A rotary stick-slip piezoelectric driver with vibration friction modulation mechanism

Abstract

This invention relates to a rotary stick-slip piezoelectric actuator with a vibration-friction modulation mechanism, addressing the problems of backlash, poor integration, and low stiffness in current rotary stick-slip piezoelectric actuators during operation. It mainly consists of a mover assembly, drive foot, outer shell, mover disk, base shaft, nut, and stator assembly. This invention, through a special structure and driving method, enables the actuator to be compatible with both sinusoidal and sawtooth wave drive signals, and allows the application of high-frequency signals to the mover to achieve ultrasonic friction reduction, thereby suppressing backlash. Compared to existing rotary stick-slip piezoelectric actuators utilizing ultrasonic friction reduction principles, this invention improves the actuator's stiffness and integration performance. Furthermore, this invention solves the problem of wire entanglement on the mover during rotation.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric actuator technology, and more particularly to a rotary stick-slip piezoelectric actuator with a vibration-friction modulation mechanism. Background Technology

[0002] Stick-slip piezoelectric actuators have been widely used in precision testing instruments due to their advantages such as small size, high speed, high resolution and large load capacity. However, due to their unique driving characteristics, stick-slip actuators can suffer from inertial backlash.

[0003] Existing methods for addressing the inertial backlash problem mainly fall into three categories: using anisotropic friction surfaces, employing cooperative motion control, and utilizing ultrasonic vibration to reduce friction. Among these, the fabrication of anisotropic friction surfaces is relatively expensive and complex, while cooperative motion control methods are difficult to apply to rotary piezoelectric actuators. Therefore, existing technologies typically employ ultrasonic friction reduction principles to design rotary stick-slip piezoelectric actuators, which offers advantages such as lower cost and ease of implementation in rotary actuators. However, existing rotary stick-slip piezoelectric actuators utilizing ultrasonic friction reduction principles still suffer from unresolved issues such as poor integration performance, weak stiffness, and lead wire entanglement. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a rotary stick-slip piezoelectric actuator with a vibration-friction modulation mechanism. Employing a unique structure and driving method, it can effectively solve the previous problems, thereby outputting good linear motion.

[0005] The technical solution adopted in this invention is as follows:

[0006] The present invention proposes a rotary stick-slip piezoelectric actuator with a vibration friction modulation mechanism, comprising a mover assembly, drive feet, a housing, a mover turntable, a bottom shaft, a nut, and a stator assembly; the bottom shaft is coaxially disposed in the lower region of the housing, and its bottom is fixedly connected to the bottom of the housing; the stator assembly is coaxially connected to the middle region of the bottom shaft; the nut is threadedly connected to the upper end of the bottom shaft and coaxially fitted with the stator assembly; the drive feet are evenly distributed around the circumferential edge of the upper end face of the stator assembly; the mover assembly is coaxially disposed in the upper region of the housing, and its upper end coaxially passes through the top of the housing, and its lower end contacts the top of the drive feet.

[0007] Furthermore, the outer shell includes a pre-tightening outer shell, an intermediate outer shell, and a bottom outer shell; the pre-tightening outer shell is a hollow cylindrical structure with a threaded hole at the center of its upper end face and an annular flange integrally formed on the outer circumference of its lower end; the intermediate outer shell is a cylindrical structure, and the bottom of the pre-tightening outer shell is coaxially fixed to the upper end of the intermediate outer shell through the flange; the bottom outer shell is a disc structure, which is coaxially fixed to the bottom end of the intermediate outer shell and has a central through hole in the middle for the bottom shaft to pass through.

[0008] Furthermore, the mover assembly includes an output shaft, a tightening preload member, a conductor shaft, a spring, an insulating shaft, bearing I, a mover connecting shaft, a preload sleeve, a mover turntable, and bearing II. The mover turntable is coaxially disposed above the stator assembly and has a central through hole, with the top of the drive feet respectively contacting the lower end face of the mover turntable. The tightening preload member is coaxially threaded to the top of the housing. The lower part of the output shaft coaxially passes through the tightening preload member and then coaxially transitions with the upper end of the conductor shaft disposed inside the preload housing. The insulating shaft has a central through hole, and the middle part of the conductor shaft is connected to the insulating shaft. The upper regions of the central through-holes of the insulating shaft are coaxially transition-fitted; the moving part connecting shaft has a central through-hole, and the lower region of the insulating shaft transitions-fitted with the upper region of the central through-hole of the moving part connecting shaft; the lower region of the moving part connecting shaft transitions-fitted with the central through-hole of the moving part turntable; the upper inner side of the preload sleeve is coaxially connected to the upper part of the conductor shaft through bearing I, and the lower inner side is rotatably connected to the upper part of the moving part connecting shaft through bearing II; the spring is coaxially disposed on the outside of the junction of the output shaft and the conductor shaft, and its upper end is connected to the lower end face of the tightening preload component, and its lower end is connected to the upper end face of the preload sleeve.

[0009] Furthermore, the wiring of the mover assembly is as follows: the positive terminal of the power supply is connected to the outer ring of bearing I through a wire, and the voltage is transmitted to the conductor shaft through the conductivity of bearing I. The wire is connected to the lower part of the conductor shaft and exits from the middle of the insulating shaft and the mover connecting shaft, and is connected to the piezoelectric element. The negative terminal of the power supply is connected to the outer ring of bearing II through a wire, and the voltage of the mover disk is transmitted to bearing II through conductivity, and then transmitted out through bearing II, thereby forming a closed loop.

[0010] Furthermore, the stator assembly includes stator I and stator II; stator II and stator I are coaxially connected from bottom to top in the middle region of the bottom shaft and are fixedly connected to each other at their centers; the upper end face of stator I is evenly distributed with spherical grooves for mounting drive feet.

[0011] Furthermore, both stator I and stator II are composed of an inner ring, an outer ring, and a vibrator beam; the inner ring is coaxially disposed at the center of the outer ring; the vibrator beams are radially connected between the inner ring and the outer ring, evenly distributed around the circumference; protrusions are provided on both sides of the lower end face of the inner ring of stator I; grooves corresponding to the protrusions are provided on both sides of the upper end face of the inner ring of stator II; stator I and stator II are connected together by a gap fit between the protrusions and the grooves, and the vibrator beams on stator I and stator II are uniformly misaligned vertically.

[0012] Furthermore, the stator assembly is wired with the positive terminal connected to both sides of the vibrator beam and the negative terminal connected to the outer ring.

[0013] Furthermore, both the output shaft and the insulating shaft are made of nylon; the conductor shaft is made of brass.

[0014] Furthermore, a bearing retaining ring is installed between the bottom end of the moving part connecting shaft and the bottom surface of the moving part turntable.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] The rotary stick-slip piezoelectric actuator designed in this invention, with its vibration-friction modulation mechanism, allows the stator to be compatible with both sinusoidal and sawtooth wave voltage driving methods due to its unique driving mechanism. To address the rollback issue, this invention applies a high-frequency sinusoidal wave to the mover, reducing friction between the mover and stator through high-frequency vibration. This results in significantly improved stiffness and integration performance of the designed rotary stick-slip piezoelectric actuator. Furthermore, it effectively solves the problem of lead wire entanglement during mover rotation by connecting the lead wire to a bearing, using the bearing's conductivity to connect to the external circuit. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view of the overall structure of a rotary stick-slip piezoelectric actuator with a vibration-friction modulation mechanism proposed in this invention.

[0018] Figure 2 This is an exploded view of the present invention;

[0019] Figure 3 for Figure 2 3D diagram of the midsole axis;

[0020] Figure 4 for Figure 2 Schematic diagram of the middle stator assembly;

[0021] Figure 5 for Figure 2 Schematic diagram of the structure of the central moving part turntable;

[0022] Figure 6 for Figure 2A schematic diagram of the structure of the middle outer shell;

[0023] Figure 7 for Figure 2 Schematic diagram of the preload sleeve;

[0024] Figure 8 for Figure 2 Schematic diagram of the structure of the connecting shaft of the central actuator;

[0025] Figure 9 for Figure 2 Schematic diagram of the structure of the central insulating shaft;

[0026] Figure 10 This is a schematic diagram showing the bonding position relationship between the positive and negative electrodes of the piezoelectric ceramic sheet on the stator and the vibrator beam.

[0027] Figure 11 This is a schematic diagram of the wiring configuration for a single oscillator beam on the stator.

[0028] Figure 12 Schematic diagram of the wiring method for the actuator assembly;

[0029] Figure 13 Diagram of stator component drive signals;

[0030] Figure 14 This is a schematic diagram illustrating the working principle of the present invention. Detailed Implementation

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] It should be noted that in the description of this invention, the terms "upper", "lower", "top", "bottom", "one side", "the other side", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not mean that the device or element must have a specific orientation, or be constructed and operated in a specific orientation.

[0033] See appendix Figure 1-14 This paper presents a specific structure of an embodiment of a rotary stick-slip piezoelectric actuator with a vibration-friction modulation mechanism proposed in this invention. The actuator includes a mover assembly, a drive foot (9), a housing, a mover turntable (11), a bottom shaft (13), a nut (14), and a stator assembly; as shown in the figure. Figure 3As shown, the bottom shaft (13) is coaxially mounted in the lower region of the housing via a fixing plate, and the bottom fixing plate is coaxially fixed to the bottom of the housing. The stator assembly is coaxially connected to the middle region of the bottom shaft. The nut (14) is threaded to the upper end of the bottom shaft and coaxially fitted with the stator assembly. The nut (14) is tightened above the bottom shaft (13) to fix the stator assembly. The drive feet (9) are evenly distributed around the circumference of the upper end face of the stator assembly. The moving part is coaxially mounted in the upper region of the housing, and its upper end coaxially passes through the top of the housing, while its lower end contacts the top of the drive feet.

[0034] The outer shell includes a pre-tightening outer shell (10), an intermediate outer shell (16), and a bottom outer shell (18). The pre-tightening outer shell (10) is a hollow cylindrical structure with a threaded hole at its upper center for connecting and tightening the pre-tightening component (2). An annular flange is integrally formed on the outer circumference of the lower end of the cylindrical structure, and four countersunk bolt holes are evenly distributed on the annular flange. The intermediate outer shell (16) is a cylindrical structure, and the flange on the outer circumference of the bottom of the pre-tightening outer shell (10) is coaxially fixed to the upper end of the intermediate outer shell (16) by bolts. The bottom outer shell (18) is a disc structure, and the circumferential edge of its upper end face is coaxially fixed to the bottom end of the intermediate outer shell (16) by bolts. A central through hole for the bottom shaft (13) to pass through is opened in the middle of the bottom outer shell (18). The specific structure of the intermediate outer shell (16) is as follows: Figure 6 As shown, square holes (161) are opened on both sides of the bottom for the routing of piezoelectric sheets on the stator assembly, and threaded holes are provided on the bottom surface for fixing to the bottom shell (18).

[0035] like Figure 2As shown, the mover assembly includes an output shaft (1), a tightening preload (2), a conductor shaft (3), a spring (4), an insulating shaft (5), a bearing I (6), a mover connecting shaft (7), a preload sleeve (8), a mover turntable (11), and a bearing II (12). The moving rotor disk (11) is coaxially disposed above the stator assembly and has a central through hole, and the top of the driving foot (9) is respectively in contact with the lower end face of the moving rotor disk (11); the tightening preload (2) is coaxially threaded to the top of the preload housing (10); the output shaft (1) is coaxially rotatably connected inside the tightening preload (2), and its lower part passes through the tightening preload (2) and is coaxially transition-fitted with the upper end of the conductor shaft (3) disposed inside the preload housing (10); the insulating shaft (5) has a central through hole, and the middle area of ​​the conductor shaft (3) is coaxially transition-fitted with the central through hole of the insulating shaft (5); the moving rotor connecting shaft (7) has a central through hole, and the lower area of ​​the insulating shaft (5) is transition-fitted with the upper area of ​​the central through hole of the moving rotor connecting shaft (7); the lower area of ​​the moving rotor connecting shaft (7) The field is fitted with the center through hole of the mover turntable (11), and a bearing retainer ring (112) is installed between the bottom end of the mover connecting shaft (7) and the bottom surface of the mover turntable (11) for fixing and preventing it from falling off; the upper inner side of the pre-tightening sleeve (8) is coaxially connected to the upper part of the conductor shaft (3) through bearing I (6), and the inner ring of bearing I (6) is connected to the conductor shaft, and the outer ring is connected to the pre-tightening sleeve (8); the lower inner side of the pre-tightening sleeve (8) is coaxially connected to the upper part of the mover connecting shaft (7) through bearing II (12), and the inner ring of bearing II (12) is connected to the mover connecting shaft (7), and the outer ring is connected to the pre-tightening sleeve (8); the spring (4) is coaxially set on the outside of the junction of the output shaft (1) and the conductor shaft (3), and its upper end is connected to the lower end face of the tightening pre-tightening member (2), and its lower end is connected to the upper end face of the pre-tightening sleeve (8). The above assembly method can ensure that the output shaft (1) is driven to rotate by the rotation of the mover turntable (11).

[0036] The insulating shaft (5) has a stepped structure that is thicker at the top and thinner at the bottom, as shown in the specific structure below. Figure 9 As shown, the insulating shaft (5) is made of nylon and has a central through hole (51) and a hole (52) on its lower side wall. The central through hole (51) is used to mate with the conductor shaft (3). The lower part is inserted into the mover connecting shaft (7), which can align the hole (52) and the hole (71) for the piezoelectric sheet wiring on the mover assembly.

[0037] The moving part connecting shaft (7) has a stepped structure that is thicker in the middle and thinner at both ends, as shown in the specific structure below. Figure 8 As shown, it is made of brass and has a hole (71) in the middle side wall.

[0038] The pre-tightening sleeve (8) has a three-section stepped structure, the specific structure of which is as follows: Figure 7As shown, the pre-tightening sleeve (8) is made of nylon material. The upper side of the pre-tightening sleeve (8) has an annular platform, which forms a concave groove with the side wall to abut against the spring (4) and generate pre-tightening force. The second layer of the side wall has a hole (81) from top to bottom, and the third layer of the side wall has a hole (82) for the piezoelectric sheet wiring on the moving disk (11).

[0039] The output shaft (1) and the insulating shaft (5) are both made of nylon; the conductor shaft (3) is made of brass.

[0040] In this embodiment, as Figure 5 As shown, the moving turntable (11) is composed of an inner ring, an outer ring and four crossbeams; the inner ring is coaxially arranged at the center of the outer ring; the crossbeams are radially connected between the inner ring and the outer ring, and each crossbeam is attached with a PZT-8 piezoelectric sheet (111).

[0041] By twisting the upper preload element (2), it can be moved downwards. By moving the compression spring (4), pressure is transmitted to the preload sleeve (8). The preload force is pressed on the outer ring of the bearing, so that the outer ring of the bearing provides the preload force and the inner ring is responsible for rotation.

[0042] like Figure 4 As shown, the stator assembly includes stator I (15) and stator II (17); stator II (17) and stator I (15) are coaxially connected from bottom to top in the middle area of ​​the bottom shaft and the center of stator II (17) and stator I (15) are fixedly connected to each other; a protrusion is coaxially provided at the center of the bottom of stator II (17) to prevent the ring from contacting the bottom shaft (13); the upper end face of stator I (15) is evenly distributed with spherical grooves for installing drive feet (9) on the circumferential edge, and a limiting groove is opened on the outer circumference of the center of the upper end face of stator I (15) for screwing in the nut (14).

[0043] Stator I (15) and Stator II (17) are both composed of an inner ring, an outer ring, and a vibrating beam. The inner ring is coaxially arranged at the center of the outer ring. The vibrating beams are radially connected between the inner ring and the outer ring, which are evenly distributed around the circumference. In this embodiment, there are four vibrating beams on both Stator I (15) and Stator II (17). The lower end face of the inner ring of Stator I (15) is provided with protrusions (152) on both sides. The upper end face of the inner ring of Stator II (17) is provided with grooves (172) corresponding to the protrusions (152). Stator I (15) and Stator II (17) are connected together by the gap fit between the protrusions (152) and the grooves (172), so that the four upper vibrating beams and the four lower vibrating beams are staggered. In this way, each vibrating beam can be staggered by 45 degrees in different planes, which is convenient for subsequent bonding of piezoelectric sheets.

[0044] The bonding positions of the positive and negative electrodes of the piezoelectric ceramic sheet with the oscillator elastomer are as follows: Figure 10 As shown, piezoelectric sheets are pasted on both sides of the same vibrating beam. The positive and negative poles of the pasted piezoelectric sheets are opposite, and the positive and negative poles of two adjacent piezoelectric sheets are also opposite. Eight PZT-5 piezoelectric sheets (151) are pasted on stator I (15), and eight PZT-5 piezoelectric sheets (171) are also pasted on stator II (17). The wiring method of a single vibrating beam on the stator is as follows. Figure 11 As shown, the positive terminal of the voltage is connected to the outside of the two piezoelectric plates, and the negative terminal is connected to the oscillator beam. Each oscillator beam is as follows: Figure 12 The wiring is done as shown. The negative terminal can be selected from the outer ring. There are 16 wires leading out from the piezoelectric element and connected to the positive terminal, and 1 wire leading out from the outer ring and connected to the negative terminal. The voltage signal applied to the stator piezoelectric element is V1.

[0045] The moving part wiring method is as follows Figure 12 As shown, the lead wire of the positive terminal of the power supply is connected to the upper bearing I (6) through the hole (81) on the pre-tightening sleeve (8). The voltage is transmitted to the conductor shaft (3) through the conductivity of the bearing I (6). The wire is connected to the conductor shaft (3) and then leads out through the hole between the insulating shaft (5) and the moving part connecting shaft (7) to the four piezoelectric plates (111) on the moving part turntable (11). The lead wire of the negative terminal of the power supply is led out through the hole (82) below the pre-tightening sleeve (8) and connected to the lower bearing II (12). Through conductivity, the voltage on the four piezoelectric plates (111) is transmitted to the moving part connecting shaft (7) through the moving part turntable (11). The moving part connecting shaft (7) transmits the voltage out from the bearing II (12), thus forming a closed loop. The voltage signal applied to the moving part piezoelectric plate (111) is V2. This design can make the circuit conductive. Since the insulating shaft (5) is made of nylon, it can prevent short circuits caused by contact between the positive and negative terminals.

[0046] Stator drive signals such as Figure 13 As shown, it is compatible with both sawtooth wave and sine wave drive signals.

[0047] The following is combined with Figure 14 The working principle of the rotary stick-slip piezoelectric actuator with vibration-friction modulation mechanism designed in this invention under sawtooth wave voltage drive will be explained in detail below: Figures (a), (b), and (c) represent the three stages of actuator motion, respectively. Figures (a), (b), and (c) each contain three diagrams from left to right. The left diagram is the voltage signal diagram, where V1 is the sawtooth wave voltage applied to the stator piezoelectric element, such as... Figure 11 As shown; V2 is the high-frequency sinusoidal voltage applied to the mover, such as... Figure 12 As shown. The middle view is a top view of the stator in the xy plane. The right view is a diagram of the relative motion between the stator and rotor. Taking the counterclockwise rotation of the actuator as an example, the actuator's motion process can be divided into three stages:

[0048] Initial stage: such as Figure 14 As shown in (a), at time t = t0, no external voltage is input, the piezoelectric element is not excited, and the driving foot (9) is in contact with the moving disk (15) under the action of preload. The light-colored driving foot is stationary at the initial position a, and there is no relative motion between the stator and the moving part. Take a point directly above the light-colored driving foot as point b. Point b is also located on the moving part, which represents the motion state of the moving part. Point b is the initial motion position of the moving part.

[0049] Adhesion stage: such as Figure 14 As shown in (b), during the time interval from t0 to t1, the sawtooth wave voltage V1 is in the rising edge stage. Under the excitation of the voltage, the piezoelectric plates (151) and (171) cause the oscillator beams of stator I (15) and stator II (17) to bend slowly, thereby driving the outer rings of stator I (15) and stator II (17) to rotate. The light-colored driving foot in the figure rotates counterclockwise from point a at the end of the dashed line to point a' at the end of the solid line (point a' is the position point of the light-colored driving foot at the end of the sticking stage), and the angle it rotates through is θ1. Due to the presence of the preload, the mover turntable (11) also rotates counterclockwise with the driving foot (9) under the action of static friction, and the angle of rotation is the same as that of the outer ring of the stator θ1. Point b on the mover rotates to point b' (point b' is the position point on the mover at the end of the sticking stage), and the angle of rotation is recorded as θ2, θ1=θ2.

[0050] Sliding phase: such as Figure 14 As shown in (c), during the time interval t1 to t2, the sawtooth wave voltage V1 is in the falling edge stage. At this time, the piezoelectric plates (151) and (171) on the stator deform rapidly under the excitation of the sawtooth wave, and the oscillator beam quickly returns to its original shape. This causes the stator I (15) and stator II (17) to rotate clockwise by an angle θ1, the stator returns to its original shape, and point a' on the drive foot (9) returns to its original position a. During this period, the four piezoelectric plates (111) on the mover are input with a high-frequency sinusoidal voltage V2, and the mover will undergo ultrasonic vibration, thereby reducing the dynamic friction between the mover and the drive foot. Thus, under the action of inertia and the friction reduction effect of ultrasonic vibration, the mover turntable (11) will basically not produce a backward displacement. During this stage, point b' remains stationary.

[0051] In summary, by repeating these three stages, the piezoelectric actuator can achieve continuous rotary motion. The rotation angles of the stator and mover are as follows: Figure 14 As shown in (d), the stator angle first slowly increases to θ1, then decreases back to the initial position. Meanwhile, the mover rotates by an angle close to θ2 with each step. Figure 14 (d) The solid line shows the displacement of the mover; compared with the inertial stick-slip method that does not use the ultrasonic friction reduction principle to suppress backlash ( Figure 14(d) As shown by the dashed line of the mover displacement), the rotation angle of the present invention will be closer to the linear upward state, and finally the mover can drive the output shaft (1) to output continuous rotational motion.

[0052] This invention employs a unique driving method. The designed rotary stick-slip piezoelectric actuator can use either sinusoidal or sawtooth wave voltage as its excitation source, enriching the actuator's excitation forms. Simultaneously, during the mover's retraction phase, applying a high-frequency sinusoidal wave to the mover causes ultrasonic vibration, thereby reducing the friction between the stator and mover and thus shortening the retraction distance. Furthermore, the actuator designed in this invention uses a top nut for pre-tightening, effectively solving the problems of adjustable pre-tightening force and large structural volume, ensuring the overall structural compactness. Moreover, the wiring method designed on the mover effectively solves the winding problem.

[0053] All matters not covered in this invention are common knowledge.

[0054] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A rotary stick-slip piezoelectric actuator with a vibration-friction modulation mechanism, characterized in that: The driver includes a mover assembly, drive feet, a housing, a mover turntable, a bottom shaft, a nut, and a stator assembly. The bottom shaft is coaxially disposed in the lower region of the housing, and its bottom is fixedly connected to the bottom of the housing. The stator assembly is coaxially connected to the middle region of the bottom shaft. The nut is threadedly connected to the upper end of the bottom shaft and coaxially fitted with the stator assembly. The drive feet are evenly distributed around the circumference of the upper end face of the stator assembly. The mover assembly is coaxially disposed in the upper region of the housing, with its upper end coaxially passing through the top of the housing and its lower end corresponding to the top of the drive feet. The outer casing includes a pre-tightening outer casing, an intermediate outer casing, and a bottom outer casing. The pre-tightening outer casing is a hollow cylindrical structure with a threaded hole at the center of its upper end face and an annular flange integrally formed on the outer circumference of its lower end. The intermediate outer casing is a cylindrical structure, and the bottom of the pre-tightening outer casing is coaxially fixed to the upper end of the intermediate outer casing via the flange. The bottom outer casing is a disc structure, coaxially fixed to the bottom end of the intermediate outer casing, and has a central through hole in the center for the bottom shaft to pass through. The mover assembly includes an output shaft, a tightening preload member, a conductor shaft, a spring, an insulating shaft, bearing I, a mover connecting shaft, a preload sleeve, a mover turntable, and bearing II. The mover turntable is coaxially disposed above the stator assembly and has a central through hole, with the top of the drive feet respectively contacting the lower end face of the mover turntable. The tightening preload member is coaxially threaded to the top of the housing. The lower part of the output shaft coaxially passes through the tightening preload member and then coaxially transitions with the upper end of the conductor shaft disposed inside the preload housing. The insulating shaft has a central through hole, and the middle part of the conductor shaft is connected to the insulating shaft. The upper regions of the central through holes are coaxially transition-fitted; the moving part connecting shaft has a central through hole, and the lower region of the insulating shaft transitions-fits with the upper region of the central through hole of the moving part connecting shaft; the lower region of the moving part connecting shaft transitions-fits with the central through hole of the moving part turntable; the upper inner side of the preload sleeve is coaxially connected to the upper part of the conductor shaft through bearing I, and the lower inner side is coaxially connected to the upper part of the moving part connecting shaft through bearing II; the spring is coaxially disposed on the outside of the junction of the output shaft and the conductor shaft, and its upper end is connected to the lower end face of the tightening preload component, and its lower end is connected to the upper end face of the preload sleeve; The stator assembly includes stator I and stator II; stator II and stator I are coaxially connected from bottom to top in the middle region of the bottom shaft and are fixedly connected to each other at their centers; the upper end face of stator I has spherical grooves evenly distributed around its circumferential edge for mounting drive feet. Both stator I and stator II are composed of an inner ring, an outer ring, and a vibrating beam; the inner ring is coaxially arranged at the center of the outer ring; the vibrating beams are radially connected between the inner ring and the outer ring, and the vibrating beams on stator I and stator II are uniformly staggered vertically; piezoelectric sheets are attached to both sides of the same vibrating beam. The moving disk consists of an inner ring, an outer ring, and four crossbeams; the inner ring is coaxially positioned at the center of the outer ring; the crossbeams are radially connected between the inner and outer rings and are evenly distributed around the circumference; each crossbeam has a piezoelectric sheet attached to its upper surface.

2. The rotary stick-slip piezoelectric actuator with vibration-friction modulation mechanism according to claim 1, characterized in that: The wiring of the mover assembly is as follows: the positive terminal of the power supply is connected to the outer ring of bearing I through a wire, and the voltage is transmitted to the conductor shaft through the conductivity of bearing I. The wire is connected to the lower part of the conductor shaft and exits from the middle of the insulating shaft and the mover connecting shaft, and is connected to the piezoelectric element. The negative terminal of the power supply is connected to the outer ring of bearing II through a wire, and the voltage of the mover disk is transmitted to bearing II through conductivity, and then transmitted out through bearing II, thus forming a closed loop.

3. A rotary stick-slip piezoelectric actuator with vibration-friction modulation mechanism according to claim 1, characterized in that: The lower end face of the inner ring of stator I has protrusions on both sides; the upper end face of the inner ring of stator II has grooves corresponding to the protrusions on both sides; stator I and stator II are connected together by a gap fit between the protrusions and the grooves.

4. A rotary stick-slip piezoelectric actuator with vibration-friction modulation mechanism according to claim 3, characterized in that: The stator assembly is wired with the positive terminal connected to both sides of the vibrator beam and the negative terminal connected to the outer ring.

5. A rotary stick-slip piezoelectric actuator with vibration-friction modulation mechanism according to claim 1, characterized in that: Both the output shaft and the insulating shaft are made of nylon; the conductor shaft is made of brass.

6. A rotary stick-slip piezoelectric actuator with vibration-friction modulation mechanism according to claim 1, characterized in that: A bearing retaining ring is installed between the bottom end of the moving part connecting shaft and the bottom surface of the moving part turntable.

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