A piezoelectric stick-slip actuator rollback suppression method based on elastic potential energy compensation

Abstract

This invention relates to a piezoelectric stick-slip actuator retraction suppression method based on elastic potential energy compensation, belonging to the field of precision drive and micro-displacement control technology. The method is based on a piezoelectric stick-slip actuator comprising a piezoelectric drive unit, a displacement transmission unit, an elastic energy storage element, a drive foot, and a mover. During the slow voltage rise phase, the piezoelectric drive unit outputs a drive displacement, which, through the displacement transmission unit and the drive foot, drives the mover to produce forward motion. Simultaneously, the elastic energy storage element undergoes recoverable elastic deformation and stores elastic potential energy. During the rapid voltage drop phase, the elastic energy storage element releases the stored elastic potential energy and generates an elastic restoring force. This force, through the drive foot, applies a compensation action along the drive direction to the mover, reducing or offsetting the mover's retraction displacement. This method can increase the effective output displacement per cycle, improve continuous drive stability, and is suitable for micro / nano positioning, precision attitude adjustment, micromanipulation, and other piezoelectric precision drive applications.

Description

Technical Field

[0001] This invention belongs to the field of precision drive and micro-displacement control technology, specifically relating to a piezoelectric stick-slip actuator retraction suppression method based on elastic potential energy compensation, and more particularly to a drive method that enables an elastic energy storage element to undergo recoverable elastic deformation and store elastic potential energy during the slow voltage rise phase, and releases the stored elastic potential energy during the rapid voltage drop phase, so as to reduce or offset the retraction displacement of the mover during the piezoelectric stick-slip drive process. Background Technology

[0002] Piezoelectric stick-slip actuation technology utilizes a piezoelectric actuation unit to generate alternating fast and slow deformations under the action of an asymmetric driving voltage signal, and achieves micro-stepping output through the frictional contact between the driving foot and the mover. It has the advantages of compact structure, fast response speed, high resolution and easy miniaturization, and has wide applications in micro-nano positioning, precision attitude adjustment, micromanipulation and micro actuators.

[0003] However, in traditional piezoelectric stick-slip actuators, the piezoelectric actuator unit typically drives the mover to produce forward motion during the voltage rise phase. However, during the voltage fall phase, as the piezoelectric actuator unit rapidly retracts, relative slippage easily occurs between the drive foot and the mover, causing the mover to retract in the opposite direction. This retraction displacement reduces the effective step distance per cycle, lowers output efficiency, and affects the stability of continuous stepping motion. Especially in miniaturized and lightweight actuator systems, the mass and inertia of the mover are relatively small, reducing its ability to maintain the original motion state solely through inertia. The retraction motion generated during the rapid voltage drop phase is more pronounced. Therefore, it is necessary to propose a retraction suppression method for piezoelectric stick-slip actuators based on elastic potential energy compensation. This method allows the elastic energy storage element to elastically deform and store elastic potential energy during the slow voltage rise phase, and releases the stored elastic potential energy during the rapid voltage drop phase. The elastic recovery along the driving direction reduces or cancels the mover's retraction displacement, thereby improving the effective output displacement per cycle and the stability of continuous drive. Summary of the Invention

[0004] The purpose of this invention is to provide a piezoelectric stick-slip actuator back-off suppression method based on elastic potential energy compensation, so as to solve the problems of existing piezoelectric stick-slip actuators that are prone to back-off displacement during the rapid voltage drop phase, reduced effective output displacement in a single cycle, and insufficient continuous driving stability.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for suppressing the retraction of a piezoelectric stick-slip actuator based on elastic potential energy compensation, the method being implemented based on a piezoelectric stick-slip actuator comprising a piezoelectric driving unit, a displacement transmission unit, an elastic energy storage element, a driving foot, and a mover.

[0007] The output displacement of the piezoelectric drive unit is transmitted to the drive foot sequentially through the displacement transmission unit and the elastic energy storage device. The elastic energy storage device is disposed between the displacement transmission unit and the drive foot, and forms a mechanical coupling relationship with the displacement transmission unit and the drive foot respectively, so as to receive the output displacement or output force of the displacement transmission unit and transmit the elastic recovery effect generated by releasing elastic potential energy to the drive foot. The drive foot maintains frictional contact with the mover.

[0008] The method includes the following steps:

[0009] A1. Apply an asymmetric drive voltage signal to the piezoelectric drive unit, including a slow voltage rise phase and a rapid voltage fall phase;

[0010] A2. During the slow voltage rise phase, the piezoelectric drive unit outputs a drive displacement, which is then transmitted to the drive foot via the displacement transmission unit and the elastic energy storage device in sequence, so as to drive the mover to move forward along the drive direction. At the same time, the elastic energy storage device undergoes recoverable elastic deformation and stores elastic potential energy.

[0011] A3. During the rapid voltage drop phase, the piezoelectric drive unit is rapidly retracted, the elastic energy storage element changes from the energy storage state to the energy release state, and releases the stored elastic potential energy to generate an elastic restoring force; the elastic restoring force applies a compensation effect along the driving direction to the mover through the drive foot to reduce or offset the retraction displacement generated by the mover during the rapid voltage drop phase.

[0012] A4. Repeat steps A2 and A3 under the action of continuous asymmetric driving voltage signal to achieve cumulative positive output in which the back displacement of the mover is suppressed during the continuous driving cycle.

[0013] The mechanical coupling relationship refers to the ability of the elastic energy storage component to receive the output displacement or output force of the displacement transmission unit and undergo recoverable elastic deformation, and to transmit the resulting elastic recovery effect to the driving foot when releasing elastic potential energy. This mechanical coupling relationship can be formed through direct connection, indirect connection, abutment, clamping, pre-compression fit, or a combination of the above methods.

[0014] The elastic energy storage component may have a preset initial elastic deformation or preload before actuation, or it may not have a preset initial elastic deformation, but gradually undergo elastic deformation and store elastic potential energy under the output of the displacement transmission unit during the slow voltage rise phase. Whether to set an initial elastic deformation or preload state can be determined based on the actuator structure, mover load, friction contact state, and expected degree of backlash compensation.

[0015] The asymmetric drive voltage signal is preferably a high duty cycle asymmetric sawtooth wave voltage signal, which includes a long-duration slow voltage rise phase and a short-duration rapid voltage fall phase. The asymmetric drive voltage signal can also be other asymmetric voltage waveforms that enable the piezoelectric drive unit to form slow drive and fast retraction motions.

[0016] From the perspective of energy conversion, during the slow voltage rise phase, part of the input electrical energy is converted into mechanical energy that drives the mover to move forward, and the other part is converted into elastic potential energy through the recoverable elastic deformation of the elastic energy storage device. During the rapid voltage drop phase, the elastic energy storage device releases the stored elastic potential energy and forms a compensating mechanical output along the drive direction of the mover to reduce the backlash caused by the rapid retraction of the piezoelectric drive unit.

[0017] Elastic energy storage components include one or more of the following: flexible hinge mechanisms, elastic beams, elastic rods, leaf springs, linear springs, and torsion springs. Any structure that can store elastic potential energy through recoverable elastic deformation and can transfer the elastic recovery action to the driving foot during release can be used as an elastic energy storage component, depending on the specific driving structure.

[0018] At least one of the energy storage level, release timing and release intensity of the elastic energy storage device can be controlled by one or more of the following: preload, driving voltage amplitude, driving frequency, driving waveform duty cycle, elastic energy storage device stiffness, contact pressure between the driving foot and the mover, friction coefficient and mover load.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] First, the present invention places the elastic energy storage component between the displacement transmission unit and the driving foot, so that the output displacement of the piezoelectric driving unit is transmitted to the driving foot in sequence through the displacement transmission unit and the elastic energy storage component, and the storage of elastic potential energy can be completed simultaneously during the displacement transmission process.

[0021] Second, the present invention utilizes the elastic energy storage component to undergo recoverable elastic deformation and store elastic potential energy during the slow voltage rise phase, and releases the stored elastic potential energy during the rapid voltage drop phase, thereby applying a compensation effect along the driving direction to the mover.

[0022] Third, the present invention can reduce or offset the back displacement during the rapid voltage drop phase, increase the effective output displacement within a single driving cycle, and improve the displacement output efficiency and continuous motion stability of the piezoelectric stick-slip actuator.

[0023] Fourth, the present invention can adjust the elastic potential energy compensation effect by parameters such as preload, driving voltage amplitude, driving frequency, driving waveform duty cycle, elastic energy storage component stiffness, contact pressure, friction coefficient and mover load, which is convenient for matching with different driving structures and load conditions.

[0024] Fifth, this invention is applicable to linear or rotary piezoelectric stick-slip actuators and can employ various elastic energy storage structures, exhibiting good structural adaptability and integration capabilities. Attached Figure Description

[0025] The accompanying drawings are used to further illustrate the technical solutions of the present invention and constitute a part of this specification. The embodiments shown in the drawings are for illustrative purposes only and should not be construed as limiting the scope of protection of the present invention.

[0026] Figure 1 A schematic diagram illustrating the mechanical coupling relationship between the piezoelectric drive unit, displacement transmission unit, elastic energy storage device, drive foot, and mover provided in an embodiment of the present invention.

[0027] Figure 2 A schematic diagram of a typical structural form of the elastic energy storage device provided in an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of energy conversion during the slow voltage rise phase and the rapid voltage fall phase provided in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of a back-off suppression process within a driving cycle provided in an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram showing the relationship between elastic restoring force and sliding friction force during the rapid voltage drop phase, as well as a comparison of displacement output, provided in an embodiment of the present invention.

[0031] Explanation of reference numerals in the attached drawings: 1. Piezoelectric drive unit; 2. Displacement transmission unit; 3. Elastic energy storage component; 3-1. Flexible hinge mechanism; 3-2. Elastic beam; 3-3. Elastic rod; 3-4. Leaf spring; 3-5. Linear spring; 3-6. Torsion spring; 4. Drive foot; 5. Moving element. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Equivalent substitutions or modifications made by those skilled in the art to the structural form, connection method, driving parameters, and elastic energy storage form without departing from the concept of the present invention should all be included within the scope of protection of the present invention.

[0033] like Figure 1As shown, this embodiment provides a piezoelectric stick-slip actuator retraction suppression method based on elastic potential energy compensation. The method is based on a piezoelectric stick-slip actuator including a piezoelectric drive unit (1), a displacement transmission unit (2), an elastic energy storage element (3), a drive foot (4), and a mover (5). The piezoelectric drive unit (1) is used to generate extensional displacement, bending displacement, or other driving deformation under the action of an external drive voltage; the piezoelectric drive unit (1) can be a piezoelectric stack, a piezoelectric ceramic sheet, a piezoelectric bending beam, or other piezoelectric elements that can generate controllable displacement output; the displacement transmission unit (2) is used to receive the output displacement of the piezoelectric drive unit (1) and transmit, convert, or amplify the output displacement. The output end of the displacement transmission unit (2) is connected to the elastic energy storage element (3), which is disposed between the displacement transmission unit (2) and the drive foot (4), and the drive foot (4) maintains frictional contact with the mover (5).

[0034] The output displacement of the piezoelectric drive unit (1) can be transmitted to the drive foot (4) through the displacement transmission unit (2) and the elastic energy storage element (3); the elastic energy storage element (3) forms a mechanical coupling relationship with the piezoelectric drive unit (1) and the drive foot (4) respectively. The mechanical coupling relationship means that the elastic energy storage element (3) can receive the output displacement or output force of the displacement transmission unit (2), undergo recoverable elastic deformation under the action of the output displacement or output force, and can transmit the generated elastic recovery effect to the drive foot (4) when releasing elastic potential energy. The mechanical coupling relationship can be formed by direct connection, indirect connection, contact abutment, clamping connection, pre-pressing fit or a combination of the above connection methods. As long as the elastic energy storage element (3) can participate in the transmission of output displacement and output force from the piezoelectric drive unit (1) to the drive foot (4) and can transmit the elastic recovery effect to the drive foot (4), the mechanical coupling relationship can be formed. The drive foot (4) and the mover (5) maintain a preset frictional contact state, so that the drive foot (4) can drive the mover (5) to generate positive movement along the driving direction through friction during the slow voltage rise stage. The contact pressure, contact area and friction coefficient between the driving foot (4) and the moving part (5) can be set according to the structure of the driver and the load requirements.

[0035] like Figure 2As shown, the elastic energy storage component (3) can be one or more combinations of a flexible hinge mechanism (3-1), an elastic beam (3-2), an elastic rod (3-3), a leaf spring (3-4), a linear spring (3-5), and a torsion spring (3-6). The flexible hinge mechanism (3-1) can store elastic potential energy through local flexible deformation, and is suitable for compact structures, backlash-free applications, and high-precision displacement transmission. The elastic beam (3-2) can store elastic potential energy through bending deformation. The elastic rod (3-3) can store elastic potential energy through stretching, compression, bending, or torsion deformation. The leaf spring (3-4) is suitable for providing elastic recovery in a limited space. The linear spring (3-5) can provide elastic recovery force in the linear direction. The torsion spring (3-6) can provide elastic recovery force in the rotational direction. The above-mentioned elastic energy storage component (3) can be used alone or in combination to adapt to different types of linear or rotary piezoelectric stick-slip actuators. Figure 2 The structure shown is only a typical example. The specific shape, size, material and installation form of the elastic energy storage component (3) can be determined according to the drive structure and backoff compensation requirements.

[0036] In one embodiment, the elastic energy storage element (3) has a preset initial elastic deformation or pre-tightening state before being driven, so that the elastic energy storage element (3) has initial elastic potential energy. In another embodiment, the elastic energy storage element (3) does not have a preset initial elastic deformation before being driven, but gradually undergoes elastic deformation and stores elastic potential energy under the output action of the displacement transmission unit (2) during the slow voltage rise stage.

[0037] Whether to set an initial elastic deformation or preload state can be determined based on the structure of the piezoelectric stick-slip actuator, the mover load, the frictional contact state, and the expected degree of backlash compensation.

[0038] like Figure 3 As shown, an asymmetric driving voltage signal, including a slow voltage rise phase and a rapid voltage fall phase, is applied to the piezoelectric drive unit (1). The asymmetric driving voltage signal is preferably a high duty cycle asymmetric sawtooth wave voltage signal, the duration of which is longer than the duration of which is longer than the duration of which is longer. During the slow voltage rise phase, the input electrical energy is converted into mechanical deformation energy by the piezoelectric drive unit (1). Part of this mechanical energy is transmitted sequentially to the mover (5) via the displacement transmission unit (2), the elastic energy storage element (3), and the drive foot (4) to drive the mover (5) to generate positive motion; the other part of the mechanical energy is converted into elastic potential energy through the recoverable elastic deformation of the elastic energy storage element (3). During the rapid voltage fall phase, the piezoelectric drive unit (1) retracts rapidly, the elastic energy storage element (3) changes from the energy storage state to the energy release state, and releases the stored elastic potential energy. The released elastic potential energy is converted into compensating mechanical action along the driving direction of the mover (5) to reduce or offset the mover retraction caused by the rapid retraction of the piezoelectric drive unit (1).

[0039] like Figure 4 As shown, within one driving cycle, the backoff suppression process of the present invention mainly includes a slow voltage rise phase and a rapid voltage fall phase.

[0040] During the slow voltage rise phase, the driving displacement output by the piezoelectric drive unit (1) is transmitted to the drive foot (4) via the displacement transmission unit (2), and the drive foot (4) pushes the mover (5) to generate the first positive displacement θ. a1 Meanwhile, the elastic energy storage component (3) undergoes recoverable elastic deformation and stores elastic potential energy.

[0041] During the rapid voltage drop phase, the piezoelectric drive unit (1) rapidly retracts as the drive voltage decreases, and the elastic energy storage element (3) releases its stored elastic potential energy and generates an elastic restoring force. This elastic restoring force is transmitted to the mover (5) via the drive foot (4) and applies a retraction compensation effect along the drive direction to the mover (5) to counteract its retraction tendency and generate a second positive displacement θ. b1 .

[0042] After repeating the above process, the mover (5) achieves a cumulative positive output with suppressed back-off within a continuous driving cycle. By reducing or canceling the back-off displacement, the effective output displacement within a single driving cycle can be increased.

[0043] like Figure 5 As shown, during the rapid voltage drop phase, the elastic energy storage component (3) releases its elastic potential energy and generates an elastic restoring force. The elastic restoring force and the friction between the driving foot (4) and the mover (5) jointly affect the displacement change of the mover (5) during the rapid voltage drop phase. When the elastic restoring effect is weak, the mover (5) may still generate a certain back displacement, but this back displacement can be smaller than the back displacement when the elastic energy storage component (3) is not installed; when the elastic restoring effect matches the back displacement trend of the driving system, the back displacement of the mover (5) can be significantly reduced or a positive displacement can be generated.

[0044] Compared with typical piezoelectric stick-slip drive methods that do not employ elastic potential energy compensation, this invention can keep the displacement output curve horizontal or continue to rise during the rapid voltage drop phase, thereby improving the effective output displacement within a single drive cycle.

[0045] Furthermore, the energy storage level, release time, and release intensity of the elastic energy storage component (3) can be adjusted by one or more of the following: preload, driving voltage amplitude, driving frequency, driving waveform duty cycle, stiffness of the elastic energy storage component (3), contact pressure between the driving foot (4) and the mover (5), friction coefficient, and mover load. By adjusting the preload, the initial elastic deformation and initial elastic potential energy of the elastic energy storage component (3) can be changed; by adjusting the driving voltage amplitude, the output displacement of the piezoelectric driving unit (1) can be changed, thereby changing the deformation of the elastic energy storage component (3) during the slow voltage rise phase; by adjusting the driving frequency and driving waveform duty cycle, the energy storage and release sequence of the elastic energy storage component (3) can be changed; by adjusting the stiffness of the elastic energy storage component (3), the elastic deformation and elastic recovery force can be changed; by adjusting the contact pressure and friction coefficient, the friction transmission state between the driving foot (4) and the mover (5) can be changed; by changing the mover load, the elastic recovery action required to achieve the predetermined back-off compensation effect can be changed. As long as the elastic energy storage component (3) can undergo recoverable elastic deformation and store elastic potential energy during the slow voltage rise phase, and release the stored elastic potential energy during the rapid voltage drop phase, the driving foot (4) can apply a compensation effect along the driving direction to the mover (5) to reduce or offset the retraction displacement of the mover (5), which is in line with the technical concept of the present invention.

[0046] In summary, this invention establishes a mechanical coupling relationship between the elastic energy storage element (3) and the piezoelectric drive unit (1), displacement transmission unit (2), or drive foot (4). This allows the elastic energy storage element (3) to undergo recoverable elastic deformation and store elastic potential energy during the slow voltage rise phase, and release the stored elastic potential energy during the rapid voltage drop phase. The drive foot (4) then applies a compensation effect along the drive direction to the mover (5), thereby reducing or offsetting the retraction displacement of the mover (5) and improving the effective output displacement per cycle and the stability of continuous drive. This method has strong structural adaptability, numerous control parameters, and is easy to miniaturize and integrate, making it suitable for micro / nano positioning, precision attitude adjustment, micromanipulation, and other piezoelectric precision drive applications.

Claims

1. A method for suppressing the retraction of a piezoelectric stick-slip actuator based on elastic potential energy compensation, characterized in that, The method is based on a piezoelectric stick-slip actuator comprising a piezoelectric drive unit (1), a displacement transmission unit (2), an elastic energy storage element (3), a drive foot (4), and a mover (5); the output displacement of the piezoelectric drive unit (1) is transmitted sequentially to the drive foot (4) via the displacement transmission unit (2) and the elastic energy storage element (3); the elastic energy storage element (3) is disposed between the displacement transmission unit (2) and the drive foot (4), and forms a mechanical coupling relationship with the displacement transmission unit (2) and the drive foot (4) respectively, so as to receive the displacement or force output by the displacement transmission unit (2), and transmit the elastic recovery effect generated by releasing elastic potential energy to the drive foot (4); the drive foot (4) and the mover (5) maintain frictional contact; The method includes the following steps: A1. Apply an asymmetric drive voltage signal, including a slow voltage rise phase and a rapid voltage fall phase, to the piezoelectric drive unit (1); A2. During the slow voltage rise phase, the piezoelectric drive unit (1) outputs a drive displacement, which is then transmitted to the drive foot (4) via the displacement transmission unit (2) and the elastic energy storage device (3) in sequence, so as to drive the mover (5) to move in the positive direction along the drive direction, while the elastic energy storage device (3) undergoes recoverable elastic deformation and stores elastic potential energy. A3. During the rapid voltage drop phase, the piezoelectric drive unit (1) is rapidly retracted, and the elastic energy storage component (3) changes from the energy storage state to the energy release state, releasing the stored elastic potential energy and generating an elastic restoring force; the elastic restoring force applies a compensation effect along the driving direction to the mover (5) through the drive foot (4) to reduce or offset the retraction displacement generated by the mover (5) during the rapid voltage drop phase. A4. Repeat steps A1 to A3 to make the mover (5) achieve a cumulative positive output with suppressed backoff in a continuous driving cycle.

2. The method for suppressing the retraction of a piezoelectric stick-slip actuator based on elastic potential energy compensation according to claim 1, characterized in that: The elastic energy storage component (3) includes one or more of the following: flexible hinge mechanism (3-1), elastic beam (3-2), elastic rod (3-3), leaf spring (3-4), linear spring (3-5), and torsion spring (3-6); the elastic energy storage component (3) has a preset initial elastic deformation or pre-tightening state before driving, or it does not have a preset initial elastic deformation but undergoes elastic deformation under the output action of displacement transmission unit (2) during the slow voltage rise stage; at least one of the following: energy storage level, release timing, and release intensity of the elastic energy storage component (3) is controlled by one or more of the following: pre-tightening force, driving voltage amplitude, driving frequency, driving waveform duty cycle, stiffness of the elastic energy storage component (3), contact pressure between driving foot (4) and mover (5), friction coefficient, and mover load.

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