阅读说明：本技术 一种实现双向驱动的粘滑式压电驱动器及控制方法 (Stick-slip piezoelectric driver for realizing bidirectional driving and control method ) 是由 凌杰 肖晓晖 邱灿程 冯朝 明敏 叶婷婷 于 2020-06-16 设计创作，主要内容包括：本发明涉及一种实现双向驱动的粘滑式压电驱动器及控制方法,所述驱动器由基座、柔顺驱动机构、滑块、两块堆叠式压电陶瓷等组成。锯齿波电压信号经过功率放大器放大后施加在压电陶瓷上,通过调节电压信号的幅值和频率能够实现驱动滑块在正负两个方向上以目标速度运动至特定位置。本发明的双向粘滑式压电驱动器采用柔顺驱动机构,使得结构简单,能够实现精密快速运动,采用的特殊结构可以大大增加负载能力和驱动速度。(The invention relates to a stick-slip piezoelectric driver for realizing bidirectional driving and a control method thereof. The sawtooth wave voltage signal is amplified by the power amplifier and then applied to the piezoelectric ceramic, and the slider can be driven to move to a specific position at a target speed in positive and negative directions by adjusting the amplitude and the frequency of the voltage signal. The bidirectional stick-slip piezoelectric driver adopts a flexible driving mechanism, so that the bidirectional stick-slip piezoelectric driver is simple in structure, can realize precise and rapid movement, and can greatly increase the loading capacity and the driving speed by adopting a special structure.)

1. A stick-slip piezoelectric driver for realizing bidirectional driving is characterized by comprising a guide rail and slider module, a flexible driving mechanism (3), positive driving piezoelectric ceramics (4), negative driving piezoelectric ceramics (5), an XY fine tuning platform (7), a base (8) and an adjusting screw (9), wherein the guide rail and slider module is composed of a guide rail (1) and a slider (2);

the positive-direction driving piezoelectric ceramic (4) and the negative-direction driving piezoelectric ceramic (5) are fixed on the compliant driving mechanism through adjusting screws (9), the positive-direction driving piezoelectric ceramic (4) and the negative-direction driving piezoelectric ceramic (5) can be fixed in a piezoelectric ceramic fixing groove (19) of the compliant driving mechanism (3) by rotating the adjusting screws (9), and the pretightening force between the driving piezoelectric ceramic and the compliant driving mechanism (3) can be adjusted; the contact condition between the compliant driving mechanism and the slide block is adjusted by adjusting the XY micro-motion platform (7).

2. The stick-slip piezoelectric actuator for achieving bidirectional driving according to claim 1, wherein the rail-slider module comprises: the roller-type roller bearing comprises a guide rail (1), a slide block (2) capable of sliding on the guide rail (1), and a roller holder (20) arranged on the guide rail (1).

3. The stick-slip piezoelectric actuator achieving the bidirectional driving according to claim 1, wherein the compliant driving mechanism comprises a base (15), a fixed hole group (16), a pseudo rigid rod (14), a straight beam type flexible hinge (17) and a right circular type flexible hinge (18), wherein the straight beam type flexible hinge (17) comprises a straight beam type flexible hinge one (17a), a straight beam type flexible hinge two (17 b); the right circular flexible hinge (18) comprises a first right circular flexible hinge (18a), a second right circular flexible hinge (18b) and a third right circular flexible hinge (18 c); the straight beam type flexible hinge I (17a), the straight beam type flexible hinge II (17b) and the circular flexible hinge III (18c) are flexible translation hinges, namely, translation can occur in the deformation process of the flexible driving mechanism (3); the first right circular flexible hinge (18a), the second right circular flexible hinge (18b) and the third circular flexible hinge (18c) are flexible bending hinges, namely bending can occur in the deformation process of the flexible driving mechanism (3); the right circular flexible hinge three (18c) is a flexible translation hinge and a flexible bending hinge.

4. A stick-slip piezoelectric actuator for realizing bidirectional driving according to claim 3, wherein the fixing hole group (16) on the compliant driving mechanism is located on the compliant driving mechanism base (15); the straight beam type flexible hinge I (17a), the straight beam type flexible hinge II (17b) and the circular flexible hinge I (18a) are of a connecting structure of the pseudo rigid body rod (14) and the flexible driving mechanism base (15); the first right circular flexible hinge (18a) and the second right circular flexible hinge (18b) are connecting structures between the pseudo rigid body rods (14).

5. The stick-slip piezoelectric actuator realizing bidirectional driving according to claim 1, wherein the compliant driving mechanism (3) is a symmetrical integrated structure, and a piezoelectric ceramic mounting groove (22) is reserved in the middle of the compliant driving mechanism for aligning and mounting piezoelectric ceramics; and a gasket is arranged between the adjusting screw (9) and the piezoelectric ceramics to protect the piezoelectric ceramics from being damaged.

6. The stick-slip piezoelectric actuator for realizing bidirectional driving of claim 1, wherein the two piezoelectric ceramics respectively drive the slide block to move in positive and negative directions; the sliding block is positively displaced when the piezoelectric ceramic is positively driven to be electrified by a sawtooth wave voltage signal meeting set conditions; and when the piezoelectric ceramic is driven to be electrified in a negative direction so as to meet the sawtooth wave signal of the set condition, the slide block generates negative displacement.

7. A two-way stick-slip piezoelectric actuator according to claim 1, wherein the base (8) is fixed on a vibration isolation table, and is provided with a plurality of fixing hole sets, the XY micro-motion platform (7) and the guide rail (1) are fixed on a base through the fixing holes, and the compliant driving mechanism (3) is fixed on the XY micro-motion platform (7) through the fixing holes.

8. A control method of a bidirectional stick-slip piezoelectric driver is characterized by comprising the following steps:

step 1, selecting negative driving piezoelectric ceramics (4) or positive driving piezoelectric ceramics (5) according to the driving direction requirement;

step 2, a sawtooth wave signal is supplied to the selected driving piezoelectric ceramic, and the time length of the signal supply is controlled by the displacement needing to be driven;

and 3, after the piezoelectric ceramic is driven to the specified position, continuously electrifying to keep the sliding block (2) fixed so as to facilitate subsequent operation.

9. The sawtooth voltage signal satisfying the condition as set forth in claim 8 is a sawtooth voltage signal having a slow rise and a fast fall.

10. A bi-directional stick-slip piezoelectric actuator according to claim 9, wherein when a voltage signal is applied to one of the piezoelectric ceramics, the other piezoelectric ceramics is in a non-operational state, i.e. no voltage signal is applied.

Technical Field

The invention relates to the technical field of precision driving, in particular to a stick-slip piezoelectric driver capable of realizing bidirectional motion.

Background

The precision positioning system is a complete system for precisely adjusting a target object in translation, rotation and the like on multiple spatial degrees of freedom, and is widely applied to the fields of aerospace, precision operation systems, biotechnology, intelligent robots, optical systems, super-precision instruments and the like. The core of the precision positioning system is to drive a target object by a precision driver to realize the expected high-precision motion, wherein the precision reaches a micro/nano level (usually, between a few nanometers and a few hundred nanometers). At present, many precision driving systems still adopt a manual or electric driving method, but with the rapid development of these fields, higher functional requirements are also put on the aspects of high resolution, high accuracy, large stroke, high speed response, large driving force and the like of the driver.

The existing precision drivers are generally divided into the following types: electrostatic actuators, electromagnetic actuators, shape memory alloy actuators, magnetostrictive actuators, electrostrictive actuators, magnetostrictive actuators, piezoelectric actuators, and the like. The piezoelectric driver utilizes the inverse piezoelectric effect of the piezoelectric material, and when voltage is applied, the piezoelectric driver stretches and contracts to generate force and displacement to drive the sliding block or the rotor to perform linear motion or rotary motion. The piezoelectric material has the advantages of small volume, large output force, high frequency response, high resolution, high power-to-weight ratio and the like, and is an ideal material for submicron and nanoscale precision driving. Piezoelectric actuators can be further divided into: direct drive type, ultrasonic type, inertial stick-slip type, inchworm type, etc.

The stick-slip piezoelectric actuator has the following advantages compared with other piezoelectric actuators: firstly, piezoelectric ceramics are adopted for driving, and the piezoelectric ceramic has the advantages of large output force, high frequency response, high resolution, low energy consumption and the like; secondly, the stick-slip driving mode enables the structure to be simple and flexible, so that the control is convenient; thirdly, periodically and circularly stepping to enable the stroke to be unlimited; and fourthly, the flexible driving mechanism is used as a driving body, and the device has the advantages of no friction, no clearance, high motion precision, high transmission efficiency and the like. The principle of stick-slip driving is that a sawtooth voltage signal is used for exciting a piezoelectric element to generate asymmetric vibration so as to realize that a driven object generates micro displacement, and the displacement is accumulated by applying a high-frequency signal, so that the aim of precise positioning is fulfilled.

Most of the existing stick-slip piezoelectric drivers can only realize unidirectional motion, and have the problems of poor load capacity, low driving speed and the like. In view of these problems, it is necessary to provide a stick-slip piezoelectric actuator that supports bidirectional motion and has both high load capacity and high driving speed.

Disclosure of Invention

In order to solve the above problems, the present invention provides a stick-slip piezoelectric actuator capable of realizing a bidirectional motion and capable of amplifying a driving force and increasing a driving speed.

Aiming at the technical problems, the technical scheme of the invention is as follows:

the utility model provides a realize two-way driven stick-slip formula piezoelectric actuator which characterized in that, the driver includes guide rail slider module, gentle and agreeable actuating mechanism, positive drive piezoceramics, negative drive piezoceramics, XY fine setting platform, base, adjusting screw that guide rail and slider are constituteed.

The positive driving piezoelectric ceramic and the negative driving piezoelectric ceramic are fixed on the compliant driving mechanism by adjusting screws, and can be fixed in a piezoelectric ceramic fixing groove of the compliant driving mechanism by rotating the adjusting screws, and the pretightening force between the driving piezoelectric ceramic and the compliant driving mechanism can be adjusted; and the contact condition between the compliant driving mechanism and the sliding block is adjusted by adjusting the XY micro-motion platform.

At foretell two-way stick-slip formula piezo-electric driver, the guide rail slider module includes: the guide rail, can be on the slider of guide rail gliding, and roller holder on setting up the guide rail.

In the bidirectional stick-slip piezoelectric actuator, the compliant driving mechanism comprises a base, a fixed hole group, a pseudo rigid rod, a straight beam type flexible hinge and a circular flexible hinge, wherein the straight beam type flexible hinge comprises a straight beam type flexible hinge I and a straight beam type flexible hinge II; the right circular flexible hinge comprises a first right circular flexible hinge, a second right circular flexible hinge and a third right circular flexible hinge; the first straight beam type flexible hinge, the second straight beam type flexible hinge and the third right circular flexible hinge are flexible translation hinges, namely translation can occur in the deformation process of the compliant driving mechanism; the first right circular flexible hinge, the second right circular flexible hinge and the third right circular flexible hinge are flexible bending hinges, namely bending can occur in the deformation process of the flexible driving mechanism. The third right circular flexible hinge is a flexible translation hinge and a flexible bending hinge.

In the bidirectional stick-slip piezoelectric driver, the fixed hole group on the flexible driving mechanism is positioned on the base of the flexible driving mechanism; the first straight beam type flexible hinge, the second straight beam type flexible hinge and the first right circular flexible hinge are of a connecting structure of a pseudo rigid rod and a compliant driving mechanism base; the first right circular flexible hinge and the second right circular flexible hinge are connecting structures between the pseudo rigid body rods.

In the bidirectional stick-slip piezoelectric actuator, the compliant driving mechanism is a symmetrical integrated structure, and a piezoelectric ceramic mounting groove is reserved in the middle of the compliant driving mechanism and used for aligning and mounting piezoelectric ceramic.

In the bidirectional stick-slip piezoelectric actuator, a gasket is arranged between the adjusting screw and the piezoelectric ceramic to protect the piezoelectric ceramic from being damaged.

In the bidirectional stick-slip piezoelectric driver, the two piezoelectric ceramics respectively drive the slide block to move positively and negatively. The sliding block is positively displaced when the piezoelectric ceramic is positively driven to be electrified by a sawtooth wave voltage signal meeting set conditions; and when the piezoelectric ceramic is driven to be electrified in a negative direction so as to meet the sawtooth wave signal of the set condition, the slide block generates negative displacement.

In the bidirectional stick-slip piezoelectric driver, the base is fixed on the vibration isolation platform, a plurality of groups of fixing hole groups are arranged on the base, the XY micro-motion platform and the guide rail are fixed on the base through the fixing holes, and the compliant driving mechanism is fixed on the XY micro-motion platform through the fixing holes.

A control method of a bidirectional stick-slip piezoelectric driver is characterized by comprising the following steps:

step 1, selecting negative driving piezoelectric ceramics or positive driving piezoelectric ceramics according to the driving direction requirement;

step 2, a sawtooth wave signal is supplied to the selected driving piezoelectric ceramic, and the time length of the signal supply is controlled by the displacement needing to be driven;

and 3, continuously electrifying the piezoelectric ceramics after the piezoelectric ceramics are driven to the specified position so as to keep the slide block fixed, thereby facilitating subsequent operation.

The effects brought by the invention are as follows: the symmetrical flexible driving mechanism can realize the bidirectional driving of the driver, thereby widening the use scene; the larger dx/dy ratio increases the driving efficiency and driving force of the driver; the parasitic displacement of the driving foot in the direction vertical to the guide rail enables the sticking process to be more sticky and the sliding process to be more slippery, and effectively improves the load capacity of the driver.

Drawings

Fig. 1 is a schematic view of the overall structure of the piezoelectric actuator according to the present invention.

FIG. 2 is a schematic structural diagram of a compliant drive mechanism according to the present invention.

FIG. 3 is a pseudo-rigid body model of a compliant drive mechanism of the present invention.

Fig. 4 is a schematic structural diagram of the guide rail slider module according to the present invention.

FIG. 5 is a schematic view of a base structure according to the present invention.

Fig. 6 is a schematic diagram of the driving principle of the piezoelectric actuator according to the present invention (initial stage, stick stage, and slip stage).

Detailed Description

The following detailed description of specific embodiments of the present invention will be described with reference to the accompanying drawings and examples. The drawings and examples are only for illustrative purposes and should not be construed as limiting the patent. In the figures, wherein: 1. a guide rail; 2. a slider; 3. a compliant drive mechanism; 4. negatively driving the piezoelectric ceramic; 5. positively driving the piezoelectric ceramic; 6. a set of fixed holes in the base; 7. an XY micromotion platform; 8. a base; 9. an adjusting screw; 10. a gasket; 11. a fixed hole group on the XY micromotion platform; 12. a set of fixed holes in the base; 13. a drive foot; 14. a pseudo rigid body bar; 15. a compliant drive mechanism base; 16. a fixed hole group on the flexible driving mechanism; 17a, a straight beam type flexible hinge I; 17b a second straight beam type flexible hinge; 18a, a first right circular flexible hinge; 18b, a second right circular flexible hinge; 18c, a right circular flexible hinge III; 19. a piezoelectric ceramic mounting groove; 20. a roller and a retainer thereof; 21. and a fixed hole group on the base.

First, the structure of the present invention is described below.

As shown in fig. 1, the piezoelectric actuator of the present invention includes the following main components: the device comprises a guide rail slider module consisting of a guide rail 1 and a slider 2, a compliant driving mechanism 3, positive driving piezoelectric ceramics 4, negative driving piezoelectric ceramics 5, an XY fine adjustment platform 7, a base 8, an adjusting screw 9 and a gasket 10.

The piezoelectric ceramics 4 and 5 can be fixed in the piezoelectric ceramic fixing groove 19 of the compliant driving mechanism 3 by rotating the adjusting screw 9, and the pretightening force between the piezoelectric ceramics 4 and 5 and the compliant driving mechanism 3 can also be adjusted.

The flexible driving mechanism 3 adopts a bilaterally symmetrical integrated structure, has a simple structure, and ensures the consistency of the bidirectional driving of the driver.

The consistency of the bidirectional driving is that the generated motion of the piezoelectric ceramics on the two sides has consistency in single-step displacement and speed under the driving of the same signal.

Wherein, the screw 9 is separated from the piezoelectric ceramics 4 and 5 by a gasket, which can prevent the adjusting screw from damaging the piezoelectric ceramics.

The working frequency of the piezoelectric ceramics can be improved by adjusting the pretightening force between the piezoelectric ceramics 4 and 5 and the compliant driving mechanism 3.

In fig. 1, the right direction is set as a positive direction, and the positive driving piezoelectric ceramic 5 and the negative driving piezoelectric ceramic 4 respectively drive the slide block 2 to move in the positive direction and the negative direction under the driving of the compliant driving mechanism 3.

There are two contact points between the compliant drive mechanism 3 and the slider 2, referred to as drive feet 13, as shown in FIG. 2.

The slide block 2 and the guide rail 1 are connected through the roller and the retainer 20 thereof, and can slide relatively, and the friction force between the two is negligible.

As shown in fig. 3, the compliant drive mechanism 3 can be simplified to be composed of a pseudo rigid rod and a kinematic pair by using a pseudo rigid body model method, and can be studied as a rigid body object.

As shown in fig. 2, the compliant driving mechanism 3 employs two types of flexible hinges, namely a straight beam type flexible hinge 17 and a circular flexible hinge 18.

In fig. 3, the angle α between the horizontal direction and the line connecting the point a of the right circular flexible hinge 18(a) and the point B of the driving foot 13 is slightly smaller than 90 degrees, and in the pseudo-rigid model, when the piezoelectric ceramic is applied with linearly increasing voltage, the piezoelectric ceramic also generates approximately linear elongation, so that the compliant driving mechanism generates deformation, as shown in the right graph of fig. 3, from the initial position to the deformed position.

The motion of the point B where the driving foot 13 is located can be regarded as the rotation motion of the point a where the circular flexible hinge 18(a) is located, the deformation position of the point B has a displacement d relative to the initial position, and the displacement d and the pressing displacement dy are obtained by decomposing the displacement d into the horizontal direction and the vertical direction, because the deformation of the piezoelectric ceramic is a small displacement compared with the structure size, the included angle alpha between the connecting line of the flexible bending hinge a and the driving foot B and the horizontal direction is slightly smaller than 90 degrees, the geometric relationship dx/dy is equal to the tangent value tan alpha of the angle, and is a large value, and the driving efficiency and the driving force of the piezoelectric driver are greatly increased by the characteristic that the dx/dy is large.

Wherein, the larger dx/dy ratio ensures that the motion of the driving foot is mostly used for driving the slide block to move, thereby obtaining higher driving efficiency and driving force.

The piezoelectric driver is energized with a sawtooth wave during operation, and has a slow-rising phase and a fast-falling phase, as shown in fig. 6. Accordingly, the piezoelectric ceramic has a slow elongation and a fast contraction stage.

In the slow extension stage of the positive piezoelectric ceramic, the driving foot has a positive driving displacement dx in the driving direction, and in addition, a positive pressing displacement dy is arranged in the direction vertical to the guide rail, so that the positive pressure between the sliding block 2 and the driving foot 13 is increased, and further the maximum static friction force is also increased, thereby ensuring that the sliding block 2 and the flexible driving mechanism 3 move together in a sticking way in the slow extension stage, and the sliding block has a positive displacement of dx;

in the rapid contraction stage of the positive piezoelectric ceramic, the driving foot has a negative driving displacement dx in the driving direction, but a negative pressing displacement dy also exists at the time, so that a 'loose' stage exists between the sliding block 2 and the driving foot, the positive pressure is reduced, the maximum static friction force is also reduced, the sliding block has a negative displacement along with the negative driving displacement of the driving foot, but relative sliding exists between the sliding block and the driving foot, the contraction stage is performed rapidly, and the negative displacement of the sliding block is certainly smaller than dx.

Therefore, the slide block has a positive net displacement through a slow extension stage and a fast contraction stage, and when the signal is applied to the piezoelectric ceramic at a periodic high frequency, the slide block can be driven to move in a positive direction.

Conversely, the same signal is applied to the negative piezoelectric ceramic, so that the slide block can be driven to move in a negative direction.

Where the minimum net displacement resolvable may be referred to as the resolution of the piezoelectric actuator.

In the scheme, the piezoelectric actuator is driven by a stick-slip driving mechanism no matter in positive driving or negative driving, the driving feet clamp the sliding block in the sticking process, and the driving feet loosen the sliding block in the slipping process, so that the load capacity of the piezoelectric actuator is effectively improved.