Bidirectional piezoelectric driven composite micro-displacement amplification device

Abstract

The utility model discloses a bidirectional piezoelectric driven composite micro-displacement amplification device, which acts on a motion platform and comprises two symmetrically arranged amplification units, each amplification unit comprises two symmetrically arranged amplification modules, and the symmetry axis of each amplification unit and the symmetry axis of each amplification module are cross-shaped; the amplifying unit comprises a driving mechanism, a first amplifying mechanism and a second amplifying mechanism; the driving mechanism adopts piezoelectric ceramics as a power source and acts on the input end of the secondary amplification mechanism; the output end of the secondary amplification mechanism is connected in series with the input end of the second amplification mechanism through a flexible hinge; the output ends of the two second amplification mechanisms in the amplification units on the same side act on the motion platform through the output rods, so that the technical effects of small size and large stroke are achieved.

Description

Technical Field

[0001] The utility model relates to the field of piezoelectric actuators, in particular to a bidirectional piezoelectric driven composite micro-displacement amplifying device. Background Art

[0002] With the rapid development of precision technology, the goals of miniaturization and micro-miniaturization are constantly explored. Piezoelectric actuators with new piezoelectric materials as driving elements have the advantages of high precision, fast response, low power consumption and good environmental adaptability, and are widely used in micro-displacement drives and precision instrument positioning systems.

[0003] For example, in the field of aerial camera image stabilization, since its micron-level displacement output often cannot meet the actual application requirements, it is necessary to design a displacement amplification device to amplify it. In order to meet the amplification ratio, the displacement amplification mechanism designed in the early stage can only increase the volume of the amplification mechanism, which cannot meet the characteristics of small volume and large stroke at the same time. Utility Model Content

[0004] In order to solve the above-mentioned multiple defects caused by the prior art, the utility model provides a bidirectional piezoelectric driven composite micro-displacement amplification device to achieve the technical effect of small volume and large stroke.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a bidirectional piezoelectric driven composite micro-displacement amplifying device, which acts on a motion platform and includes two symmetrically arranged amplifying units, the amplifying units include two symmetrically arranged amplifying modules, and the symmetry axes of the amplifying units and the amplifying modules are in a cross shape;

[0006] The amplification unit includes a driving mechanism, a first amplification mechanism and a second amplification mechanism; the driving mechanism adopts piezoelectric ceramics as a power source, which acts on the input end of the secondary amplification mechanism; the output end of the secondary amplification mechanism is connected in series with the input end of the second amplification mechanism through a flexible hinge; the output ends of the two second amplification mechanisms in the amplification unit on the same side act on the moving platform through the output rod.

[0007] Preferably, the driving mechanism comprises a pre-tightening fixing block, a piezoelectric ceramic and an input rod, the piezoelectric ceramic is arranged between the pre-tightening fixing block and the input rod, and both pre-tighten the piezoelectric ceramic, and the input rod acts on the first amplifying mechanism.

[0008] Preferably, the first amplification mechanism includes a primary lever and a secondary lever, which are hinged, the input end of the primary lever is hinged to the input rod, the output end of the secondary lever is hinged to the second amplification mechanism, and also includes a fixed end for fixing the primary lever and the secondary lever, and the two fixed ends are hinged to the primary lever and the secondary lever respectively.

[0009] Preferably, the second amplification mechanism comprises a connecting rod, and both ends of the connecting rod are respectively hinged to the secondary lever and the output rod.

[0010] The beneficial effects of adopting the above technical scheme are: the utility model of the utility model structure adopts two groups of symmetrical amplification units, each amplification unit includes two groups of amplification modules, which amplify four input displacements from two directions respectively, and eliminate lateral displacement errors by offsetting; it can achieve a large amplification factor, a small mechanism volume, and a small additional displacement.

[0011] The utility model adopts a flexible hinge to connect the components, the gap and friction between the components are small, the error of the magnification is reduced, and the precision is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the utility model;

[0013] Figure 2 is a structural diagram of the first amplification mechanism;

[0014] Figure 3 is a structural diagram of the second amplification mechanism;

[0015] Figure 4 It is a schematic diagram of using the construction method to find the large multiple of liberation;

[0016] Figure 5 It is a schematic diagram of the mechanism simulation magnification;

[0017] Figure 6 This is a comparison chart of displacement simulation value and theoretical value.

[0018] Among them, 1-amplification unit, 2-amplification module, 3-motion platform, 4-preload fixing block, 5-piezoelectric ceramic, 6-input rod, 7-primary lever, 8-secondary lever, 9-fixed end, 10-connecting rod, 11-output rod. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0020] Combination Figure 1-Figure 6 The specific implementation of the utility model is presented: a bidirectional piezoelectric driven composite micro-displacement amplification device, the device acts on a motion platform 3, and includes two symmetrically arranged amplification units 1, the amplification unit 1 includes two symmetrically arranged amplification modules 2, and the symmetry axis of the amplification unit 1 and the symmetry axis of the amplification module 2 are cross-shaped;

[0021] The amplifying unit 1 includes a driving mechanism, a first amplifying mechanism and a second amplifying mechanism; the driving mechanism adopts piezoelectric ceramics 5 as a power source, which acts on the input end of the secondary amplifying mechanism; the output end of the secondary amplifying mechanism is connected in series with the input end of the second amplifying mechanism through a flexible hinge; the output ends of the two second amplifying mechanisms in the amplifying unit 1 on the same side act on the motion platform 3 through the output rod 11.

[0022] The driving mechanism includes a pre-tightening fixing block 4, a piezoelectric ceramic 5 and an input rod 6. The piezoelectric ceramic 5 is arranged between the pre-tightening fixing block 4 and the input rod 6, and both pre-tighten the piezoelectric ceramic 5. The input rod 6 acts on the first amplifying mechanism. When the piezoelectric ceramic expands and contracts, the input displacement is transmitted to the first amplifying mechanism by the interaction of forces. The pre-tightening thread in the pre-tightening block adopts a fine pitch thread, which has a good anti-loosening and anti-vibration effect, can accurately adjust the pre-tightening force, and avoid damage to the piezoelectric ceramic during use or installation.

[0023] The first amplifying mechanism includes a primary lever 7 and a secondary lever 8, which are hinged. The input end of the primary lever 7 is hinged to the input rod 6, and the output end of the secondary lever 8 is hinged to the second amplifying mechanism, and also includes a fixed end 9 for fixing the primary lever 7 and the secondary lever 8, and the two fixed ends 9 are hinged to the primary lever 7 and the secondary lever 8 respectively; when in use, a small displacement is input by the piezoelectric ceramic and applied to the input rod, which is transmitted to the first amplifying mechanism, driving the primary lever to generate displacement amplification, and the primary lever amplifies the displacement again through the secondary lever.

[0024] according to Figure 2 As shown, on the primary lever, the distance between the hinge of the input rod and the hinge of the fixed end is L1, and the distance between the hinge of the fixed end and the hinge of the secondary lever is L2; ​​on the secondary lever, the distance between the hinge of the second amplification mechanism and the hinge of the primary lever is L4, and the distance between the hinge of the primary lever and the hinge of the fixed end is L3. The magnification of the secondary lever of this design model is:

[0025] (1)

[0026] (2)

[0027] (3)

[0028] The second amplification mechanism includes a connecting rod 10, and the two ends of the connecting rod 10 are respectively hinged to the secondary lever 8 and the output rod 11. The two groups of amplification modules of the amplification unit on the same side form a triangular area. When in use, the displacement amplified by the secondary lever is transmitted to the connecting rod, so that the displacement amplified by the secondary lever is further amplified, and the amplified displacement is transmitted to the output rod through the flexible hinge, and serves as the displacement output end of the amplification mechanism.

[0029] according to Figure 3 As shown, there is an input displacement in the horizontal direction According to the triangular amplification principle, there will be output displacement in the vertical direction , then the magnification We can get:

[0030] (4)

[0031] When the horizontal displacement changes After that, the angle from 1 becomes 2. Define variables = , we can get:

[0032] (5)

[0033] (6)

[0034] From equations (4), (5) and (6), we can get:

[0035] (7)

[0036] At this time due to The change is usually small, so the angle change is also very small and can be ignored. Therefore, equation (7) can be simplified to:

[0037] (8)

[0038] From formula (8), we can see that the magnification of the triangular magnification mechanism has nothing to do with other parameters, but only with the angle related, The smaller the better. Therefore, when designing the mechanism, try to minimize , so that it meets the requirements.

[0039] In the present device, the hinged positions are all hinged by flexible hinges, and each flexible hinge is a straight circular flexible hinge. The flexible hinge and the rod are integrally connected, and the hinge deformation is only half of that of the existing micro-displacement amplification device, which greatly reduces the structural stress and enables the micro-displacement amplification mechanism to have better mechanism parameters and effect.

[0040] In this embodiment, in the first amplification mechanism, the corresponding parameters of the primary lever and the secondary lever are L1=7.15, L2=14.46, L3=8.7, and L4=56.65, respectively. That is, the amplification factor of the first amplification mechanism can be calculated by formula (3) to obtain its theoretical amplification factor: for:

[0041] (9)

[0042] In the second magnifying mechanism, the triangular magnifying mechanism tilts at an angle is 19.3°. From the drawing method, we can know that the angle changes from 19.3° to 19.73°. The average value of 19.515° is taken to calculate the magnification of the triangular mechanism [7]. The theoretical magnification can be calculated from formula (8): for:

[0043] (10)

[0044] The overall magnification of the mechanism is:

[0045] (11)

[0046] like Figure 4 As shown, the input displacement is 0.01mm by the drawing method. Adding two lever lengths to the secondary lever in the figure, the displacement becomes 0.13mm. The drawing method obtains that the magnification is 13 times, which is close to the theoretical value of 13.214. Adding angles to the triangle magnification in the figure =19.32°, symmetrical drawing, while keeping the same distance, the deflection angle becomes 19.73°, the overall output displacement of the amplifying mechanism is 0.37mm, the overall magnification of the model is 37 times by drawing method, which is close to the theoretical value of 37.29.

[0047] In order to verify the correctness and accuracy of the theoretical calculation, the displacement stroke and stiffness of this model were simulated using Workbench. The mechanism uses 65Mn material, with a Poisson's ratio of 0.3, a density of 7850kg / m3, a bulk modulus of 1.67×1011Pa, and a shear modulus of 7.69×1010Pa.

[0048] After the static analysis of the mechanism, the three-dimensional model of the mechanism was imported into the software to establish a finite element model. The minimum size of the network cell was 2mm. Fixed constraints were added at the hole position and the fixed end of the lever. A horizontal displacement of 0.01mm was applied to the two output ends of the secondary lever to simulate the piezoelectric ceramics stretching 0.01mm when subjected to voltage. The output displacement of the model in the vertical direction was obtained. The loading nodes established by the model were subjected to displacement loading. The displacement cloud diagram and strain diagram of the model are shown in the figure. Figure 5 shown.

[0049] Through simulation analysis, it can be obtained that the corresponding data of input displacement and output displacement have an amplification factor of 36.72 times. According to formula (11), the theoretical amplification factor of the mechanism is 37.29. The comparison between the simulation value and the theoretical value is as follows: Figure 6 shown.

[0050] Depend on Figure 6 It can be seen from the data that the overall magnification of the composite amplifying mechanism is relatively close to the theoretical calculated value, and the simulation magnification is slightly lower than the theoretical magnification. This is because the influence of the model's own stiffness is not taken into account during the theoretical calculation, which makes the overall magnification of the mechanism slightly lower, with an error of 2%.

[0051] Depend on Figure 6 It can be seen that the displacement can be generated by the piezoelectric ceramic drive input end, and through the entire amplification mechanism, the lens can obtain a relatively large displacement compensation stroke, providing conditions for maintaining the stability of the lens. According to the requirements, NAC2013-H10 piezoelectric ceramics can be selected, with a driving voltage of 0-150V, a displacement stroke of 0-13.2μm, a maximum output of 1050N, a stiffness of 79N / μm, and a resonant frequency of 100kHz. One-dimensional micro-displacement compensation requirements for a larger stroke range can be achieved.

[0052] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A bidirectional piezoelectrically driven composite micro-displacement amplifying device, which acts on a motion platform (3), characterized in that: The invention comprises two symmetrically arranged amplifying units (1), wherein the amplifying unit (1) comprises two symmetrically arranged amplifying modules (2), and the symmetry axes of the amplifying units (1) and the symmetry axes of the amplifying modules (2) are in a cross shape; The amplification unit (1) comprises a driving mechanism, a first amplification mechanism and a second amplification mechanism; the driving mechanism uses piezoelectric ceramics (5) as a power source, which acts on the input end of the secondary amplification mechanism; the output end of the secondary amplification mechanism is connected in series with the input end of the second amplification mechanism through a flexible hinge; the output ends of the two second amplification mechanisms in the amplification unit (1) on the same side act on the motion platform (3) through an output rod (11).

2. The bidirectional piezoelectric driven composite micro-displacement amplification device according to claim 1, characterized in that: The driving mechanism comprises a pre-tightening fixing block (4), a piezoelectric ceramic (5) and an input rod (6); the piezoelectric ceramic (5) is arranged between the pre-tightening fixing block (4) and the input rod (6), and both pre-tighten the piezoelectric ceramic (5); and the input rod (6) acts on a first amplifying mechanism.

3. The bidirectional piezoelectric driven composite micro-displacement amplifying device according to claim 1, characterized in that: The first amplification mechanism comprises a primary lever (7) and a secondary lever (8), the two being hinged, the input end of the primary lever (7) being hinged to the input rod (6), the output end of the secondary lever (8) being hinged to the second amplification mechanism, and further comprising a fixed end (9) for fixing the primary lever (7) and the secondary lever (8), the two fixed ends (9) being hinged to the primary lever (7) and the secondary lever (8) respectively.

4. The bidirectional piezoelectric driven composite micro-displacement amplifying device according to claim 1, characterized in that: The second amplification mechanism comprises a connecting rod (10), and two ends of the connecting rod (10) are respectively hinged to the secondary lever (8) and the output rod (11).

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