Multi-mode piezoelectric actuator based on double-stator structure and working method thereof

Abstract

The multi-mode piezoelectric actuator based on the double-stator structure comprises a base, a guide rail and a piezoelectric driving module are arranged on the base, and the guide rail is connected with a sliding block in a sliding mode; the piezoelectric driving module comprises a stator frame, and one end of the stator frame is integrally provided with a displacement transmission structure. The stator frame at the opposite end of the displacement transmission structure is in threaded connection with a piezoelectric stack pre-pressing bolt, the piezoelectric stack pre-pressing bolt extends into the stator frame and is in compression joint with the piezoelectric stack, and the piezoelectric stack is in compression joint with the inner surface of the displacement transmission side wall; the polarization direction of the piezoelectric stack is parallel to the sliding block; the piezoelectric driving modules are arranged in pairs, a triangular elastic beam is integrally connected between the outer surfaces of the two displacement transmission side walls, the triangular elastic beam is fixedly connected with a driving foot, and the driving foot faces the sliding block and is used for driving the sliding block to do linear motion along the guide rail. The problems of contradiction between high precision and large stroke, a rollback phenomenon and the like of a piezoelectric actuator are solved, macro / micro continuous driving and nano-scale positioning can be achieved, and the micro / micro continuous driving and nano-scale positioning can be achieved only through one set of actuator.

Description

Technical Field

[0001] The present invention relates to the field of piezoelectric driving, in particular to a multi-mode piezoelectric actuator and a working method thereof. Background Art

[0002] The piezoelectric actuator device is a driving device based on the inverse piezoelectric effect. Due to its advantages such as high precision, fast response, no electromagnetic interference, and self-locking when power is off, it is widely used in systems with nano-level positioning capabilities such as semiconductor manufacturing technology, biotechnology, optical instruments, and ultra-precision machining motion platforms.

[0003] Existing piezoelectric actuators still have problems such as the contradiction between high precision and long stroke, and the phenomenon of backlash, which leads to a low application rate in the high-end equipment market. Therefore, further developing piezoelectric actuators with indicators such as nanometer-level high-precision positioning-micrometer-level step displacement-centimeter-level large stroke continuous movement, cross-scale drive, non-backlash motion, and simple structure and control system has important theoretical significance and engineering application value.

[0004] In addition, the prior art still has the following deficiencies: The polarization direction of the piezoelectric stack is either perpendicular to the driven slider (mover) or arranged at a certain angle to the slider (mover). As a result, the actuator structure formed by the piezoelectric stack and the slider (mover) as a whole can only be relatively loose, which brings difficulties to the structural design of the piezoelectric stack in application scenarios with limited space in micro-mechanical systems, precision instruments, and semiconductor manufacturing.

[0005] The piezoelectric actuator has a single-stator structure, and its structural rigidity and stability need to be improved. Summary of the invention

[0006] The purpose of the present invention is to provide a multi-mode piezoelectric actuator based on a dual-stator structure, which provides a structural basis for achieving large stroke, high precision and non-retraction movement by matching the dual-stator structure with a displacement transfer structure, and provides a basis for the structure in which the stator is parallel to the slider.

[0007] To achieve the above-mentioned purpose, the multi-mode piezoelectric actuator based on the dual-stator structure of the present invention comprises a base, a guide rail and a piezoelectric driving module are arranged on the base, a slider is slidably connected to the guide rail, and the guide rail is used to constrain the slider to move linearly along the guide rail direction; The piezoelectric drive module includes a stator frame, one end of the stator frame is integrally provided with a displacement transmission structure, the displacement transmission structure includes a displacement transmission side wall integrally provided with the stator frame, and both ends of the displacement transmission side wall are provided with deformation holes which are transparent from top to bottom; The stator frame at the opposite end of the displacement transmission structure is threadedly connected with a piezoelectric stack pre-stressing bolt, the piezoelectric stack pre-stressing bolt extends into the stator frame and is pressed against the piezoelectric stack, and the other end of the piezoelectric stack is pressed against the inner surface of the displacement transmission side wall; the polarization direction of the piezoelectric stack is parallel to the slider; The piezoelectric drive modules are arranged in pairs, and the displacement transfer structures of the two piezoelectric drive modules arranged in pairs are arranged opposite to each other, and a triangular elastic beam is integrally connected between the outer surfaces of the two oppositely arranged displacement transfer side walls, and the ends of the triangular elastic beam are integrally connected to the outer surfaces of the displacement transfer side walls to form a flexible hinge structure; the tip of the triangular elastic beam is fixedly connected to a driving foot, which faces the slider and is used to drive the slider to move linearly along the guide rail.

[0008] A friction plate made of ceramic is fixedly connected to the side of the slider facing the driving foot; the friction plate serves as the friction contact surface between the slider and the driving foot, and is used to reduce the wear caused by friction during the working process; The horizontal cross section of the driving foot is semicircular, and the top of the semicircle faces the friction plate.

[0009] The driving foot, the triangular elastic beam and two piezoelectric driving modules connected to the triangular elastic beam form a set of piezoelectric driving mechanism; The piezoelectric drive mechanism is mounted on the base through an adjustable mounting structure; the adjustable mounting structure is used to match different working modes by adjusting the preload force between the drive foot and the friction plate; The adjustable mounting structure includes a pre-pressed fixing block and a connecting seat; The pre-stress fixing block is fixedly connected to the base through a vertical bolt, with the direction vertically pointing to the slider as the forward direction, and a horizontally arranged pre-stress adjusting bolt is passed through the pre-stress fixing block from front to back, the pre-stress adjusting bolt cooperates with the pre-stress fixing block bolt and extends forward from the pre-stress fixing block, and the front end of the pre-stress adjusting bolt is pressed and matched with the rear end of the connecting seat; The connecting seat is provided with an elongated hole extending in the front-to-back direction, and a connecting bolt is provided in the elongated hole. The connecting bolt is fixedly connected to the base downward, and the elongated hole and the connecting bolt are used to adjust the position of the connecting seat in the front-to-back direction; the stator frames of the two piezoelectric drive modules are fixedly connected to the connecting seat by installing bolts, and the front end of each stator frame extends forward of the connecting seat.

[0010] The piezoelectric drive mechanism and the adjustable mounting structure are provided with two sets at intervals on the base. Both sets of piezoelectric drive modules are used to drive the slider to move linearly along the guide rail through their drive feet. Different working modes are matched by applying different voltage signals to the two sets of piezoelectric drive modules.

[0011] The present invention also discloses a working method of the multi-mode piezoelectric actuator based on the dual-stator structure, including a macro / micro continuous driving mode; the macro / micro continuous driving mode is performed according to the following steps: Step 1), the driving foot applies a pre-pressure Fn1 matching the macro / micro continuous driving mode to the friction plate through the pre-pressure adjusting bolt; Step 2), the driving voltages applied to the four piezoelectric driving modules of the two sets of piezoelectric driving mechanisms are V1, V2, V3, and V4 respectively; V1 to V4 are sinusoidal voltage signals that are 90° apart in phase; 2.1) The four piezoelectric drive modules of the two piezoelectric drive mechanisms generate periodic telescopic motion with a phase difference, pushing the triangular elastic beam to deform, so that the two drive feet of the two piezoelectric drive mechanisms perform alternating elliptical motion; the drive feet of the first set of piezoelectric drive mechanisms enter the upper half of the elliptical trajectory and contact the friction plate, thereby pushing the friction plate and the slider forward by a distance of x1 through friction; at the same time, the drive feet of the second set of piezoelectric drive mechanisms enter the lower half of the elliptical trajectory and separate from the friction plate, so no work is done on the friction plate and the slider; 2.2) After the driving feet of the two piezoelectric driving mechanisms simultaneously move to the equilibrium positions of their respective elliptical trajectories, the driving feet of the second piezoelectric driving mechanism enter the upper half of the elliptical trajectory and contact the friction plate, thereby pushing the friction plate and the slider forward by a distance of x2 through friction force; at the same time, the driving feet of the first piezoelectric driving mechanism enter the lower half of the elliptical trajectory and separate from the friction plate, thus not doing work on the friction plate and the slider; Driven by driving voltages V1, V2, V3, and V4 respectively, 2.1) and 2.2) are performed cyclically, pushing the friction plate and the slider to move continuously in one direction; Changing the frequency of the sinusoidal voltage signal can match the speed of the slider movement, allowing the slider to achieve centimeter-level continuous motion or micron-level continuous motion; when the slider needs to move in the opposite direction, V1 to V4 are sinusoidal voltage signals with a phase difference of -90° respectively, to achieve reverse continuous movement of the slider.

[0012] It also includes a nanometer positioning mode, which is performed as follows: Step 1), using two sets of pre-pressure adjustment bolts of the piezoelectric drive mechanism to make the two drive feet apply a pre-pressure Fn2 matching the nano-level positioning mode to the friction plate; Step 2), the two piezoelectric driving modules of the first set of piezoelectric driving mechanisms are, from left to right, a first piezoelectric driving module and a second piezoelectric driving module, and the two piezoelectric driving modules of the second set of piezoelectric driving mechanisms are, from left to right, a third piezoelectric driving module and a fourth piezoelectric driving module; Apply driving voltage signals V1 and V3 to the first piezoelectric driving module and the third piezoelectric driving module, the piezoelectric stacks in the first piezoelectric driving module and the third piezoelectric driving module slowly extend, and the piezoelectric stacks in the second piezoelectric driving module and the fourth piezoelectric driving module maintain their original lengths. At this time, the two driving feet simultaneously make oblique movements, thereby pushing the friction plate and the slider to generate a nanometer-level displacement x1 in one direction, and the position of the slider remains unchanged after the movement, thereby achieving nanometer-level precise positioning of the slider; When reverse nanometer-level precise positioning is required, driving voltage signals V2 and V4 are applied to the second piezoelectric driving module and the fourth piezoelectric driving module, and the first piezoelectric driving module and the third piezoelectric driving module maintain their original lengths, thereby achieving reverse nanometer-level precise positioning of the slider.

[0013] The present invention has the following advantages: The piezoelectric drive module in the present invention adopts a dual-stator structure, matched with a corresponding slider and guide rail structure, and has the following technical effects: ① It reduces the stress concentration of a single stator, significantly improves the structural rigidity and stability of the overall actuator, and is more suitable for applications that require high stability and high load capacity (such as robot joints, high-precision positioning platforms, etc.). ② It provides a structural basis for overcoming the contradiction between high precision and long stroke, the existence of backlash phenomenon, and other problems existing in the single-stator piezoelectric actuator in the prior art, and can achieve large stroke, high precision, and no backlash phenomenon.

[0014] The polarization direction of the piezoelectric stack in the present invention is parallel to the slider, so that the overall structure of the actuator can be more compact than the prior art, and the piezoelectric actuator can be more conveniently used in micro-mechanical systems, precision instruments, robot joints and other occasions with limited space.

[0015] The deformation hole can enhance the deformation capacity of the displacement transmission side wall under the action of the piezoelectric stack, and transmit the displacement to the triangular elastic beam through deformation when the piezoelectric stack is extended or shortened.

[0016] The structure of the driving foot is convenient for being fixedly connected with the triangular elastic beam through its plane part, and is also convenient for driving the friction plate and the slider to move through its arc top (tip) part.

[0017] The adjustable mounting structure allows the front and rear positions of the front end of the preload adjustment bolt to be adjusted by rotating the preload adjustment bolt, thereby adjusting the preload force of the drive foot on the friction plate and the slider, so that the preload force is maintained at an appropriate level to adapt to different working conditions (such as different workloads); in order to improve positioning accuracy, the preload force can be appropriately increased; in order to reduce wear, the preload force can be appropriately lowered. The macro / micro continuous drive mode can be matched with an appropriate preload force, and the positioning accuracy can be improved with a relatively higher preload force, thereby matching the nano-level positioning working mode. In short, the adjustable mounting structure facilitates the adjustment of the preload force between the drive foot and the friction plate, providing a structural basis for matching different working modes.

[0018] Two sets of piezoelectric drive mechanisms are not a technical effect of 1+1=2. The piezoelectric drive mechanism and the adjustable mounting structure are arranged in two sets on the base at intervals, which further improves the load capacity of the present invention (this is the technical effect of 1+1=2), and more importantly, provides a structural basis for continuous drive, so that the present invention can drive the slider to make a large stroke continuous linear motion in a macro / micro continuous drive mode (this is a technical effect that a single piezoelectric drive mechanism does not have). By applying different voltage signals (groups) to the four piezoelectric drive modules of the two sets of piezoelectric drive mechanisms, the present invention can be operated in a macro / micro continuous drive mode or in a nano-level positioning mode (this is also a technical effect that a single piezoelectric drive mechanism does not have).

[0019] The working method of the present invention is simple and convenient to control. It only needs to adjust the pre-pressure adjustment bolt and control the driving voltage signals V1, V2, V3, and V4 to achieve the macro / micro continuous driving mode or nano-level positioning mode, which makes the present invention highly versatile and does not require matching different piezoelectric actuators for different magnitudes of displacement or positioning requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional structural schematic diagram of the present invention.

[0021] Figure 2 yes Figure 1 Enlarged view of point A in the middle.

[0022] Figure 3 It is a driving voltage signal diagram matching the macro / micro continuous driving mode.

[0023] Figure 4 is a graph of the driving voltage signal that matches the nanoscale positioning pattern.

[0024] Figure 5 This is the working principle diagram of the macro / micro continuous drive mode.

[0025] Figure 6 This is a diagram of the working principle of the nano-positioning mode. DETAILED DESCRIPTION

[0026] like Figures 1 to 6 As shown, the multi-mode piezoelectric actuator based on the dual-stator structure of the present invention comprises a base 1, on which a guide rail 2 and a piezoelectric driving module are arranged, and a slider 3 is slidably connected to the guide rail 2, and the guide rail 2 is used to constrain the slider 3 to move linearly along the direction of the guide rail 2; The piezoelectric drive module includes a stator frame 4 (the stator frame 4 has a certain flexibility), and a displacement transfer structure is integrally provided at one end of the stator frame 4. The displacement transfer structure includes a displacement transfer side wall 5 integrally provided with the stator frame 4, and deformation holes 6 that are transparent from top to bottom are provided at both ends of the displacement transfer side wall 5; the deformation holes 6 can enhance the deformation ability of the displacement transfer side wall 5 under the action of the piezoelectric stack, and transfer displacement to the triangular elastic beam through deformation when the piezoelectric stack is extended or shortened.

[0027] The stator frame 4 at the opposite end of the displacement transmission structure is threadedly connected with a piezoelectric stack pre-stress bolt 7, which extends into the stator frame 4 and is crimped with the piezoelectric stack 8, and the other end of the piezoelectric stack 8 is crimped with the inner surface of the displacement transmission side wall 5; the polarization direction of the piezoelectric stack 8 is parallel to the slider 3; the piezoelectric stack pre-stress bolt 7 is used to adjust the pre-stress between the piezoelectric stack 8 and the displacement transmission side wall 5.

[0028] The piezoelectric drive modules are arranged in pairs, and the displacement transmission structures of the two piezoelectric drive modules arranged in pairs are arranged oppositely, and a triangular elastic beam 9 is integrally connected between the outer surfaces of the two displacement transmission side walls 5 arranged oppositely, and the end of the triangular elastic beam 9 is integrally connected to the outer surface of the displacement transmission side wall 5 to form a flexible hinge structure; the tip of the triangular elastic beam 9 is a plane structure and is fixedly connected with a driving foot 10, which faces the slider 3 and is used to drive the slider 3 to move linearly along the guide rail 2. Specifically, the driving foot 10 is preferably attached to the top plane of the triangular elastic beam 9 by epoxy resin.

[0029] In the present invention, the stator frame 4, the displacement transfer structure and the triangular elastic beam 9 are preferably an integrated structure (currently there is no specific solution that can achieve the same technical effect of an integrated setting by connecting them after being separately set), and are usually made of materials such as phosphor bronze, spring steel or aluminum alloy with good elasticity to ensure that the displacement transfer structure and the triangular elastic beam 9 can undergo normal deformation and transmit movement.

[0030] Selecting triangular elastic beams 9 with different bottom angles can affect the longitudinal stiffness of the driving foot 10 , and the specific angle is determined by the designer through experiments according to the design objectives.

[0031] The piezoelectric drive module in the present invention adopts a dual-stator structure, matching the corresponding slider 3 and guide rail 2 structure, and has the following technical effects: ① It reduces the stress concentration of a single stator, significantly improves the structural rigidity and stability of the overall actuator, and is more suitable for applications that require high stability and high load capacity (such as robot joints, high-precision positioning platforms, etc.). ② It provides a structural basis for overcoming the contradiction between high precision and long stroke, the existence of backlash phenomenon, and other problems existing in the single-stator piezoelectric actuator in the prior art, and can achieve large stroke, high precision, and no backlash phenomenon.

[0032] The polarization direction is the driving direction of the piezoelectric stack 8. In the prior art, the polarization direction of the piezoelectric stack 8 is either perpendicular to the driven slider 3 (mover) or arranged at a certain angle to the slider 3 (mover). In this way, the actuator structure formed by the piezoelectric stack 8 and the slider 3 (mover) as a whole can only be relatively loose, which brings difficulties to the structural design of the piezoelectric stack 8 in the application scenarios with limited space in micro-mechanical systems, precision instruments, and semiconductor manufacturing. In the present invention, the polarization direction of the piezoelectric stack 8 is parallel to the slider 3, so that the overall structure of the actuator can be more compact than the prior art, so that the piezoelectric actuator can be more conveniently used in micro-mechanical systems, precision instruments, robot joints and other occasions with limited space.

[0033] A friction plate 11 made of ceramic is fixedly connected to the side of the slider 3 facing the driving foot 10; the friction plate 11 serves as the friction contact surface between the slider 3 and the driving foot 10, and is used to reduce the wear caused by friction during operation; the horizontal cross-section of the driving foot 10 is semicircular, and the top of the semicircle faces the friction plate 11.

[0034] The structure of the driving foot 10 is convenient for being fixedly connected to the triangular elastic beam 9 through its plane portion, and is also convenient for driving the friction plate 11 and the slider 3 to move through its arc top (tip) portion.

[0035] The material of the driving foot 104 is preferably a ceramic material such as alumina or zirconia, which can effectively increase the friction driving force and improve the wear resistance of the contact surface; The driving foot 10, the triangular elastic beam 9 and two piezoelectric driving modules connected to the triangular elastic beam 9 form a set of piezoelectric driving mechanism; The piezoelectric drive mechanism is mounted on the base 1 via an adjustable mounting structure; the adjustable mounting structure is used to match different working modes by adjusting the preload force between the drive foot 10 and the friction plate 11; The adjustable mounting structure includes a pre-pressed fixing block 12 and a connecting seat 13; The pre-stress fixing block 12 is fixedly connected to the base 1 by a vertical bolt 14, with the direction vertically pointing to the slider 3 as the forward direction. A horizontally arranged pre-stress adjusting bolt 15 is passed through the pre-stress fixing block 12 from front to back. The pre-stress adjusting bolt 15 is bolted together with the pre-stress fixing block 12 and extends forward from the pre-stress fixing block 12. The front end of the pre-stress adjusting bolt 15 is pressed together with the rear end of the connecting seat 13. An operating hole 18 that is transparent from top to bottom is provided on the base 1 at the pre-stress adjusting bolt 15, and the operating hole 18 is used to facilitate the adjustment of the pre-stress adjusting bolt 15.

[0036] The connection seat 13 is provided with a long hole 16 extending in the front-to-back direction, and a connecting bolt 17 is provided in the long hole 16. The connecting bolt 17 is fixedly connected to the base 1 downwardly. The long hole 16 and the connecting bolt 17 are used to adjust the position of the connection seat 13 in the front-to-back direction; the stator frames 4 of the two piezoelectric drive modules are fixedly connected to the connection seat 13 by mounting bolts, and the front end of each stator frame 4 extends forward from the connection seat 13. The connection seat 13 is slidably pressed on the upper surface of the base 1.

[0037] The adjustable mounting structure allows the front and rear positions of the front end of the preload adjusting bolt 15 to be adjusted by rotating the preload adjusting bolt 15, thereby adjusting the preload force of the driving foot 10 on the friction plate 11 and the slider 3, so that the preload force is maintained at a suitable level to adapt to different working conditions (such as different workloads); in order to improve positioning accuracy, the preload force can be appropriately increased; in order to reduce wear, the preload force can be appropriately lowered. The macro / micro continuous drive mode can be matched by a suitable preload force, and the positioning accuracy can be improved by a relatively higher preload force, thereby matching the nano-level positioning working mode. In short, the adjustable mounting structure facilitates the adjustment of the preload force between the driving foot 10 and the friction plate 11, providing a structural basis for matching different working modes.

[0038] The piezoelectric drive mechanism and the adjustable mounting structure are provided with two sets at intervals on the base 1. Both sets of piezoelectric drive modules are used to drive the slider 3 to move linearly along the guide rail 2 through its drive foot 10. Different working modes are matched by applying different voltage signals to the two sets of piezoelectric drive modules.

[0039] Two sets of piezoelectric drive mechanisms are not a technical effect of 1+1=2. The piezoelectric drive mechanism and the adjustable mounting structure are arranged in two sets on the base 1 at intervals, which further improves the load capacity of the present invention (this is the technical effect of 1+1=2), and more importantly, provides a structural basis for continuous drive, so that the present invention can drive the slider 3 to make a large stroke continuous linear motion in a macro / micro continuous drive mode (this is a technical effect that a single piezoelectric drive mechanism does not have). By applying different voltage signals (groups) to the four piezoelectric drive modules of the two sets of piezoelectric drive mechanisms, the present invention can be operated in a macro / micro continuous drive mode or in a nano-level positioning mode (this is also a technical effect that a single piezoelectric drive mechanism does not have).

[0040] The present invention also discloses a working method of the above-mentioned multi-mode piezoelectric actuator based on a dual-stator structure, including a macro / micro continuous driving mode and a nano-level positioning mode; the macro / micro continuous driving mode is performed according to the following steps: Step 1), through the pre-pressure adjustment bolt 15, the driving foot 10 applies a pre-pressure Fn1 matching the macro / micro continuous driving mode to the friction plate 11; the value of Fn1 is determined by the designer through experiments during the design stage, and is used as the factory parameter of the piezoelectric actuator of the present invention after manufacturing.

[0041] Step 2), the driving voltages applied to the four piezoelectric driving modules of the two sets of piezoelectric driving mechanisms are V1, V2, V3, and V4 respectively; V1 to V4 are sinusoidal voltage signals with phase differences of 90° (as shown in the attached figure); Figure 3 and Figure 5 shown); 2.1) The four piezoelectric drive modules of the two piezoelectric drive mechanisms generate periodic telescopic motion with a phase difference, pushing the triangular elastic beam 9 to deform, so that the two drive feet 10 of the two piezoelectric drive mechanisms perform alternating elliptical motion; the drive foot 10 of the first set of piezoelectric drive mechanisms (i.e., the drive foot 10 of the stator Ⅰ in the figure) enters the upper half of the elliptical trajectory and contacts the friction plate 11, thereby pushing the friction plate 11 and the slider 3 forward by a distance x1 through friction; at the same time, the drive foot 10 of the second set of piezoelectric drive mechanisms enters the lower half of the elliptical trajectory and separates from the friction plate 11, so that no work is done on the friction plate 11 and the slider 3; 2.2) After the driving feet 10 of the two sets of piezoelectric driving mechanisms simultaneously move to the equilibrium positions of their respective elliptical trajectories, the driving foot 10 of the second set of piezoelectric driving mechanisms (i.e., the driving foot 10 of stator II in the figure) moves into the upper half of the elliptical trajectory and contacts the friction plate 11, thereby pushing the friction plate 11 and the slider 3 forward by a distance x2 through the friction force; at the same time, the driving foot 10 of the first set of piezoelectric driving mechanisms moves into the lower half of the elliptical trajectory, separates from the friction plate 11, and thus does not do work on the friction plate 11 and the slider 3; Driven by driving voltages of V1, V2, V3, and V4 respectively, 2.1) and 2.2) are cyclically performed to push the friction plate 11 and the slider 3 to move continuously in one direction; when running N cycles, the slider 31 runs a total length of N*(x1+x2) without any back-off phenomenon.

[0042] Changing the frequency of the sinusoidal voltage signal can match the speed of the slider 3, so that the slider 3 can achieve continuous movement at the centimeter level (corresponding to the high-frequency sinusoidal voltage signal) or continuous movement at the micrometer level (corresponding to the low-frequency sinusoidal voltage signal); according to the target moving distance and target moving speed, sinusoidal voltage signals of different frequencies are matched through experiments.

[0043] When the slider 3 needs to move in the reverse direction, V1 to V4 are respectively sinusoidal voltage signals with a phase difference of -90°, so as to realize the reverse continuous movement of the slider 3.

[0044] Nanoscale positioning mode is performed as follows: Step 1), through the pre-pressure adjustment bolts 15 of the two sets of piezoelectric drive mechanisms, the two drive feet 10 apply a pre-pressure Fn2 matching the nano-level positioning mode to the friction plate 11; the value of Fn2 is determined by the designer through experiments during the design stage, and is used as the factory parameter of the piezoelectric actuator of the present invention after manufacturing.

[0045] Step 2), the two piezoelectric driving modules of the first set of piezoelectric driving mechanisms are, from left to right, a first piezoelectric driving module and a second piezoelectric driving module, and the two piezoelectric driving modules of the second set of piezoelectric driving mechanisms are, from left to right, a third piezoelectric driving module and a fourth piezoelectric driving module; Apply driving voltage signals V1 and V3 (such as Figure 4 and Figure 6 As shown in FIG. 1 , the piezoelectric stack 8 in the first piezoelectric driving module and the third piezoelectric driving module (i.e., the two left piezoelectric driving modules in the two sets of piezoelectric driving mechanisms) slowly extends, and the extension amount is referred to as L1 (nanometers); the piezoelectric stack 8 in the second piezoelectric driving module and the fourth piezoelectric driving module (i.e., the two right piezoelectric driving modules) maintains the original length (no driving voltage is applied), and at this time, the two driving feet 10 simultaneously make an oblique motion to push the friction plate 11 and the slider 3 to generate a nanometer-level displacement x1 in one direction, and the position of the slider 3 remains unchanged after the motion, thereby achieving nanometer-level precise positioning of the slider 3; When reverse nanometer-level precise positioning is required, driving voltage signals V2 and V4 are applied to the second piezoelectric driving module and the fourth piezoelectric driving module (i.e., the two right-side piezoelectric driving modules), and the first piezoelectric driving module and the third piezoelectric driving module (i.e., the two frost-side piezoelectric driving modules) maintain their original length (no driving voltage is applied), thereby achieving reverse nanometer-level precise positioning of the slider 3.

[0046] According to the characteristics of the piezoelectric stack 8, if the voltage increase is small enough, the elongation of the piezoelectric stack 8 can reach the picometer level, which means that the slider 3 can theoretically achieve a positioning accuracy of the picometer level. However, the thrust of the piezoelectric stack 8 will decrease as the input voltage decreases. If the thrust is too small, the triangular elastic beam 9 cannot be pushed to deform, resulting in the inability of the driving foot 10 to drive the slider 3 to move. According to experiments, the reliable positioning accuracy of the multi-mode piezoelectric actuator based on the dual-stator structure of the present invention is nanometer level.

[0047] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A multi-mode piezoelectric actuator based on a dual-stator structure comprises a base, a guide rail and a piezoelectric drive module are arranged on the base, and is characterized in that: The guide rail is slidably connected with a slider, and the guide rail is used to constrain the slider to move linearly along the guide rail direction; The piezoelectric drive module includes a stator frame, one end of the stator frame is integrally provided with a displacement transmission structure, the displacement transmission structure includes a displacement transmission side wall integrally provided with the stator frame, and both ends of the displacement transmission side wall are provided with deformation holes which are transparent from top to bottom; The stator frame at the opposite end of the displacement transmission structure is threadedly connected with a piezoelectric stack pre-stressing bolt, the piezoelectric stack pre-stressing bolt extends into the stator frame and is pressed against the piezoelectric stack, and the other end of the piezoelectric stack is pressed against the inner surface of the displacement transmission side wall; the polarization direction of the piezoelectric stack is parallel to the slider; The piezoelectric drive modules are arranged in pairs, and the displacement transfer structures of the two piezoelectric drive modules arranged in pairs are arranged opposite to each other, and a triangular elastic beam is integrally connected between the outer surfaces of the two oppositely arranged displacement transfer side walls, and the ends of the triangular elastic beam are integrally connected to the outer surfaces of the displacement transfer side walls to form a flexible hinge structure; the tip of the triangular elastic beam is fixedly connected to a driving foot, which faces the slider and is used to drive the slider to move linearly along the guide rail.

2. The multi-mode piezoelectric actuator based on a dual-stator structure according to claim 1, characterized in that: A friction plate made of ceramic is fixedly connected to the side of the slider facing the driving foot; the friction plate serves as the friction contact surface between the slider and the driving foot, and is used to reduce the wear caused by friction during the working process; The horizontal cross section of the driving foot is semicircular, and the top of the semicircle faces the friction plate.

3. The multi-mode piezoelectric actuator based on a dual-stator structure according to claim 1 or 2, characterized in that: The driving foot, the triangular elastic beam and two piezoelectric driving modules connected to the triangular elastic beam form a set of piezoelectric driving mechanism; The piezoelectric drive mechanism is mounted on the base through an adjustable mounting structure; the adjustable mounting structure is used to match different working modes by adjusting the preload force between the drive foot and the friction plate; The adjustable mounting structure includes a pre-pressed fixing block and a connecting seat; The pre-stress fixing block is fixedly connected to the base through a vertical bolt, with the direction vertically pointing to the slider as the forward direction, and a horizontally arranged pre-stress adjusting bolt is passed through the pre-stress fixing block from front to back, the pre-stress adjusting bolt cooperates with the pre-stress fixing block bolt and extends forward from the pre-stress fixing block, and the front end of the pre-stress adjusting bolt is pressed and matched with the rear end of the connecting seat; The connecting seat is provided with an elongated hole extending in the front-to-back direction, and a connecting bolt is provided in the elongated hole. The connecting bolt is fixedly connected to the base downward, and the elongated hole and the connecting bolt are used to adjust the position of the connecting seat in the front-to-back direction; the stator frames of the two piezoelectric drive modules are fixedly connected to the connecting seat by installing bolts, and the front end of each stator frame extends forward of the connecting seat.

4. The multi-mode piezoelectric actuator based on a dual-stator structure according to claim 3, characterized in that: The piezoelectric drive mechanism and the adjustable mounting structure are provided with two sets at intervals on the base. Both sets of piezoelectric drive modules are used to drive the slider to move linearly along the guide rail through their drive feet. Different working modes are matched by applying different voltage signals to the two sets of piezoelectric drive modules.

5. The working method of the multi-mode piezoelectric actuator based on the dual-stator structure according to claim 4 is characterized in that Including macro / micro continuous driving mode; the macro / micro continuous driving mode is performed according to the following steps: Step 1), the driving foot applies a pre-pressure Fn1 matching the macro / micro continuous driving mode to the friction plate through the pre-pressure adjusting bolt; Step 2), the driving voltages applied to the four piezoelectric driving modules of the two sets of piezoelectric driving mechanisms are V1, V2, V3, and V4 respectively; V1 to V4 are sinusoidal voltage signals that are 90° apart in phase; 2.1) The four piezoelectric drive modules of the two piezoelectric drive mechanisms generate periodic telescopic motion with a phase difference, pushing the triangular elastic beam to deform, so that the two drive feet of the two piezoelectric drive mechanisms perform alternating elliptical motion; the drive feet of the first set of piezoelectric drive mechanisms enter the upper half of the elliptical trajectory and contact the friction plate, thereby pushing the friction plate and the slider forward by a distance of x1 through friction; at the same time, the drive feet of the second set of piezoelectric drive mechanisms enter the lower half of the elliptical trajectory and separate from the friction plate, so no work is done on the friction plate and the slider; 2.2) After the driving feet of the two piezoelectric driving mechanisms simultaneously move to the equilibrium positions of their respective elliptical trajectories, the driving feet of the second piezoelectric driving mechanism enter the upper half of the elliptical trajectory and contact the friction plate, thereby pushing the friction plate and the slider forward by a distance of x2 through friction force; at the same time, the driving feet of the first piezoelectric driving mechanism enter the lower half of the elliptical trajectory and separate from the friction plate, thus not doing work on the friction plate and the slider; Driven by driving voltages V1, V2, V3, and V4 respectively, 2.1) and 2.2) are performed cyclically, pushing the friction plate and the slider to move continuously in one direction; Changing the frequency of the sinusoidal voltage signal can match the speed of the slider movement, allowing the slider to achieve centimeter-level continuous motion or micron-level continuous motion; when the slider needs to move in the opposite direction, V1 to V4 are sinusoidal voltage signals with a phase difference of -90° respectively, to achieve reverse continuous movement of the slider.

6. The working method according to claim 5, characterized in that It also includes a nanometer positioning mode, which is performed as follows: Step 1), using two sets of pre-pressure adjustment bolts of the piezoelectric drive mechanism to make the two drive feet apply a pre-pressure Fn2 matching the nano-level positioning mode to the friction plate; Step 2), the two piezoelectric driving modules of the first set of piezoelectric driving mechanisms are, from left to right, a first piezoelectric driving module and a second piezoelectric driving module, and the two piezoelectric driving modules of the second set of piezoelectric driving mechanisms are, from left to right, a third piezoelectric driving module and a fourth piezoelectric driving module; Apply driving voltage signals V1 and V3 to the first piezoelectric driving module and the third piezoelectric driving module, the piezoelectric stacks in the first piezoelectric driving module and the third piezoelectric driving module slowly extend, and the piezoelectric stacks in the second piezoelectric driving module and the fourth piezoelectric driving module maintain their original lengths. At this time, the two driving feet simultaneously make oblique movements, thereby pushing the friction plate and the slider to generate a nanometer-level displacement x1 in one direction, and the position of the slider remains unchanged after the movement, thereby achieving nanometer-level precise positioning of the slider; When reverse nanometer-level precise positioning is required, driving voltage signals V2 and V4 are applied to the second piezoelectric driving module and the fourth piezoelectric driving module, and the first piezoelectric driving module and the third piezoelectric driving module maintain their original lengths, thereby achieving reverse nanometer-level precise positioning of the slider.

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