple sets of bending composite piezoelectric actuators, abandoning the rigid transmission structures such as gears, lead screws, and connecting rods of traditional piezoelectric turntables. It achieves rotational deformation drive by directly coupling the piezoelectric actuators with a quasi-zero stiffness flexible rotary guide mechanism, completely eliminating mechanical transmission backlash and assembly fit errors. Simultaneously, through the adaptive bending deformation of the bending composite piezoelectric actuators in the vertical direction, the contact preload between the drive foot and the outer ring can be dynamically fine-tuned, maintaining a gapless, close-fitting drive state throughout the entire process. This effectively avoids the motion jamming, speed fluctuations, and positioning lag problems caused by transmission dead zones, contact detachment, and other issues in traditional rotary piezoelectric platforms, significantly improving the continuity and stability of the turntable's rotational motion and adapting to the requirements of precision rotational applications across multiple scales.

[0014] 2. This invention innovatively designs a quasi-zero stiffness flexible rotary guide mechanism with parallel positive and negative stiffness. It replaces traditional contact-type guide structures such as ball bearings and guide rails with synergistic coupling between circumferentially arranged positive and negative stiffness flexible beams between the inner and outer rings. This flexible guide structure achieves rotary guidance through the deformation of the elastic beams, possessing the core characteristics of no mechanical friction, no movement backlash, and no wear. It fundamentally eliminates the interference of frictional damping and rolling slip errors on the rotary accuracy of the turntable. Simultaneously, the parallel positive and negative stiffness structure can achieve stiffness cancellation within the rotational equilibrium range, forming a high static and low dynamic mechanical characteristic. This ensures the static support stability of the turntable while significantly reducing rotational stiffness, effectively improving the guiding accuracy and motion sensitivity of the turntable's micro-angle and cross-scale precision rotation.

[0015] 3. This invention is equipped with an independent stiffness adjustment component, which can precisely control the deformation and preload of the circumferentially arranged positive stiffness flexible beams and negative stiffness flexible beams, achieving matching optimization and dynamic calibration of positive and negative stiffness parameters. By precisely adjusting the stiffness coupling state of the two types of flexible beams, the effective working range of quasi-zero stiffness can be accurately locked and widened, solving the defects of fixed working range and poor adaptability of traditional quasi-zero stiffness structures. It can accurately adapt the optimal stiffness characteristics according to different cross-scale rotation strokes and different load conditions, achieving precise and controllable quasi-zero stiffness working state of the turntable, and significantly improving the working condition adaptability and precision drive stability of the piezoelectric turntable.

[0016] 4. This invention proposes a coordinated driving method of alternating stick-slip stepping and active control of contact force, which increases the output torque in the stick motion stage, suppresses the back displacement in the slip motion stage, and achieves smooth actuation.

[0017] The quasi-zero stiffness flexible mechanism-guided cross-scale piezoelectric turntable described in this invention is suitable for process control with low speed fluctuations, such as biomedical puncture, micro-nano manufacturing, and optical focusing. Attached Figure Description

[0018] Figure 1This is an isometric view of a cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism as described in this invention. Figure 2 This is a schematic diagram of the quasi-zero stiffness flexible rotary guide mechanism described in this invention; Figure 3 This is a schematic diagram of the bending composite piezoelectric actuator structure described in this invention; Figure 4 This is a schematic diagram of the deformation of the bending composite piezoelectric actuator described in this invention; Figure 5 This is a schematic diagram of the stiffness matching and pre-deformation adjustment of the flexible beam described in this invention; Figure 6 This is a schematic diagram of the excitation signal and timing of the alternating stick-slip stepping according to the present invention; Among them, 1-quasi-zero stiffness flexible rotary guide mechanism; 1-1-inner ring; 1-2-outer ring; 1-3-positive stiffness flexible beam; 1-4-negative stiffness flexible beam; 2- Bending composite piezoelectric actuator; 2-1- Mounting base; 2-2- Substrate; 2-3- Drive foot; 2-4- Piezoelectric element 3-Stiffness adjustment assembly; 3-1-Bolt mounting base; 3-2-Circumferential preload bolt; 4-Sensing and detection assembly. Detailed Implementation

[0019] The structure of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] For an example of a cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism, please refer to [link / reference]. Figures 1-6 The invention features a quasi-zero stiffness flexible rotary guide mechanism 1, a bending composite piezoelectric actuator 2, a stiffness adjustment component 3, and a sensing and detection component 4.

[0021] The quasi-zero stiffness flexible rotary guide mechanism consists of an inner ring 1-1, an outer ring 1-2, and a positive stiffness flexible beam 1-3 and a negative stiffness flexible beam 1-4 arranged circumferentially between the inner and outer rings. The inner ring 1-1 of the quasi-zero stiffness flexible rotary guide mechanism is fixed, while the outer ring 1-2 and the inner ring 1-1 can undergo eccentric relative rotational deformation. The positive stiffness flexible beam 1-3 and the negative stiffness flexible beam 1-4 of the zero stiffness flexible rotary guide mechanism 1 are uniformly and symmetrically distributed between the inner and outer rings, ensuring that the rotation center coincides.

[0022] The mechanical characteristics of the positive stiffness flexible beam 1-3 are that the elastic force is positively correlated with the rotation angle. It can adopt a straight beam type flexible hinge, an arc type flexible hinge or a leaf type flexible hinge to provide positive stiffness load-bearing support in the direction of rotation.

[0023] The mechanical characteristics of the negative stiffness flexible beams 1-4 are that the elastic force is negatively correlated with the rotation angle. They can adopt buckling beam type flexible hinges, inclined type flexible hinges or diaphragm type negative stiffness structures. Through geometric nonlinearity, preload induction, etc., the elastic deformation force promotes deformation and drives the structure to deviate from the initial equilibrium position, so as to provide negative stiffness bearing support in the rotation direction.

[0024] The bending composite piezoelectric actuator 2 is arranged circumferentially along the quasi-zero stiffness flexible rotary guide mechanism 1, and the number of bending composite piezoelectric actuators 2 can be set to be greater than or equal to 2.

[0025] The bending composite piezoelectric actuator 2 consists of a mounting base 2-1, a base 2-2, a drive foot 2-3, and a piezoelectric element 2-4. The mounting base of the bending composite piezoelectric actuator is fixedly connected to the inner ring of the quasi-zero stiffness flexible rotary guide mechanism.

[0026] The piezoelectric element can be arranged in, but is not limited to, two forms: Form 1: The piezoelectric element adopts a four-section piezoelectric ceramic stack, which is connected in series between the mounting base 2-1 and the base 2-2. The four-section piezoelectric ceramic stack generates elongation and shortening deformation in opposite sections, driving the base to generate composite bending deformation.

[0027] Form 2: The inner end of the substrate is fixedly connected to the base. The piezoelectric element is a single-section piezoelectric rectangular sheet polarized in the thickness direction, which is fixedly connected around the substrate 2-2. The two piezoelectric elements on opposite sides each produce elongation and shortening deformation, driving the substrate to produce composite bending deformation.

[0028] The aforementioned composite bending deformation includes bending deformation along the driving direction (along the circumferential direction of the outer ring) and bending deformation along the clamping direction (orthogonal to the axial direction of the outer ring; if the axial direction of the outer ring is set vertically, then the clamping direction is the pitch direction).

[0029] The piezoelectric elements 2-4 of the bending composite piezoelectric actuator 2 can be arranged in a sandwich or patch configuration.

[0030] The driving foot is fixedly mounted on the upper outer end of the base and contacts the lower outer ring surface of the quasi-zero stiffness flexible rotary guide mechanism.

[0031] The bending composite piezoelectric actuator 2 bends circumferentially along the outer ring to drive the outer ring 1-2 of the quasi-zero stiffness flexible rotary guide mechanism to produce an eccentric rotational deformation relative to the inner ring 1-1. The bending deformation of the bending composite piezoelectric actuator 2 along the perpendicular direction of the outer ring is used to actively adjust the contact force between the driving foot and the outer ring 1-2 of the quasi-zero stiffness flexible rotary guide mechanism.

[0032] The stiffness adjustment component 3 is located in the rotational tangential direction of the quasi-zero stiffness flexible rotary guide mechanism and is used to adjust the pre-deformation of the guide mechanism. The stiffness adjustment component 3 includes a bolt mounting base 3-1 and an axial preload bolt 3-2. The bolt mounting base is a fixing component, and a threaded hole along the rotational tangential direction of the quasi-zero stiffness flexible rotary guide mechanism is provided on the bolt mounting base. The axial preload bolt is connected in the threaded hole, and its end contacts the top pressure block fixed at the lower part of the outer ring of the quasi-zero stiffness flexible rotary guide mechanism. By adjusting the screwing amount of the circumferential preload bolt 3-2, the initial deformation of the negative stiffness flexible beam is adjusted, thereby adjusting the rotational negative stiffness value of the negative stiffness flexible beam 1-4, realizing precise control and adaptation of the quasi-zero stiffness working range.

[0033] The sensing and detection component 4 is installed on the quasi-zero stiffness flexible rotary guide mechanism 1 and is used to detect the motion information parameters of the outer ring relative to the inner ring.

[0034] The sensing and detection component 4 may include a circular grating and its reading unit fixed coaxially with the outer ring, or a detection unit such as a capacitive displacement sensor, a laser displacement sensor, or a laser interferometer arranged circumferentially, for real-time acquisition of the angular displacement signal of the piezoelectric turntable and feedback to the drive control unit to achieve closed-loop motion control.

[0035] The rotation centers of the positive stiffness flexible beam 1-3 and the negative stiffness flexible beam 1-4 coincide. By connecting one or more positive stiffness flexible beams 1-3 and one or more negative stiffness flexible beams 1-4 in parallel, the stiffness values ​​of the two beams in the rotation direction match and cancel each other within a certain rotation angle range, thereby achieving cross-scale, rebound-free, and gapless guidance.

[0036] The positive stiffness flexible beam 1-3 and the negative stiffness flexible beam 1-4 are connected in parallel between the inner and outer rings, ensuring that the outer ring 1-2 of the zero stiffness flexible rotary guide mechanism has only a single rotational degree of freedom around the central axis, and has high stiffness limiting constraints on the other 5 spatial degrees of freedom.

[0037] The motion mode of the cross-scale piezoelectric rotary table guided by the quasi-zero stiffness flexible mechanism is as follows: The piezoelectric elements 2-4 of the bending composite piezoelectric actuator 2 along the driving direction achieve minute bending deformation by applying a DC driving signal, thereby driving the outer ring of the quasi-zero stiffness flexible rotary guide mechanism 1 to output high-precision rotary motion. The piezoelectric elements 2-4 of the bending composite piezoelectric actuator 2 along the driving direction are driven by alternating dynamic and static friction by applying a sawtooth wave signal. When one group of bending composite piezoelectric actuators 2 performs sliding motion, the other several groups of bending composite piezoelectric actuators 2 perform adhesive motion, balancing static friction and sliding friction, reducing displacement back, and sequentially alternating to achieve large-angle rotational motion. The piezoelectric elements 2-4 of the bending composite piezoelectric actuator 2 along the clamping direction control the contact force between the driving foot and the outer ring of the quasi-zero stiffness flexible rotary guide mechanism 1 by applying a trapezoidal wave signal. This causes the outer ring of the quasi-zero stiffness flexible rotary guide mechanism 1 to be clamped during the adhesive motion phase and released during the sliding motion phase, suppressing back displacement and achieving smooth actuation. Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism, characterized in that: It includes a quasi-zero stiffness flexible rotary guide mechanism (1), a bending composite piezoelectric actuator (2), a stiffness adjustment assembly (3), and a sensing and detection assembly (4). The quasi-zero stiffness flexible rotary guide mechanism (1) consists of an inner ring (1-1), an outer ring (1-2), a positive stiffness flexible beam (1-3) and a negative stiffness flexible beam (1-4) arranged circumferentially between the inner ring (1-1) and the outer ring (1-2); There are at least two bending composite piezoelectric actuators (2), which are arranged circumferentially along the quasi-zero stiffness flexible rotary guide mechanism (1). The bending composite piezoelectric actuators (2) are connected to the inner ring (1-1) through the mounting base (2-1). The bending composite piezoelectric actuators (2) bend circumferentially along the outer ring (1-2) to drive the outer ring (1-2) of the quasi-zero stiffness flexible rotary guide mechanism (1) to generate an eccentric rotational deformation relative to the inner ring (1-1). The bending deformation of the bending composite piezoelectric actuators (2) in the direction perpendicular to the outer ring (1-2) is used to actively adjust the contact force between its driving foot (2-3) and the outer ring (1-2) of the quasi-zero stiffness flexible rotary guide mechanism (1). The stiffness adjustment component (3) is set in the rotational tangential direction of the quasi-zero stiffness flexible rotary guide mechanism (1) and is used to adjust the pre-deformation of the guide mechanism. The sensing and detection component (4) is installed on the quasi-zero stiffness flexible rotary guide mechanism (1) and is used to detect the motion information parameters of the outer ring (1-2) rotating relative to the inner ring (1-1).

2. The cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism according to claim 1, characterized in that: The mechanical characteristics of the positive stiffness flexible beam (1-3) are that the elastic force is positively correlated with the rotation angle. Straight beam type flexible hinge, arc type flexible hinge or leaf type flexible hinge is used to provide positive stiffness bearing support in the direction of rotation. The mechanical characteristics of the negative stiffness flexible beam (1-4) are that the elastic force is negatively correlated with the rotation angle. It adopts a buckling beam type flexible hinge, an oblique type flexible hinge or a diaphragm type negative stiffness structure. It obtains elastic deformation force through geometric nonlinearity and preload induction. It relies on the elastic deformation force to promote deformation and drive the structure to deviate from the initial equilibrium position, so as to provide negative stiffness bearing support in the rotation direction.

3. The cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism according to claim 1, characterized in that: The piezoelectric element (2-4) of the bending composite piezoelectric actuator (2) adopts a four-section piezoelectric ceramic stack, which is connected in series between the mounting base (2-1) and the base (2-2). The four-section piezoelectric ceramic stack generates elongation and shortening deformation in opposite sections, driving the base (2-2) to generate composite bending deformation; or the inner end of the base (2-2) is fixedly connected to the base, and the piezoelectric element (2-4) is fixedly connected around the base (2-2). The two piezoelectric elements (2-4) on opposite sides generate elongation and shortening deformation, driving the base (2-2) to generate composite bending deformation; the composite bending deformation includes bending deformation along the driving direction and bending deformation along the clamping direction; the driving foot (2-3) is fixedly set on the upper part of the outer end of the base (2-2) and contacts the lower end face of the outer ring (1-2) of the quasi-zero stiffness flexible rotary guide mechanism (1), and the contact force is adjusted by the bending deformation of the base along the clamping direction.

4. The cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism according to claim 3, characterized in that: The piezoelectric elements (2-4) are arranged in a sandwich or patch configuration.

5. The cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism according to claim 1, characterized in that: The stiffness adjustment component (3) includes a bolt mounting base (3-1) and an axial preload bolt (3-2). The bolt mounting base (3-1) is a fixing component. A threaded hole is provided on the bolt mounting base (3-1) along the rotational tangential direction of the quasi-zero stiffness flexible rotary guide mechanism (1). The axial preload bolt (3-2) is connected in the threaded hole, and its end contacts the top pressure block fixed at the lower part of the outer ring (1-2) of the quasi-zero stiffness flexible rotary guide mechanism (1). By adjusting the screwing amount of the circumferential preload bolt, the initial deformation of the negative stiffness flexible beam (1-4) is adjusted, thereby realizing the adjustment of the rotational negative stiffness value of the negative stiffness flexible beam (1-4).

6. The cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism according to claim 1, characterized in that: The sensing and detection component (4) includes a circular grating and its reading unit coaxially mounted on the central axis of the outer ring (1-2), or a capacitive displacement sensor, a laser displacement sensor, and a laser interferometer arranged circumferentially, for real-time acquisition of the angular displacement signal of the piezoelectric turntable and feedback to the drive control unit of the piezoelectric turntable to realize closed-loop motion control.

7. The cross-scale piezoelectric turntable guided by a quasi-zero stiffness flexible mechanism according to claim 3, characterized in that: The motion modes of the multi-scale piezoelectric rotary table include: The piezoelectric element (2-4) of the bending composite piezoelectric actuator (2) along the driving direction achieves minute bending deformation by applying a DC driving signal, driving the outer ring (1-2) of the quasi-zero stiffness flexible rotary guide mechanism (1) to output high-precision rotary motion. The piezoelectric elements (2-4) of the bending composite piezoelectric actuator (2) along the driving direction are driven by alternating dynamic and static friction by applying a sawtooth wave signal. When one group of bending composite piezoelectric actuators (2) performs sliding motion, the other several groups of bending composite piezoelectric actuators (2) perform adhesive motion, balancing static friction and sliding friction, reducing displacement back, and sequentially alternating to achieve large-angle rotational motion. The piezoelectric element (2-4) of the bending composite piezoelectric actuator (2) along the clamping direction controls the contact force between the driving foot (2-3) and the outer ring (1-2) of the quasi-zero stiffness flexible rotary guide mechanism (1) by applying a trapezoidal wave signal. This causes the outer ring (1-2) of the quasi-zero stiffness flexible rotary guide mechanism (1) to be clamped during the adhesive motion phase and to be released during the sliding motion phase, thereby suppressing the back displacement and achieving smooth actuation.

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