Piezoelectric stick-slip linear motor driving platform

Abstract

The invention relates to the technical field of micro-nano precision driving and positioning, and discloses a piezoelectric stick-slip linear motor driving platform which comprises a platform body, a moving surface, a guide rail and a piezoelectric driving mechanism. The piezoelectric driving mechanism comprises a base, a first flexible hinge, piezoelectric ceramics, an adapter, a push rod and a second flexible hinge. The first flexible hinge comprises a cavity structure. And the piezoelectric ceramic is arranged in the cavity structure. And the first flexible hinge is connected with the push rod through the adapter. The push rod penetrates through the second flexible hinge and is clamped by the second flexible hinge. And the second flexible hinge is connected with the moving surface. The push rod drives the second flexible hinge through friction coupling. And the second flexible hinge drives the moving surface to linearly move. According to the invention, a'needle type direct drive 'piezoelectric driving mechanism is adopted, so that the device has the characteristics of high repeated positioning precision, high resolution, stable operation and high response speed, and nano-scale positioning and millimeter-scale stroke are realized. The piezoelectric driving mechanism is integrated in the table body, the structure is compact, and integration with other positioning systems is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano precision drive and positioning, and specifically relates to a piezoelectric stick-slip linear motor drive platform. Background Art

[0002] Due to the rapid development of micro-nano technology, traditional macro-scale drive devices, such as ordinary motors, gear transmissions, lead screw nuts, worm gears, etc., can hardly meet the precision requirements of modern technology. In various high-tech scientific and technological fields such as precision ultra-precision machining and measurement technologies, micro-electromechanical systems, precision optics, semiconductor manufacturing, modern medicine and biological genetic engineering, aerospace, robotics, military technology, etc., there is an urgent need for precision drive motors at the sub-micron and micro-nano levels. The discovery of the inverse piezoelectric effect of piezoelectric materials and the emergence of piezoelectric ceramic materials with excellent properties have attracted extensive attention to the research of piezoelectric precision motors, and shown broad application prospects in the field of precision drive.

[0003] A piezoelectric stick-slip linear motor is a precision micro-nano driver that utilizes the inverse piezoelectric effect of piezoelectric elements to excite an oscillator (or stator) to generate micro-amplitude vibrations under the excitation of an asymmetric electrical signal, and realizes the output of mechanical energy through the frictional coupling between the oscillator and the mover. Piezoelectric stick-slip drive mainly applies a sawtooth excitation electrical signal to the piezoelectric element to excite the stator to generate fast and slow alternating motion deformations, controls the mutual conversion between the "sticking" and "slipping" motion states of the stator and the mover, and uses the frictional force to drive the mover to realize the output of mechanical motion. Existing piezoelectric stick-slip linear motors have complex structures, poor motion stability, and positioning accuracy and resolution that cannot meet the requirements of application scenarios.

[0004] Based on the above, the problem to be solved currently is: to provide a piezoelectric stick-slip linear motor drive platform with a simple structure, stable motion, high repeat positioning accuracy, and high resolution. Summary of the Invention

[0005] The purpose of the present invention is to provide a piezoelectric stick-slip linear motor drive platform, aiming to solve the problems in the prior art that the piezoelectric stick-slip linear motor platform has a complex structure, large volume, poor operation stability, and resolution and repeat positioning accuracy that cannot meet the requirements of application scenarios.

[0006] The present invention is implemented as follows. A piezoelectric stick-slip linear motor drive platform includes a table body, a moving surface, and a guide rail. A piezoelectric drive mechanism is provided between the table body and the moving surface; the piezoelectric drive mechanism includes a base, a first flexible hinge, a piezoelectric ceramic, an adapter seat, a push rod, and a second flexible hinge;

[0007] Both sides of the base are respectively connected to the table body and the first flexible hinge; the first flexible hinge includes a cavity structure, and the piezoelectric ceramic is arranged inside the cavity structure; one side of the first flexible hinge away from the base is connected to the adapter seat, and the adapter seat is connected to the push rod; the push rod penetrates through the second flexible hinge and is clamped by the second flexible hinge; the second flexible hinge is also connected to the moving surface, and the push rod drives the second flexible hinge by frictional coupling, and the second flexible hinge drives the moving surface to move linearly.

[0008] Further, the first flexible hinge includes a first fixed end, a second fixed end, a first flexible arm and a second flexible arm symmetrically arranged with the first flexible arm; the first fixed end, the first flexible arm, the second fixed end and the second flexible arm sequentially enclose the cavity structure, and both ends of the piezoelectric ceramic are respectively connected to the first fixed end and the second fixed end; the first flexible arm and the second flexible arm are set as arc-shaped structures with pre-tightening force.

[0009] Further, the first flexible hinge further includes a connection end for connecting to the adapter seat, and the connection end is connected to the side of the second fixed end away from the piezoelectric ceramic.

[0010] Further, the second flexible hinge includes a first through hole and a spring piece, the push rod penetrates through the first through hole and contacts the spring piece, and the spring piece is used to clamp the push rod to the hole wall of the first through hole.

[0011] Further, a convex block is arranged at the bottom of the moving surface, a receiving cavity for installing the second flexible hinge is arranged on the convex block, a second through hole allowing the push rod to pass through is arranged in the receiving cavity, and the convex block and the second flexible hinge are tightened by a set screw.

[0012] Further, the piezoelectric driving mechanism further includes a retaining piece for protecting the piezoelectric ceramic, and the retaining piece covers the outside of the piezoelectric ceramic and the first flexible hinge.

[0013] Further, a grating sensor is arranged between the table body and the moving surface.

[0014] Further, the grating sensor includes a grating scale and an incremental encoder, the grating scale is arranged at the bottom of the moving surface, the incremental encoder is arranged inside the table body, and the reading head of the incremental encoder is arranged corresponding to the grating scale.

[0015] Further, the base is set as a columnar body, the table body is provided with a columnar hole with a comparable size corresponding to the columnar body, and the columnar body is arranged in the columnar hole and fixed by a set screw.

[0016] Further, one end of the push rod away from the adapter seat is set as a free end, and the table body is provided with a third through hole allowing the push rod to pass through corresponding to the free end of the push rod.

[0017] The beneficial effects of the piezoelectric stick-slip linear motor driven platform provided by the present invention are as follows:

[0018] 1. The present invention adopts a "needle-type direct drive" piezoelectric drive mechanism, which has the characteristics of high repeat positioning accuracy and high resolution, and realizes nanometer-level positioning and millimeter-level stroke. The displacement direction of the piezoelectric ceramic is the same as that of the push rod and parallel to the friction force direction. The movement of the push rod will not generate a lateral force on the second flexible hinge, making the operation of the present invention more stable and the response speed faster. At the same time, the present invention has a power-off self-locking function.

[0019] 2. The piezoelectric drive mechanism is integrated in the table body, with a compact structure, small volume, high reliability, and is convenient for integration with other positioning systems. Multiple piezoelectric stick-slip linear motor driven platforms can be used in series to achieve multi-dimensional movement.

[0020] 3. The present invention is provided with a grating sensor with a displacement measurement function, and the closed-loop setting further ensures the high precision of the positioning of the present invention. Description of the Drawings

[0021] Figure 1 An exploded view of the piezoelectric stick-slip linear motor driven platform provided by the present invention;

[0022] Figure 2 A three-dimensional structural schematic diagram of the combination of the table body, guide rail, piezoelectric drive mechanism and incremental encoder provided by the present invention;

[0023] Figure 3 A three-dimensional structural schematic diagram of the combination of the moving surface, partial guide rail, piezoelectric drive mechanism and grating scale provided by the present invention;

[0024] Figure 4 A three-dimensional structural schematic diagram of the moving surface provided by the present invention;

[0025] Figure 5 A front view of the piezoelectric stick-slip linear motor driven platform provided by the present invention;

[0026] Figure 6 The present invention provides Figure 5 A sectional view taken along the A-A direction;

[0027] Figure 7 The present invention provides Figure 5 A sectional view taken along the B-B direction;

[0028] Figure 8 A partial exploded view of the piezoelectric drive mechanism provided by the present invention;

[0029] Figure 9 Left view of the second flexible hinge provided by the present invention;

[0030] In the figure: 1 - table body; 11 - columnar hole; 12 - third through hole; 13 - bottom cover; 2 - moving surface; 21 - bump; 211 - accommodation cavity; 212 - second through hole; 3 - guide rail; 4 - piezoelectric driving mechanism; 41 - base; 42 - first flexible hinge; 421 - cavity structure; 422 - first fixed end; 423 - first flexible arm; 424 - second fixed end; 425 - second flexible arm; 426 - connection end; 427 - insulating gasket; 43 - piezoelectric ceramic; 44 - adapter seat; 45 - push rod; 46 - second flexible hinge; 461 - first through hole; 462 - elastic sheet; 47 - retaining piece; 5 - setscrew; 61 - grating scale; 62 - incremental encoder; 621 - reading head. Detailed implementation manners

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0033] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and cannot be construed as limiting the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0034] Refer to Figures 1-9 as shown, which is a preferred embodiment provided by the present invention.

[0035] The piezoelectric stick-slip linear motor-driven platform includes a table body 1, a moving surface 2 provided above the table body 1, and a guide rail 3 provided between the table body 1 and the moving surface 2. Refer to Figures 1-2 . A piezoelectric driving mechanism 4 is provided between the table body 1 and the moving surface 2. A groove is provided in the table body 1, and the piezoelectric driving mechanism 4 is provided in the groove. The piezoelectric driving mechanism 4 includes a base 41, a first flexible hinge 42, a piezoelectric ceramic 43, an adapter seat 44, a push rod 45 and a second flexible hinge 46. Refer to Figure 8 .

[0036] On both sides of the base 41, it is respectively connected to the table body 1 and the first flexible hinge 42. Refer to Figure 2 . The base 41 is used to fix the first flexible hinge 42 on the table body 1. In a preferred manner, the base 41 is set as a columnar body, and the table body 1 is provided with a columnar hole 11 with a comparable size corresponding to the columnar body. The columnar body is arranged in the columnar hole 11 and fixed by a setscrew 5. One side of the base 41 away from the columnar hole 11 is connected to the first flexible hinge 42.

[0037] The first flexible hinge 42 includes a cavity structure 421. Refer to Figure 8 . The piezoelectric ceramic 43 is arranged in the cavity structure 421. The first flexible hinge 42 includes a first fixed end 422, a second fixed end 424, a first flexible arm 423, and a second flexible arm 425 symmetrically arranged with the first flexible arm 423. The first fixed end 422, the first flexible arm 423, the second fixed end 424, and the second flexible arm 425 enclose the cavity structure 421 in sequence. Both ends of the piezoelectric ceramic 43 are respectively connected to the first fixed end 422 and the second fixed end 424 through insulating gaskets 427. The first flexible arm 423 and the second flexible arm 425 are set as arc-shaped structures with a pre-tightening force, so that the piezoelectric ceramic 43 is arranged in the cavity structure 421 with a pre-tightening force. The first flexible hinge 42 further includes a connection end 426 for connecting to the adapter base 44, and the connection end 426 is connected to the side of the second fixed end 424 away from the piezoelectric ceramic 43.

[0038] One side of the first flexible hinge 42 away from the base 41 is connected to the adapter base 44. One side of the adapter base 44 away from the first flexible hinge 42 is connected to the push rod 45. The push rod 45 penetrates through the second flexible hinge 46 and is clamped by the second flexible hinge 46. Preferably, the push rod 45 is coaxially arranged with the piezoelectric ceramic 43. The outer side surface of the second flexible hinge 46 is also connected to the moving surface 2. The push rod 45 makes a linear motion along the axial direction under the action of the piezoelectric ceramic 43. The push rod 45 contacts the second flexible hinge 46 and drives the second flexible hinge 46 to make a linear motion by frictional coupling. The second flexible hinge 46 drives the moving surface 2 to move together. Refer to Figures 5-7 .

[0039] The present invention adopts a piezoelectric driving mechanism of "needle-type direct drive", that is, the piezoelectric ceramic 43 is used to directly drive the axial motion of the push rod 45. The push rod 45 drives the second flexible hinge 46 and the moving surface 2 to move through friction. By controlling the excitation voltage and using the "stick-slip principle", the present invention has the characteristics of high repeat positioning accuracy and high resolution, and realizes nanometer-level positioning and millimeter-level stroke. The displacement direction of the piezoelectric ceramic 43 is the same as the displacement direction of the push rod 45 and is parallel to the friction force direction. The movement of the push rod 45 will not generate a lateral force on the second flexible hinge 46, making the operation of the present invention more stable and the response speed faster. At the same time, the present invention has a power-off self-locking function.

[0040] The second flexible hinge 46 includes a first through hole 461 and an elastic piece 462. Refer to Figure 9 . The push rod 45 passes through the first through hole 461 and contacts the elastic piece 462. The elastic piece 462 presses against the outer wall of the push rod 45 and clamps the push rod 45 to the hole wall of the first through hole 461. The first through hole 461 preferably has a triangular cross section. One end of the push rod 45 away from the adapter 44 is set as a free end. The table body 1 is provided with a third through hole 12 allowing the push rod 45 to pass through corresponding to the free end of the push rod 45. The push rod 45 drives the second flexible hinge 46 to move by using the frictional force between it and the elastic piece 462 and the hole wall of the first through hole 461, and further pushes the moving surface 2 to move.

[0041] The bottom of the moving surface 2 is provided with a convex block 21 extending towards the table body 1. Refer to Figure 4 . The convex block 21 is provided with a receiving cavity 211 for installing the second flexible hinge 46. The receiving cavity 211 is provided with a second through hole 212 allowing the push rod 45 to pass through. The second flexible hinge 46 is installed in the receiving cavity 211, and the push rod 45 passes through the second through hole 212. The convex block 21 and the second flexible hinge 46 are tightened by a setscrew 5.

[0042] The piezoelectric driving mechanism 4 further includes a retaining piece 47 for protecting the piezoelectric ceramic 43. The retaining piece 47 covers the outside of the piezoelectric ceramic 43 and the first flexible hinge 42. Refer to Figures 8-9 .

[0043] A grating sensor 6 for displacement measurement is provided between the table body 1 and the moving surface 2. The closed-loop setting of the present invention makes its positioning more accurate. The grating sensor 6 includes a grating scale 61 and an incremental encoder 62. The grating scale 61 is provided at the bottom of the moving surface 2. An installation groove is provided in the table body 1, and the incremental encoder 62 is provided in the installation groove. The bottom of the installation groove is provided with a bottom cover 13, and the bottom cover 13 seals the installation groove by bolts. A receiving hole is provided on one side of the installation groove facing the grating scale 61. The reading head 621 of the incremental encoder 62 is provided in the receiving hole and corresponds to the grating scale 61. Refer to Figures 1-3 .

[0044] It is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A piezoelectric stick-slip linear motor-driven platform, comprising a table body (1), a moving surface (2) and a guide rail (3), characterized in that, A piezoelectric drive mechanism (4) is provided between the frustum (1) and the moving surface (2); the piezoelectric drive mechanism (4) includes a base (41), a first flexible hinge (42), a piezoelectric ceramic (43), an adapter seat (44), a push rod (45), and a second flexible hinge (46); Both sides of the base (41) are respectively connected to the frustum (1) and the first flexible hinge (42); the first flexible hinge (42) includes a cavity structure (421), and the piezoelectric ceramic (43) is arranged in the cavity structure (421); one side of the first flexible hinge (42) away from the base (41) is connected to the adapter seat (44), and the adapter seat (44) is connected to the push rod (45); the push rod (45) penetrates through the second flexible hinge (46) and is clamped by the second flexible hinge (46); the second flexible hinge (46) is also connected to the moving surface (2), the push rod (45) drives the second flexible hinge (46) by friction coupling, and the second flexible hinge (46) drives the moving surface (2) to move linearly.

2. The piezoelectric stick-slip linear motor-driven platform according to claim 1, wherein The first flexible hinge (42) includes a first fixed end (422), a second fixed end (424), a first flexible arm (423), and a second flexible arm (425) symmetrically arranged with the first flexible arm (423); the first fixed end (422), the first flexible arm (423), the second fixed end (424), and the second flexible arm (425) successively enclose the cavity structure (421), and both ends of the piezoelectric ceramic (43) are respectively connected to the first fixed end (422) and the second fixed end (424); the first flexible arm (423) and the second flexible arm (425) are arranged as arc-shaped structures with pre-tightening force.

3. The piezoelectric stick-slip linear motor-driven platform according to claim 2, characterized in that, The first flexible hinge (42) further includes a connection end (426) for connecting to the adapter seat (44), and the connection end (426) is connected to the side of the second fixed end (424) away from the piezoelectric ceramic (43).

4. The piezoelectric stick-slip linear motor-driven platform according to claim 2, wherein The second flexible hinge (46) includes a first through hole (461) and a spring piece (462), the push rod (45) penetrates through the first through hole (461) and contacts the spring piece (462), and the spring piece (462) is used to clamp the push rod (45) to the hole wall of the first through hole (461).

5. The piezoelectric stick-slip linear motor-driven platform according to claim 4, characterized in that, A convex block (21) is provided at the bottom of the moving surface (2), and the convex block (21) is provided with a receiving cavity (211) for installing the second flexible hinge (46), the receiving cavity (211) is provided with a second through hole (212) allowing the push rod (45) to pass through, and the convex block (21) and the second flexible hinge (46) are tightened by a setscrew (5).

6. The piezoelectric stick-slip linear motor-driven platform according to claim 1, wherein The piezoelectric drive mechanism (4) further includes a retaining piece (47) for protecting the piezoelectric ceramic (43), and the retaining piece (47) covers the outside of the piezoelectric ceramic (43) and the first flexible hinge (42).

7. The piezoelectric stick-slip linear motor-driven platform according to claim 1, wherein, A grating sensor (6) is provided between the frustum (1) and the moving surface (2).

8. The piezoelectric stick-slip linear motor-driven platform according to claim 1, wherein The grating sensor (6) includes a grating scale (61) and an incremental encoder (62). The grating scale (61) is disposed at the bottom of the moving surface (2), and the incremental encoder (62) is disposed within the table body (1). The reading head (621) of the incremental encoder (62) is arranged corresponding to the grating scale (61).

9. The piezoelectric stick-slip linear motor-driven platform according to claim 1, wherein The base (41) is arranged as a columnar body. The table body (1) is provided with a columnar hole (11) of a comparable size corresponding to the columnar body. The columnar body is disposed within the columnar hole (11) and fixed by a setscrew (5).

10. The piezoelectric stick-slip linear motor-driven platform according to claim 1, wherein One end of the push rod (45) away from the adapter seat (44) is set as a free end. The table body (1) is provided with a third through hole (12) allowing the push rod (45) to pass through corresponding to the free end of the push rod (45).

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