阅读说明：本技术 一种高速谐振冲击式压电电机 (High-speed resonance impact type piezoelectric motor ) 是由 李瑞君 李晨 王雅 潘巧生 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种高速谐振冲击式压电电机,包括定子、动子、第一振子驱动机构和第二振子驱动机构,定子固定在两个振子驱动机构的中间位置上作为输出端,在定子的表面形成准锯齿波振动,动子为交叉滚柱滑台,固定在一维微调平台上,动子的前侧通过摩擦界面与定子相互接触产生摩擦力形成粘滑效应,并由此驱动动子作定向运动。本发明通过跨频段激励实现高速和高分辨率兼顾的跨尺度输出,能有效提高冲击式压电电机的工作频率和输出速度,利于大功率输出,适合高速运动。(The invention discloses a high-speed resonance impact type piezoelectric motor which comprises a stator, a rotor, a first vibrator driving mechanism and a second vibrator driving mechanism, wherein the stator is fixed at the middle position of the two vibrator driving mechanisms and serves as an output end, quasi sawtooth wave vibration is formed on the surface of the stator, the rotor is a crossed roller sliding table and is fixed on a one-dimensional fine adjustment platform, the front side of the rotor is in mutual contact with the stator through a friction interface to generate friction force to form a stick-slip effect, and the rotor is driven to do directional motion. The invention realizes the cross-scale output with high speed and high resolution by cross-frequency band excitation, can effectively improve the working frequency and the output speed of the impact type piezoelectric motor, is beneficial to high-power output, and is suitable for high-speed movement.)

1. A high-speed resonance impact type piezoelectric motor is characterized by comprising a stator (7), a rotor (17) and two vibrator driving mechanisms, wherein the two vibrator driving mechanisms are a first vibrator driving mechanism and a second vibrator driving mechanism respectively;

the stator (7) is a friction vibrator and is fixed in the middle of the two vibrator driving mechanisms to serve as an output end, and quasi sawtooth wave vibration is formed on the surface of the stator (7);

the rotor (17) is a cross roller sliding table, and the rotor (17) is fixed on the one-dimensional fine adjustment platform (16) through a bolt; the front side of the rotor (17) is in mutual contact with the stator (7) through a friction interface to generate friction force to form a stick-slip effect, and the rotor (17) is driven to move directionally;

the first vibrator driving mechanism is characterized in that a first friction vibrator driving source is fixedly arranged on a first vibrator seat (1), and the first friction vibrator driving source is composed of a first displacement amplifying mechanism (2), a second displacement amplifying mechanism (3) and a first piezoelectric stack (10); the first piezoelectric stack (10) is fixed in the first displacement amplification mechanism (2) through initial pre-tightening;

the second vibrator driving mechanism is characterized in that a second friction vibrator driving source is fixedly arranged on a second vibrator seat (4), and the second friction vibrator driving source is composed of a third displacement amplifying mechanism (5), a fourth displacement amplifying mechanism (6) and a second piezoelectric stack (13); the second piezoelectric stack (13) is fixed in the third displacement amplification mechanism (5) through initial pre-tightening;

the first piezoelectric stack (10) and the second piezoelectric stack (13) work in a compressed state through initial pre-tightening, and the pre-tightening force of the initial pre-tightening is 200N-500N;

the second displacement amplification mechanism (3), the fourth displacement amplification mechanism (6) and the stator (7) jointly form a spring mass damping system, wherein the second displacement amplification mechanism (3) and the fourth displacement amplification mechanism (6) are equivalent to springs, the stator (7) is equivalent to a mass block, and the stiffness and the mass of the springs are adjusted to optimize impedance matching between the stator and the rotor;

the cross-scale output with high speed and high resolution is realized through cross-frequency band excitation according to the following control method:

giving a high-frequency excitation signal, enabling the friction vibrator driving source to work in a high-frequency resonance mode to realize high-speed output, and completing quick coarse positioning;

giving a low-frequency excitation signal, enabling the friction vibrator driving source to work in a low-frequency quasi-static mode to realize high-resolution output, and completing high-resolution driving;

and giving a direct current excitation signal to enable the friction vibrator driving source to work in a direct current static mode to complete high-precision micro positioning.

2. The high-speed resonant impact piezoelectric motor of claim 1, wherein:

in the high-frequency resonance state mode, two modes of two friction vibrator driving sources need to be excited out simultaneously; the frequency ratio of a first-order longitudinal vibration mode to a second-order longitudinal vibration mode in the friction vibrator driving source is 1: 2; in the first-order longitudinal vibration mode, the deformation of the output end of the stator is generated by the vibration of the first displacement amplification mechanism (2) and the third displacement amplification mechanism (5), and the displacement is transmitted by the second displacement amplification mechanism (3) and the fourth displacement amplification mechanism (6); under the second-order longitudinal vibration mode, the deformation of the output end of the stator is generated by the vibration of the second displacement amplification mechanism (3) and the fourth displacement amplification mechanism (6); the first friction vibrator driving source and the second friction vibrator driving source are excited by resonance frequency, the frequency of the first friction vibrator driving source and the frequency of the second friction vibrator driving source are set to be 1:2, the initial phase difference is 0 degree, the voltage amplitude ratio of the first friction vibrator driving source and the second friction vibrator driving source is adjusted to enable the amplitude ratio of mechanical vibration to be 2:1, by adjusting phase difference and combining first-order and second-order longitudinal vibration modes of a friction vibrator driving source, positive quasi sawtooth wave vibration is formed on the surface of a stator (7), and a rotor (17) is driven to move positively through a friction interface; or the phase difference is adjusted to form reverse quasi sawtooth wave vibration on the surface of the stator (7), so that the rotor (17) is driven to move reversely;

under the low-frequency quasi-static mode, the frequency ratio of the first friction vibrator driving source to the second friction vibrator driving source is 1:2, the initial phase difference is 0 degree, the voltage amplitude ratio of the first friction vibrator driving source to the second friction vibrator driving source is adjusted to enable the mechanical vibration amplitude ratio to be 2:1, by adjusting a phase difference and combining a first-order longitudinal vibration mode and a second-order longitudinal vibration mode of a friction vibrator driving source, positive quasi sawtooth wave vibration is formed on the surface of a stator (7), and a rotor (17) is driven to move at a low speed in a positive direction through a friction interface; or the phase difference is adjusted to form reverse quasi sawtooth wave vibration on the surface of the stator (7), so that the rotor (17) is driven to move reversely;

in the direct current static mode, excitation signals of the first friction vibrator driving source and the second friction vibrator driving source are direct current voltage signals, and the phase difference of the two excitation signals is adjusted to realize the reverse driving of the rotor (17).

3. The resonant impact piezoelectric motor of claim 1, wherein: each displacement amplification mechanism comprising a first displacement amplification mechanism (2), a second displacement amplification mechanism (3), a third displacement amplification mechanism (5) and a fourth displacement amplification mechanism (6) adopts a rhombic hollow frame with the same structure; the first piezoelectric stack (10) is fixed on the long diagonal of the first displacement amplification mechanism (2) in a pre-tightening mode, and the second piezoelectric stack (13) is fixed on the long diagonal of the third displacement amplification mechanism (5) in a pre-tightening mode.

4. The resonant impact piezoelectric motor of claim 1, wherein: and the excitation signals of the first friction vibrator driving source and the second friction vibrator driving source are sine wave excitation signals.

5. The resonant impact piezoelectric motor of claim 1, wherein:

setting the input stiffness of the first displacement amplification mechanism (2) within 1/10-1/6 of the output stiffness of the first piezoelectric stack (10);

the input stiffness of the third displacement amplification mechanism (5) is set within 1/10-1/6 of the output stiffness of the second piezoelectric stack (13).

6. The resonant impact piezoelectric motor of claim 1, wherein:

a first aluminum oxide gasket (9) and a second aluminum oxide gasket (11) are respectively arranged between two ends of the first piezoelectric stack (10) and the first displacement amplifying mechanism (2) and are used for adjusting the piezoelectric stack pretightening force of the first piezoelectric stack (10);

and a third aluminum oxide gasket (12) and a fourth aluminum oxide gasket (14) are respectively arranged between the two ends of the second piezoelectric stack (13) and the third displacement amplifying mechanism (5) and are used for adjusting the piezoelectric stack pre-tightening force of the second piezoelectric stack (13).

7. The resonant impact piezoelectric motor of claim 1, wherein: and a pressure spring (18) is arranged at the rear side of the one-dimensional fine adjustment platform (16) and is used for adjusting the pre-pressure between the rotor (17) and the stator (7).

8. The resonant impact piezoelectric motor of claim 1, wherein:

a fixed block is arranged at one end of the first displacement amplification mechanism (2) facing the first vibrator seat (1), a C-shaped groove is arranged on the first vibrator seat (1), and the opening of the C-shaped groove faces one side where the first displacement amplification mechanism (2) is located; the fixed block is embedded in the C-shaped groove, a puller bolt is arranged on the side wall of the C-shaped groove, and the fixed block is positioned in the C-shaped groove by the puller bolt, so that the first displacement amplification mechanism (2) is fixed on the first vibrator seat (1);

a fixed block is arranged at one end of the second displacement amplifying mechanism (5) facing the second vibrator seat (4), a C-shaped groove is formed in the second vibrator seat (4), the fixed block is matched with the C-shaped groove, and a jacking bolt is used for positioning, so that the second displacement amplifying mechanism (5) is fixed on the second vibrator seat (4).

Technical Field

The invention belongs to the technical field of piezoelectric motors, and particularly relates to a resonance impact type piezoelectric motor.

Background

The piezoelectric motor utilizes the inverse piezoelectric effect of a piezoelectric material, applies voltage to the piezoelectric motor to generate micro-deformation to realize motor motion, has the advantages of short response time, no electromagnetic interference and the like, and is widely applied to the fields of robots, spaceflight, medical treatment and the like. At present, two main types of piezoelectric motors are a resonant type and a quasi-static type.

The resonant piezoelectric motor mainly refers to an ultrasonic motor, and utilizes a stator to generate high-frequency elliptical motion in an ultrasonic frequency band, and converts the elliptical motion of the stator into continuous linear or rotary output of a rotor through friction coupling, thereby realizing the conversion of electric energy into mechanical energy. Because the working frequency is higher, the speed of the ultrasonic motor is relatively higher, but the friction loss is larger. The quasi-static piezoelectric motor is driven by non-sinusoidal voltage, and realizes continuous linear or rotary output of the rotor by controlling voltage parameters or designing a mechanical structure. According to different working principles, quasi-static piezoelectric motors can be divided into inchworm type and inertial impact type. The inchworm type motor has the working principle that single-step micro displacement of the piezoelectric element is continuously accumulated to form continuous displacement output through the alternate matching of the piezoelectric driving unit and the clamping unit. The working principle of the inertia impact type piezoelectric motor is that the rotor moves by using static friction force and inertia force between the stator and the rotor. The quasi-static piezoelectric motor can realize high-resolution large-stroke output, and the quasi-static piezoelectric motor is low in speed which is mostly lower than 20mm/s due to low working frequency. Such as: the maximum speed of an inchworm type motor based on a two-way spiral clamping principle, such as the time of arrival of Nanjing aerospace university is 2.58 mm/s; the velocity of the impact type piezoelectric motor realized by utilizing the parallelogram flexible hinge structure, such as the Lijianpei at Jilin university, is only 14.25 mm/s.

The traditional impact motor works at non-resonant frequency, most of the traditional impact motors are soft ceramics which can realize large displacement, the materials are PZT5 and called soft ceramics, the materials are PZT4 and PZT8 and called hard ceramics, the main difference is that the mechanical quality factor of the soft ceramics is far lower than that of the hard ceramics, and the soft ceramics are not suitable for high-speed movement.

Disclosure of Invention

The invention aims to overcome the defect that the existing impact type piezoelectric motor is low in motion speed, provides a resonance impact type piezoelectric motor, carries out accurate structural design on a plurality of modal frequencies of a friction vibrator driving source based on a multi-frequency harmonic synthesis principle, realizes the resonance impact type piezoelectric motor, and greatly improves the output speed of the impact type piezoelectric motor by utilizing hard ceramic driving.

The invention adopts the following technical scheme for solving the technical problems:

the high-speed resonance impact type piezoelectric motor is characterized by comprising a stator, a rotor and two vibrator driving mechanisms, wherein the two vibrator driving mechanisms are a first vibrator driving mechanism and a second vibrator driving mechanism respectively;

the stator is a friction vibrator and is fixed in the middle of the two vibrator driving mechanisms to serve as an output end, and quasi sawtooth wave vibration is formed on the surface of the stator;

the rotor is a crossed roller sliding table and is fixed on the one-dimensional fine adjustment platform through bolts; the front side of the rotor is contacted with the stator through a friction interface to generate friction force to form a stick-slip effect, and the rotor is driven to do directional motion;

the first vibrator driving mechanism is characterized in that a first friction vibrator driving source is fixedly arranged on a first vibrator seat, and the first friction vibrator driving source is composed of a first displacement amplifying mechanism, a second displacement amplifying mechanism and a first piezoelectric stack; the first piezoelectric stack is fixed in the first displacement amplifying mechanism through initial pre-tightening;

the second vibrator driving mechanism is characterized in that a second friction vibrator driving source is fixedly arranged on a second vibrator seat and consists of a third displacement amplifying mechanism, a fourth displacement amplifying mechanism and a second piezoelectric stack; the second piezoelectric stack is fixed in the third displacement amplification mechanism through initial pre-tightening;

the first piezoelectric stack and the second piezoelectric stack work in a compressed state through initial pre-tightening, and the pre-tightening force of the initial pre-tightening is 200N-500N;

the second displacement amplifying mechanism, the fourth displacement amplifying mechanism and the stator jointly form a spring mass damping system, wherein the second displacement amplifying mechanism and the fourth displacement amplifying mechanism are equivalent to springs, the stator is equivalent to a mass block, and the rigidity and the mass of the springs are adjusted to optimize impedance matching between the stator and the rotor;

the cross-scale output with high speed and high resolution is realized through cross-frequency band excitation according to the following control method:

giving a high-frequency excitation signal, enabling the friction vibrator driving source to work in a high-frequency resonance mode to realize high-speed output, and completing quick coarse positioning;

giving a low-frequency excitation signal, enabling the friction vibrator driving source to work in a low-frequency quasi-static mode to realize high-resolution output, and completing high-resolution driving;

and giving a direct current excitation signal to enable the friction vibrator driving source to work in a direct current static mode to complete high-precision micro positioning.

The high-speed resonance impact type piezoelectric motor is also characterized in that:

in the high-frequency resonance state mode, two modes of two friction vibrator driving sources need to be excited out simultaneously; the frequency ratio of a first-order longitudinal vibration mode to a second-order longitudinal vibration mode in the friction vibrator driving source is 1: 2; under the first-order longitudinal vibration mode, the deformation of the output end of the stator is generated by the vibration of the first displacement amplification mechanism and the third displacement amplification mechanism, and the displacement is transmitted by the second displacement amplification mechanism and the fourth displacement amplification mechanism; under the second-order longitudinal vibration mode, the deformation of the output end of the stator is generated by the vibration of the second displacement amplification mechanism and the fourth displacement amplification mechanism; the first friction vibrator driving source and the second friction vibrator driving source are excited by resonance frequency, the frequency of the first friction vibrator driving source and the frequency of the second friction vibrator driving source are set to be 1:2, the initial phase difference is 0 degree, the voltage amplitude ratio of the first friction vibrator driving source and the second friction vibrator driving source is adjusted to enable the amplitude ratio of mechanical vibration to be 2:1, by adjusting phase difference and combining first-order and second-order longitudinal vibration modes of a friction vibrator driving source, positive quasi sawtooth wave vibration is formed on the surface of a stator, and a rotor is driven to move positively through a friction interface; or the phase difference is adjusted to form reverse quasi sawtooth wave vibration on the surface of the stator, so that the rotor is driven to move reversely;

under the low-frequency quasi-static mode, the frequency ratio of the first friction vibrator driving source to the second friction vibrator driving source is 1:2, the initial phase difference is 0 degree, the voltage amplitude ratio of the first friction vibrator driving source to the second friction vibrator driving source is adjusted to enable the mechanical vibration amplitude ratio to be 2:1, by adjusting a phase difference and combining a first-order longitudinal vibration mode and a second-order longitudinal vibration mode of a friction vibrator driving source, positive quasi sawtooth wave vibration is formed on the surface of a stator, and a rotor is driven to move at a low speed in a positive direction through a friction interface; or the phase difference is adjusted to form reverse quasi sawtooth wave vibration on the surface of the stator, so that the rotor is driven to move reversely;

in the direct current static mode, excitation signals of the first friction vibrator driving source and the second friction vibrator driving source are direct current voltage signals, and the phase difference of the two excitation signals is adjusted to realize the reverse driving of the rotor.

The resonance impact type piezoelectric motor of the invention is also characterized in that: each displacement amplification mechanism comprises a first displacement amplification mechanism, a second displacement amplification mechanism, a third displacement amplification mechanism and a fourth displacement amplification mechanism, and each displacement amplification mechanism adopts a rhombic hollow frame with the same structure; the first piezoelectric stack is fixed on a long diagonal of the first displacement amplification mechanism in a pre-tightening mode, and the second piezoelectric stack is fixed on a long diagonal of the third displacement amplification mechanism in a pre-tightening mode.

The resonance impact type piezoelectric motor of the invention is also characterized in that: and the excitation signals of the first friction vibrator driving source and the second friction vibrator driving source are sine wave excitation signals.

The resonance impact type piezoelectric motor of the invention is also characterized in that: setting the input stiffness of the first displacement amplification mechanism to be within 1/10-1/6 of the output stiffness of the first piezoelectric stack; the input stiffness of the third displacement amplification mechanism is set to be within 1/10-1/6 of the output stiffness of the second piezoelectric stack.

The resonance impact type piezoelectric motor of the invention is also characterized in that: a first aluminum oxide gasket and a second aluminum oxide gasket are respectively arranged between the two ends of the first piezoelectric stack and the first displacement amplifying mechanism and are used for adjusting the pretightening force of the piezoelectric stack of the first piezoelectric stack; and a third aluminum oxide gasket and a fourth aluminum oxide gasket are respectively arranged between the two ends of the second piezoelectric stack and the third displacement amplifying mechanism and are used for adjusting the pretightening force of the piezoelectric stack of the second piezoelectric stack.

The resonance impact type piezoelectric motor of the invention is also characterized in that: and a pressure spring is arranged at the rear side of the one-dimensional fine adjustment platform and used for adjusting the pre-pressure between the rotor and the stator.

The resonance impact type piezoelectric motor of the invention is also characterized in that:

a fixed block is arranged at one end of the first displacement amplification mechanism facing the first vibrator seat, a C-shaped groove is arranged on the first vibrator seat, and the opening of the C-shaped groove faces one side of the first displacement amplification mechanism; the fixed block is embedded in the C-shaped groove, a puller bolt is arranged on the side wall of the C-shaped groove, and the fixed block is positioned in the C-shaped groove by the puller bolt, so that the first displacement amplification mechanism is fixed on the first vibrator seat;

and a fixed block is arranged at one end of the second displacement amplifying mechanism facing the second vibrator seat, a C-shaped groove is arranged on the second vibrator seat, and the fixed block is matched with the C-shaped groove and positioned by utilizing a puller bolt, so that the second displacement amplifying mechanism is fixed on the second vibrator seat.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, through cross-frequency-band excitation, the piezoelectric motor completes quick coarse positioning under resonance, high-resolution driving under quasi-static state and high-precision micro positioning under direct-current static state, so that high-speed and high-resolution cross-scale output is realized.

2. According to the invention, the precise structural design is carried out on a plurality of modal frequencies of the friction vibrator driving source, and a symmetrical structure is adopted to obtain a first-order longitudinal vibration mode and a second-order longitudinal vibration mode, so that quasi sawtooth wave vibration is obtained, and the working frequency of the impact type piezoelectric motor is improved.

3. The invention utilizes hard ceramic for driving, the mechanical quality factor of the hard ceramic is very high, the heating is not serious, the high-power output is facilitated, and the invention is suitable for high-speed motion, thereby improving the output speed of the impact type piezoelectric motor.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural diagram of a mover and a pre-pressure adjusting device according to the present invention;

FIG. 3 is a schematic structural diagram of two vibrator driving mechanisms according to the present invention;

FIG. 4 is a schematic diagram of two vibrator driving sources according to the present invention;

FIG. 5 is a graph showing the mechanical vibration curve and the synthetic graph of quasi-sawtooth wave of two vibrator driving sources in the present invention;

FIG. 6 is a first-order longitudinal vibration mode diagram of two vibrator driving sources according to the present invention;

FIG. 7 is a second-order longitudinal vibration mode diagram of two vibrator driving sources according to the present invention;

FIG. 8 shows the present invention at t₀A schematic diagram of the movement position of the motor at the moment;

FIG. 9 shows the present invention at t₁A schematic diagram of the movement position of the motor at the moment;

FIG. 10 shows the present invention t₂A schematic diagram of the movement position of the motor at the moment;

reference numbers in the figures: the device comprises a first vibrator seat 1, a first displacement amplification mechanism 2, a second displacement amplification mechanism 3, a second vibrator seat 4, a third displacement amplification mechanism 5, a fourth displacement amplification mechanism 6, a stator 7, a first alumina ceramic piece 8, a first alumina gasket 9, a first piezoelectric stack 10, a second alumina gasket 11, a third alumina gasket 12, a second piezoelectric stack 13, a fourth alumina gasket 14, a second alumina ceramic piece 15, a one-dimensional fine tuning platform 16, a rotor 17, a pressure spring 18 and a bottom plate 19.

Detailed Description

Referring to fig. 1, 2 and 3, the high-speed resonance impact type piezoelectric motor in the present embodiment includes a stator 7, a mover 17, and two vibrator driving mechanisms, which are a first vibrator driving mechanism and a second vibrator driving mechanism, respectively.

The stator 7 is a friction vibrator and is fixed in the middle of the two vibrator driving mechanisms to be used as an output end, and quasi sawtooth wave vibration is formed on the surface of the stator 7; the rotor 17 is a cross roller sliding table, and the rotor 17 is fixed on the one-dimensional fine adjustment platform 16 through bolts; the front side of the mover 17 is in contact with the stator 7 through a friction interface to generate friction force to form a stick-slip effect, and thereby the mover 17 is driven to move directionally.

The first vibrator driving mechanism is characterized in that a first friction vibrator driving source is fixedly arranged on a first vibrator seat 1, and the first friction vibrator driving source is composed of a first displacement amplifying mechanism 2, a second displacement amplifying mechanism 3 and a first piezoelectric stack 10; the first piezoelectric stack 10 is fixed in the first displacement amplification mechanism 2 by initial pre-tightening; the second vibrator driving mechanism is characterized in that a second friction vibrator driving source is fixedly arranged on a second vibrator seat 4, and the second friction vibrator driving source is composed of a third displacement amplifying mechanism 5, a fourth displacement amplifying mechanism 6 and a second piezoelectric stack 13; the second piezoelectric stack 13 is fixed in the third displacement amplification mechanism 5 through initial pre-tightening; the first piezoelectric stack 10 and the second piezoelectric stack 13 work under a compressed state through initial pre-tightening, and the pre-tightening force of the initial pre-tightening is 200N-500N.

The second displacement amplifying mechanism 3, the fourth displacement amplifying mechanism 6 and the stator 7 jointly form a spring mass damping system, wherein the second displacement amplifying mechanism 3 and the fourth displacement amplifying mechanism 6 are equivalent to springs, the stator 7 is equivalent to a mass block, and the stiffness and the mass of the springs are adjusted to optimize impedance matching between the stator and the rotor, so that the displacement generated by the piezoelectric stack is transmitted to the output end, and the purpose of driving the piezoelectric motor at a high speed is achieved.

In the embodiment, the cross-scale output with high speed and high resolution is realized through cross-frequency band excitation according to the following control method:

giving a high-frequency excitation signal, enabling the friction vibrator driving source to work in a high-frequency resonance mode to realize high-speed output, and completing quick coarse positioning; giving a low-frequency excitation signal, enabling the friction vibrator driving source to work in a low-frequency quasi-static mode to realize high-resolution output, and completing high-resolution driving; and giving a direct current excitation signal to enable the friction vibrator driving source to work in a direct current static mode to complete high-precision micro positioning.

In the high-frequency resonance mode, two modes of two friction vibrator driving sources need to be excited simultaneously; the frequency ratio of a first-order longitudinal vibration mode to a second-order longitudinal vibration mode in the friction vibrator driving source is 1: 2; in a first-order longitudinal vibration mode, the deformation of the output end of the stator is generated by the vibration of the first displacement amplification mechanism 2 and the third displacement amplification mechanism 5, and the displacement is transmitted by the second displacement amplification mechanism 3 and the fourth displacement amplification mechanism 6; in the second-order longitudinal vibration mode, the deformation of the output end of the stator is generated by the vibration of the second displacement amplification mechanism 3 and the fourth displacement amplification mechanism 6; the first friction vibrator driving source and the second friction vibrator driving source are excited by resonance frequency, the frequency of the first friction vibrator driving source and the frequency of the second friction vibrator driving source are set to be 1:2, the initial phase difference is 0 degree, the voltage amplitude ratio of the first friction vibrator driving source and the second friction vibrator driving source is adjusted to enable the amplitude ratio of mechanical vibration to be 2:1, by adjusting phase difference and combining first-order and second-order longitudinal vibration modes of a friction vibrator driving source, positive quasi sawtooth wave vibration is formed on the surface of a stator 7, and a rotor 17 is driven to move positively through a friction interface; or the opposite quasi sawtooth wave vibration is formed on the surface of the stator 7 by adjusting the phase difference, so that the rotor 17 is driven to move in the opposite direction.

Under the low-frequency quasi-static mode, the frequency ratio of the first friction vibrator driving source to the second friction vibrator driving source is 1:2, the initial phase difference is 0 degree, the voltage amplitude ratio of the first friction vibrator driving source to the second friction vibrator driving source is adjusted to enable the mechanical vibration amplitude ratio to be 2:1, forming forward quasi sawtooth wave vibration on the surface of a stator 7 by adjusting a phase difference and combining a first-order longitudinal vibration mode and a second-order longitudinal vibration mode of a friction vibrator driving source, and driving a rotor 17 to move forward at a low speed through a friction interface; or the opposite quasi sawtooth wave vibration is formed on the surface of the stator 7 by adjusting the phase difference, so that the rotor 17 is driven to move in the opposite direction.

In the direct current static mode, excitation signals of the first friction vibrator driving source and the second friction vibrator driving source are direct current voltage signals, and the phase difference of the two excitation signals is adjusted to realize the reverse driving of the rotor 17.

Each displacement amplification mechanism comprising a first displacement amplification mechanism 2, a second displacement amplification mechanism 3, a third displacement amplification mechanism 5 and a fourth displacement amplification mechanism 6 adopts a rhombic hollow frame with the same structure; the first piezoelectric stack 10 is fixed on the long diagonal of the first displacement amplification mechanism 2 in a pre-tightening manner, and the second piezoelectric stack 13 is fixed on the long diagonal of the third displacement amplification mechanism 5 in a pre-tightening manner.

The excitation signals of the first friction vibrator driving source and the second friction vibrator driving source are sine wave excitation signals.

Setting the input stiffness of the first displacement amplification mechanism 2 within 1/10-1/6 of the output stiffness of the first piezoelectric stack 10;

the input stiffness of the third displacement magnification mechanism 5 is set within 1/10-1/6 of the output stiffness of the second piezoelectric stack 13.

A first alumina gasket 9 and a second alumina gasket 11 are respectively arranged between the two ends of the first piezoelectric stack 10 and the first displacement amplifying mechanism 2 and are used for adjusting the piezoelectric stack pretightening force of the first piezoelectric stack 10.

And a third aluminum oxide gasket 12 and a fourth aluminum oxide gasket 14 are respectively arranged between the two ends of the second piezoelectric stack 13 and the third displacement amplifying mechanism 5 and are used for adjusting the piezoelectric stack pretightening force of the second piezoelectric stack 13.

As shown in fig. 1 and 2, a pressure spring 18 is arranged at the rear side of the one-dimensional fine adjustment platform 16 and between a micrometer head and a sliding table of the one-dimensional fine adjustment platform, the one-dimensional fine adjustment platform 16 and the pressure spring 18 form a pre-pressure adjusting device, and the front side of the mover 17 is in contact with a stator through a second aluminum oxide ceramic sheet 15 to generate friction force; the prepressing force between the stator and the rotor is adjusted by adjusting the micrometer head of the one-dimensional fine adjustment platform 16 and combining the pressure spring 18; and (3) changing the deformation x of the compressed pressure spring, and calculating to obtain the magnitude of the pre-pressure change through F ═ kx, so as to obtain the magnitude of the friction force change.

As shown in fig. 3 and 4, the first displacement amplification mechanism 2 has a fixed block at one end facing the first vibrator holder 1, the first vibrator holder 1 has a "C" shaped groove, and the opening of the "C" shaped groove faces the side of the first displacement amplification mechanism 2; the fixed block is embedded in the C-shaped groove, a puller bolt is arranged on the side wall of the C-shaped groove, and the fixed block is positioned in the C-shaped groove by the puller bolt, so that the first displacement amplification mechanism 2 is fixed on the first vibrator seat 1; a fixed block is arranged at one end, facing the second vibrator seat 4, of the second displacement amplification mechanism 5, a C-shaped groove is formed in the second vibrator seat 4, the fixed block is matched with the C-shaped groove, and a jacking bolt is used for positioning, so that the second displacement amplification mechanism 5 is fixed on the second vibrator seat 4; the first vibrator seat 1 and the second vibrator seat 4 are of a symmetrical structure and are fixed on the bottom plate 19.

As shown in fig. 4, sine wave signals with a frequency ratio of 1:2 are respectively fed into the first piezoelectric stack 10 and the second piezoelectric stack 13, the amplitude ratio of the two sine wave signals is 2:1, and the phase difference isThe first displacement amplification mechanism 2 pre-assembled with the first piezoelectric stack 10 and the third displacement amplification mechanism 5 pre-assembled with the second piezoelectric stack 13 generate sinusoidal mechanical vibration under the excitation of two paths of sinusoidal signals, so that the second displacement amplification mechanism 3 and the fourth displacement amplification mechanism 6 are respectively pulled to generate sinusoidal mechanical vibration, the mechanical vibration frequency is consistent with the excitation frequency of an excitation signal, but the amplitude is not consistent with the amplitude of an excitation electric signal, and therefore, the amplitude of the electric signal needs to be adjusted to enable the mechanical vibration amplitude ratio to be 2:1, quasi sawtooth wave vibration can be generated on the surface of the stator 7 by adjusting the phase difference.

From the fourier transform, the sawtooth waveform can be decomposed into a number of sine waves:

fig. 5 shows a mechanical vibration curve and a fourier transform curve of two piezoelectric vibrator driving sources, where the fourier transform is as shown in formula (1):

in the formula (1), f (t) is a sawtooth wave function, A is the amplitude of a first sine wave signal, and a sawtooth wave form is composed of multiple integral multiple harmonics; the second harmonic is half of the first harmonic, the third harmonic is one third of the first harmonic, and so on. The wave synthesized by the fundamental wave and the second harmonic wave is a quasi-sawtooth wave.

Fig. 6 shows that the two vibrator driving sources respectively drive the second displacement amplification mechanism 3 and the fourth displacement amplification mechanism 6 to move in the horizontal direction by the deformation of the first displacement amplification mechanism 2 and the third displacement amplification mechanism 5, and the stator 7 displaces in the horizontal direction.

Fig. 7 shows that the two vibrator driving sources respectively drive the first displacement amplification mechanism 2 and the third displacement amplification mechanism 5 to move in the horizontal direction by the deformation of the second displacement amplification mechanism 3 and the fourth displacement amplification mechanism 6, and the stator 7 displaces in the horizontal direction.

Shown in FIG. 8 as t₀At the moment of motor movement position, in t₀The time is the initial state, i.e., at the quasi-sawtooth wave crest, in which the VRU2035 cross roller ramp as the mover is at the initial position.

At t₀-t₁In the time period, the amplitude of a quasi-sawtooth wave signal synthesized on the surface of the stator gradually drops from a wave crest to a wave trough, the stator slowly moves towards the horizontal positive direction, under the state, the friction force between the stator and the crossed roller sliding table is larger than the self inertia force of the crossed roller sliding table, the quasi-sawtooth wave synthesized on the surface of the stator drives an upper end cover of the crossed roller sliding table to start moving towards the horizontal direction through the friction action of a first alumina ceramic wafer, namely the crossed roller sliding table serving as a rotor slowly moves towards the horizontal positive direction along with the stator, and the process is sticky movement; reaches t₁At that moment, the upper end cap moves to the furthest point of the cyclic movement, as shown in figure 9.

At t₁-t₂At the moment, the amplitude of a quasi sawtooth wave signal synthesized on the surface of the stator rapidly rises from a wave trough to a wave crest, and the stator rapidly moves towards the horizontal reverse direction; to t₂At that time, the upper end cap is backed off a little from the furthest point of the cyclic motion, as shown in FIG. 10.

When the quasi-sawtooth signal is according to t₀-t₁-t₂When the stator is driven in a period, the stator moves back and forth, the rotor crossed roller sliding table steps for a certain distance, and when the rotor crossed roller sliding table is driven in a plurality of continuous periods, the rotor crossed roller sliding table continuously moves in the same direction. When the driving signal is turned off when the piezoelectric motor works, the piezoelectric stack stops working at the moment, the piezoelectric driving mechanism also stops working, and the mover also stops moving due to friction force. The piezoelectric stack is then excited again without adjustmentCan be normally moved.