Piezoelectric inertia bidirectional smooth precise focusing platform with z degree of freedom and driving method

Abstract

This invention discloses a Z-DOF piezoelectric inertial bidirectional smooth precision focusing platform and its driving method. Utilizing the contact assembly characteristics of piezoelectric stacks and flexible hinge mechanisms, a single-direction displacement surge is achieved. Then, the stator assembly generates parasitic motion through the weight of the optical electron microscope and the moving guide rail, combined with voltage bias. This allows for adjustment of the locking force between the stator assembly and the moving guide rail to balance the forward displacement surge and the reverse displacement retraction, achieving bidirectional smooth drive. Addressing the displacement retraction problem of traditional piezoelectric inertial drive platforms, this invention employs contact assembly between the piezoelectric stack and the flexible hinge mechanism, uses a 100% duty cycle sawtooth wave, and mounts the moving guide rail and the optical electron microscope with Z-DOF. This effectively utilizes the weight of the driven target, and the voltage bias of the piezoelectric stack adjusts the locking force between the stator assembly and the moving guide rail, thereby enabling bidirectional smooth drive and improving its bidirectional consistency.

Description

Technical Field

[0001] This invention relates to the field of precision positioning, specifically to a Z-degree-of-freedom piezoelectric inertial bidirectional smooth precision focusing platform and its driving method. Background Technology

[0002] Precision positioning, as a key technology, has become a research hotspot in advanced industrial fields. As one of the main driving mechanisms of precision positioning platforms, piezoelectric actuators possess high precision, fast response, and strong environmental adaptability, and have been widely used in aerospace, bioengineering, medical devices, materials science, and optical engineering. Compared with other piezoelectric stepping actuators, such as inchworm and traveling wave actuators, piezoelectric inertial actuators are easier to integrate and control because they can achieve motion with only a single excitation source. Typically, piezoelectric inertial actuators achieve long strokes and high resolution through periodic stepping motion. However, friction in the slip phase can lead to undesirable displacement backlash. This problem reduces actuator stability and limits its application in areas such as cell micromanipulation engineering and optical engineering. Therefore, research on solving displacement backlash has been ongoing. Related research generally falls into three categories: friction material modification, drive waveform optimization, and drive mechanism improvement. Currently, research using these three methods has failed to achieve smooth bidirectional angular displacement driving of piezoelectric inertial actuators by exciting only a single piezoelectric element.

[0003] The main technologies for addressing displacement backlash in piezoelectric inertial actuators (PIAs) fall into three categories: friction material modification, drive waveform optimization, and drive mechanism improvement. Currently, friction material modification primarily involves chemical micromachining and laser texturing. Both methods can impart anisotropy to the material surface, improving output performance in one direction but degrading performance in the other. Drive waveform optimization can improve output performance in both directions simultaneously, but it cannot completely eliminate displacement backlash. Existing technologies that improve the drive mechanism achieve smooth bidirectional drive of a single degree of freedom in a PIA through multiple excitation sources, but this is still not achievable with a single excitation source. Summary of the Invention

[0004] This invention addresses the displacement back-off problem of traditional piezoelectric inertial drive platforms by proposing a Z-degree-of-freedom piezoelectric inertial bidirectional smooth precision focusing platform and its driving method.

[0005] The technical solution of the present invention is as follows:

[0006] This invention first proposes a Z-degree-of-freedom piezoelectric inertial bidirectional smooth precision focusing platform, comprising a motion component, a stator component, a frame component, and an end cap; the motion component, stator component, and end cap are all mounted on the frame component; the end cap is fixed to the outside of the stator component;

[0007] The frame assembly includes a fixed base, a pre-tightening block, a platform base, a spotlight, and slide clips; the pre-tightening block is mounted on the fixed base, and the fixed base is assembled on the platform base; the platform base has spotlight mounting holes; the spotlight is installed in the spotlight mounting holes by interference fit; slide clip mounting screws fix two slide clips to both sides of the spotlight respectively;

[0008] The motion assembly includes an optical electron microscope, a microscope mounting screw motion guide rail, and a fixed guide rail; the optical electron microscope mounting screw is fixed to the motion guide rail, and the motion guide rail and the fixed guide rail form a set of cross-roller guide rails, and the motion guide rail is used to slide freely relative to the fixed guide rail along the guide rail direction.

[0009] The stator assembly includes a flexible hinge mechanism, a hemispherical piezoelectric stack, a Jimi screw, and a locking screw. The Jimi screw fixes the hemispherical piezoelectric stack to the flexible hinge mechanism and adjusts the locking force between the hemispherical piezoelectric stack and the flexible hinge mechanism. The locking screw locks the hemispherical piezoelectric stack and the Jimi screw and reduces the change in locking force when the hemispherical piezoelectric stack vibrates.

[0010] As a preferred embodiment of the present invention, the flexible hinge mechanism includes a drive foot, a straight-round flexible hinge, a boss I, a countersunk hole for mounting the flexible mechanism, a straight beam flexible hinge, a threaded hole for a kiomet screw, and a boss II. The drive foot is located at the top of the flexible hinge mechanism and is in contact with the motion guide rail. The straight-round flexible hinge and the straight beam flexible hinge are respectively located on the two hemispherical piezoelectric stacked drive feet on both sides of the flexible hinge mechanism. The boss I has a countersunk hole for mounting the flexible mechanism, which is used to fix the stator assembly to the frame assembly. The contact surface between the flexible hinge mechanism and the frame assembly has a boss II, which is used to avoid interference between the drive foot and the frame assembly when the drive foot vibrates.

[0011] In a preferred embodiment of the present invention, the end cap includes end cap sidewalls and end cap arc-shaped grooves; the two end cap sidewalls are symmetrically arranged at both ends of the end cap; the end cap arc-shaped grooves are formed on the end cap sidewalls to avoid motion interference between the end cap and the optical electron microscope.

[0012] As a preferred embodiment of the present invention, the fixed base is provided with a fixed guide rail mounting groove, a fixed guide rail mounting threaded hole, a boss III, an end cover mounting threaded hole, a pre-tightening block adjustment threaded hole, a stator assembly mounting threaded hole, a pre-tightening block fixing threaded hole, a trapezoidal rib, and a fixed base mounting countersunk hole; the fixed guide rail is placed and installed in the fixed guide rail mounting groove and fixedly connected by screws passing through the fixed guide rail mounting threaded hole; the boss III contacts and assembles with the pre-tightening block, and the pre-tightening block is fixed on the fixed base through the pre-tightening block adjustment threaded hole and further locked through the pre-tightening block fixing threaded hole; the stator assembly is fixed in the stator assembly mounting threaded hole through the stator assembly mounting threaded hole.

[0013] As a preferred embodiment of the present invention, the pre-tightening block includes a block mounting boss, a block mounting hole, a block pre-tightening beam, a screw pre-reserved groove, a locking screw countersunk hole, and a locking screw mounting hole; the pre-tightening block is fixed to the fixed base through the block mounting hole; the block pre-tightening beam contacts the end of the flexible hinge mechanism, the screw pre-reserved groove is used to avoid interference with the ferrule screw and the locking screw; the locking screw mounting hole is used to further lock the pre-tightening block to the fixed base.

[0014] As a preferred embodiment of the present invention, the platform base includes a countersunk hole, a spotlight mounting hole, a slide clip mounting threaded hole, a cable routing hole, a mounting groove for a fixed base, and a mounting threaded hole for a fixed base. The mounting groove for a fixed base is used to assemble a fixed base, and the platform base and the fixed base are fixed together by screws through the mounting threaded hole for a fixed base. The mounting groove for a fixed guide rail is used to install a fixed guide rail. The countersunk hole for a platform base is used to fix the platform base to external equipment by screws. The spotlight is installed in the spotlight mounting hole by an interference fit, and its power supply wire is led out through the cable routing hole. The mounting screws for the slide clips pass through the slide clips and the mounting threaded hole for a slide clip to fix the slide clips onto the platform base.

[0015] The present invention also provides a driving method for the above-mentioned Z-degree-of-freedom piezoelectric inertial bidirectional smooth precision focusing platform:

[0016] Vertically upward is defined as the positive direction; during positive drive, a sawtooth wave with a duty cycle of 100% is applied to the precision focusing platform to achieve positive motion; specifically, it is divided into the following three stages:

[0017] Adhesion stage: From time t0 to t1, the excitation voltage gradually increases; the flexible hinge mechanism slowly elongates under the action of the hemispherical piezoelectric stack, and the normal pressure F N As parasitic motion increases, the static friction of the moving guide rail increases. s The downward motion Δ produces forward motion xend .

[0018] Sliding phase: The voltage drops rapidly at time t1. Since the response speed of the hemispherical piezoelectric stack is faster than that of the flexible hinge mechanism, the hemispherical piezoelectric stack separates from the flexible hinge mechanism and then contracts to its minimum value within a very short time Δt. After the parasitic motion during the preloading and adhesion phases of the stator assembly, the flexible hinge mechanism deforms and stretches. When the elastic restoring force of the flexible hinge mechanism is greater than or equal to the contact force between the hemispherical piezoelectric stack and the flexible hinge mechanism, no displacement return occurs in the motion guide rail. The preloading force of the stator assembly and the locking force between the stator assembly and the motion guide rail have a significant impact on friction.

[0019] Oscillation Phase: The hemispherical piezoelectric stack slowly elongates again starting at time t1+Δt; subsequently, due to elastic restoring force, the flexible hinge mechanism contracts and collides with the hemispherical piezoelectric stack; due to damping and collision energy loss, the vibration will rapidly decay; the vibration generated by the flexible hinge mechanism will be transmitted from the driving foot to the motion guide rail; at this time, the frictional force f c It varies with oscillation; the forward driving force will cause a surge in displacement of the motion guide rail upon the first collision; at time t c1 At that moment, the contact between the flexible hinge mechanism and the hemispherical piezoelectric stack becomes stable, and the platform motion begins to enter the next cycle;

[0020] During reverse drive, a sawtooth wave with a duty cycle of 0% is applied to the precision focusing platform to achieve reverse motion. Unlike forward motion, due to the slow contraction of the hemispherical piezoelectric stack, the hemispherical piezoelectric stack and the flexible hinge mechanism remain in contact. The time period t0~t0+Δt is the sliding stage, during which the hemispherical piezoelectric stack rapidly elongates, and the dynamic friction between the driving foot and the motion guide rail causes a significant displacement and retraction of the motion guide rail. The time period t0+Δt~t1 is the sticking stage, during which the hemispherical piezoelectric stack slowly contracts, and the static friction between the driving foot and the motion guide rail causes the motion guide rail to move in a large step, after which the next cycle of motion begins.

[0021] When the friction of the focusing platform approaches zero during the forward sliding phase, the focusing platform applies reverse auxiliary gravity to suppress the backward displacement during reverse motion and alleviate the displacement surge generated during forward motion; the locking force between the stator assembly and the motion guide is adjusted by voltage bias; in forward drive, the voltage bias is increased to improve the upper limit of load capacity under smooth motion; in reverse drive, the voltage bias is decreased to reduce friction during the sliding phase, and the total gravity F of the optical electron microscope and the motion guide is utilized. G To achieve balance, the precision focusing platform is adjusted by voltage bias to achieve smooth bidirectional drive along the Z degree of freedom.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The Z-degree-of-freedom piezoelectric inertial bidirectional smooth precision focusing platform proposed in this invention actively utilizes the self-weight of the optical electron microscope and the motion guide rail, the piezoelectric inertial driving principle, and the contact assembly characteristics to improve bidirectional consistency; this invention has great application prospects in precision microscopic imaging and precision positioning systems.

[0024] 2) The piezoelectric stack and flexible hinge mechanism adopt contact assembly, the sawtooth wave adopts 100% duty cycle sawtooth wave, and the motion guide rail and optical electron microscope adopt Z degree of freedom installation. It effectively utilizes the self-weight of the driving target. By adjusting the assembly locking force, the precision focusing platform can obtain bidirectional smooth drive.

[0025] 3) By utilizing the parasitic motion of the stator assembly, the locking force between the stator assembly and the motion guide rail is adjusted by adjusting the piezoelectric stack voltage bias. Combined with the optical electron microscope and the self-weight balance of the motion guide rail, the forward displacement surge and reverse displacement retreat are achieved, thus realizing bidirectional smooth drive. Attached Figure Description

[0026] Figure 1 A schematic diagram of the Z-degree-of-freedom piezoelectric inertial bidirectional smooth precision focusing platform;

[0027] Figure 2 Exploded view of the Z-DOF piezoelectric inertial bidirectional smooth precision focusing platform structure;

[0028] Figure 3 This is a schematic diagram of the motion components;

[0029] Figure 4 This is a schematic diagram of the stator assembly;

[0030] Figure 5 This is a schematic diagram of a flexible hinge mechanism;

[0031] Figure 6 This is a schematic diagram of the rack assembly;

[0032] Figure 7 This is a schematic diagram of a fixed base;

[0033] Figure 8 This is a schematic diagram of the pre-tightening clamping block;

[0034] Figure 9 This is a schematic diagram of the platform base;

[0035] Figure 10 End cap schematic diagram;

[0036] Figure 11 This is a schematic diagram illustrating the working principle when there is no gravity assistance during contact.

[0037] Figure 12 A schematic diagram of a bidirectional smooth drive scheme for the Z-degree of freedom considering contact conditions and gravity assistance;

[0038] Figure 13 This is a schematic diagram of bidirectional displacement curves.

[0039] 1. Motion assembly; 2. Stator assembly; 3. Frame assembly; 4. End cap; 1-1. Optical electron microscope; 1-2. Microscope mounting screw; 1-3. Motion guide rail; 1-4. Fixed guide rail; 2-1. Flexible hinge mechanism; 2-2. Hemispherical piezoelectric stack; 2-3. Kimi screw; 2-4. Locking screw; 2-1-1. Drive foot; 2-1-2. Straight round flexible hinge; 2-1-3. Boss I; 2-1- 4. Countersunk hole for flexible mechanism installation; 2-1-5. Straight beam type flexible hinge; 2-1-6. Threaded hole for screw; 2-1-7. Boss II; 3-1. Fixed base; 3-2. Preload block; 3-3. Platform base; 3-4. Spotlight; 3-5. Slide clip; 3-6. Slide clip mounting screw; 3-1-1. Fixed guide rail mounting groove; 3-1-2. Threaded hole for fixed guide rail installation; 3-1-3. Boss III 3-1-4. End cap mounting threaded hole; 3-1-5. Preload block adjustment threaded hole; 3-1-6. Stator assembly mounting threaded hole; 3-1-7. Preload block fixing threaded hole; 3-1-8. Trapezoidal rib; 3-1-9. Fixing base mounting countersunk hole; 3-2-1. Block assembly boss; 3-2-2. Block assembly hole; 3-2-3. Block preload beam; 3-2-4. Screw pre-reserved groove; 3-2-5. Lock 3-2-6, Locking screw mounting hole; 3-3-1, Platform base countersunk hole; 3-3-2, Spotlight mounting hole; 3-3-3, Slide clip mounting threaded hole; 3-3-4, Cable routing hole; 3-3-5, Fixing base mounting groove; 3-3-6, Fixing base mounting threaded hole; 4-1, End cap screw mounting countersunk hole; 4-2, End cap sidewall; 4-3, End cap arc groove; 4-4, End cap boss. Detailed Implementation

[0040] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0041] A schematic diagram of the Z-degree-of-freedom piezoelectric inertial bidirectional smooth precision focusing platform designed in this invention is shown below. Figure 1 As shown, the exploded view of the Z-degree-of-freedom piezoelectric inertial bidirectional smooth precision focusing platform structure is as follows: Figure 2 As shown, it mainly includes a motion component 1, a stator component 2, a frame component 3, and an end cover 4. The motion component 1, the stator component 2, and the end cover 4 are fixedly installed on the frame component 3 by screws.

[0042] The stator assembly 2 is as follows Figure 4 As shown, it consists of a flexible hinge mechanism 2-1, a hemispherical piezoelectric stack 2-2, a Jimi screw 2-3, and a locking screw 2-4. The Jimi screw 2-3 fixes the hemispherical piezoelectric stack 2-2 into the flexible hinge mechanism 2-1. The locking force between the hemispherical piezoelectric stack 2-2 and the flexible hinge mechanism 2-1 can be adjusted by the Jimi screw 2-3, and locked by the locking screw 2-4 to reduce the change in locking force when the hemispherical piezoelectric stack 2-2 vibrates.

[0043] The flexible hinge mechanism 2-1 is as follows: Figure 5 As shown, it includes a driving foot 2-1-1, a straight-round flexible hinge 2-1-2, a boss I 2-1-3, a countersunk hole for flexible mechanism mounting 2-1-4, a straight beam flexible hinge 2-1-5, a threaded hole for a screw 2-1-6, and a boss II 2-1-7; the driving foot is located at the top of the flexible hinge mechanism 2-1 and is assembled in contact with the motion guide rail 1-3; the straight-round flexible hinge 2-1-2 and the straight beam flexible hinge 2-1-5 are respectively located on the flexible hinge mechanism 2-1-1. -1 On both sides, when the hemispherical piezoelectric stack 2-2 vibrates, the driving foot 2-1-1 can obtain parasitic motion; the boss I 2-1-3 is provided with a flexible mechanism mounting countersunk hole 2-1-4, and the screw passes through the flexible mechanism mounting countersunk hole 2-1-4 to fix the stator assembly 2 to the frame assembly 3; the flexible hinge mechanism 2-1 and the frame assembly 3 mounting contact surface are provided with a boss II 2-1-7 to avoid interference between the driving foot 2-1-1 and the frame assembly 3 when the driving foot 2-1-1 vibrates;

[0044] The rack assembly 3, as Figure 6 As shown, it includes a fixed base 3-1, a pre-tightening block 3-2, a platform base 3-3, a spotlight 3-4, a slide clip 3-5, and a slide clip mounting screw 3-6; the pre-tightening block 3-2 is installed on the fixed base 3-1 by screws, the fixed base 3-1 is connected to the platform base 3-3 by screws, the slide clip mounting screw 3-6 fixes the slide clip 3-5 on the platform base 3-3, and the spotlight 3-4 is installed inside the platform base 3-3 by interference fit;

[0045] The fixed base 3-1 is as follows Figure 7 As shown, it includes a fixed guide rail mounting groove 3-1-1, a fixed guide rail mounting threaded hole 3-1-2, a boss Ⅲ 3-1-3, an end cover mounting threaded hole 3-1-4, a pre-tightening block adjusting threaded hole 3-1-5, a stator assembly mounting threaded hole 3-1-6, a pre-tightening block fixing threaded hole 3-1-7, a trapezoidal rib 3-1-8, and a fixed base mounting countersunk hole 3-1-9; the pre-tightening block 3-2 is as follows Figure 8The aforementioned features include a locking block mounting boss 3-2-1, a locking block mounting hole 3-2-2, a locking block pre-tightening beam 3-2-3, a screw pre-reserved groove 3-2-4, a locking screw countersunk hole 3-2-5, and a locking screw mounting hole 3-2-6; the platform base is as follows Figure 9 As shown, it includes a platform base countersunk hole 3-3-1, a spotlight mounting hole 3-3-2, a slide clip mounting threaded hole 3-3-3, a cable hole 3-3-4, a fixed base mounting groove 3-3-5, and a fixed base mounting threaded hole 3-3-6; the fixed guide rail 1-4 is placed and installed within the fixed guide rail mounting groove 3-1-1 and fixedly connected by screws passing through three arrays of fixed guide rail mounting threaded holes 3-1-2; the clamping block pre-tightening beam 3-2-3 contacts the end of the flexible hinge mechanism 2-1, and the screw pre-reserved groove 3-2-4 is used for... To avoid interference with the ferrule screws 2-3 and 2-4; the boss Ⅲ 3-1-3 contacts and assembles with the locking block assembly boss 3-2-1, and the screw passes through the locking block assembly hole 3-2-2 and the pre-tightening locking block adjustment threaded hole 3-1-5 to assemble the pre-tightening locking block 3-2 onto the fixed base 3-1, and the friction between the drive foot 2-1-1 and the motion guide rail 1-3 is adjusted by the screw screw insertion depth; after the friction is adjusted to an appropriate value, the screw passes through the flexible mechanism mounting countersunk hole 2-1-4 and is screwed into the stator assembly mounting threaded hole 3-1-6 to mount the stator assembly 2. For further fixing, screws are passed through the locking screw mounting holes 3-2-6 and screwed into the pre-tightening block fixing threaded holes 3-1-7 for further tightening, in order to reduce the change in friction between the drive foot 2-1-1 and the motion guide rail 1-3 caused by the vibration of the stator assembly 2; the opening of the fixed base mounting groove 3-3-5 is to reserve space for screw assembly, making the whole machine easier to integrate; the two arrays of end cover mounting threaded holes 3-1-4 are used for fixing the end cover 4 to the frame assembly 3; the ends of the trapezoidal ribs 3-1-8 are assembled into the fixed base mounting groove 3-3-5, using The screw passes through the countersunk hole 3-1-9 of the mounting base and is screwed into the threaded hole 3-3-6 of the mounting base to fix the two together; the platform base 3-3 can be fixed by passing the screw through the countersunk hole 3-3-1 of the four arrays of platform bases; the spotlight 3-4 is installed in the spotlight mounting hole 3-3-2 by interference fit, and its power wire is led out through the cable hole 3-3-4; the slide clip mounting screw 3-6 passes through the slide clip 3-5 and the slide clip mounting threaded hole 3-3-3 to fix the slide clip 3-5 to the platform base 3-3;

[0046] The end cap is as follows Figure 10As shown, it includes end cap screw mounting countersunk holes 4-1, end cap sidewall 4-2, end cap arc-shaped groove 4-3, and end cap boss 4-4; the end cap 4 is fixed to the frame assembly 3 by screwing through two symmetrically arranged end cap screw mounting countersunk holes 4-1 and screwing them into the end cap mounting threaded holes 3-1-4; the end cap arc-shaped groove 4-3 is provided on the end cap sidewall 4-2 to avoid motion interference between the end cap 4 and the optical electron microscope 1-1; the end cap boss 4-4 is used to enhance the connection strength and reliability between the end cap 4 and the frame assembly 3.

[0047] Normally, the contact assembly between the flexible hinge mechanism 2-1 and the hemispherical piezoelectric stack 2-2 is considered a fixed constraint, and the beneficial effects of this contact assembly are usually ignored. Recent findings suggest that this contact assembly holds promise for achieving smooth unidirectional actuation of piezoelectric inertial actuators; motion along the Z-degree of freedom is defined as positive motion. Figure 11 The working principle under contact conditions and without gravity assistance is given; as shown in Figure 11(a), the precision focusing platform is driven by a sawtooth wave with a duty cycle of 100% to achieve forward motion; specifically, it is divided into the following three stages:

[0048] Adhesion stage: From time t0 to t1, the excitation voltage gradually increases. The flexible hinge mechanism 2-1 slowly elongates under the action of the hemispherical piezoelectric stack 2-2, with normal pressure F... N As parasitic motion increases, the motion guide rails 1-3 experience static friction f s The downward motion Δ produces forward motion xend .

[0049] Sliding Phase: The voltage drops rapidly at time t1. Because the response speed of the hemispherical piezoelectric stack 2-2 is faster than that of the flexible hinge mechanism 2-1, the hemispherical piezoelectric stack 2-2 separates from the flexible hinge mechanism 2-1, and then contracts to its minimum value within a very short time Δt. After the parasitic motion during the stator assembly preloading and adhesion phases, the flexible hinge mechanism 2-1 acts like a stretched spring. When the elastic restoring force of the flexible hinge mechanism 2-1 is greater than or equal to the contact force between the hemispherical piezoelectric stack 2-2 and the flexible hinge mechanism 2-1, the normal pressure F... N and kinetic friction f d The force is almost zero; under these conditions, no displacement or backflow occurs in the motion guide rails 1-3. The preload force of the stator assembly 2 and the locking force between the stator assembly 2 and the motion guide rails 1-3 have a significant impact on friction.

[0050] Oscillation Phase: The hemispherical piezoelectric stack 2-2 slowly elongates again starting at time t1+Δt; subsequently, due to elastic restoring force, the flexible hinge mechanism 2-1 contracts and collides with the hemispherical piezoelectric stack 2-2. Due to damping and collision energy loss, the vibration will rapidly decay; the vibration generated by the flexible hinge mechanism 2-1 will be transmitted from the driving foot 2-1-1 to the motion guide rail 1-3; at this time, the frictional force f c It varies with oscillation; the forward driving force is most significant during the first collision, causing a surge in displacement of the motion guides 1-3. At time t... c1 At that moment, the contact between the flexible hinge mechanism 2-1 and the hemispherical piezoelectric stack 2-2 becomes stable, and the platform motion begins to enter the next cycle.

[0051] When the weight of the optical electron microscope 1-1 and the motion guide rail 1-3 is not considered in the case of Z-degree-of-freedom assembly, the working principle of the reverse motion of this precision focusing platform is similar to that of a traditional piezoelectric inertial positioning platform, such as... Figure 11 As shown in (b), the precision focusing platform is excited by a sawtooth wave with 0% symmetry. Unlike the forward motion, due to the slow contraction of the hemispherical piezoelectric stack 2-2, the hemispherical piezoelectric stack 2-2 and the flexible hinge mechanism 2-1 remain in contact; the time period t0~t0+Δt is the sliding stage, during which the hemispherical piezoelectric stack 2-2 rapidly extends, and the dynamic friction between the driving foot 2-1-1 and the motion guide rail 1-3 will cause the motion guide rail 1-3 to produce a significant displacement and retraction; the time period t0+Δt~t1 is the sticking stage, during which the hemispherical piezoelectric stack 2-2 slowly contracts, and the static friction between the driving foot 2-1-1 and the motion guide rail 1-3 causes the motion guide rail 1-3 to produce a large step displacement, and then enters the next cycle motion; the forward and reverse displacement curves considering the contact state without gravity assistance are shown in the figure. Figure 11 As shown in (c).

[0052] When the friction of the focusing platform during the forward sliding phase approaches zero, even with a small load, no backward displacement will occur due to the inertia of the optical electron microscope 1-1 and the motion guide rail 1-3, and the extremely short duration of this phase. Therefore, applying appropriate reverse auxiliary gravity to the focusing platform can suppress backward displacement during reverse motion and mitigate the displacement surge caused by forward motion. Figure 12 As shown in (a), if the dynamic friction force f in the reverse motion d The total weight F of the optical electron microscope 1-1 and the motion guide rail 1-3 G If these forces are offset, bidirectional smooth motion can be achieved. However, the preconditions for positive smooth motion limit F. G The force cannot be too large. Due to the parasitic motion mechanism of this focusing platform, the locking force between the stator assembly 2 and the motion guide rails 1-3 can be adjusted by voltage bias, such as... Figure 12As shown in (b). In forward drive, the voltage bias is increased to improve the upper limit of load capacity under smooth motion. In reverse drive, the voltage bias is decreased to reduce friction during the sliding phase and to utilize the total gravity F of the optical electron microscope 1-1 and the motion guide rail 1-3. G To achieve balance, a smooth bidirectional drive along the Z-degree of freedom is achieved by adjusting the precision focusing platform with appropriate voltage bias, such as... Figure 13 As shown.

[0053] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A Z-degree-of-freedom piezoelectric inertial bidirectional smoothing precision focusing platform, characterized in that, It includes a motion assembly (1), a stator assembly (2), a frame assembly (3), and an end cap (4); the Z degree of freedom is the vertical degree of freedom; the motion assembly (1), the stator assembly (2), and the end cap (4) are all mounted on the frame assembly (3); the end cap (4) is fixed to the outside of the stator assembly (2); The frame assembly (3) includes a fixed base (3-1), a pre-tightening block (3-2), a platform base (3-3), a spotlight (3-4), and slide clips (3-5); the pre-tightening block (3-2) is installed on the fixed base (3-1), and the fixed base (3-1) is assembled on the platform base (3-3); the platform base (3-3) has a spotlight mounting hole (3-3-2); the spotlight (3-4) is installed in the spotlight mounting hole (3-3-2) by interference fit; the slide clip mounting screws (3-6) fix two slide clips (3-5) to both sides of the spotlight (3-4); The motion assembly (1) includes an optical electron microscope (1-1), a microscope mounting screw (1-2), a motion guide rail (1-3), and a fixed guide rail (1-4); the optical electron microscope (1-1) and the microscope mounting screw (1-2) are fixed on the motion guide rail (1-3), and the motion guide rail (1-3) and the fixed guide rail (1-4) form a set of cross-shaped roller guide rails. The motion guide rail (1-3) is used to slide freely along the guide rail direction relative to the fixed guide rail (1-4). The stator assembly (2) includes a flexible hinge mechanism (2-1), a hemispherical piezoelectric stack (2-2), a Jimi screw (2-3), and a locking screw (2-4). The Jimi screw (2-3) fixes the hemispherical piezoelectric stack (2-2) within the flexible hinge mechanism (2-1), and adjusts the locking force between the hemispherical piezoelectric stack (2-2) and the flexible hinge mechanism (2-1) by adjusting the Jimi screw (2-3). The locking screw (2-4) locks the hemispherical piezoelectric stack (2-2) and the Jimi screw (2-3), and reduces the change in locking force when the hemispherical piezoelectric stack (2-2) vibrates. The flexible hinge mechanism (2-1) is provided with a driving foot (2-1-1), a round flexible hinge (2-1-2), a boss I (2-1-3), a countersunk hole for flexible mechanism mounting (2-1-4), a straight beam flexible hinge (2-1-5), a threaded hole for a screw (2-1-6), and a boss II (2-1-7). The driving foot (2-1-1) is located at the top of the flexible hinge mechanism (2-1) and is in contact with the motion guide rail (1-3). The round flexible hinge (2-1-2) and the straight beam flexible hinge (2-1-5) are respectively located at... The flexible hinge mechanism (2-1) on both sides allows the driving foot (2-1-1) to obtain parasitic motion when the hemispherical piezoelectric stack (2-2) vibrates; the boss I (2-1-3) is provided with a flexible mechanism mounting countersunk hole (2-1-4), which is used to fix the stator assembly (2) on the frame assembly (3); the flexible hinge mechanism (2-1) and the frame assembly (3) mounting contact surface are provided with a boss II (2-1-7), which is used to avoid interference between the driving foot (2-1-1) and the frame assembly (3) when vibrating.

2. The Z-freedom piezoelectric inertial bidirectional smoothing precision focusing platform according to claim 1, wherein, The end cap (4) includes an end cap sidewall (4-2) and an end cap arc groove (4-3); the two end cap sidewalls (4-2) are symmetrically arranged at both ends of the end cap (4); the end cap arc groove (4-3) is opened on the end cap sidewall (4-2) to avoid motion interference between the end cap (4) and the optical electron microscope (1-1).

3. The Z-freedom piezoelectric inertial bidirectional smoothness precision focusing platform according to claim 1, wherein, The fixed base (3-1) is provided with a fixed guide rail mounting groove (3-1-1), a fixed guide rail mounting threaded hole (3-1-2), a boss III (3-1-3), an end cover mounting threaded hole (3-1-4), a preload adjustment threaded hole (3-1-5), a stator assembly mounting threaded hole (3-1-6), a preload fixing threaded hole (3-1-7), a trapezoidal rib (3-1-8), and a fixed base mounting countersunk hole (3-1-9); the fixed guide rail (1-4) is placed and installed in the fixed guide rail mounting groove (3-1-1-2). 1) The screw passes through the mounting threaded hole (3-1-2) of the fixed guide rail and is fixedly connected; the boss III (3-1-3) is in contact with the pre-tightening block (3-2) and assembled. The pre-tightening block (3-2) is fixed on the fixed base (3-1) through the pre-tightening block adjusting threaded hole (3-1-5) and further locked through the pre-tightening block fixing threaded hole (3-1-7); the stator assembly (2) is fixed in the stator assembly mounting threaded hole (3-1-6) through the stator assembly mounting threaded hole (3-1-6).

4. The Z-freedom piezoelectric inertial bidirectional smoothness precision focusing platform according to claim 1, wherein, The pre-tightening block (3-2) includes a block mounting boss (3-2-1), a block mounting hole (3-2-2), a block pre-tightening beam (3-2-3), a screw pre-reserved groove (3-2-4), a locking screw countersunk hole (3-2-5), and a locking screw mounting hole (3-2-6). The pre-tightening block (3-2) is fixed to the fixed base (3-1) through the block mounting hole (3-2-2). The block pre-tightening beam (3-2-3) contacts the end of the flexible hinge mechanism (2-1). The screw pre-reserved groove (3-2-4) is used to avoid interference with the fin screw (2-3) and the locking screw (2-4). The locking screw mounting hole (3-2-6) is used to further lock the pre-tightening block (3-2) to the fixed base (3-1).

5. The Z-freedom piezoelectric inertial bidirectional smoothing precision focusing platform according to claim 1, wherein, The platform base (3-3) includes a countersunk hole (3-3-1), a spotlight mounting hole (3-3-2), a slide clip mounting threaded hole (3-3-3), a cable routing hole (3-3-4), a mounting groove for the fixed base (3-3-5), and a mounting threaded hole for the fixed base (3-3-6). The mounting groove (3-3-5) is used to assemble the fixed base (3-1), and the platform base (3-3) and the fixed base (3-1) are fixed by screws through the mounting threaded hole (3-3-6). A fixed guide rail is also included. The mounting slot (3-1-1) is used to install and fix the guide rail (1-4); the countersunk hole 3-3-1 of the platform base is used to fix the platform base (3-3) to the external equipment with screws; the spotlight (3-4) is installed in the spotlight mounting hole (3-3-2) by interference fit, and its power wire is led out through the cable hole (3-3-4); the slide clip mounting screw (3-6) passes through the slide clip (3-5) and the slide clip mounting threaded hole (3-3-3) to fix the slide clip (3-5) on the platform base (3-3).

6. A driving method for a Z-degree-of-freedom piezoelectric inertial bidirectional smooth precision focusing platform as described in claim 1, characterized in that, Vertically upward is defined as the positive direction; during positive drive, a sawtooth wave with a duty cycle of 100% is applied to the precision focusing platform to achieve positive motion; specifically, it is divided into the following three stages: Adhesion stage: from time t 0 to t During a time period, the excitation voltage gradually increases; the flexible hinge mechanism (2-1) slowly elongates under the action of the hemispherical piezoelectric stack (2-2), and the normal pressure... F N With the increase of parasitic motion, the motion guide rails (1-3) experience static friction. f s The downward motion Δ produces forward motion xend ; Sliding phase: Voltage in time t At time 1, the response speed drops rapidly. Since the response speed of the hemispherical piezoelectric stack (2-2) is faster than that of the flexible hinge mechanism (2-1), the hemispherical piezoelectric stack (2-2) separates from the flexible hinge mechanism (2-1) and then contracts to a minimum value within a very short time Δt. After the parasitic motion during the assembly preloading and adhesive stage of the stator, the flexible hinge mechanism (2-1) deforms and stretches. When the elastic restoring force of the flexible hinge mechanism (2-1) is greater than or equal to the contact force between the hemispherical piezoelectric stack (2-2) and the flexible hinge mechanism (2-1), the motion guide rail (1-3) does not have any displacement back; the preload force of the stator assembly (2) and the locking force between the stator assembly 2 and the motion guide rail (1-3) have an important influence on friction. Oscillation phase: the hemispherical head piezoelectric stack (2-2) from time t 1 + Δ t Start to slowly extend again; Subsequently, due to the elastic restoring force, the flexible hinge mechanism (2-1) contracts and collides with the hemispherical piezoelectric stack (2-2); due to damping and collision energy loss, the vibration will rapidly decay; the vibration generated by the flexible hinge mechanism (2-1) will be transmitted from the drive foot (2-1-1) to the motion guide rail (1-3); at this time, the friction force f c It varies with oscillation; the forward driving force at the first collision will cause the motion guide rails (1-3) to produce a surge in displacement; in time... t c1 At that moment, the contact between the flexible hinge mechanism (2-1) and the hemispherical piezoelectric stack (2-2) becomes stable, and the platform motion begins to enter the next cycle; During reverse drive, a sawtooth wave with a duty cycle of 0% is applied to the precision focusing platform to achieve reverse motion; unlike forward motion, due to the slow contraction of the hemispherical piezoelectric stack (2-2), the hemispherical piezoelectric stack (2-2) and the flexible hinge mechanism (2-1) remain in contact; t0~ t 0+Δ t During the sliding phase, the hemispherical piezoelectric stack (2-2) elongates rapidly, and the dynamic friction between the driving foot (2-1-1) and the motion guide rail (1-3) will cause the motion guide rail (1-3) to produce a significant displacement and retraction. t 0+Δ t~t During the first time period, the sticking phase occurs. The hemispherical piezoelectric stack (2-2) slowly contracts, driving the foot (2-1-1) and the motion guide rail (1-3) to generate static friction, which in turn drives the motion guide rail (1-3) to move in a large step, and then enters the next cycle of motion. When the friction of the focusing platform during the forward sliding phase approaches zero, the focusing platform applies reverse auxiliary gravity to suppress the backward displacement of the reverse movement and alleviate the displacement surge generated by the forward movement; the locking force between the stator assembly (2) and the motion guide rail (1-3) is adjusted by voltage bias; in the forward drive, the voltage bias is increased to increase the upper limit of the load capacity under smooth movement; in the reverse drive, the voltage bias is decreased to weaken the friction during the sliding phase, and the total gravity of the optical electron microscope (1-1) and the motion guide rail (1-3) is used to reduce the friction during the sliding phase. F G To achieve balance, the precision focusing platform is adjusted by voltage bias to achieve smooth bidirectional drive along the Z degree of freedom.

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