Piezoelectric stick-slip vertical motion platform

Abstract

The application discloses a piezoelectric stick-slip vertical motion platform, which comprises a base and a moving platform arranged above the base, a column body is arranged below the moving platform, and a first driving unit, a second driving unit, a third driving unit and a fourth driving unit are sequentially and equally distributed on the outer periphery of the column body; the first driving unit, the second driving unit, the third driving unit and the fourth driving unit are the same in structure and comprise a flexible mechanism and a piezoelectric actuator supported in the flexible mechanism, and the axis of the piezoelectric actuator is parallel to the column body; the flexible mechanism comprises an inclined wedge block arranged on the elongated end of the piezoelectric actuator; the inclined wedge block comprises an inclined surface portion which is inclined upward and away from the column body, and a limiting piece is arranged on the inclined surface portion; the first driving unit and the third driving unit are linked, the second driving unit and the fourth driving unit are linked, and through time sequence linkage, the column body can realize continuous lifting motion; and the application has the advantages of simple assembly and adjustment, high motion speed, strong load capacity and small friction and wear between the stator and the mover.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nano-positioning, and relates to a small-size precision displacement driver with millimeter-level large stroke and nanometer-level high resolution, in particular to a piezoelectric stick-slip positioning platform capable of moving in a vertical direction. BACKGROUND

[0002] The piezoelectric stick-slip linear motion platform is a precision displacement driver capable of realizing millimeter-level or even centimeter-level large stroke and nanometer-level high resolution. Under the action of a sawtooth wave voltage, the piezoelectric stick-slip linear motion platform continuously accumulates nanometer-level displacement of a piezoelectric actuator by means of slow elongation and rapid shortening of the piezoelectric actuator, so as to form continuous millimeter-level or even centimeter-level large stroke by the difference between static and dynamic frictional forces between a stator and a mover. Compared with an electromagnetic positioning platform, the piezoelectric stick-slip linear motion platform has the advantages of no magnetic field, easy control, no end effect and thrust fluctuation. Compared with an ultrasonic resonant type and a inchworm driving type piezoelectric linear platform, the piezoelectric stick-slip linear motion platform has the advantages of slight wear, simple control system and fast stepping speed. Therefore, the piezoelectric stick-slip linear motion platform has unique advantages in the field of micro-nano operation technology, such as micro-electro-mechanical system (MEMS) assembly, cell micro-operation, scanning electron microscope (SEM) observation and the like. However, the current piezoelectric stick-slip vertical motion platform still has the following disadvantages:

[0003] 1) The overall structure of the platform is complex and not compact;

[0004] 2) The assembly and adjustment process of the stator and the mover are complex;

[0005] 3) The platform has large motion back-off displacement and slow motion speed;

[0006] 4) The platform has small driving force and low load capacity;

[0007] 5) Most of the guiding mechanisms of the platform are not linear guides as standard parts, which on the one hand increases the processing and manufacturing cost, and on the other hand causes serious friction and wear between the stator and the mover, thereby reducing the service life of the platform. SUMMARY

[0008] The present application solves the technical problem of the prior art by providing a piezoelectric stick-slip vertical motion platform with reasonable structure layout, simple assembly and adjustment of the mover and the stator, fast motion speed, high load capacity and small friction and wear between the stator and the mover.

[0009] The technical scheme adopted by the present application to solve the above technical problem is as follows: a piezoelectric stick-slip vertical motion platform, comprising a base and a movable platform arranged above the base, wherein a column is arranged below the movable platform, and a first driving unit, a second driving unit, a third driving unit and a fourth driving unit are sequentially and equally distributed around the column.

[0010] The first driving unit, the second driving unit, the third driving unit and the fourth driving unit have the same structure, comprising a flexible mechanism and a piezoelectric actuator supported in the flexible mechanism, an axis of the piezoelectric actuator being parallel to the column body; the flexible mechanism comprises a wedge block on an elongated end of the piezoelectric actuator.

[0011] The wedge block comprises an inclined surface portion facing away from the column body, the inclined surface portion being inclined upwardly, and a limiting member on the inclined surface portion.

[0012] To optimize the above technical solution, the following measures are taken:

[0013] The flexible mechanism further comprises a first rectangular flexible hinge, a first rigid portion, an arc-shaped flexible hinge, a second rigid portion and a second rectangular flexible hinge connected in sequence, the arc-shaped flexible hinge being shared and arranged on both sides of the piezoelectric actuator; the second rectangular flexible hinge is connected to the wedge block; a gasket is arranged between the first rigid portion and the fixed end of the piezoelectric actuator, and the first rectangular flexible hinge is connected to the base.

[0014] In the preferred solution, a tubular sleeve is arranged on the base.

[0015] The tubular sleeve is arranged outside the first driving unit, the second driving unit, the third driving unit and the fourth driving unit.

[0016] In the preferred solution, the limiting member is an elastic ball head pre-tightening screw, and the tubular sleeve is provided with a first screw hole for the limiting member to be screwed into.

[0017] In the preferred solution, a limiting platform for the column body to pass through is further arranged between the tubular sleeve and the moving platform, the limiting platform is connected with a first connecting screw at the upper end of the tubular sleeve; a guide pipe for the column body to slide is arranged below the limiting platform.

[0018] In the preferred solution, the column body comprises a cylindrical segment sliding in the guide pipe and a square column segment for the wedge block to frictionally push.

[0019] In the preferred solution, the wedge block further comprises a flat portion in contact with the square column segment, and the wedge block is in flat contact with the square column segment.

[0020] In the preferred solution, a second connecting screw is connected between the base and the tubular sleeve.

[0021] In another solution, the wedge block further comprises a right-angled groove portion in contact with the square column segment, and the right-angled groove portion is clamped on the edge of the square column segment.

[0022] In another improved solution, a guide groove is arranged on the inclined surface portion to allow the limiting member to roll and slide, thereby avoiding the wedge block from shaking during movement.

[0023] Compared with the prior art, the piezoelectric stick-slip vertical motion platform of the present invention includes a base and a moving platform disposed above the base. A column is provided below the moving platform. A first driving unit, a second driving unit, a third driving unit and a fourth driving unit are distributed sequentially and equally on the outer periphery of the column. The first driving unit, the second driving unit, the third driving unit and the fourth driving unit have the same structure, including a flexible mechanism and a piezoelectric actuator supported in the flexible mechanism. The axis of the piezoelectric actuator is parallel to the column. The flexible mechanism includes a wedge block that rests on the extended end of the piezoelectric actuator. The wedge block includes an inclined surface facing away from the column, the inclined surface is inclined upward, and a limit member rests on the inclined surface.

[0024] A voltage (t) is slowly applied to the piezoelectric actuators of the first and third drive units. 10 To t 11 The elongated piezoelectric actuator then drives the column to achieve vertical movement, which in turn drives the moving platform to achieve vertical lifting. During the elongation process, the static friction between the column and the wedge increases continuously under the action of the wedge; after a certain phase difference, at t... 20 A voltage (t) is slowly applied to the piezoelectric actuators of the second and fourth drive units. 20 To t 21 Then, the elongated piezoelectric actuator also drives the column to achieve vertical movement. When the piezoelectric actuators of the first and third drive units reach their rated voltage (t... 11 If the piezoelectric actuators of the first and third drive units are suddenly de-energized, the first and third drive units will quickly resume their original states. Meanwhile, the moving platform and column will continue to move vertically under the push of the second and fourth drive units, thereby increasing the speed and driving force. After the first and third drive units complete one cycle of motion, the next cycle begins (t...). 12 To t 13 The second and fourth drive units are also in t 22 The next motion cycle begins, repeating continuously to propel the moving platform upwards, achieving large strokes at the millimeter or even centimeter level. This invention features simple assembly and adjustment of the mover and stator, high motion speed, strong load capacity, and low friction and wear between the mover and stator. Attached Figure Description

[0025] Figure 1 This is a three-dimensional structural schematic diagram of the present invention;

[0026] Figure 2 yes Figure 1 Internal structure diagram;

[0027] Figure 3 yes Figure 2 A schematic diagram of the decomposition process;

[0028] Figure 4 is Figure 3 an enlarged structural schematic view of part A in

[0029] Figure 5 is Figure 4 an exploded schematic view of

[0030] Figure 6 is Figure 3 an enlarged structural schematic view of part B in

[0031] Figure 7 is Figure 6 an exploded schematic view of

[0032] Figure 8 is a structural schematic view of the flexible mechanism in example one;

[0033] Figure 9 is an assembly cross-sectional schematic view of the inclined wedge block and the square column segment in example one;

[0034] Figure 10 is an assembly cross-sectional schematic view of the inclined wedge block and the square column segment in example two;

[0035] Figure 11 is a structural schematic view of the guide groove on the inclined wedge block in example three;

[0036] Figure 12 is a working timing diagram of the piezoelectric stick-slip vertical motion platform. DETAILED DESCRIPTION

[0037] The embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0038] Figures 1 to 11 is a structural schematic view of the present application.

[0039] wherein the reference signs are: moving platform 1, column body 11, cylindrical segment 111, square column segment 112, limiting platform 2, guide tube 21, tubular sleeve 3, first screw hole 31, base 4, first driving unit 51, second driving unit 52, third driving unit 53, fourth driving unit 54, flexible mechanism 6, inclined wedge block 61, inclined surface part 611, flat surface part 612, right-angle groove part 613, guide groove 614, second rectangular flexible hinge 62, second rigid part 63, arc-shaped flexible hinge 64, first rigid part 65, first rectangular flexible hinge 66, piezoelectric actuator 71, gasket 72, limiting part 8, first connecting screw 91, second connecting screw 92.

[0040] Example one, as Figures 1 to 5As shown in the figure, a piezoelectric inchworm vertical motion platform comprises a base 4 and a moving platform 1 arranged above the base 4, and a column 11 is arranged below the moving platform 1, and the outer periphery of the column 11 is sequentially and equally divided into a first driving unit 51, a second driving unit 52, a third driving unit 53 and a fourth driving unit 54;

[0041] The first driving unit 51, the second driving unit 52, the third driving unit 53 and the fourth driving unit 54 are the same in structure, comprising a flexible mechanism 6 and a piezoelectric actuator 71 supported in the flexible mechanism 6, and the axis of the piezoelectric actuator 71 is parallel to the column 11; the flexible mechanism 6 comprises a wedge block 61 arranged on the elongated end of the piezoelectric actuator 71.

[0042] The wedge block 61 comprises an inclined surface part 611 facing away from the column 11, and the inclined surface part 611 is inclined upward, and a limiting part 8 is arranged on the inclined surface part 611.

[0043] In the embodiment, as shown in the figure, Figures 1 to 5 , and Figure 8 The flexible mechanism 6 further comprises a first rectangular flexible hinge 66, a first rigid part 65, an arc-shaped flexible hinge 64, a second rigid part 63 and a second rectangular flexible hinge 62 connected in sequence, and the arc-shaped flexible hinge 64 is shared by a pair of hinges arranged on both sides of the piezoelectric actuator 71; the second rectangular flexible hinge 62 is connected to the wedge block 61; the first rigid part 65 is clamped between the fixed end of the piezoelectric actuator 71 and a gasket 72, and the first rectangular flexible hinge 66 is connected to the base 4.

[0044] In the embodiment, as shown in the figure, Figure 2 and Figure 3 A tubular sleeve 3 is arranged on the base 4.

[0045] The tubular sleeve 3 covers the outside of the first driving unit 51, the second driving unit 52, the third driving unit 53 and the fourth driving unit 54.

[0046] In the embodiment, the limiting part 8 is an elastic ball head pre-tightening screw, and the tubular sleeve 3 is provided with a first screw hole 31 for the limiting part 8 to be screwed into, as shown in the figures, Figure 3 and Figure 6 .

[0047] In the embodiment, as shown in the figures, Figure 2 , 3 , 6, a limiting platform 2 is further arranged between the tubular sleeve 3 and the moving platform 1 for the column 11 to pass through, and the limiting platform 2 is connected with a first connecting screw 91 at the upper end of the tubular sleeve 3; a guide pipe 21 is arranged below the limiting platform 2 for the column 11 to slide.

[0048] In the embodiment, as shown in the figure, Figure 5 The column 11 comprises a cylindrical segment 111 sliding in the guide pipe 21 and a square column segment 112 for the wedge block 61 to frictionally push.

[0049] As shown in Figure 9 embodiment, the inclined wedge block 61 further comprises a flat portion 612 in contact with the square column segment 112, and the inclined wedge block 61 is in flat contact with the square column segment 112.

[0050] As shown in Figure 2 and Figure 6 , the base 4 and the tubular sleeve 3 are connected by a second connecting screw 92.

[0051] In the second embodiment, the structure of the second embodiment is similar to that of the first embodiment, and the difference lies in the contact mode of the inclined wedge block 61 with the square column segment 112, as shown in Figure 10 , the inclined wedge block 61 further comprises a right-angled groove portion 613 in contact with the square column segment 112, and the right-angled groove portion 613 is clamped on the edge of the square column segment 112.

[0052] As shown in Figure 11 , the structure of the third embodiment is based on the first embodiment, and a guide groove 614 is arranged on the inclined surface portion 611 for the rolling and sliding of the limiting member 8.

[0053] In the optimization scheme of the third embodiment, the guide groove 614 is in communication between the flat portion 612 and the inclined surface portion 611, and the guide groove 614 is filled with rubber. When the limiting member 8 presses the rubber in the guide groove 614, the guide groove 614 will slightly overflow from the flat portion 612, thereby increasing the static friction between the flat portion 612 and the square column segment 112.

[0054] Working principle of the first to third embodiments:

[0055] As shown in Figure 12 , the piezoelectric actuators 71 of the first driving unit 51 and the third driving unit 53 are slowly applied with voltage (t 10 to t 11 ), and the elongated piezoelectric actuators 71 push the column body 11 to realize vertical movement, and then push the moving platform 1 to realize vertical lifting movement. During the elongation of the piezoelectric actuators 71, the static friction between the column body 11 and the inclined wedge block 61 is continuously increased under the action of the inclined wedge block 61; after a certain phase difference, at t 20 , the piezoelectric actuators 71 of the second driving unit 52 and the fourth driving unit 54 are slowly applied with voltage (t 20 to t 21 ), and the elongated piezoelectric actuators 71 also push the column body 11 to realize vertical movement. When the piezoelectric actuators 71 of the first driving unit 51 and the third driving unit 53 reach the rated voltage (t 11If the piezoelectric actuators 71 of the first drive unit 51 and the third drive unit 53 are suddenly de-energized, the first drive unit 51 and the third drive unit 53 will quickly resume their original states. Meanwhile, the moving platform 1 and the column 11 will continue to move vertically under the push of the second drive unit 52 and the fourth drive unit 54, thereby increasing the speed and driving force. After the first drive unit 51 and the third drive unit 53 complete one cycle of motion, the next motion cycle begins (t). 12 To t 13 The second drive unit 52 and the fourth drive unit 54 are also in t 22 The next motion cycle begins, repeating endlessly, continuously pushing the motion platform 1 upwards to achieve large strokes at the millimeter or even centimeter level.

[0056] The preferred embodiments of the present invention have been described, and various changes or modifications made by those skilled in the art will not depart from the scope of the present invention.

Claims

1. A piezoelectric inchworm vertical motion platform comprising a base (4) and a moving platform (1) disposed above the base (4), characterized in that, The lower part of the moving platform (1) is provided with a column (11), the outer periphery of the column (11) is sequentially and equally divided to be provided with a first driving unit (51), a second driving unit (52), a third driving unit (53) and a fourth driving unit (54); The first driving unit (51), the second driving unit (52), the third driving unit (53) and the fourth driving unit (54) are the same in structure, comprising a flexible mechanism (6) and a piezoelectric actuator (71) supported in the flexible mechanism (6), the axis of the piezoelectric actuator (71) is parallel to the column (11); the flexible mechanism (6) comprises an inclined wedge block (61) supported on the elongated end of the piezoelectric actuator (71); The inclined wedge block (61) comprises an inclined surface part (611) away from the column (11), the inclined surface part (611) is inclined upward, and the inclined surface part (611) is provided with a limiting part (8) on the top; The flexible mechanism (6) further comprises a first rectangular flexible hinge (66), a first rigid part (65), an arc-shaped flexible hinge (64), a second rigid part (63) and a second rectangular flexible hinge (62) connected in sequence, the arc-shaped flexible hinge (64) has a pair, which is arranged on both sides of the piezoelectric actuator (71); the second rectangular flexible hinge (62) is connected to the inclined wedge block (61); the first rigid part (65) and the fixed end of the piezoelectric actuator (71) are clamped with a gasket (72), and the first rectangular flexible hinge (66) is connected to the base (4); The base (4) is provided with a tubular sleeve (3); The tubular sleeve (3) is covered outside the first driving unit (51), the second driving unit (52), the third driving unit (53) and the fourth driving unit (54); The limiting part (8) is an elastic ball head pre-tightening screw, and the tubular sleeve (3) is provided with a first screw hole (31) for the limiting part (8) to be screwed into.

2. The piezoelectric inchworm vertical motion platform of claim 1, wherein, The tubular sleeve (3) and the moving platform (1) are further provided with a limiting platform (2) for the column (11) to pass through, the limiting platform (2) is connected with a first connecting screw (91) at the upper end of the tubular sleeve (3); the lower part of the limiting platform (2) is provided with a guide pipe (21) for the column (11) to slide.

3. The piezoelectric inchworm vertical motion platform of claim 2, wherein, The column (11) comprises a cylindrical segment (111) sliding in the guide pipe (21) and a square column segment (112) for the inclined wedge block (61) to frictionally push.

4. The piezoelectric inchworm vertical motion platform of claim 3, wherein, The inclined wedge block (61) further comprises a flat part (612) in contact with the square column segment (112), and the inclined wedge block (61) is in contact with the flat part of the square column segment (112).

5. A piezoelectric inchworm vertical motion platform according to claim 4, wherein, The inclined wedge block (61) further comprises a right-angle groove part (613) in contact with the square column segment (112), and the right-angle groove part (613) is clamped on the edge of the square column segment (112).

6. A piezoelectric inchworm vertical motion platform according to any one of claims 4 to 5, wherein, The base (4) and the tubular sleeve (3) are connected with a second connecting screw (92).

7. A piezoelectric inchworm vertical motion platform according to claim 6, wherein, The inclined wedge block (61) is provided with a guide groove (614) on the inclined surface part (611) for the limiting part (8) to roll and slide.

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