Bionic stepping plane universal piezoelectric positioning platform based on differential friction driving

Abstract

The invention discloses a bionic stepping plane universal piezoelectric positioning platform based on differential friction driving, which belongs to the technical field of precision driving and comprises a nesting unit A, a nesting unit B, a nesting unit C and a connecting seat. The nesting unit C comprises four pairs of piezoelectric wafers, an outer driving mechanism, an inner driving mechanism and a driving foot; the inner driving mechanisms and the outer driving mechanisms in the three nested units are pushed to generate time sequence deformation by controlling time sequence excitation of voltage on the piezoelectric wafers, so that the driving feet generate time sequence displacement under the action of friction force difference; therefore, the universal stepping displacement output of the positioning platform in the plane and the stepping rotation displacement output around the central axis of the positioning platform are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of precision driving, and in particular relates to a bionic stepping plane universal piezoelectric positioning platform based on differential friction driving. Background Art

[0002] With the continuous development of technology fields such as aerospace, life sciences, precision instruments, and semiconductor manufacturing, the demand for precision driving modes such as micro-displacement, high resolution, large stroke, and compact structure is also increasing. Traditional precision driving technology is mostly achieved by combining mechanical, fluid, and electromagnetic technologies, but due to the limitations of its working principle, it is difficult to achieve driving requirements such as high resolution and compact structure. Piezoelectric drive is based on the inverse piezoelectric effect of piezoelectric materials. It controls the mechanical deformation of piezoelectric materials by applying voltage to generate rotation or linear motion. Piezoelectric drive has quickly become a hot research direction in the field of new precision drive technology due to its fast response speed, high resolution, and large stroke. Most of the existing piezoelectric drive technologies only realize single-degree-of-freedom and two-degree-of-freedom movements and often produce large parasitic displacements, which is not conducive to precision driving. There is a lack of piezoelectric drive mechanisms that can integrate output universal displacement and rotation in a plane.

[0003] The present invention theoretically eliminates parasitic displacement based on the differential friction principle and has a compact structural design, so that the driving foot can be universally displaced in a plane, thereby realizing the universal stepping displacement output of the positioning platform in the plane and the stepping rotation displacement output around its own central axis. Summary of the invention

[0004] The purpose of the present invention is to solve the problems in the prior art that the piezoelectric drive mechanism generates large parasitic displacement when working, which is not conducive to precise driving; and lacks a piezoelectric drive mechanism that can integrate output universal displacement and rotation in a plane.

[0005] A bionic stepping plane universal piezoelectric positioning platform based on differential friction drive, comprising a nesting unit A, a nesting unit B, a nesting unit C and a connecting seat; The nested unit A, the nested unit B and the nested unit C have the same structure, and the three nested units are evenly distributed on the same circumference; The nested unit C includes four pairs of piezoelectric wafers, an outer driving mechanism, an inner driving mechanism and a driving foot; The external driving mechanism includes a driving end I, two plate-shaped flexible hinges I, a support seat and a connecting platform I. The support seat is provided with a rectangular through hole. The first ends of the two plate-shaped flexible hinges I are respectively fixedly connected to the two sides of the driving end I, and the tail ends of the two plate-shaped flexible hinges I are respectively fixedly connected to the two sides of the support seat. The connecting platform I is connected to the support seat. The inner driving mechanism comprises a connecting platform II, two plate-shaped flexible hinges II and a driving end II, the ends of the two plate-shaped flexible hinges II are respectively fixedly connected to the two sides of the driving end II, the head ends of the two plate-shaped flexible hinges II are respectively fixedly connected to the two sides of the connecting platform II, the upper end of the outer driving mechanism is fixedly connected to the upper end of the inner driving mechanism, and a fastening threaded hole II is opened at the center of the driving end II; The driving foot is installed in the fastening threaded hole Ⅱ; Piezoelectric chips are glued on both sides of the two plate-type flexible hinges I and the two plate-type flexible hinges II; By controlling the voltage to sequentially excite the piezoelectric chip, the inner and outer drive mechanisms in the three nested units are driven to produce sequential deformation, so that the driving foot produces sequential displacement under the action of the friction difference, thereby realizing the universal stepping displacement output of the positioning platform in the plane and the stepping rotation displacement output around its own central axis.

[0006] Preferably, the connecting seat includes a base and three connecting platforms III, the base is provided with a center hole and three through holes II, the three through holes II are evenly distributed in a circle outside the center hole, the center hole and the three through holes II are used for later installation of the stage, the three connecting platforms III are evenly distributed on the same circle and fixedly connected to the base, and the three connecting platforms III are provided with two fastening threaded holes III for connecting nested unit A, nested unit B and nested unit C.

[0007] Preferably, a rectangular through groove is opened at the driving end I, two through holes I are arranged on the driving end I, a rectangular through groove is opened at the connecting platform II, two fastening threaded holes I corresponding to the through holes I are processed on the connecting platform II, two fastening bolts II respectively pass through the through holes I and are installed in the fastening threaded holes I, so that the upper surface of the rectangular through groove of the driving end I and the lower surface of the rectangular through groove of the connecting platform II are tightly fitted.

[0008] Preferably, the connecting platform I is provided with two countersunk holes corresponding to the fastening threaded holes III, and two fastening bolts I respectively pass through the countersunk holes and are installed in the fastening threaded holes III, thereby fixing the nested unit C and the connecting seat.

[0009] Preferably, the nested unit C also includes a fastening nut, and the fastening nut is threadedly connected to the driving foot. The driving foot is a ceramic ball screw, and a ceramic ball is installed at the bottom of the screw.

[0010] Preferably, the length and width of the rectangular through hole in the outer driving mechanism are respectively greater than the length and width of the driving end II in the inner driving mechanism, ensuring that the driving end II in the inner driving mechanism can be displaced in the rectangular through hole of the outer driving mechanism.

[0011] Preferably, the outer driving mechanism and the inner driving mechanism are respectively integrally machined from a whole piece of elastic metal material.

[0012] Beneficial effects of the present invention: By controlling the voltage to sequentially excite the piezoelectric chip, the inner and outer drive mechanisms in the three centrally symmetrically distributed nested units are driven to produce sequential deformation, so that the drive foot produces sequential displacement under the action of the friction difference, thereby realizing the universal stepping displacement output of the positioning platform in the plane and the stepping rotation displacement output around its own central axis. In theory, parasitic displacement is eliminated, providing new ideas for the design of a piezoelectric drive mechanism that can integrate the output of universal displacement and rotation in a plane. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is an exploded view of the three-dimensional structure of the nested unit of the present invention; Figure 3 It is a schematic diagram of the three-dimensional structure of the external driving mechanism of the present invention; Figure 4 It is a schematic diagram of the three-dimensional structure of the internal driving mechanism of the present invention; Figure 5 This is a schematic diagram of the three-dimensional structure of the connecting seat of the present invention; Figure 6 It is a cross-sectional view of the overall structure of the present invention; Figure 7 It is a bottom view of the overall structure of the present invention; Figure 8 This is a working principle diagram of the nested unit of the present invention; Fig. 9 This is a working principle diagram of the present invention outputting step linear displacement along the positive direction of the X-axis; Fig.10 This is a working principle diagram of the present invention outputting step linear displacement along the positive direction of the Y axis; Fig.11 This is a working principle diagram of the present invention outputting step rotation displacement clockwise around the Z axis; Fig.12 Graph showing the driving signal for outputting step-by-step linear displacement along the X and Y axes of the present invention; wherein e, f, and g are out-of-phase trapezoidal waveform graphs, and h and i are out-of-phase triangular waveform graphs; Fig.13 This is a driving signal diagram of the present invention outputting step rotation displacement clockwise around the Z axis; wherein j and k are out-of-phase trapezoidal waveform diagrams, and m is an out-of-phase triangular waveform diagram; Wherein, each reference numeral is: 1: Nesting unit A; 2: Nesting unit B; 3: Nesting unit C; 4: Fastening bolt Ⅰ; 5: Connecting seat; 6: Fastening bolt Ⅱ; 7: External driving mechanism; 8: Piezoelectric chip; 9: Fastening nut; 10: Internal driving mechanism; 11: Driving foot; 12: Through hole Ⅰ; 13: Driving end Ⅰ; 14: Plate-type flexible hinge Ⅰ; ​​15: Rectangular through hole; 16: Support seat; 17: Countersunk hole; 18: Connecting platform Ⅰ; 19: Fastening threaded hole Ⅰ; 20: Connecting platform Ⅱ; 21: Plate-type flexible hinge Ⅱ; 22: Fastening threaded hole Ⅱ; 23: Driving end Ⅱ; 24: Connecting platform Ⅲ; 25: Fastening threaded hole Ⅲ; 26: Base; 27: Center hole; 28: Through hole Ⅱ; 1-1: piezoelectric chip D; 1-2: piezoelectric chip E; 1-3: piezoelectric chip F; 1-4: piezoelectric chip G; 1-5: piezoelectric chip H; 1-6: piezoelectric chip I; 1-7: piezoelectric chip J; 1-8: piezoelectric chip K; 2-1: piezoelectric chip L; 2-2: piezoelectric chip M; 2-3: piezoelectric chip N; 2-4: piezoelectric chip O; 2-5: piezoelectric chip P; 2-6: piezoelectric chip Q; 2-7: piezoelectric chip R; 2-8: piezoelectric chip S; 3-1: piezoelectric chip n; 3-2: piezoelectric chip o; 3-3: piezoelectric chip p; 3-4: piezoelectric chip q; 3-5: piezoelectric chip r; 3-6: piezoelectric chip s; 3-7: piezoelectric chip u; 3-8: piezoelectric chip w. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are protected by the present application.

[0015] like Figure 1-Figure 7 As shown, a bionic stepping plane universal piezoelectric positioning platform based on differential friction drive includes a nesting unit A1, a nesting unit B2, a nesting unit C3 and a connecting seat 5; The connecting base 5 includes a base 26 and three connecting platforms III 24. The base 26 is provided with a center hole 27 and three through holes II 28. The three through holes II 28 are evenly distributed on the outside of the center hole 27. The center hole 27 and the three through holes II 28 are used for later installation of the stage. The three connecting platforms III 24 are evenly distributed on the same circumference and fixedly connected to the base 26. The three connecting platforms III 24 are provided with two fastening threaded holes III 25 for connecting the nesting unit A1, the nesting unit B2 and the nesting unit C3. The nested unit C3 includes four pairs of piezoelectric wafers 8, an outer drive mechanism 7, an inner drive mechanism 10, a fastening nut 9 and a drive foot 11; The external driving mechanism 7 includes a driving end Ⅰ13, two plate-type flexible hinges Ⅰ14, a support seat 16 and a connecting platform Ⅰ18. The driving end Ⅰ13 is provided with a rectangular through groove, the support seat 16 is provided with a rectangular through hole 15, the head ends of the two plate-type flexible hinges Ⅰ14 are respectively fixedly connected to the two sides of the driving end Ⅰ13, the tail ends of the two plate-type flexible hinges Ⅰ14 are respectively fixedly connected to the two sides of the support seat 16, the connecting platform Ⅰ18 ​​is connected to the support seat 16, the connecting platform Ⅰ18 ​​is provided with two countersunk holes 17 corresponding to the fastening threaded holes Ⅲ25, the two fastening bolts Ⅰ4 respectively pass through the countersunk holes 17 and are installed in the fastening threaded holes Ⅲ25, so as to fix the nesting unit C3 and the connecting seat 5, and the driving end Ⅰ13 is provided with two through holes Ⅰ12; The inner driving mechanism 10 includes a connecting platform Ⅱ20, two plate-shaped flexible hinges Ⅱ21 and a driving end Ⅱ23. The connecting platform Ⅱ20 is provided with a rectangular through groove. The ends of the two plate-shaped flexible hinges Ⅱ21 are respectively fixedly connected to the two sides of the driving end Ⅱ23. The head ends of the two plate-shaped flexible hinges Ⅱ21 are respectively fixedly connected to the two sides of the connecting platform Ⅱ20. Two fastening threaded holes Ⅰ19 corresponding to the through holes Ⅰ12 are processed on the connecting platform Ⅱ20. Two fastening bolts Ⅱ6 pass through the through holes Ⅰ12 and are installed in the fastening threaded holes Ⅰ19, so that the upper surface of the rectangular through groove of the driving end Ⅰ13 and the lower surface of the rectangular through groove of the connecting platform Ⅱ20 are closely fitted, thereby fixing the outer driving mechanism 7 and the inner driving mechanism 10. A fastening threaded hole Ⅱ22 is provided at the center of the driving end Ⅱ23. The driving foot 11 is a ceramic ball screw, and a ceramic ball is installed at the bottom of the screw. The driving foot 11 passes through the fastening nut 9 and is installed in the fastening threaded hole II 22, so that the driving foot 11 is fixedly connected to the internal driving mechanism 10; The two plate-shaped flexible hinges Ⅰ14 and the two plate-shaped flexible hinges Ⅱ21 are both glued with piezoelectric chips 8 on both sides; The structure configurations of the nesting unit B2, the nesting unit A1 and the nesting unit C3 are completely consistent, and the three nesting units are evenly distributed on the same circumference and mounted on the connecting platform III 24 of the connecting seat 5; By controlling the voltage to sequentially excite the piezoelectric chip, the inner driving mechanism 10 and the outer driving mechanism 7 in the three nested units are driven to produce sequential deformation, so that the driving foot 11 produces sequential displacement under the action of the friction difference, thereby realizing the universal stepping displacement output of the positioning platform in the plane and the stepping rotation displacement output around its own central axis.

[0016] like Figure 2 , Figure 3 , Figure 6 , Figure 7As shown, further, the two pairs of piezoelectric chips 8 used by the external driving mechanism 7 included in the nested unit C3 are piezoelectric chip n3-1, piezoelectric chip o3-2, piezoelectric chip u3-7 and piezoelectric chip w3-8; The piezoelectric chip n3-1 and the piezoelectric chip o3-2 are symmetrically glued on both sides of a plate-type flexible hinge Ⅰ14; The piezoelectric chip u3-7 and the piezoelectric chip w3-8 are symmetrically glued on both sides of another plate-type flexible hinge Ⅰ14; The two pairs of piezoelectric chips 8 used in the inner driving mechanism 10 included in the nested unit C3 are piezoelectric chip p3-3, piezoelectric chip q3-4, piezoelectric chip r3-5 and piezoelectric chip s3-6 respectively; The piezoelectric chip p3-3 and the piezoelectric chip q3-4 are symmetrically glued on both sides of a plate-type flexible hinge II 21; The piezoelectric chip r3-5 and the piezoelectric chip s3-6 are symmetrically glued on both sides of another plate-type flexible hinge II21; The two pairs of piezoelectric chips 8 used in the external driving mechanism 7 included in the nested unit A1 are piezoelectric chip F1-3, piezoelectric chip G1-4, piezoelectric chip H1-5 and piezoelectric chip I1-6; The piezoelectric chip F1-3 and the piezoelectric chip G1-4 are symmetrically glued on both sides of a plate-type flexible hinge Ⅰ14; The piezoelectric chip H1-5 and the piezoelectric chip I1-6 are symmetrically glued on both sides of another plate-shaped flexible hinge I14; The two pairs of piezoelectric chips 8 used in the inner driving mechanism 10 included in the nested unit A1 are piezoelectric chip D1-1, piezoelectric chip E1-2, piezoelectric chip J1-7 and piezoelectric chip K1-8; The piezoelectric chip D1-1 and the piezoelectric chip E1-2 are symmetrically glued on both sides of a plate-type flexible hinge II21; The piezoelectric chip J1-7 and the piezoelectric chip K1-8 are symmetrically glued on both sides of another plate-type flexible hinge II21; The two pairs of piezoelectric chips 8 used by the external driving mechanism 7 included in the nested unit B2 are piezoelectric chip N2-3, piezoelectric chip O2-4, piezoelectric chip P2-5 and piezoelectric chip Q2-6; The piezoelectric chip N2-3 and the piezoelectric chip O2-4 are symmetrically glued on both sides of a plate-type flexible hinge Ⅰ14; The piezoelectric chip P2-5 and the piezoelectric chip Q2-6 are symmetrically glued on both sides of another plate-type flexible hinge Ⅰ14; The two pairs of piezoelectric chips 8 used in the inner driving mechanism 10 included in the nested unit A1 are piezoelectric chip L2-1, piezoelectric chip M2-2, piezoelectric chip R2-7 and piezoelectric chip S2-8; The piezoelectric chip L2-1 and the piezoelectric chip M2-2 are symmetrically glued on both sides of a plate-type flexible hinge Ⅰ14; The piezoelectric chip R2-7 and the piezoelectric chip S2-8 are symmetrically glued on both sides of another plate-type flexible hinge Ⅰ14.

[0017] like Figure 3 and Figure 4 As shown, further, the length and width of the rectangular through hole 15 in the outer drive mechanism 7 are respectively greater than the length and width of the driving end II 23 in the inner drive mechanism 10, ensuring that the driving end II 23 in the inner drive mechanism 10 can perform a slight displacement in the rectangular through hole 15 of the outer drive mechanism 7.

[0018] like Figure 3 and Figure 4 As shown, more specifically, the outer driving mechanism 7 and the inner driving mechanism 10 are each integrally machined from a whole piece of elastic metal material.

[0019] Working principle of the present invention: Reference Figure 1-Figure 8 as well as Fig.12 As shown, the driving foot can achieve a circular range of motion in the XY plane, taking nested unit A1 as an example; Apply to piezoelectric chip E1-2 and piezoelectric chip K1-8 at the same time Fig.12 The type I signal in f is applied to the piezoelectric chip D1-1 and the piezoelectric chip J1-7 at the same time. Fig.12 f, the type II signal is applied to the piezoelectric chip G1-4 and the piezoelectric chip I1-6 at the same time Fig.12 The type I signal in h is applied to the piezoelectric chip F1-3 and the piezoelectric chip H1-5 at the same time. Fig.12 h type II signal; Figure 8 As shown, during the time T / 4-T / 2, the piezoelectric chip E1-2 and the piezoelectric chip K1-8 are driven to extend by the positive voltage signal, and the piezoelectric chip D1-1 and the piezoelectric chip J1-7 are driven to shorten by the negative voltage signal. The two plate-type flexible hinges II21 are bent in the negative direction of the X-axis under the joint action of the four piezoelectric chips, driving the driving end II23 to move a distance t1 in the negative direction of the X-axis in the rectangular through hole 15, so that the driving foot 11 is displaced from point a to point a′; during the time T / 2-3T / 4, the piezoelectric chip G1-4 and the piezoelectric chip I1-6 are driven to extend by the positive voltage signal, and the piezoelectric chip F1-3 and the piezoelectric chip H1-5 are driven to shorten by the negative voltage signal. The two plate-type flexible hinges I14 are bent in the positive direction of the Y-axis under the joint action of the four piezoelectric chips, driving the entire internal driving mechanism 10 to move a distance t1 in the positive direction of the Y-axis in the rectangular through hole 15, so that the driving foot 11 is displaced from point a′ to point a". By controlling the magnitude of the excitation signal voltage of each piezoelectric chip in the nested unit A1, the driving foot 11 can be displaced to any point on the trajectory circle at a", thereby realizing the universal displacement of the driving foot 11 in the plane.

[0020] Reference Figure 1-Figure 9 as well as Fig.12 , taking the output of stepping linear displacement along the positive direction of the X-axis as an example, the specific process is as follows: Apply the same pressure to the piezoelectric chip D1-1 and the piezoelectric chip J1-7 Fig.12 The type I signal in e is applied simultaneously to the piezoelectric chip E1-2 and the piezoelectric chip K1-8 Fig.12 e Type II signal; applied simultaneously to piezoelectric chip N2-3 and piezoelectric chip P2-5 Fig.12 f, the type I signal is applied simultaneously to the piezoelectric chip O2-4 and the piezoelectric chip Q2-6 Fig.12 f Type II signal; applied simultaneously to piezoelectric chip M2-2 and piezoelectric chip S2-8 Fig.12 g, the type I signal is applied to the piezoelectric chip L2-1 and the piezoelectric chip R2-7 at the same time. Fig.12 g; Type II signal is applied to piezoelectric chip n3-1 and piezoelectric chip u3-7 at the same time Fig.12 The type I signal in h is applied simultaneously to the piezoelectric chip o3-2 and the piezoelectric chip w3-8 Fig.12 h Type II signal; applied simultaneously to piezoelectric chip p3-3 and piezoelectric chip r3-5 Fig.12 The type I signal in i is applied simultaneously to the piezoelectric chip q3-4 and the piezoelectric chip s3-6 Fig.12 Type II signal in i; 1. During the 0-T / 4 process, the voltage of the piezoelectric chip D1-1 and the piezoelectric chip J1-7 rises linearly from 0 to U1, and the voltage of the piezoelectric chip E1-2 and the piezoelectric chip K1-8 drops linearly from 0 to -U1; under the action of the inverse piezoelectric effect, the piezoelectric chip D1-1 and the piezoelectric chip J1-7 gradually extend, and the piezoelectric chip E1-2 and the piezoelectric chip K1-8 gradually shorten. Since the maximum static friction of the ground and the driving foot 11 in the three nested units is equal, the driving foot 11 in the nested unit B2 and the nested unit C3 are both in a stationary state. Therefore, at this time, the maximum reverse static friction force applied by the ground to the driving foot 11 in the nested unit A1 is less than the sum of the maximum positive friction forces applied by the ground to the driving foot 11 in the nested unit B2 and the nested unit C3. Therefore, the center of the positioning platform is stationary, and the two plate-type flexible hinges II21 in the nested unit A1 are bent, which drives the driving end II23 in the nested unit A1 to produce a displacement t, so that the driving foot 11 in the nested unit A1 is displaced from point a to point a1; 2. In the process of T / 4-T / 2, the voltage of piezoelectric chip N2-3 and piezoelectric chip P2-5 increases linearly from 0 to U2, and the voltage of piezoelectric chip O2-4 and piezoelectric chip Q2-6 decreases linearly from 0 to -U2; the voltage of piezoelectric chip M2-2 and piezoelectric chip S2-8 increases linearly from 0 to U3, and the voltage of piezoelectric chip L2-1 and piezoelectric chip R2-7 decreases linearly from 0 to -U3; under the action of the inverse piezoelectric effect, the piezoelectric chip N2-3, piezoelectric chip P2-5, piezoelectric chip M2-2 and piezoelectric chip S2-8 gradually extend, and the piezoelectric chip O2-4, piezoelectric chip Q2-6, piezoelectric chip L2-1 and piezoelectric chip R2-7 gradually shorten. Due to the maximum ground and the driving foot 11 in the three nested units, The static friction forces are equal, and the driving feet 11 in the nested unit A1 and the nested unit C3 are both in a stationary state. Therefore, at this time, the maximum reverse static friction force applied by the ground to the driving foot 11 in the nested unit B2 is less than the sum of the maximum positive friction forces applied by the ground to the driving feet 11 in the nested unit A1 and the nested unit C3. Therefore, the center of the positioning platform is stationary, and the two plate-type flexible hinges Ⅱ21 in the nested unit B2 are bent, driving the driving end Ⅱ23 in the nested unit B2 to produce a displacement t2. At the same time, the two plate-type flexible hinges Ⅰ14 in the nested unit B2 are bent, driving the entire internal driving mechanism 10 in the nested unit B2 to produce a displacement t1. Under the synthesis of displacement t1 and displacement t2, the driving foot 11 in the nested unit B2 is displaced from point b to point b1; 3. During the T / 2-3T / 4 process, the voltage of the piezoelectric chip n3-1 and the piezoelectric chip u3-7 increases linearly from 0 to U2, and the voltage of the piezoelectric chip o3-2 and the piezoelectric chip w3-8 decreases linearly to -U2; the voltage of the piezoelectric chip p3-3 and the piezoelectric chip r3-5 increases linearly from 0 to U3, and the voltage of the piezoelectric chip q3-4 and the piezoelectric chip s3-6 decreases linearly from 0 to -U3; under the action of the inverse piezoelectric effect, the piezoelectric chip n3-1, the piezoelectric chip u3-7, the piezoelectric chip p3-3 and the piezoelectric chip r3-5 gradually extend, and the piezoelectric chip o3-2, the piezoelectric chip w3-8, the piezoelectric chip q3-4 and the piezoelectric chip s3-6 gradually shorten. Due to the maximum static load of the driving foot 11 in the ground and the three nested units, The friction forces are equal, and the driving feet 11 in the nested unit A1 and the nested unit B2 are both in a stationary state. Therefore, at this time, the maximum reverse static friction force applied by the ground to the driving foot 11 in the nested unit C3 is less than the sum of the maximum positive friction forces applied by the ground to the driving feet 11 in the nested unit A1 and the nested unit B2. Therefore, the center of the positioning platform is stationary, and the two plate-type flexible hinges II21 in the nested unit C3 are bent, driving the driving end II23 in the nested unit C3 to produce a displacement t2. At the same time, the two plate-type flexible hinges I14 in the nested unit C3 are bent, driving the entire internal driving mechanism 10 in the nested unit C3 to produce a displacement t1. Under the synthesis of displacement t1 and displacement t2, the driving foot 11 in the nested unit C3 is displaced from point c to point c1; 4. During the 3T / 4-T process, the voltages of all piezoelectric chips rise / fall linearly to 0. Since there is static friction between the driving feet 11 in the three nested units and the ground, the three driving feet 11 are stationary, and the center displacement of the positioning platform is t, from point d to point d1.

[0021] If the above process is repeated continuously, the positioning platform can achieve large-stroke step linear displacement output along the positive direction of the X-axis; by changing the voltage direction, large-stroke step linear displacement output along the negative direction of the X-axis can be achieved, which will not be repeated here.

[0022] Reference Figure 1-Figure 8 as well as Fig.10 , Fig.12 , taking the output of stepping linear displacement along the positive direction of the Y axis as an example, the specific process is as follows: Apply to piezoelectric chip G1-4 and piezoelectric chip I1-6 at the same time Fig.12 The type I signal in e is applied simultaneously to the piezoelectric chip F1-3 and the piezoelectric chip H1-5 Fig.12 e Type II signal; applied simultaneously to piezoelectric chip q3-4 and piezoelectric chip s3-6 Fig.12 The type I signal in f is applied simultaneously to the piezoelectric chip p3-3 and the piezoelectric chip r3-5 Fig.12 f Type II signal; applied simultaneously to piezoelectric chip n3-1 and piezoelectric chip u3-7 Fig.12 The type I signal in g is applied simultaneously to the piezoelectric chip o3-2 and the piezoelectric chip w3-8 Fig.12 g Type II signal; applied simultaneously to piezoelectric chip M2-2 and piezoelectric chip S2-8 Fig.12 The type I signal in h is applied to the piezoelectric chip L2-1 and the piezoelectric chip R2-7 at the same time. Fig.12 h Type II signal; applied simultaneously to piezoelectric chip O2-4 and piezoelectric chip Q2-6 Fig.12 The type I signal in i is applied to the piezoelectric chip N2-3 and the piezoelectric chip P2-5 at the same time. Fig.12 Type II signal in i; 1. In the 0-T / 4 process, the voltage of the piezoelectric chip G1-4 and the piezoelectric chip I1-6 rises linearly from 0 to U1, and the voltage of the piezoelectric chip F1-3 and the piezoelectric chip H1-5 drops linearly from 0 to -U1; under the action of the inverse piezoelectric effect, the piezoelectric chip G1-4 and the piezoelectric chip I1-6 gradually extend, and the piezoelectric chip F1-3 and the piezoelectric chip H1-5 gradually shorten. Since the maximum static friction of the ground and the driving foot 11 in the three nested units are equal, the driving foot 11 in the nested unit B2 and the nested unit C3 are both in a stationary state. Therefore, at this time, the maximum reverse static friction force applied by the ground to the driving foot 11 in the nested unit A1 is less than the sum of the maximum positive friction forces applied by the ground to the driving foot 11 in the nested unit B2 and the nested unit C3. Therefore, the center of the positioning platform is stationary, and the two plate-type flexible hinges Ⅰ14 in the nested unit A1 are bent, driving the entire internal driving mechanism 10 in the nested unit A1 to produce a displacement t, so that the driving foot 11 in the nested unit A1 is displaced from point a to point a2; 2. In the process of T / 4-T / 2, the voltage of piezoelectric chip q3-4 and piezoelectric chip s3-6 increases linearly from 0 to U2, and the voltage of piezoelectric chip p3-3 and piezoelectric chip r3-5 decreases linearly from 0 to -U2; the voltage of piezoelectric chip n3-1 and piezoelectric chip u3-7 increases linearly from 0 to U3, and the voltage of piezoelectric chip o3-2 and piezoelectric chip w3-8 decreases linearly from 0 to -U3; under the action of inverse piezoelectric effect, piezoelectric chip q3-4, piezoelectric chip s3-6, piezoelectric chip n3-1 and piezoelectric chip u3-7 gradually extend, and piezoelectric chip p3-3, piezoelectric chip r3-5, piezoelectric chip o3-2 and piezoelectric chip w3-8 gradually shorten. Due to the maximum static load of the driving foot 11 in the ground and the three nested units, the piezoelectric chip q3-4, piezoelectric chip s3-6, piezoelectric chip n3-1 and piezoelectric chip u3-7 gradually extend, and the piezoelectric chip p3-3, piezoelectric chip r3-5, piezoelectric chip o3-2 and piezoelectric chip w3-8 gradually shorten. The friction forces are equal, and the driving feet 11 in the nested unit A1 and the nested unit B2 are both in a stationary state. Therefore, at this time, the maximum reverse static friction force applied by the ground to the driving foot 11 in the nested unit C3 is less than the sum of the maximum positive friction forces applied by the ground to the driving feet 11 in the nested unit A1 and the nested unit B2. Therefore, the center of the positioning platform is stationary, and the two plate-type flexible hinges II21 in the nested unit C3 are bent, driving the driving end II23 in the nested unit C3 to produce a displacement t1. At the same time, the two plate-type flexible hinges I14 in the nested unit C3 are bent, driving the entire internal driving mechanism 10 in the nested unit C3 to produce a displacement t2. Under the synthesis of displacement t1 and displacement t2, the driving foot 11 in the nested unit C3 is displaced from point c to point c2; 3. In the process of T / 2-3T / 4, the voltage of piezoelectric chip M2-2 and piezoelectric chip S2-8 increases linearly from 0 to U2, and the voltage of piezoelectric chip L2-1 and piezoelectric chip R2-7 decreases linearly to -U2; the voltage of piezoelectric chip O2-4 and piezoelectric chip Q2-6 increases linearly from 0 to U3, and the voltage of piezoelectric chip N2-3 and piezoelectric chip P2-5 decreases linearly from 0 to -U3; under the action of the inverse piezoelectric effect, the piezoelectric chip M2-2, piezoelectric chip S2-8, piezoelectric chip O2-4 and piezoelectric chip Q2-6 gradually extend, and the piezoelectric chip L2-1, piezoelectric chip R2-7, piezoelectric chip N2-3 and piezoelectric chip P2-5 gradually shorten. Due to the maximum static load of the driving foot 11 in the ground and the three nested units, the piezoelectric chip M2-2, piezoelectric chip S2-8, piezoelectric chip O2-4 and piezoelectric chip Q2-6 gradually extend, and the piezoelectric chip L2-1, piezoelectric chip R2-7, piezoelectric chip N2-3 and piezoelectric chip P2-5 gradually shorten. The friction forces are equal, and the driving feet 11 in the nested unit A1 and the nested unit C3 are both in a stationary state. Therefore, at this time, the maximum reverse static friction force applied by the ground to the driving foot 11 in the nested unit B2 is less than the sum of the maximum positive friction forces applied by the ground to the driving feet 11 in the nested unit A1 and the nested unit C3. Therefore, the center of the positioning platform is stationary, and the two plate-type flexible hinges Ⅱ21 in the nested unit B2 are bent, driving the driving end Ⅱ23 in the nested unit B2 to produce a displacement t1. At the same time, the two plate-type flexible hinges Ⅰ14 in the nested unit B2 are bent, driving the entire internal driving mechanism 10 in the nested unit B2 to produce a displacement t2. Under the synthesis of displacement t1 and displacement t2, the driving foot 11 in the nested unit B2 is displaced from point b to point b2; 4. During the 3T / 4-T process, the voltages of all piezoelectric chips rise / fall linearly to 0. Since there is static friction between the driving feet 11 in the three nested units and the ground, the three driving feet 11 are stationary, and the center displacement of the positioning platform is t, from point d to point d2; If the above process is repeated continuously, the positioning platform can achieve large-stroke step linear displacement output along the positive direction of the Y-axis; by changing the voltage direction, large-stroke step linear displacement output along the negative direction of the Y-axis can be achieved, which will not be repeated here.

[0023] In one cycle, the voltage of the excitation signal received by the piezoelectric chips in each nested unit is controlled. The excitation sequence can be based on the friction difference and displacement synthesis to make the three driving feet produce the same displacement to any position on their respective trajectory circles in the plane, and then drive the entire positioning platform to make corresponding displacement. If the above process is repeated continuously, the positioning platform can achieve universal displacement in the plane.

[0024] Reference Figure 1-Figure 8 as well as Fig.11 , Fig.13 The specific process of the clockwise rotation displacement output around the Z axis of the present invention is as follows: Apply to piezoelectric chip G1-4 and piezoelectric chip I1-6 at the same time Fig.13 The type I signal in j is applied to the piezoelectric chip F1-3 and the piezoelectric chip H1-5 at the same time. Fig.13 j Type II signal; applied simultaneously to piezoelectric chip o3-2 and piezoelectric chip w3-8 Fig.13 The type I signal in k is applied to the piezoelectric chip n3-1 and the piezoelectric chip u3-7 at the same time. Fig.13 k type II signal; simultaneously applied to piezoelectric chip N2-3 and piezoelectric chip P2-5 Fig.13 The type I signal in m is applied to the piezoelectric chip O2-4 and the piezoelectric chip Q2-6 at the same time. Fig.13 Type II signal in m; 1. In the 0-T / 4 process, the voltage of the piezoelectric chip G1-4 and the piezoelectric chip I1-6 rises linearly from 0 to U1, and the voltage of the piezoelectric chip F1-3 and the piezoelectric chip H1-5 drops linearly from 0 to -U1; under the action of the inverse piezoelectric effect, the piezoelectric chip G1-4 and the piezoelectric chip I1-6 gradually extend, and the piezoelectric chip F1-3 and the piezoelectric chip H1-5 gradually shorten. Since the maximum static friction of the ground and the driving foot 11 in the three nested units is equal, the driving foot 11 in the nested unit B2 and the nested unit C3 are both in a stationary state. Therefore, at this time, the maximum reverse static friction force applied by the ground to the driving foot 11 in the nested unit A1 is less than the sum of the maximum positive friction forces applied by the ground to the driving foot 11 in the nested unit B2 and the nested unit C3. Therefore, the center of the positioning platform is stationary, and the two plate-type flexible hinges Ⅰ14 in the nested unit A1 are bent, driving the entire internal driving mechanism 10 in the nested unit A1 to produce a displacement t, so that the driving foot 11 in the nested unit A1 is displaced from point a to point a3; 2. In the process of T / 4-T / 2, the voltage of piezoelectric chip o3-2 and piezoelectric chip w3-8 rises linearly from 0 to U1, and the voltage of piezoelectric chip n3-1 and piezoelectric chip u3-7 drops linearly from 0 to -U1; under the action of the inverse piezoelectric effect, piezoelectric chip o3-2 and piezoelectric chip w3-8 gradually extend, and piezoelectric chip n3-1 and piezoelectric chip u3-7 gradually shorten. Since the maximum static friction of the ground and the driving foot 11 in the three nested units are equal, the driving foot 11 in the nested unit B2 and the nested unit A1 are both in a stationary state. Therefore, at this time, the maximum reverse static friction force applied by the ground to the driving foot 11 in the nested unit C3 is less than the sum of the maximum positive friction forces applied by the ground to the driving foot 11 in the nested unit B2 and the nested unit A1. Therefore, the center of the positioning platform is stationary, and the two plate-type flexible hinges Ⅰ14 in the nested unit C3 are bent, driving the entire internal driving mechanism 10 in the nested unit C3 to produce a displacement t, so that the driving foot 11 in the nested unit C3 is displaced from point c to point c3; 3. During the T / 2-3T / 4 process, the voltage of the piezoelectric chip N2-3 and the piezoelectric chip P2-5 increases linearly from 0 to U1, and the voltage of the piezoelectric chip O2-4 and the piezoelectric chip Q2-6 decreases linearly from 0 to -U1; under the action of the inverse piezoelectric effect, the piezoelectric chip N2-3 and the piezoelectric chip P2-5 gradually extend, and the piezoelectric chip O2-4 and the piezoelectric chip Q2-6 gradually shorten. Since the maximum static friction of the ground and the driving foot 11 in the three nested units is equal, the driving foot 11 in the nested unit C3 and the nested unit A1 are both in a stationary state. Therefore, at this time, the maximum reverse static friction force applied by the ground to the driving foot 11 in the nested unit B2 is less than the sum of the maximum positive friction forces applied by the ground to the driving foot 11 in the nested unit C3 and the nested unit A1. Therefore, the center of the positioning platform is stationary, and the two plate-type flexible hinges Ⅰ14 in the nested unit B2 are bent, driving the entire internal driving mechanism 10 in the nested unit B2 to produce a displacement t, so that the driving foot 11 in the nested unit B2 is displaced from point b to point b3; 4. In the 3T / 4-T process, the voltages of all piezoelectric chips rise / fall linearly to 0. Since there is static friction between the driving feet 11 in the three nested units and the ground, the positioning platform rotates around the Z axis by an angle Φ. At the same time, the three driving feet are displaced W toward the Z axis under the action of the plate-type flexible hinge Ⅰ14 and the plate-type flexible hinge Ⅱ21. The three driving feet 11 are displaced from point a3 to point a4, from point b3 to point b4, and from point c3 to point c4, respectively, completing a rotational displacement output.

[0025] If the above process is repeated continuously, the positioning platform can achieve a large-stroke clockwise step rotation displacement output around the Z axis; by changing the voltage direction, a large-stroke counterclockwise step rotation displacement output around the Z axis can be achieved, which will not be repeated here.

[0026] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A bionic stepping plane universal piezoelectric positioning platform based on differential friction drive, characterized in that: It comprises a nesting unit A (1), a nesting unit B (2), a nesting unit C (3) and a connecting seat (5); The nested unit A (1), the nested unit B (2) and the nested unit C (3) have the same structure, and the three nested units are evenly distributed on the same circumference; The nested unit C (3) comprises four pairs of piezoelectric chips (8), an external driving mechanism (7), an internal driving mechanism (10) and a driving foot (11); The external driving mechanism (7) comprises a driving end I (13), two plate-shaped flexible hinges I (14), a support seat (16) and a connecting platform I (18); the support seat (16) is provided with a rectangular through hole (15); the head ends of the two plate-shaped flexible hinges I (14) are respectively fixedly connected to the two sides of the driving end I (13); the rear ends of the two plate-shaped flexible hinges I (14) are respectively fixedly connected to the two sides of the support seat (16); and the connecting platform I (18) is connected to the support seat (16); The inner driving mechanism (10) comprises a connecting platform II (20), two plate-shaped flexible hinges II (21) and a driving end II (23), the ends of the two plate-shaped flexible hinges II (21) are respectively fixedly connected to the two sides of the driving end II (23), the head ends of the two plate-shaped flexible hinges II (21) are respectively fixedly connected to the two sides of the connecting platform II (20), the upper end of the outer driving mechanism (7) is fixedly connected to the upper end of the inner driving mechanism (10), and a fastening threaded hole II (22) is opened at the center of the driving end II (23); The driving foot (11) is installed in the fastening threaded hole II (22); Piezoelectric chips (8) are glued on both sides of the two plate-shaped flexible hinges I (14) and the two plate-shaped flexible hinges II (21); By controlling the voltage to sequentially excite the piezoelectric chip, the inner driving mechanism (10) and the outer driving mechanism (7) in the three nested units are driven to produce sequential deformation, so that the driving foot (11) produces sequential displacement under the action of the friction difference, thereby realizing the universal stepping displacement output of the positioning platform in the plane and the stepping rotation displacement output around its own central axis.

2. The bionic stepping planar universal piezoelectric positioning platform based on differential friction drive according to claim 1, characterized in that: The connecting seat (5) comprises a base (26) and three connecting platforms III (24). The base (26) is provided with a center hole (27) and three through holes II (28). The three through holes II (28) are evenly distributed on the outer side of the center hole (27). The center hole (27) and the three through holes II (28) are used for later installation of the loading platform. The three connecting platforms III (24) are evenly distributed on the same circumference and are fixedly connected to the base (26). The three connecting platforms III (24) are each provided with two fastening threaded holes III (25) for connecting the nesting unit A (1), the nesting unit B (2) and the nesting unit C (3).

3. The bionic stepping planar universal piezoelectric positioning platform based on differential friction drive according to claim 2, characterized in that: The driving end I (13) is provided with a rectangular through groove, and two through holes I (12) are provided on the driving end I (13). The connecting platform II (20) is provided with a rectangular through groove, and two fastening threaded holes I (19) corresponding to the through holes I (12) are processed on the connecting platform II (20). Two fastening bolts II (6) respectively pass through the through holes I (12) and are installed in the fastening threaded holes I (19), so that the upper surface of the rectangular through groove of the driving end I (13) and the lower surface of the rectangular through groove of the connecting platform II (20) are closely fitted.

4. The bionic stepping planar universal piezoelectric positioning platform based on differential friction drive according to claim 3, characterized in that: The connecting platform I (18) is provided with two countersunk holes (17) corresponding to the fastening threaded holes III (25), and two fastening bolts I (4) respectively pass through the countersunk holes (17) and are installed in the fastening threaded holes III (25), thereby fixing the nesting unit C (3) and the connecting seat (5) together.

5. The bionic stepping planar universal piezoelectric positioning platform based on differential friction drive according to claim 4, characterized in that: The nested unit C (3) further comprises a fastening nut (9), and a driving foot (11) is threadedly connected with the fastening nut (9), and the driving foot (11) is a ceramic ball screw, and a ceramic ball is installed at the bottom of the screw.

6. The bionic stepping planar universal piezoelectric positioning platform based on differential friction drive according to claim 5, characterized in that: The length and width of the rectangular through hole (15) in the outer drive mechanism (7) are respectively greater than the length and width of the drive end II (23) in the inner drive mechanism (10), thereby ensuring that the drive end II (23) in the inner drive mechanism (10) can be displaced in the rectangular through hole (15) of the outer drive mechanism (7).

7. The bionic stepping planar universal piezoelectric positioning platform based on differential friction drive according to claim 6, characterized in that: The outer driving mechanism (7) and the inner driving mechanism (10) are respectively integrally machined from a whole piece of elastic metal material.

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