A micro-positioning table with adjustable angular stiffness for complex load deflection

Abstract

The application belongs to the field of precision engineering, and particularly discloses a micro-positioning table with adjustable complex load deflection angle stiffness, which comprises a compliant deflection positioning mechanism, a piezoelectric driver, a coil magnetic group and a magnetic yoke. The compliant deflection positioning mechanism comprises a workbench, a bridge type displacement amplification mechanism, a rotary gap flexible hinge, a center support column structure and a base plate. The bridge type displacement amplification mechanism is arranged on the upper surface of the base plate in the front, rear, left and right directions. The top of each bridge type displacement amplification mechanism is connected to the bottom of the workbench through the rotary gap flexible hinge. The center of the workbench is connected to the base plate through the center support column structure. The piezoelectric driver is arranged in each bridge type displacement amplification mechanism. The coil magnetic group is vertically inserted between the workbench and the base plate, and is fixed through the magnetic yoke.

Description

Technical Field

[0001] This invention relates to a component that can be used in the field of precision engineering, and more specifically to a micro-positioning stage with adjustable yaw angle stiffness for complex loads. Background Technology

[0002] With the widespread application of micro- and nanotechnology in aerospace, bioscience, and integrated circuit (IC) technology, compliant mechanisms have gained extensive use due to their high precision and repeatability. In recent years, many applications, such as micro / nano fabrication, precision manipulation, and precision positioning platforms, have emerged, all relying on the deflection of flexible components. This, in turn, presents challenges to the design of compliant mechanisms. While significant progress has been made in research on planar micro / nano positioning mechanisms in recent years, research on spatial / rotational mechanisms remains relatively insufficient.

[0003] Patent CN112563179 B discloses a flexible piezoelectric micro / nano wafer deflection stage, comprising a piezoelectric-driven micro-displacement module, a ceramic chuck holder, a ceramic chuck, and a wafer. The piezoelectric-driven micro-displacement module includes a substrate and a hinge body mounted on top of the substrate. The hinge body houses a stacked piezoelectric ceramic, a flexible amplification structure, and a double parallel hinge structure. The displacement end of the stacked piezoelectric ceramic is connected to the input end of the flexible amplification structure via a primary displacement input end. The flexible amplification structure and the double parallel hinge structure are connected via a primary displacement output end. The secondary displacement output end is rigidly connected to an output end adapter fixture via screws. A plunger end and a plunger elastic end are fixed to the top of the adapter fixture. The ceramic chuck holder is connected to the plunger elastic end via a pin hole. This invention uses piezoelectric ceramic as the power driver and achieves wafer deflection through a multi-stage displacement amplification mechanism.

[0004] However, the aforementioned patents do not consider the unique characteristics of yaw micro-motion stages (isotropic angular stiffness) in spatial motion mechanisms, particularly the decrease in yaw motion stability due to load variations. This is primarily because, when the load exceeds a certain range, the flexible hinges connecting the rigid parts will experience significant axial drift and localized stress concentration. These geometric and material nonlinearities not only severely impact the platform's lifespan—for example, in existing designs, Hooke's joints / universal joints are typically used to support the translational-rotational coupling of the yaw micro-positioning platform—but this motion decoupling structure is prone to stress concentration at the four corners of the rectangular cross-section under combined loads, severely limiting the yaw platform's motion range and shortening its lifespan—but also pose significant challenges to the platform's accurate modeling and controller design.

[0005] It is important to note that since flexible mechanisms primarily rely on the elastic deformation of the flexible hinges for transmission, almost all flexible mechanisms are extremely sensitive to changes in external loads. This contradicts the high-precision requirements of positioning platforms. Furthermore, these external loads are usually not fixed but rather act as random external disturbances. Therefore, it is also necessary to actively resist random disturbances caused by the loads in real time. Summary of the Invention

[0006] To address this problem, this invention proposes a micro-positioning stage with adjustable yaw angle stiffness for complex loads. This device employs an energized coil to achieve real-time adjustment of the positioning stage stiffness, enabling flexible handling of load variations in the actuator under harsh operating conditions. Furthermore, this invention utilizes a rotary notch-type flexible hinge as a spatial multi-axis decoupling structure, effectively avoiding the aforementioned problems. This unique combination of yaw angle stiffness adjustment and motion decoupling scheme has significant value and guiding significance for the development of more high-precision spatial positioning platforms.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A micro-positioning stage with adjustable yaw angle stiffness for complex loads includes a compliant yaw positioning mechanism, a piezoelectric actuator, a coil magnetic assembly, and a magnetic yoke.

[0009] The compliant yaw positioning mechanism includes a worktable, a bridge-type displacement amplification mechanism, a rotary notch flexible hinge, a central support structure, and a base plate. Bridge-type displacement amplification mechanisms are symmetrically arranged in the front, back, left, and right directions on the upper surface of the base plate. The top of each bridge-type displacement amplification mechanism is connected to the bottom of the worktable via a rotary notch flexible hinge. The center of the worktable is connected to the base plate via a central support structure. A piezoelectric actuator is installed inside each bridge-type displacement amplification mechanism, and a coil magnetic assembly is vertically inserted into the worktable, fixed by a magnetic yoke.

[0010] Furthermore, the front and rear bridge displacement amplification mechanisms are symmetrically arranged, as are the left and right bridge displacement amplification mechanisms.

[0011] Furthermore, the worktable is a circular worktable with multiple through holes. A coil magnetic assembly is installed in each through hole, and a magnetic yoke is provided on top of each coil magnetic assembly.

[0012] Furthermore, a piezoelectric actuator is horizontally installed within each bridge displacement amplification mechanism; the piezoelectric actuator is connected to the bridge displacement amplification mechanism via preload screws.

[0013] Furthermore, four coil magnetic groups are vertically inserted on the workbench, and the four coil magnetic groups are evenly arranged around the central support column structure.

[0014] Furthermore, the four coil magnetic groups are located in the front, back, left, and right directions of the worktable.

[0015] Furthermore, the base plate is provided with mounting holes.

[0016] Furthermore, the rotary notch flexible hinge is located at the center of the top of its respective bridge displacement amplification mechanism.

[0017] The beneficial effects of this invention are as follows:

[0018] By optimizing the platform's own structure and resisting external random interference in real time, the system ensures synergy and effectively achieves the normal operation of the yaw platform with isotropic properties, making it particularly suitable as a multi-angle adjustment device in complex environments.

[0019] Specifically, the optimization of the platform's own structure includes symmetrically arranged bridge displacement amplification mechanisms in the front, back, left, and right directions on the upper surface of the base plate. The top of each bridge displacement amplification mechanism is connected to the bottom of the worktable through a flexible hinge with a rotary notch. The center of the worktable is connected to the base plate through a central support column structure. At the same time, coil magnetic groups are vertically inserted into the worktable and fixed by magnetic yokes to resist external random interference in real time.

[0020] The flexible structure design proposed in this invention facilitates integrated molding and miniaturization of the overall structure, enabling it to adapt to normal operation in confined environments.

[0021] In terms of configuration, the platform of this invention adopts a symmetrical over-constraint configuration. Compared with the asymmetrical and hollow forms with full constraints, the configuration scheme adopted by this invention can better suppress the parasitic motion and center point drift of the yaw platform, and ultimately achieve a further improvement in the platform's motion accuracy. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0023] Figure 1 3D schematic diagram of a compliant oscillating micro-positioning stage;

[0024] Figure 2 Front view of the compliant oscillating micro-positioning stage;

[0025] Figure 3 Top view of the compliant oscillating micro-positioning stage;

[0026] Figure 4 Exploded view of a compliant oscillating micro-positioning stage;

[0027] Figure 5Schematic diagram of an integrated compliant oscillation mechanism;

[0028] Figure 6 Cross-sectional view of the compliant oscillating micro-positioning stage;

[0029] Figure 7 Section A of the compliant oscillating micro-positioning stage;

[0030] Figure 8 Section B of the compliant oscillating micro-positioning stage;

[0031] Figure 9 Coil magnetic assembly structure diagram;

[0032] Figure 10 Force analysis diagram of the workbench;

[0033] Among them, 1-compliant yaw positioning mechanism, 101-worktable, 102-bridge displacement amplification mechanism, 103-rotation notch flexible hinge, 104-central support column structure, 105-base plate, 2-piezoelectric actuator, 3-coil magnetic assembly, 301-armature, 302-coil, 4-preload screw, 5-fixing bolt, 6-limiting block, 7-nut, 8-magnetic yoke, 9-assembly hole. Detailed Implementation

[0034] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0035] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] As described in the background section, existing yaw micro-positioning stages do not consider the special characteristics of this type of spatial motion mechanism (isotropic angular stiffness). The problem of decreased stability in yaw motion due to load variations arises primarily because, when the load exceeds a certain range, the flexible hinges connecting the rigid parts experience significant axial drift and localized stress concentration. These geometric and material nonlinearities not only severely affect the platform's service life but also pose significant challenges to accurate platform modeling and controller design. Therefore, this embodiment addresses the problems in the prior art by simultaneously focusing on accurately resisting external loads and optimizing the yaw stage mechanism. Specifically, this embodiment provides a heavy-duty yaw micro-positioning stage device with variable angular stiffness; using piezoelectric materials or other smart materials as actuators, it can realize the yaw motion of the working platform. Furthermore, this invention introduces... Figure 10 The electromagnetically adjustable negative stiffness shown utilizes the nonlinear characteristic of the electromagnetic stiffness changing with current in Maxwell's normal stress actuator. Armatures and coiled magnetic yokes are added to both sides of the deflection stage, forming an antagonistic variable electromagnetic negative stiffness structure. This serves as an auxiliary variable stiffness actuator, enabling real-time adjustment of angular stiffness to adapt to positioning requirements under different load scenarios. Simultaneously, the development of additive manufacturing technology provides significant potential for the miniaturized, integrated manufacturing of this design.

[0037] Furthermore, the overall configuration of the micro-positioning stage device with adjustable yaw angle stiffness for complex loads proposed in this invention is a symmetrical over-constraint form, which can further suppress the generation of parasitic motion and thus improve the motion accuracy of the yaw platform.

[0038] Specifically, the micro-positioning stage device with adjustable yaw angle stiffness for complex loads disclosed in this embodiment includes a compliant yaw positioning mechanism 1, a piezoelectric actuator 2, a coil magnetic assembly 3, a preload screw 4, a fixing bolt 5, a limiting block 6, a nut 7, and a magnetic yoke 8.

[0039] The compliant yaw positioning mechanism 1 includes a worktable 101, a bridge-type displacement amplification mechanism 102, a rotary notch flexible hinge 103, a central support column structure 104, and a base plate 105. The worktable 101, bridge-type displacement amplification mechanism 102, rotary notch flexible hinge 103, central support column structure 104, and base plate 105 are integrally formed. Specifically, they can be integrally formed by additive manufacturing or other processing methods. Bridge-type displacement amplification mechanisms 102 are provided in the front, back, left, and right directions on the upper surface of the base plate 105, that is, four bridge-type displacement amplification mechanisms 102 are provided on the base plate 105. The top of each bridge-type displacement amplification mechanism 102 is connected to the bottom of the worktable 101 through the rotary notch flexible hinge 103. The center of the worktable 101 is connected to the base plate 105 through the central support column structure 104.

[0040] Furthermore, the four bridge displacement amplification mechanisms 102 mentioned above have identical structures. The front and rear bridge displacement amplification mechanisms 102 are symmetrically arranged, and the left and right bridge displacement amplification mechanisms 102 are symmetrically arranged. The aforementioned rotary notch flexible hinge 103 is located at the center of each bridge displacement amplification mechanism 102. That is, the platform adopts a symmetrical over-constraint configuration. Compared with the asymmetrical and hollow forms with complete constraints, the configuration scheme adopted by the present invention can better suppress the parasitic motion and center point drift of the yaw platform, and ultimately achieve a further improvement in the platform's motion accuracy.

[0041] Furthermore, the aforementioned workbench 101 is a circular workbench with multiple through holes. A coil magnetic assembly 3 is installed in each through hole, and a magnetic yoke 8 is provided on the top of each coil magnetic assembly 3. In this embodiment, four through holes are provided on the circular workbench, a coil magnetic assembly 3 is installed in each through hole, and a magnetic yoke 8 is provided on the top of each coil magnetic assembly 3. The four coil magnetic assemblies 3 are arranged sequentially along the front, back, left, and right directions of the circular workbench.

[0042] Furthermore, a piezoelectric actuator 2 is horizontally installed in each bridge displacement amplification mechanism 102; the piezoelectric actuator 2 is connected to the bridge displacement amplification mechanism 102 via a preload screw 4.

[0043] Furthermore, a limiting block 6 is provided between the pre-tightening screw 4 and the piezoelectric actuator 2. The limiting block 6 is mainly provided to accommodate the installation of the piezoelectric ceramic actuator.

[0044] Furthermore, the coil magnetic assembly 2 includes an armature 301 and coils 302, with a plurality of coils 302 wound around the armature 301, and a magnetic yoke 8 at the top of the armature 301.

[0045] Furthermore, four mounting holes 9 are provided on the base plate 105. The four mounting holes 9 are used to cooperate with other devices to realize the installation of the micro positioning platform.

[0046] The working principle of this micro-positioning stage is as follows:

[0047] When the driving element is activated, the output of the bridge displacement amplification mechanism in its active module can output an amplified upward displacement, such as... Figure 10 As shown, this forms a lever with the central support column structure 104 and the mirror passive module (bridge displacement amplification mechanism 102), ultimately achieving the deflection movement of the worktable 101. Meanwhile, the four coil magnetic groups 3 form a magnetic field within the yoke 8 composed of magnetic conductors and the armature; when the coils are energized, they can simultaneously provide upward or downward thrust and maintain the balance of the worktable when the deflection table does not deflect, thereby achieving the effect of changing the load-bearing capacity of the deflection table.

[0048] When the worktable deflects in a certain direction, the electromagnetic attraction between the closer magnetic yoke and the armature increases, while the electromagnetic attraction between the farther magnetic yoke and the armature decreases. The resulting electromagnetic net force increases with the deflection angle, creating electromagnetic negative stiffness. This electromagnetic negative stiffness increases continuously with the increase of current, further reducing the angular stiffness of the pendulum positioning table.

[0049] This embodiment ensures coordinated and effective operation of the isotropic yaw platform by optimizing the platform's own structure and resisting external random interference in real time, making it particularly suitable as a multi-angle adjustment device in complex environments.

[0050] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A micro-positioning stage with adjustable yaw angle stiffness for complex loads, characterized in that, Includes a compliant yaw positioning mechanism, a piezoelectric actuator, a coil magnet assembly, and a magnetic yoke; The compliant yaw positioning mechanism includes a worktable, a bridge-type displacement amplification mechanism, a rotary notch flexible hinge, a central support column structure, and a base plate. Bridge-type displacement amplification mechanisms are arranged in the front, rear, left, and right directions on the upper surface of the base plate. The top of each bridge-type displacement amplification mechanism is connected to the bottom of the worktable via a rotary notch flexible hinge. The center of the worktable is connected to the base plate via a central support column structure. A piezoelectric actuator is installed inside each bridge-type displacement amplification mechanism. A coil magnetic assembly is vertically inserted between the worktable and the base plate, and the coil magnetic assembly is fixed by a magnetic yoke. The workbench is a circular workbench with multiple through holes. A coil magnetic assembly is installed in each through hole, and a magnetic yoke is installed on top of each coil magnetic assembly. Four coil magnetic assemblies are vertically inserted on the workbench and are evenly arranged around the central support column structure.

2. The micro-positioning stage with adjustable yaw angle stiffness for complex loads as described in claim 1, characterized in that, The front and rear bridge displacement amplification mechanisms are symmetrically arranged, and the left and right bridge displacement amplification mechanisms are symmetrically arranged.

3. The micro-positioning stage with adjustable yaw angle stiffness for complex loads as described in claim 1, characterized in that, A piezoelectric actuator is horizontally mounted inside each bridge displacement amplification mechanism.

4. The micro-positioning stage with adjustable yaw angle stiffness for complex loads as described in claim 1, characterized in that, The piezoelectric actuator is connected to the bridge displacement amplification mechanism via a preload screw.

5. The micro-positioning stage with adjustable yaw angle stiffness for complex loads as described in claim 4, characterized in that, A limit block is provided between the preload screw and the piezoelectric actuator.

6. The micro-positioning stage with adjustable yaw angle stiffness for complex loads as described in claim 1, characterized in that, The four coil magnetic groups are located in the front, back, left and right directions of the worktable.

7. The micro-positioning stage with adjustable yaw angle stiffness for complex loads as described in claim 1, characterized in that, The rotary notch flexible hinge is located at the center of the top of its respective bridge displacement amplification mechanism.

8. The micro-positioning stage with adjustable yaw angle stiffness for complex loads as described in claim 1, characterized in that, The base plate is provided with mounting holes.

Images