Elastically assembled dual-channel force loop piezoelectric nano-displacement stage and driving method thereof

Abstract

The present invention discloses an elastically assembled dual-channel force loop piezoelectric nano-displacement stage and a driving method thereof. Firstly, the rigid tight assembly mode of the inner slider, the platform slider and the piezoelectric body in the original scheme is changed to an elastic tight assembly mode; secondly, the three-piezoelectric body drive is changed to a combination of two piezoelectric body drives and a spring body preload, and a new stepping drive control method is used; even when the ambient temperature changes greatly, it is always in a tight assembly state, and has strong adaptability to ambient temperature changes; moreover, the piezoelectric body is always in a steady preload state, which reduces the influence of the discontinuity of the output force and output displacement of the piezoelectric body near the critical point of the mutual transformation between elongation and shortening during the stepping process of the displacement stage, greatly reduces the nonlinearity of the displacement step, and the new displacement stage can maintain uniform step length and stable speed even under open-loop conditions; in addition, the stepping speed of the nano-displacement stage has a good linear relationship with the driving signal.

Description

Technical Field

[0001] The present invention relates to a piezoelectric nano-displacement stage, in particular to an elastically assembled dual-channel force loop piezoelectric nano-displacement stage and a driving method thereof, belonging to the technical field of precision instruments. Background Art

[0002] The piezoelectric body of the push-pull piezoelectric nano-displacement stage expands and contracts in a specific order along the guide rail direction, thereby causing the piezoelectric body and each contact point of the guide rail to push and pull in a specific order, thereby achieving stepping. The driving signal of the piezoelectric body of this type of piezoelectric nano-displacement stage is stable and has no pulse signal. Therefore, they are quiet and vibration-free when working, and have little external electromagnetic interference. They are powerful positioning tools for precision optical instruments, scanning probe microscopes, and nano-machining. Its development trend is high thrust, low-voltage drive, and good environmental adaptability.

[0003] The applicant has previously applied for an invention patent "A high-load piezoelectric nano-displacement stage with a closed dual-channel force loop", application number 202011164691.0. The overall performance of the displacement stage is excellent, and its technical features are: it includes more than two inner sliders, more than three piezoelectric bodies, a platform slider, a transverse preload element, and a guide rail. The inner slider is adapted to the shape of the guide rail, and the platform slider is placed on the upper part of the guide rail. The platform slider is a hollow closed or semi-closed frame structure adapted to the shape of the guide rail. The inner slider is placed on the upper part of the guide rail and is distributed inside the platform slider along the direction of the guide rail. Piezoelectric bodies are provided between two adjacent inner sliders, between the front inner wall of the platform slider and the adjacent front inner slider, and between the rear inner wall of the platform slider and the adjacent rear inner slider; positive pressure is generated between the platform slider and the guide rail and between the inner slider and the guide rail through the transverse preload element to generate a suitable maximum static friction force.

[0004] However, an important disadvantage of the translation stage is that it has poor adaptability to changes in ambient temperature. When the ambient temperature changes, its stepping performance deteriorates sharply. This is because the two inner sliders and three piezoelectric bodies of the translation stage are rigidly and tightly assembled inside the platform slider along the guide rail direction, and the assembly deformation margin is small. The thermal expansion coefficients of these components are not the same. When the ambient temperature changes, the deformation of the platform slider is different from the total deformation of other components, which will cause the length of the piezoelectric body, the inner slider and the platform slider to mismatch, causing overall assembly looseness or even a tiny assembly gap. At this time, the deformation of the piezoelectric body driven by the control signal can often only make the assembly gap between the piezoelectric body and the inner slider or the platform slider smaller or tighter, but cannot be effectively converted into an effective displacement of the inner slider or the platform slider on the guide rail, and the driving force generated by the piezoelectric body driven by the control signal cannot be effectively transmitted, which leads to uneven step length and sometimes fast and sometimes slow speed when the translation stage steps. Especially in an environment without temperature control or an environment with a large temperature difference, the translation stage often stumbles when stepping, or even cannot step at all, which greatly affects its application range. Summary of the invention

[0005] In order to solve the above problems and avoid the relative position mismatch of the internal components of the displacement platform caused by the change of ambient temperature, the present invention designs an elastically assembled dual-channel force loop piezoelectric nano-displacement platform. First, the rigid tight assembly mode of the inner slider, the platform slider and the piezoelectric body in the original scheme is changed to an elastic tight assembly mode; secondly, the three-piezoelectric drive is changed to a combination of two piezoelectric drives and a spring body preload, and a new stepping drive control method is used; after multiple tests, it is found that under the action of the spring body preload, the relative positions of the internal components of the new nano-displacement platform are automatically adjusted, and it is always in a tight assembly state even when the ambient temperature changes greatly. Therefore, it has strong adaptability to ambient temperature changes and can work in a variable temperature environment; moreover, the piezoelectric body is always in a steady preload state, which reduces the influence of the discontinuity of the output force and output displacement of the piezoelectric body near the critical point of the mutual transformation between elongation and shortening during the stepping process of the displacement platform, greatly reduces the nonlinearity of the displacement step, and the new displacement platform can maintain uniform step length and stable speed even under open-loop conditions; in addition, the stepping speed of the nano-displacement platform has a good linear relationship with the driving signal.

[0006] The object of the present invention is achieved as follows: an elastically assembled dual-channel force loop piezoelectric nano-displacement stage, comprising a first plate, a first inner slider, a second inner slider, a first piezoelectric body, a second piezoelectric body, a spring body, a guide rail, an auxiliary preload spring and a second plate; the guide rail is fixed on the second plate, the first plate is a hollow closed or semi-closed frame structure, the first plate, the first inner slider and the second inner slider are placed on the guide rail, a first piezoelectric body is arranged between the first inner slider and the front inner wall of the first plate, A spring body is provided between the first inner slider and the second inner slider, and a second piezoelectric body is provided between the second inner slider and the rear inner wall of the first plate; the spring body produces a pre-tightening deformation, so that the first inner slider, the second inner slider, the first piezoelectric body, the second piezoelectric body and the first plate are under the effect of a constant pre-tightening force along the guide rail direction; an auxiliary pre-tightening spring is provided between the first plate and the guide rail, an auxiliary pre-tightening spring is provided between the first inner slider and the guide rail, and an auxiliary pre-tightening spring is provided between the second inner slider and the guide rail, and the auxiliary pre-tightening spring is used to ensure that the first plate, the first inner slider and the second inner slider have a suitable maximum static friction force with the guide rail.

[0007] In the elastically assembled dual-channel force loop piezoelectric nano-displacement stage, the auxiliary preload spring is a spring plunger.

[0008] In the elastically assembled dual-channel force loop piezoelectric nano-displacement stage, the total length of the first inner slider, the second inner slider, the first piezoelectric body, the second piezoelectric body and the spring body is limited by the distance between the front inner wall and the rear inner wall of the first plate.

[0009] In the above-mentioned elastically assembled dual-channel force-loop piezoelectric nanodisplacement stage, the first piezoelectric body and the second piezoelectric body can be controlled both individually and synchronously; when the first piezoelectric body or the second piezoelectric body is controlled individually, the first piezoelectric body or the second piezoelectric body extends or shortens by L, and the spring body shortens or extends by L; when the first piezoelectric body and the second piezoelectric body are controlled synchronously, the first piezoelectric body extends or shortens by L, and the second piezoelectric body shortens or extends by L.

[0010] The preload force generated by the spring body is greater than the maximum static friction force between any one of the first inner slider, the second inner slider and the first flat plate and the guide rail.

[0011] The preload deformation amount of the spring body is much larger than the maximum deformation amount of any one of the first piezoelectric body and the second piezoelectric body.

[0012] A driving method implemented on the elastically assembled dual-channel force loop piezoelectric nano-displacement stage described in any one of the above items, comprising a plurality of control cycles, each control cycle comprising the following steps:

[0013] Step a, controlling the first piezoelectric body to extend or shorten by L alone, the first inner slider slides relative to the guide rail, and at the same time, the second piezoelectric body remains stationary, and the spring body shortens or extends by L;

[0014] Step b, controlling the second piezoelectric body to shorten or lengthen L alone, the second inner slider slides relative to the guide rail, and at the same time, the first piezoelectric body remains stationary, and the spring body lengthens or shortens L;

[0015] Step c: Control the first piezoelectric body and the second piezoelectric body simultaneously, so that the first piezoelectric body is shortened or extended by L, the second piezoelectric body is extended or shortened by L, and the first plate slides by L relative to the guide rail.

[0016] Beneficial effects of the present invention:

[0017] First, when the ambient temperature changes, the internal components of the new translation stage will automatically adjust their relative positions under the pressure of the preload force of the spring body, and are always in a tightly assembled state. Therefore, the new translation stage has a strong adaptability to ambient temperature changes and can be used in variable temperature environments;

[0018] Second, the preload deformation of the spring body is in the millimeter range, which is much larger than the expansion and contraction deformation of the piezoelectric body and the thermal deformation of the components of the translation stage when the temperature changes. Therefore, the preload deformation of the spring body can be approximated as a constant value, and the piezoelectric body of the new translation stage is under a constant preload force.

[0019] Third, the piezoelectric nano-displacement stage has uniform step length and good consistency, and the step speed has a good linear relationship with the driving signal;

[0020] Fourthly, because the pre-tightening deformation of the spring body is of a macroscopic scale, the piezoelectric nano-displacement stage of the present invention is simple to debug and easy to assemble. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the elastically assembled dual-channel force loop piezoelectric nano-displacement stage of the present invention.

[0022] Figure 2 yes Figure 1 AA cross-section diagram.

[0023] Figure 3 It is a top view of the elastically assembled dual-channel force loop piezoelectric nano-displacement stage of the present invention.

[0024] Figure 4 yes Figure 3 BB cross-section diagram.

[0025] Figure 5 yes Figure 3 CC cross-section diagram.

[0026] Figure 6 yes Figure 3 DD cross-sectional view.

[0027] Figure 7 This is a step voltage control waveform diagram of the present invention.

[0028] Figure 8 It is a time-displacement diagram of the elastically assembled dual-channel force loop piezoelectric nano-displacement stage of the present invention measured experimentally.

[0029] In the figure: 1 first plate, 2-1 first inner slider, 2-2 second inner slider, 3-1 first piezoelectric body, 3-2 second piezoelectric body, 4 spring body, 5 guide rail, 6 auxiliary preload spring, 7 second plate. DETAILED DESCRIPTION

[0030] The specific implementation modes of the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] Embodiment 1

[0032] The following is a specific implementation of the elastically assembled dual-channel force loop piezoelectric nano-displacement stage of the present invention.

[0033] The elastically assembled dual-channel force loop piezoelectric nano-displacement stage under this specific embodiment is as follows Figure 1-Figure 6 As shown, it includes a first plate 1, a first inner slider 2-1, a second inner slider 2-2, a first piezoelectric body 3-1, a second piezoelectric body 3-2, a spring body 4, a guide rail 5, an auxiliary preload spring 6 and a second plate 7; wherein the first piezoelectric body 3-1 and the second piezoelectric body 3-2 are both voltage stacks; the guide rail 5 is fixed on the second plate 7, the first plate 1 is a hollow closed or semi-closed frame structure, the first plate 1, the first inner slider 2-1 and the second inner slider 2-2 are placed on the guide rail 5, and the first piezoelectric body 3-1 is provided between the first inner slider 2-1 and the front inner wall of the first plate 1, A spring body 4 is provided between the first inner slider 2-1 and the second inner slider 2-2, and a second piezoelectric body 3-2 is provided between the second inner slider 2-2 and the rear inner wall of the first plate 1; the spring body 4 produces a pre-tightening deformation, so that the first inner slider 2-1, the second inner slider 2-2, the first piezoelectric body 3-1, the second piezoelectric body 3-2 and the first plate 1 are under the effect of a constant pre-tightening force along the guide rail 5; an auxiliary pre-tightening spring 6 is provided between the first plate 1 and the guide rail 5, an auxiliary pre-tightening spring 6 is provided between the first inner slider 2-1 and the guide rail 5, and an auxiliary pre-tightening spring 6 is provided between the second inner slider 2-2 and the guide rail 5. The auxiliary pre-tightening spring 6 is used to ensure that the first plate 1, the first inner slider 2-1 and the second inner slider 2-2 all have a suitable maximum static friction force with the guide rail 5.

[0034] In this specific embodiment, the maximum static friction between the first plate 1 and the guide rail 5, the maximum static friction between the first inner slider 2-1 and the guide rail 5, and the maximum static friction between the second inner slider 2-2 and the guide rail 5 are all equal.

[0035] In this specific embodiment, the auxiliary preload spring 6 is a spring plunger.

[0036] In this specific embodiment, the total length of the first inner slider 2 - 1 , the second inner slider 2 - 2 , the first piezoelectric body 3 - 1 , the second piezoelectric body 3 - 2 and the spring body 4 is limited by the distance between the front inner wall and the rear inner wall of the first plate 1 .

[0037] In this specific embodiment, the first piezoelectric body 3-1 and the second piezoelectric body 3-2 can be controlled either individually or synchronously. When the first piezoelectric body 3-1 or the second piezoelectric body 3-2 is controlled individually, the first piezoelectric body 3-1 or the second piezoelectric body 3-2 is extended or shortened by L, and the spring body 4 is shortened or extended by L. When the first piezoelectric body 3-1 and the second piezoelectric body 3-2 are controlled synchronously, the first piezoelectric body 3-1 is extended or shortened by L, and the second piezoelectric body 3-2 is shortened or extended by L.

[0038] The preload force generated by the spring body 4 is greater than the maximum static friction force between any one of the first inner slider 2 - 1 , the second inner slider 2 - 2 and the first plate 1 and the guide rail 5 .

[0039] The preload deformation of the spring body 4 is much greater than the maximum deformation of any one of the first piezoelectric body 3 - 1 and the second piezoelectric body 3 - 2 .

[0040] Embodiment 2

[0041] The following is a specific implementation of the driving method of the elastically assembled dual-channel force loop piezoelectric nano-displacement stage of the present invention.

[0042] The driving method of the elastically mounted dual-channel force loop piezoelectric nano-displacement stage under this specific implementation is implemented on the elastically mounted dual-channel force loop piezoelectric nano-displacement stage described in the first specific implementation. The driving method includes multiple control cycles, each of which includes the following steps:

[0043] Step a, controlling the first piezoelectric body 3-1 to extend or shorten L alone, the first inner slider 2-1 slides relative to the guide rail 5, and at the same time, the second piezoelectric body 3-2 remains stationary, and the spring body 4 shortens or extends L;

[0044] Step b, controlling the second piezoelectric body 3-2 to shorten or lengthen L alone, the second inner slider 2-2 slides relative to the guide rail 5, and at the same time, the first piezoelectric body 3-1 remains stationary, and the spring body 4 lengthens or shortens L;

[0045] Step c: simultaneously control the first piezoelectric body 3-1 and the second piezoelectric body 3-2, so that the first piezoelectric body 3-1 is shortened or extended by L, the second piezoelectric body 3-2 is extended or shortened by L, and the first plate 1 slides by L relative to the guide rail 5.

[0046] like Figure 7 As shown, the specific principles are as follows:

[0047] In the time interval T0 to T1, the voltage V2 on the second piezoelectric body 3-2 remains constant, the second piezoelectric body 3-2 remains in an undeformed state, the second inner slider 2-2 and the first plate 1 form a rigid whole through the second piezoelectric body 3-2, and in this stage, the voltage V1 gradually increases, the first piezoelectric body 3-1 gradually stretches, and because the sum of the maximum static friction forces between the second inner slider 2-2 and the first plate 1 and the guide rail 5 is greater than the maximum static friction force between the first inner slider 2-1 and the guide rail 5, the spring body 4 contracts, the first inner slider 2-1 slides toward the side of the spring body 4, and the second inner slider 2-2 and the first plate 1 remain stationary relative to the guide rail;

[0048] During the time interval T1 to T2, the voltage V1 on the first piezoelectric body 3-1 remains constant, the first piezoelectric body 3-1 remains in a stationary non-deformed state, the first slider 2-1 and the first plate 1 form a rigid whole through the first piezoelectric body 3-1, and during this stage, the voltage V2 gradually decreases, and the second piezoelectric body 2-2 shortens. Since the preload force in the spring body 4 is much greater than the resistance of the piezoelectric body when it moves and greater than the friction between the first inner slider 2-1 or the second inner slider 2-2 or the first plate 1 and the guide rail 5, the spring body 4 stretches and the second inner slider 2-2 slides toward the side of the second piezoelectric body 3-2.

[0049] In the time interval T2 to T3, under the simultaneous action of voltages V2 and V1, the second piezoelectric body 3-2 stretches, the first piezoelectric body 3-1 contracts, and when the thrust difference between the second piezoelectric body and the first piezoelectric body on the two inner sides of the first plate 1 is greater than the maximum static friction between the first plate and the guide rail, the first plate 1 slides along the direction of the stretching of the piezoelectric body 3-2;

[0050] By repeating the above-mentioned stepping steps continuously, the piezoelectric nanostepper can achieve continuous stepping, so that its stroke can reach the macroscopic level (theoretically, the stroke is limited to the length of the guide rail). The positive pressure provided by the transverse preload element can ensure that the nanostepper can remain stationary and step stably in the horizontal, vertical and any tilt angle.

[0051] The following is a specific implementation method for testing the elastically assembled dual-channel force loop piezoelectric nano-displacement stage of the present invention.

[0052] Figure 8The time-displacement curve of the linear piezoelectric nanostepper with a constant preload force is actually measured. The amplitude and frequency of the driving signal tested are 10V and 10Hz respectively. The signal waveform is as follows: Figure 7 As shown, in Figure 8 In order to more clearly demonstrate the excellent performance of the piezoelectric nanostepper of the present invention in stepping upward and stepping downward, the displacement coordinate of the downward stepping has a 100um offset. Figure 8 It can be seen that the displacement y of the linear piezoelectric nanostepper with a constant preload in the present invention increases linearly with time t, and the upward and downward stepping curves of the piezoelectric nanostepper almost completely overlap. The relationship between the stepping displacement y and time t is as follows: upward stepping: y=88.0t+0.2, linearity L=0.20%; downward stepping: y=-88.6t+2555.1, linearity L=0.22%.

[0053] It should be noted that the above is only a preferred specific implementation method of the present invention, and does not impose any form of limitation on the present invention. Any simple modifications, equivalent changes and improvements made to the above specific implementation methods based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. An elastically assembled dual-channel force loop piezoelectric nano-displacement stage, characterized in that: The invention comprises a first plate (1), a first inner slider (2-1), a second inner slider (2-2), a first piezoelectric body (3-1), a second piezoelectric body (3-2), a spring body (4), a guide rail (5), an auxiliary preload spring (6) and a second plate (7); the guide rail (5) is fixed on the second plate (7); the first plate (1) is a hollow closed or semi-closed frame structure; the first plate (1), the first inner slider (2-1) and the second inner slider (2-2) are placed on the guide rail (5); a first piezoelectric body (3-1) is provided between the first inner slider (2-1) and the front inner wall of the first plate (1); a spring body (4) is provided between the first inner slider (2-1) and the second inner slider (2-2); the second inner slider (2-2) and the first plate (1) are connected to each other; ) and a second piezoelectric body (3-2) is arranged between the inner wall and the rear wall; the spring body (4) generates a pre-tightening deformation, so that the first inner slider (2-1), the second inner slider (2-2), the first piezoelectric body (3-1), the second piezoelectric body (3-2) and the first plate (1) are under the effect of a constant pre-tightening force along the guide rail (5); an auxiliary pre-tightening spring (6) is arranged between the first plate (1) and the guide rail (5), an auxiliary pre-tightening spring (6) is arranged between the first inner slider (2-1) and the guide rail (5), and an auxiliary pre-tightening spring (6) is arranged between the second inner slider (2-2) and the guide rail (5); the auxiliary pre-tightening spring (6) is used to ensure that the first plate (1), the first inner slider (2-1) and the second inner slider (2-2) have a suitable maximum static friction force with the guide rail (5).

2. The elastically assembled dual-channel force loop piezoelectric nano-displacement stage according to claim 1, characterized in that: The auxiliary preload spring (6) is a spring plunger.

3. The elastically assembled dual-channel force loop piezoelectric nano-displacement stage according to claim 1, characterized in that: The total length of the first inner slider (2-1), the second inner slider (2-2), the first piezoelectric body (3-1), the second piezoelectric body (3-2) and the spring body (4) is limited by the distance between the front inner wall and the rear inner wall of the first flat plate (1).

4. The elastically assembled dual-channel force loop piezoelectric nano-displacement stage according to claim 1, characterized in that: The first piezoelectric body (3-1) and the second piezoelectric body (3-2) can be controlled either individually or synchronously. When the first piezoelectric body (3-1) or the second piezoelectric body (3-2) is controlled individually, the first piezoelectric body (3-1) or the second piezoelectric body (3-2) is extended or shortened by L, and the spring body (4) is shortened or extended by L. When the first piezoelectric body (3-1) and the second piezoelectric body (3-2) are controlled synchronously, the first piezoelectric body (3-1) is extended or shortened by L, and the second piezoelectric body (3-2) is shortened or extended by L.

5. The elastically assembled dual-channel force loop piezoelectric nano-displacement stage according to claim 4, characterized in that: The preload force generated by the spring body (4) is greater than the maximum static friction force between any one of the first inner slider (2-1), the second inner slider (2-2) and the first flat plate (1) and the guide rail (5).

6. The elastically assembled dual-channel force loop piezoelectric nano-displacement stage according to claim 4, characterized in that: The preload deformation of the spring body (4) is much greater than the maximum deformation of any one of the first piezoelectric body (3-1) and the second piezoelectric body (3-2).

7. A driving method implemented on the elastically assembled dual-channel force loop piezoelectric nano-displacement stage according to any one of claims 1 to 6, characterized in that: It includes multiple control cycles, each of which includes the following steps: Step a, controlling the first piezoelectric body (3-1) to extend or shorten by L alone, causing the first inner slider (2-1) to slide relative to the guide rail (5), while the second piezoelectric body (3-2) remains stationary and the spring body (4) shortens or extends by L; Step b, controlling the second piezoelectric body (3-2) to shorten or lengthen L alone, the second inner slider (2-2) slides relative to the guide rail (5), and at the same time, the first piezoelectric body (3-1) remains stationary, and the spring body (4) lengthens or shortens L; Step c: simultaneously controlling the first piezoelectric body (3-1) and the second piezoelectric body (3-2) so that the first piezoelectric body (3-1) is shortened or extended by L, the second piezoelectric body (3-2) is extended or shortened by L, and the first plate (1) slides by L relative to the guide rail (5).

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