Multi-axis vibration piezoelectric motor and control method thereof

Abstract

The invention discloses a multi-axis vibration piezoelectric motor and a control method thereof.The multi-axis vibration piezoelectric motor comprises a plurality of piezoelectric cantilever beam sets arranged on the periphery of a center objective table in a circumferential array mode, a motor shell is fixed to the outer ring of each piezoelectric cantilever beam set, each piezoelectric cantilever beam set comprises a cantilever beam, the end of each cantilever beam is fixedly connected with the center objective table, and piezoelectric patches are arranged on the surfaces of the cantilever beams; a plurality of piezoelectric cantilever beam groups are rigidly connected with an external frame through a motor shell, and a plurality of cantilever beam structures are rigidly connected to the motor shell, so that space optimization distribution and multi-degree-of-freedom vibration output of vibration energy are realized; the problems of inherent noise superposition and volume redundancy of a multi-motor system, non-uniform spatial distribution of output intensity of a linear vibration motor and difficulty in precise regulation and control of a vibration mode are effectively solved. According to the piezoelectric motor, the direction controllability of vibration output and the energy utilization efficiency are remarkably improved while compact design is kept, and under the condition of the same driving voltage, the vibration quantity of the piezoelectric motor is greatly improved compared with that of a traditional piezoelectric motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of drive motors, and particularly relates to a multi-axis vibration piezoelectric motor and a control method thereof. Background Art

[0002] With the continuous development of intelligent electronic devices and the increasing functions, the user's demand for the human-computer interaction experience has been increasing day by day. Especially during calls, reminders, and notifications, vibration, as an important human-computer interaction mechanism, has become an indispensable function of intelligent terminals. Currently, the vibration motors used in intelligent terminals on the market are mainly divided into two types: one is the traditional eccentric rotary vibration motor driven by a DC brushed motor, and the other is the linear vibration motor using the electromagnetic linear drive principle.

[0003] The traditional eccentric rotary vibration motor generates a vibration effect by driving an asymmetric eccentric wheel to rotate through an electric motor. However, this type of motor has several inherent defects: First, its start-stop response time is relatively long (usually in the order of hundreds of milliseconds), which may cause obvious delay phenomena in application scenarios that require fast response; Second, the vibration control accuracy is limited, and it is difficult to achieve precise adjustment of the vibration amplitude and frequency; Moreover, its relatively large physical size is contrary to the development trend of modern electronic devices towards thinness and lightness, and it is difficult to provide a uniform vibration intensity distribution, resulting in poor performance in application scenarios that require precise vibration feedback (such as system notifications and interaction prompts). In addition, the power consumption of this type of motor is relatively high (the typical value is in the order of hundreds of milliwatts), significantly affecting the battery life of the device; the complexity of its mechanical structure also leads to potential problems in terms of reliability and durability. Another type of electromagnetic vibration motor (linear vibration motor) is based on the electromagnetic linear drive principle and generates vibration through linear motion under the action of a magnetic field. Compared with the traditional rotary motor, it has advantages in terms of volume efficiency and energy consumption performance. However, this technology also has certain limitations: it has relatively high requirements for power supply stability, and power fluctuations will affect the vibration effect; the vibration mode mainly shows lateral vibration, and it is difficult to meet specific requirements in vibration feedback scenarios that require uniform intensity and precise control.

[0004] In contrast, piezoelectric vibration motors utilize the inverse piezoelectric effect of piezoelectric materials, which can generate relatively precise and efficient vibration output in a smaller volume. They have the advantages of fast response speed (in the order of dozens of milliseconds), wide vibration frequency range, low power consumption (in the order of dozens of milliwatts), and can achieve precise control of vibration direction and intensity. However, most of the existing piezoelectric vibration motors are designed for single-direction vibration. For example, the Chinese patents "A Piezoelectric Linear Mobile Phone Vibration Motor with Mechanical Vibration Amplification" (Patent No. CN106936331A) and "Piezoelectric Vibration Motor" (Patent No. CN112838783A), which have certain limitations for some applications with multi-directional vibration feedback. Moreover, the existing piezoelectric vibration motors vibrating in the vertical direction are relatively large in size. For example, the US patent "PIEZOELECTRIC VIBRATION DEVICE FOR MOBILE TERMINAL" (Patent No. US9595659B2) designs a piezoelectric vibration motor for mobile phones in the vertical direction, which requires four motors to drive the mobile phone to vibrate together, greatly increasing the volume of the piezoelectric motor. At the same time, in the structure designed in this patent, the piezoelectric sheets are connected and cooperated with multiple components. During long-term use or when subjected to vibration and impact, these connection parts may become loose or have poor contact, not only reducing the stability of the motor but also significantly shortening the service life of the motor.

[0005] With the diversification of the interactive feedback requirements of intelligent terminals, the limitations of single-direction vibration are becoming increasingly prominent. Multi-axis vibration technology has gradually become a research hotspot, but its practical application still faces many challenges. In the existing technology, the design of multi-axis piezoelectric vibration motors mainly relies on multiple motors to achieve multiple degrees of freedom, that is, a motor module contains multiple piezoelectric motors, and each motor corresponds to the movement in a different axial direction. It mainly has the following disadvantages: (1) Multiple motors jointly control the movement in multiple axial directions, that is, there are driving motors in at least two directions, which has problems such as large module size, complex mechanical structure, high power consumption, heavy weight of moving parts, and high cost. It is difficult to design anti-interference for each other, ultimately reducing the reliability of the entire motor structure; (2) Limited by the space size of multiple motors, it is impossible to achieve a very thin design. (3) Once a problem occurs in one of the multiple motors (such as being impacted or having poor contact), it may cause the entire system to malfunction, greatly shortening the service life of the motor.

[0006] Therefore, the above problems limit the popularization of multi-axis piezoelectric vibration motors in intelligent terminals, and there is an urgent need for a new type of piezoelectric vibration motor with a compact structure, flexible control, and stable multi-directional vibration output. Summary of the Invention

[0007] The object of the present invention is to provide a multi-axis vibrating piezoelectric motor and its control method, so as to overcome the problems of noise and volume of existing rotary vibrating motors, and the problems that linear vibrating motors cannot achieve uniform strength and precise control.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows: A multi-axis vibrating piezoelectric motor includes a central carrier platform and a plurality of groups of piezoelectric cantilever beam groups arranged in a circumferential array around the central carrier platform. The outer ring of the piezoelectric cantilever beam group is fixed with a motor housing. The piezoelectric cantilever beam group includes a cantilever beam whose end is fixedly connected to the central carrier platform. Piezoelectric sheets are arranged on the surface of the cantilever beam. The ends of the cantilever beams of the plurality of groups of piezoelectric cantilever beam groups are rigidly connected to an external frame through the motor housing.

[0009] Preferably, a mass block is fixed on the central carrier platform.

[0010] Preferably, the plurality of groups of piezoelectric cantilever beam groups are orthogonally distributed around the central carrier platform, forming a spatial cross array with the central carrier platform.

[0011] Preferably, one piezoelectric sheet is arranged on each of the upper and lower sides of the cantilever beam in the piezoelectric cantilever beam group.

[0012] Preferably, one piezoelectric sheet is arranged alone on the upper side or the lower side of the cantilever beam.

[0013] Preferably, the polarization directions of the piezoelectric sheets on the upper and lower sides of the cantilever beam are the same or opposite.

[0014] Preferably, the cantilever beams arrayed on the central carrier platform and the central carrier platform adopt an integrated structure.

[0015] Preferably, a first electrode coating and a second electrode coating are respectively arranged on the upper and lower surfaces of the piezoelectric sheet, and the first electrode coating of the piezoelectric sheet is electrically connected to the cantilever beam.

[0016] A control method for a multi-axis vibrating piezoelectric motor includes the following steps: Apply a driving signal to the piezoelectric sheets on the piezoelectric cantilever beam group, and realize the vibration of the motor in the direction of the axis where a single piezoelectric cantilever beam group is located through the periodic driving signal.

[0017] Preferably, if one piezoelectric sheet is arranged on each of the upper and lower sides of the same cantilever beam in the piezoelectric cantilever beam group, if the polarization directions of the piezoelectric sheets on the upper and lower sides of the same cantilever beam are the same, the same driving signal is applied to the piezoelectric sheets on the upper and lower sides of the same cantilever beam. If the polarization directions of the piezoelectric sheets on the upper and lower sides of the same cantilever beam are opposite, driving signals with a phase difference of 180° are applied to the piezoelectric sheets on the upper and lower sides of the same cantilever beam.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a multi-axis vibrating piezoelectric motor, which includes a central carrier platform and multiple groups of piezoelectric cantilever beam groups arranged in a circular array around the central carrier platform. The outer ring of the piezoelectric cantilever beam group is fixed with a motor housing. The piezoelectric cantilever beam group includes a cantilever beam with one end fixedly connected to the central carrier platform, and a piezoelectric sheet is arranged on the surface of the cantilever beam. The ends of the cantilever beams of multiple groups of piezoelectric cantilever beam groups are rigidly connected to an external frame through the motor housing. This design realizes the spatial optimization distribution of vibration energy and multi-degree-of-freedom vibration output by rigidly connecting multiple cantilever beam structures to the motor housing. Compared with the traditional multi-motor parallel connection scheme, this scheme effectively solves the following technical bottlenecks: (1) the inherent noise superposition and volume redundancy problems of the multi-motor system; (2) the uneven spatial distribution of the output intensity of the linear vibrating motor; (3) the key problems such as the difficulty in accurately regulating the vibration mode. The experimental results show that while maintaining a compact design, this structure significantly improves the direction controllability of the vibration output and the energy utilization efficiency. Under the same driving voltage conditions, the vibration amount of the present invention is greatly improved compared with the traditional piezoelectric motor.

[0019] Preferably, an innovative optimization is carried out on the structure of the central carrier platform. By increasing its thickness and configuring an adjustable mass block thereon, the flexible adjustment of vibration characteristics is realized.

[0020] Preferably, multiple groups of piezoelectric cantilever beam groups are orthogonally distributed around the central carrier platform, and a parallel cantilever beam structure is adopted, which maintains a compact size while achieving a powerful vibration effect.

[0021] A control method for the multi-axis vibrating piezoelectric motor of the present invention can achieve precise control of the six-axis vibration mode by adjusting the driving signals and their phase differences of each cantilever beam, and can generate diverse vibration modes, greatly expanding its application scenarios in human-computer interaction. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the overall structure of the multi-axis vibrating piezoelectric motor in the embodiment of the present invention.

[0023] Figure 2 It is a schematic diagram of the upward bending vibration mode of a single cantilever beam in the embodiment of the present invention.

[0024] Figure 3 It is a schematic diagram of the structure of the central carrier platform and the mass block of the piezoelectric motor in the embodiment of the present invention.

[0025] Figure 4 It is a schematic diagram of the driving voltage distribution of the motor in the embodiment of the present invention.

[0026] Figure 5 It is a schematic diagram of the X-axis vibration principle in the embodiment of the present invention.

[0027] Figure 6This is the schematic diagram of the Z-axis vibration principle in the embodiments of the present invention.

[0028] Figure 7 This is the schematic diagram of the X-axis vibration driving voltage and vibration mode in the embodiments of the present invention.

[0029] Figure 8 This is the schematic diagram of the Y-axis vibration driving voltage and vibration mode in the embodiments of the present invention.

[0030] Figure 9 This is the schematic diagram of the Z-axis vibration driving voltage and vibration mode in the embodiments of the present invention.

[0031] Figure 10 This is the schematic diagram of the XZ-axis vibration driving voltage and vibration mode in the embodiments of the present invention.

[0032] Figure 11 This is the schematic diagram of the YZ-axis vibration driving voltage and vibration mode in the embodiments of the present invention.

[0033] Figure 12 This is the schematic diagram of the XY-axis vibration driving voltage and vibration mode in the embodiments of the present invention.

[0034] In the figure, 101 is the upper piezoelectric sheet, 102 is the lower piezoelectric sheet, 103 is the cantilever beam, 104 is the motor housing, 301 is the upper mass block, 302 is the lower mass block, 303 is the central stage, 401 is V A up, 402 is V A down, 404 is V B up, 405 is V B down, 407 is V C up, 408 is V C down, 410 is V D up, 411 is V D down, 403 is beam A composed of the overall two-layer piezoelectric sheet and metal beam, 406 is beam B, 409 is beam C, 412 is beam D. Detailed implementation manners

[0035] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0037] The present invention provides a multi-axis vibration piezoelectric motor, as Figures 1 to 3 shown, specifically including a central carrier 303 and multiple groups of piezoelectric cantilever beam groups arranged in a circumferential array around the central carrier. The outer ring of the piezoelectric cantilever beam group is fixed with a motor housing 104. The piezoelectric cantilever beam group includes a cantilever beam 103 with an end fixedly connected to the central carrier 303. A piezoelectric sheet is arranged on the surface of the cantilever beam 103. The ends of the cantilever beams 103 of multiple groups of piezoelectric cantilever beam groups are rigidly connected to an external frame through the motor housing 104. By adopting the cooperative working mechanism of multiple cantilever beams rigidly fixed to the motor housing 104, the optimal distribution of vibration energy can be achieved. The central carrier 303, the piezoelectric cantilever beam group and the motor housing 104 can be integrally formed. This integrated structure design effectively reduces the energy loss during the vibration transmission process and significantly improves the output vibration force of the system. Under the same driving voltage conditions, the vibration amount of the present invention is greatly improved compared with traditional piezoelectric motors; the cantilever beam 103 is made of a conductive material.

[0038] In the specific embodiment of the present invention, as Figures 1 to 3 shown, a mass block is fixed on the central carrier 303 to enhance the vibration effect. As Figure 1 and Figure 3 shown, an upper mass block 301 and a lower mass block 302 are respectively fixed on the upper and lower sides of the central carrier 303.

[0039] In the specific embodiment of the present application, as Figure 1As shown in the figure, multiple groups of piezoelectric cantilever beam groups are orthogonally distributed around the central stage 303, forming a spatial cross array with the central stage 303. The orthogonal parallel layout significantly optimizes the structural compactness through the principle of vector superposition, which is more conducive to the thin and flat design of intelligent terminals. Moreover, the structural design with multiple groups of piezoelectric cantilever beam groups orthogonally distributed can achieve multi-axis vibration and multi-directional vibration, effectively solving the problems that the existing rotary vibration motors cannot achieve multi-directional vibration and have noise, volume issues, and that the linear vibration motors cannot achieve uniform strength and precise control. The height dimension of the central stage is preferably greater than the vertical height of the cantilever beam. In this application, the cantilever beam is driven by the inverse piezoelectric effect to generate multi-directional vibration, thereby realizing the multi-axis vibration feedback function of the intelligent terminal device.

[0040] As Figure 4 shown, piezoelectric wafers are respectively arranged on the upper and lower sides of the cantilever beam 103 in the piezoelectric cantilever beam group to form a piezoelectric bimorph configuration; or a piezoelectric wafer is separately arranged on the upper side or the lower side of the cantilever beam 103 to form a piezoelectric monomorph configuration. Specifically, the piezoelectric bimorph configuration adopts a symmetric distribution mode, that is, a piezoelectric wafer is integrated on each of the upper and lower surfaces of the cantilever beam; while the piezoelectric monomorph configuration adopts an asymmetric distribution mode, and only a single piezoelectric wafer is integrated on the upper surface or the lower surface of the cantilever beam. Through this structure, the vibration amplitude of the cantilever beam can be effectively increased, and the polarization directions of the piezoelectric wafers on the upper and lower surfaces are the same or opposite to achieve the optimal vibration effect. The ends of multiple cantilever beams are connected to the central stage, and the mass block on the central stage can not only effectively reduce the vibration frequency of the motor, but also use the inertial vibration of the mass block to increase the overall vibration amount of the motor.

[0041] First electrode coatings and second electrode coatings are respectively arranged on the upper and lower surfaces of the piezoelectric wafer. The first electrode coating of the piezoelectric wafer is fixedly connected to the cantilever beam 103 through conductive adhesive and is directly grounded through the cantilever beam 103. This design enables the two electrode surfaces of the piezoelectric wafer to reverse the signal through the parallel drive voltage. Based on the principle of the inverse piezoelectric effect, when an alternating electric field matching the resonant frequency of the physical size and structural characteristics of the piezoelectric wafer is applied, periodic telescopic deformation will be induced. This deformation drives the central stage to generate forced vibration through mechanical coupling, and then drives the mass block to move synchronously. Finally, the inertial vibration amount is transmitted to the intelligent terminal through the beam structure.

[0042] The cantilever beams arrayed on the central stage 303 and the central stage 303 adopt an integrated structure, effectively reducing the loss generated during the vibration amount transmission. The end of each cantilever beam is connected to the motor housing, which can not only fix the tail of the cantilever beam for fixed restraint, making the vibration of the cantilever beam all transmitted to the free end to increase the vibration, but also the motor housing can be directly connected and fixed to the intelligent terminal without adding other hardware for fixation.

[0043] In the specific embodiments of the present application, the piezoelectric sheet material includes, but is not limited to, lead zirconate titanate piezoelectric ceramics, bismuth scandate-lead titanate piezoelectric ceramics, barium titanate piezoelectric ceramics, potassium sodium niobate piezoelectric ceramics, as well as lead magnesium niobate-lead titanate piezoelectric single crystals, lead zinc niobate-lead titanate piezoelectric single crystals, and piezoelectric fiber composites.

[0044] The above-mentioned cantilever beam needs to have appropriate flexibility and strength to ensure that the vibration generated by the piezoelectric sheet can be effectively transmitted and generate a large vibration on the surface of the external frame (here, the external frame is specifically the mobile phone housing).

[0045] The mass block used in the present application changes the natural frequency of the system and increases the mass of the vibration to enhance the vibration effect. It can make the cantilever beam close to or reach the resonance state with the frequency of the driving signal. At the resonance frequency, the vibration amplitude of the system will reach the maximum. The material of the mass block can be, according to requirements, not limited to metal materials such as stainless steel, lead, copper, and tungsten. It is usually installed on the upper and lower surfaces of the central carrier platform. The central carrier platform is connected to the free end of the cantilever beam. Since the amplitude of the free end is the largest, the increased mass at this position can significantly increase the vibration amplitude.

[0046] To facilitate the description of the working state of the motor, now taking the central carrier platform as the center, the structure of the carrier platform is as Figure 3 shown. The four cantilever beams are named by position and described in the left-right, up-down directions of the XY plane. For example, beam A on the left is named beam A, beam B on the right is named beam B, beam C on the upper is named beam C, and beam D on the lower is named beam D; the cantilever beam is a metal beam. The main surfaces of the non-contact metal beams of the two piezoelectric sheets on each cantilever beam are connected to an external power supply. The main surfaces in contact with the metal beam are directly adhered to the metal beam through conductive adhesive and grounded through the conductive metal beam. The driving voltages are named according to the upper and lower electrode surfaces respectively. For example, the main surface drives of the non-contact metal beams of the two piezoelectric sheets on the left-end cantilever beam are V A up and V A down; the main surface drives of the non-contact metal beams of the two piezoelectric sheets on the right-end cantilever beam are V B up and V B down; the main surface drives of the non-contact metal beams of the two piezoelectric sheets on the upper-end cantilever beam are V C up and V C down; the main surface drives of the non-contact metal beams of the two piezoelectric sheets on the lower-end cantilever beam are V D up and V D down, as Figure 4 shown.

[0047] The present invention provides a control method for a multi-axis vibration piezoelectric motor, including the following steps: A driving signal is applied to the piezoelectric wafers on the piezoelectric cantilever beam group, and the vibration of the motor along the axis where a single piezoelectric cantilever beam group is located is realized through the periodic driving signal. The driving signal adopted in this application is specifically a sine wave signal.

[0048] If a piezoelectric wafer is respectively arranged on the upper and lower sides of the same cantilever beam in the piezoelectric cantilever beam group, and if the polarization directions of the piezoelectric wafers on the upper and lower sides of the same cantilever beam are the same, the same driving signal is applied to the piezoelectric wafers on the upper and lower sides of the same cantilever beam. If the polarization directions of the piezoelectric wafers on the upper and lower sides of the same cantilever beam are opposite, driving signals with a phase difference of 180° are applied to the piezoelectric wafers on the upper and lower sides of the same cantilever beam.

[0049] In order to realize different vibration modes in multiple directions, different-phase driving signals can be applied to each cantilever beam, so that each cantilever beam works in a different mode, and the four cantilever beams vibrate and couple to generate up to six different vibration direction modes.

[0050] If a piezoelectric wafer is arranged on each of the two cantilever beams located on both sides of the central stage 303 and with their length directions on the same axis, and the polarization directions of the two piezoelectric wafers are the same, then driving signals with a phase difference of 180° or the same driving signal are applied to the piezoelectric wafers on the two cantilever beams. When driving signals with a phase difference of 180° are applied to the piezoelectric wafers on the two cantilever beams, vibration along the axis where the two cantilever beams are located is generated. When the same driving signal is applied to the piezoelectric wafers on the two cantilever beams, vibration along the direction perpendicular to the plane where the two cantilever beams are located is generated.

[0051] Two piezoelectric wafers are arranged on each of the two cantilever beams located on both sides of the central stage 303 and with their length directions on the same axis. The piezoelectric wafers on the upper and lower sides of the same cantilever beam are taken as a group. If the polarization directions of the piezoelectric wafers on the upper and lower sides of the same cantilever beam are the same, the same driving signal is applied to the two piezoelectric wafers in the same group, and the two piezoelectric wafers generate a coupling effect to drive the cantilever beam to bend in the same direction. If the polarization directions of the piezoelectric wafers on the upper and lower sides of the same cantilever beam are opposite, driving signals with a phase difference of 180° are applied to the two piezoelectric wafers in the same group, and the two piezoelectric wafers generate a coupling effect to drive the cantilever beam to bend in the same direction. By arranging a piezoelectric wafer on each of the upper and lower sides of the cantilever beam, the coupling effect of the two piezoelectric wafers is adopted to improve the vibration effect.

[0052] Taking the example that a piezoelectric wafer is respectively arranged on the upper and lower sides of the cantilever beam 103 in the piezoelectric cantilever beam group, and the polarization directions of the piezoelectric wafers on the upper and lower sides of the same cantilever beam 103 are the same, the control principles of six different vibration modes of the multi-axis vibration piezoelectric motor are described: X-axis vibration mode: In the length expansion and contraction mode of the piezoelectric element, the polarization direction of the piezoelectric element is the thickness direction. An electric field is applied to the piezoelectric element along the Z-axis direction. Specifically, the way of applying the electric field is: V A on and V AWhen receiving the same driving signal, when the polarization direction of the piezoelectric sheet at the upper end of beam A is the same as (or opposite to) the electric field direction, the polarization direction of the piezoelectric sheet at the lower end is opposite to (or the same as) the electric field direction. Through d 31 the piezoelectric working mode successfully stimulates beam A to bend upward; and applying a driving voltage with a phase difference of 180° from that of beam A to beam B. Similarly, V B on is the same as V B under when receiving the same driving signal, beam B bends downward. Under the action of the cooperative strain effect of beam A and beam B, the central stage is finally driven to move in the negative X-axis direction, as shown in Figure 5 the left figure. Similarly, when T / 2 has passed (T is the period of the driving voltage), beams A and B reverse, driving the central stage to move in the positive X-axis direction, as shown in Figure 5 the right figure. By means of a periodic sine wave signal, the vibration of the motor along the X-axis direction is realized, as shown in Figure 7 the figure shows.

[0053] Y-axis vibration mode: In the length expansion and contraction mode of the piezoelectric element, the polarization direction of the piezoelectric element is the thickness direction. An electric field is applied to the piezoelectric element along the Z-axis direction. Specifically, the way of applying the electric field is: V C on is the same as V C under when receiving the same driving signal, when the polarization direction of the piezoelectric sheet at the upper end of beam C is the same as (or opposite to) the electric field direction, the polarization direction of the piezoelectric sheet at the lower end is opposite to (or the same as) the electric field direction. Through d 31 the piezoelectric working mode successfully stimulates beam C to bend upward; and applying a driving voltage with a phase difference of 180° from that of beam C to beam D. Similarly, V D on is the same as V D under when receiving the same driving signal, beam D bends downward. Under the action of the cooperative strain effect of beam C and beam D, the central stage is finally driven to move in the positive Y-axis direction. Similarly, when T / 2 has passed, beams C and D reverse, driving the central stage to move in the negative Y-axis direction. By means of a periodic sine wave signal, the vibration of the motor along the Y-axis direction is realized, as shown in Figure 8 the figure shows.

[0054] Z-axis vibration mode: In the length expansion and contraction mode of the piezoelectric element, the polarization direction of the piezoelectric element is the thickness direction. An electric field is applied to the piezoelectric element along the Z-axis direction. Specifically, the way of applying the electric field is: When V A on, V A under, V B on, V B under are all externally applied with the same driving signal, when the polarization direction of the piezoelectric sheets at the upper ends of beam A and beam B is the same as (or opposite to) the electric field direction, the polarization direction of the piezoelectric sheets at the lower ends is opposite to (or the same as) the electric field direction. Through d 31The piezoelectric working mode successfully excited the upward bending of both Beam C and Beam D simultaneously, ultimately driving the central stage to move in the positive Z-axis direction; similarly, when T / 2 passed, Beams A and B reversed, driving the central stage to move in the negative Z-axis direction. In practical applications, it is possible to consider whether to apply the same driving signal to Beams C and D according to the magnitude of the vibration requirement to generate a greater vibration in the Z-axis direction, such as Figure 6 , Figure 9 as shown.

[0055] The above three working modes are the basic three-axis motions. The following three working modes are all coupled motions of the above three-axis basic motions, and their working principles are as follows: XZ-axis vibration mode: In the length expansion and contraction mode of the piezoelectric element, the polarization direction of the piezoelectric element is the thickness direction. An electric field is applied to the piezoelectric element along the Z-axis direction. Specifically, the way of applying the electric field is: V A on and V A under are connected with the same driving signal. When the polarization direction of the upper piezoelectric sheet of Beam A is the same (or opposite) as the electric field direction, the polarization direction of the lower piezoelectric sheet is opposite (or the same) as the electric field direction. Through d 31 the piezoelectric working mode successfully excited the upward bending of Beam A; and a driving voltage with a 180° phase difference from that of Beam A is applied to Beam B. Similarly, V B on and V B under are connected with the same driving signal, Beam B generates a downward bending. Under the action of the cooperative strain effect of Beam A and Beam B, the central stage is driven to move in the negative X-axis direction; when V C on, V C under, V D on, V D under are all externally applied with the same driving signal, when the polarization direction of the upper piezoelectric sheets of Beams C and D is the same (or opposite) as the electric field direction, the polarization direction of the lower piezoelectric sheets is opposite (or the same) as the electric field direction. Through d 31 the piezoelectric working mode successfully excited the upward bending of both Beams C and D simultaneously, ultimately driving the central stage to move in the positive Z-axis direction. By adjusting the amplitude ratio and phase relationship of the two groups of driving signals, the X-axis and Z-axis vibration components are superimposed in space, ultimately realizing the oblique vibration mode of the XZ axis, such as Figure 10 as shown.

[0056] YZ-axis vibration mode: In the length expansion and contraction mode of the piezoelectric element, the polarization direction of the piezoelectric element is the thickness direction. An electric field is applied to the piezoelectric element along the Z-axis direction. Specifically, the way of applying the electric field is: V C on and V CWhen receiving the same driving signal below, when the polarization direction of the piezoelectric sheet at the upper end of beam C is the same as (or opposite to) the electric field direction, the polarization direction of the piezoelectric sheet at the lower end is opposite to (or the same as) the electric field direction. Through d 31 the piezoelectric working mode successfully excites beam C to bend upward; and applying a driving voltage with a 180° phase difference from the driving voltage of beam C to beam D. Similarly, V D above and V D below receive the same driving signal, beam D bends downward. Under the action of the cooperative strain effect of beam C and beam D, the central stage is driven to move in the positive Y-axis direction; when V A above, V A below, V B above, V B below are all externally applied with the same driving signal. When the polarization direction of the piezoelectric sheet at the upper end of beam A and beam B is the same as (or opposite to) the electric field direction, the polarization direction of the piezoelectric sheet at the lower end is opposite to (or the same as) the electric field direction. Through d 31 the piezoelectric working mode successfully excites beam A and beam D to bend upward simultaneously, and finally drives the central stage to move in the positive Z-axis direction. By adjusting the amplitude ratio and phase relationship of the two groups of driving signals, the vibration components of the Y-axis and Z-axis are superposed in space, and finally the oblique vibration mode of the YZ-axis is realized, as Figure 11 shown.

[0057] XY-axis vibration mode: In the length expansion and contraction mode of the piezoelectric element, the polarization direction of the piezoelectric element is the thickness direction. An electric field is applied to the piezoelectric element along the Z-axis direction. Specifically, the way to apply the electric field is: V A above and V A below receive the same driving signal. When the polarization direction of the piezoelectric sheet at the upper end of beam A is the same as (or opposite to) the electric field direction, the polarization direction of the piezoelectric sheet at the lower end is opposite to (or the same as) the electric field direction. Through d 31 the piezoelectric working mode successfully excites beam A to bend upward; and applying a driving voltage with a 180° phase difference from the driving voltage of beam A to beam B. Similarly, V B above and V B below receive the same driving signal, beam B bends downward. Under the action of the cooperative strain effect of beam A and beam B, the central stage is driven to move in the negative X-axis direction; V C above and V C below receive the same driving signal. When the polarization direction of the piezoelectric sheet at the upper end of beam C is the same as (or opposite to) the electric field direction, the polarization direction of the piezoelectric sheet at the lower end is opposite to (or the same as) the electric field direction. Through d 31 the piezoelectric working mode successfully excites beam C to bend upward; and applying a driving voltage with a 180° phase difference from the driving voltage of beam C to beam D. Similarly, V D above and VD Receiving the same driving signal below, beam D bends downward. Under the action of the cooperative strain effect of beam C and beam D, the central stage is driven to move in the positive Y-axis direction. By adjusting the amplitude ratio and phase relationship of the two groups of driving signals, the vibration components in the X-axis and Y-axis are superposed in space, and finally the oblique vibration mode of the XY-axis is realized, as Figure 12 shown.

[0058] It should be noted that the above d 31 piezoelectric mode can also be realized by inducing the up-and-down bending motion of the piezoelectric sheet in the shear piezoelectric mode, producing a similar motion effect.

[0059] The three basic motions of the triaxial include vibrations in the horizontal directions along the X-axis and Y-axis; vibrations in the vertical direction along the Z-axis; and three coupling vibration modes in the horizontal and vertical directions, namely the XZ-axis, YZ-axis, and XY-axis vibration modes. Specific embodiments: As Figure 1 shown, the upper piezoelectric sheet 101 and the lower piezoelectric sheet 102 are respectively arranged on the upper and lower sides of the cantilever beam 103. The lower electrode surface of the upper piezoelectric sheet 101 is electrically connected to the upper electrode surface of the lower piezoelectric sheet 102 through the conductive cantilever beam 103. The upper electrode surface of the upper piezoelectric sheet 101 and the lower electrode surface of the lower piezoelectric sheet 102 are connected to the driving voltage. That is, when the electric field direction is upward along the Z-axis (where the cantilever beams 103 arrayed on the central stage 303 are arrayed along the XY plane), the polarization direction of the upper piezoelectric sheet 101 is the same as the electric field direction, and the polarization direction of the lower piezoelectric sheet 102 is opposite to the electric field direction. Under the action of the driving voltage, when the upper piezoelectric sheet 101 shortens along the X-axis, the lower piezoelectric sheet 102 elongates along the X-axis, and the end generates an upward bend, as Figure 2 shown; when the upper piezoelectric sheet 101 elongates along the X-axis, the lower piezoelectric sheet 102 shortens along the X-axis, and the end generates a downward bend, and the end drives the central stage to vibrate. The inertial motion generated by the mass block is transmitted to the load surface through the beam and the piezoelectric housing, thereby driving the load to generate a large vibration.

[0061] The cantilever beam of the present invention adopts an integrated design, that is, the tails of the four cantilever beams are connected to the motor housing and fixed inside the smart terminal through the motor housing. The ends of the cantilever beams are fixed to the sides of the central stage. It ensures that each cantilever beam can stably maintain its predetermined vibration mode during the vibration process.

[0062] As Figure 3As shown, mass blocks can be attached to the central stage as needed. The material and size of the mass blocks can be selected according to specific requirements. Ensure that it can provide sufficient mass within a small volume, thereby enhancing the vibration intensity. The installation position of the mass blocks is on the upper and lower surfaces of the central stage at the free end of the cantilever beam, so that the mass blocks can make the most of the vibration amplitude at the free end and enhance the vibration effect. The fixed end of the cantilever beam is connected to the load surface through the motor housing; the connection position can firmly fix the motor inside the smart terminal by means of hard soldering with metal materials. This fixing method ensures that the cantilever beam will not loosen or displace during operation. The inside of the smart terminal can be a mobile phone case, the body of a wearable device, or other components that require vibration feedback.

[0063] In summary, the vibration motor of this embodiment can be widely applied to electronic products such as smart phones, wearable devices, and game controllers that require precise multi-directional vibration feedback. This design can provide efficient and stable multi-directional vibration output, enhancing the user's vibration experience, especially suitable for scenarios such as notification reminders, message vibrations, and game vibrations. The integrated design reduces the connection components and installation steps of the cantilever beam, simplifies the production process; the four parallel cantilever beams work together to ensure stable multi-directional vibration and meet various application requirements; the vibration frequency and intensity can be flexibly adjusted by adjusting the voltage signal and the mass of the mass block to meet the needs of different devices; the selection of piezoelectric materials is thinner compared with electromagnetic motors, more suitable for thin and flattened electronic devices, and not easily affected by magnetic fields; the piezoelectric drive method reduces the noise and wear caused by mechanical friction in traditional vibration motors and extends the service life.

[0064] The present invention conducts experimental simulation. Under the condition of the same driving voltage, the vibration amount of the present invention is greatly improved compared with traditional piezoelectric motors. For the vibration motor designed based on the cantilever beam in the present invention, before the integrated structure optimization, the acceleration generated when driving a 100g load at 140V was 0.74Gpp. After the integrated structure design, the acceleration generated when driving a 100g load at 70V was 1Gpp, and the improvement amplitude has reached 35%.

[0065] The cantilever beam structure of the present invention supports independent control. By adjusting the driving signals of each cantilever beam and their phase differences, precise control of the six-axis vibration mode can be achieved. This programmable control mechanism enables the motor to generate diverse vibration modes, greatly expanding its application scenarios in human-computer interaction. According to different usage requirements, the system can automatically select the optimal vibration mode to achieve precise tactile feedback. At the same time, the present invention realizes six-axis stable vibration, meeting the multi-dimensional tactile feedback requirements of modern smartphones. Compared with traditional linear vibration motors and eccentric rotary vibration motors, this design has significant advantages in the stability and uniformity of multi-axis vibration. The system can maintain stable vibration output under various complex usage scenarios, effectively avoiding vibration misalignment problems caused by changes in device posture or environmental interference.

[0066] The present invention has made innovative optimizations to the central stage structure. By increasing its thickness and configuring adjustable mass blocks on it, flexible adjustment of vibration characteristics is achieved. The mass blocks are prepared from materials with different densities, and their sizes can be adjusted within a large range. In the experiments of the cantilever beam piezoelectric vibration motor of our research group, as the mass blocks gradually increase, the characteristic frequency of the motor gradually decreases, and the vibration amount shows a trend of first increasing and then decreasing. By changing the material and size of the mass blocks and controlling the mass of the mass blocks, precise control of the vibration frequency and acceleration can be achieved.

[0067] The vibration motor of the present invention adopts a parallel cantilever beam structure, achieving a powerful vibration effect while maintaining a compact size. Its thickness is reduced by 35% compared with traditional rotary vibration motors (the thickness of traditional rotary vibration motors is about 8 mm, and the thickness of the present invention is about 5 mm), and the volume is reduced by 40%. It is particularly suitable for mobile devices with limited space (such as smartphones, smart watches, etc.). This miniaturized design not only improves the integration of the device but also provides more space for the layout of other functional modules.

Claims

1. A multi-axis vibration piezoelectric motor, characterized in that: The invention comprises a central stage (303) and a plurality of piezoelectric cantilever beam groups arranged in a circular array around the central stage, wherein a motor housing (104) is fixed to the outer ring of the piezoelectric cantilever beam group, and the piezoelectric cantilever beam group comprises a cantilever beam (103) whose end is fixedly connected to the central stage (303), and a piezoelectric sheet is arranged on the surface of the cantilever beam (103), and the ends of the cantilever beams (103) of the plurality of piezoelectric cantilever beam groups are rigidly connected to an external frame via the motor housing (104).

2. A multi-axis vibration piezoelectric motor according to claim 1, characterized in that: A mass block is fixed on the central object platform (303).

3. The multi-axis vibration piezoelectric motor according to claim 1, characterized in that: A plurality of piezoelectric cantilever beam groups are orthogonally distributed around the central object carrier (303), and form a spatial cross array with the central object carrier (303).

4. The multi-axis vibration piezoelectric motor according to claim 1, characterized in that: A piezoelectric sheet is provided on the upper and lower sides of the cantilever beam (103) in the piezoelectric cantilever beam group, respectively.

5. The multi-axis vibration piezoelectric motor according to claim 1, characterized in that: A piezoelectric sheet is separately arranged on the upper side of the cantilever beam (103) or on the lower side of the cantilever beam (103).

6. The multi-axis vibration piezoelectric motor according to claim 4, characterized in that: The polarization directions of the piezoelectric sheets on the upper and lower sides of the cantilever beam (103) are the same or opposite.

7. The multi-axis vibration piezoelectric motor according to claim 1, characterized in that: The cantilever beams of the array on the central object carrier (303) and the central object carrier (303) adopt an integrated structure.

8. The multi-axis vibration piezoelectric motor according to claim 1, characterized in that: The upper and lower surfaces of the piezoelectric sheet are respectively provided with a first electrode coating and a second electrode coating, and the first electrode coating of the piezoelectric sheet is electrically connected to the cantilever beam (103).

9. A control method for a multi-axis vibration piezoelectric motor as claimed in claim 1, characterized in that: The following steps are involved: A driving signal is applied to the piezoelectric sheet on the piezoelectric cantilever beam group, and the phase, frequency and amplitude parameters of the driving signal are adjusted to achieve precise control of the linear vibration mode of the motor along the axis of a single piezoelectric cantilever beam group or the rotational vibration mode around the axis.

10. The control method of a multi-axis vibration piezoelectric motor according to claim 9, characterized in that: If a piezoelectric sheet is provided on the upper and lower sides of the same cantilever beam in the piezoelectric cantilever beam group, respectively, if the polarization directions of the piezoelectric sheets on the upper and lower sides of the same cantilever beam are the same, then the same driving signal is applied to the piezoelectric sheets on the upper and lower sides of the same cantilever beam; if the polarization directions of the piezoelectric sheets on the upper and lower sides of the same cantilever beam are opposite, then the piezoelectric sheets on the upper and lower sides of the same cantilever beam apply driving signals with a phase difference of 180°.

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