A spatial over-constrained compliant positioning platform with three-dimensional parasitic compensation

Abstract

The application discloses a spatial over-constrained compliant positioning platform with three-dimensional parasitic compensation, which comprises a workbench, active modules arranged on four sides and a bottom of the workbench, wherein the active modules are arranged at the center positions of each face, the upper part of each active module is connected with the first end of two first prismatic structures through two first gap type flexible hinges, the lower part of each active module is connected with the first end of two second prismatic structures through two second gap type flexible hinges, four connecting rods are extended from the four corners of the sides of the workbench, each connecting rod is connected with the second end of a third prismatic structure through a third gap type flexible hinge, and the second end of the first, second and third prismatic structures located on the same side or the outside of the bottom is connected with the same parasitic compensation module through a fourth gap type flexible hinge.

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 design scheme for a space over-constrained compliant positioning device that combines spatial parasitic displacement compensation, multi-axis motion decoupling, and micro-nano positioning functions. Background Technology

[0002] Existing flexible mechanism designs have made significant contributions to achieving micro / nano positioning. Recent research has explored single-axis flexible motion systems based on a combination of active and passive modules. However, practical engineering applications often require platforms to have more motion dimensions; for example, a three-dimensional platform needs three dimensions, and the motion system places high demands on the mechanisms that generate decoupled motion.

[0003] Patent CN201910362620.2 discloses a three-dimensional constant-force parallel flexible micro-positioning platform, which includes a main frame and a force input mechanism, a force output mechanism, and a constant-force mechanism located within the main frame. The constant-force mechanism includes a parallel leaf spring mechanism and X-direction constant-force mechanism, Y-direction constant-force structure, and Z-direction constant-force mechanism respectively connected to the parallel leaf spring mechanism. The X-direction constant-force mechanism, Y-direction constant-force mechanism, and Z-direction constant-force mechanism are orthogonal to each other. The X-direction constant-force mechanism includes a first negative stiffness mechanism and a first leaf spring flexible structure connected in series. The Y-direction constant-force mechanism includes a second negative stiffness mechanism and a second leaf spring flexible structure connected in series. The Z-direction constant-force mechanism includes a third negative stiffness mechanism and a third leaf spring flexible structure connected in series. This invention uses a parallel structure to achieve motion decoupling, giving the positioning platform three independent degrees of freedom in the XYZ directions. At the same time, it uses flexible hinge connections to avoid the shortcomings of traditional connections, thereby achieving high-precision positioning. However, from an overall structural perspective, this three-axis translational mechanism has a complex configuration, making it difficult to manufacture as a single unit and miniaturize it to adapt to micro-nano positioning operations in confined spaces. It is worth noting that the mechanism does not consider the compensation for three-dimensional parasitic motion, which has a significant impact on the accuracy of the mechanism. Therefore, this issue is extremely critical for precision positioning platforms. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention proposes a spatial over-constraint compliant positioning platform with three-dimensional parasitic compensation.

[0005] The technical solution adopted in this invention is as follows:

[0006] A spatial over-constraint compliant positioning platform with three-dimensional parasitic compensation consists of an active module, a passive module, and a worktable.

[0007] Active modules are respectively provided on the four sides and bottom of the workbench; the active modules are located at the center of each side, and the upper part of each active module is connected to the first end of two first prism structures through two first notch-type flexible hinges, and the lower part is connected to the first end of two second prism structures through two second notch-type flexible hinges; and four connecting rods extend from the four corners of the side of the workbench, and each connecting rod is connected to the second end of the third prism structure through a third notch-type flexible hinge; the second ends of the first, second and third prism structures located on the outer side of the same side or bottom are connected to the same parasitic compensation module through a fourth notch-type flexible hinge.

[0008] As a further technical solution, the first, second, third, and fourth notched flexible hinges, together with the first, second, and third prism structures and the parasitic compensation module, form a passive module, and the active and passive modules on each surface of the worktable have the same structure.

[0009] As a further technical solution, the two first prism structures and the two second prism structures located on the same plane are arranged symmetrically from top to bottom.

[0010] As a further technical solution, the four third prism structures located on the same plane are symmetrical about the top and bottom and about the left and right with respect to the center of the worktable.

[0011] As a further technical solution, the active module includes a main frame, within which a driving element is installed.

[0012] As a further technical solution, the main frame includes a top beam, a bottom beam, and a connecting column; one end of the top beam and the bottom beam are connected by the connecting column, and the other end of each is connected to the driven component by two leaf springs, and a drive element installation space is formed between the driven component and the connecting column.

[0013] As a further technical solution, the driven component is a rectangular block structure, which is connected to the first ends of two first prism structures through two first notch-type flexible hinges on the top and to the first ends of two second prism structures through two second notch-type flexible hinges on the bottom.

[0014] As a further technical solution, the driving element is a piezoelectric ceramic.

[0015] As a further technical solution, active and passive modules are set on the top surface of the workbench, but not on the bottom surface.

[0016] In this invention, before the compliant positioning platform operates, piezoelectric ceramic and other driving elements are first added to the active module, and then assembled, pre-tightened, and grounded. During operation, under the excitation of the driving elements, the active module in a certain axis deforms, simultaneously driving the worktable to move. The deformation of the passive module decouples the movements in other directions. When the driving elements stop working, the flexible mechanism returns to its initial state.

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

[0018] 1. This invention, through the design of the specific structure and layout of the active and passive modules, forms a flexible micro-nano positioning motion device that combines multi-axis motion decoupling and micro-nano positioning functions. The three-axis micro-nano motion platform can achieve multi-axis micro-nano motion through the cooperation of the active and passive modules. The notched flexible hinge and the compensated parasitic passive module can effectively reduce the inter-axis coupling of the motion platform and improve the positioning accuracy of the micro-nano motion platform.

[0019] 2. By introducing an over-constrained symmetric configuration, this triaxial micro-nano motion platform can further suppress parasitic motion in non-functional directions, thereby improving the platform's precision positioning effect.

[0020] 3. This flexible micro-nano motion platform adopts an integrated design, which has certain advantages in miniaturization. Its structural dimensions can be reasonably designed according to application requirements, and it has broad application prospects in the field of precision engineering. Attached Figure Description

[0021] 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.

[0022] Figure 1 Schematic diagram of the three-dimensional structure of the flexible triaxial micro / nano motion platform;

[0023] Figure 2 Front view of the three-dimensional structure of the flexible triaxial micro / nano motion platform;

[0024] Figure 3 Top view of the three-dimensional structure of the flexible triaxial micro / nano motion platform;

[0025] Figure 4 Schematic diagram of the active module structure;

[0026] Figure 5 Passive module structure diagram;

[0027] Figure 6 Schematic diagram of the driving element structure;

[0028] Figure 7(a) and Figure 7(b) show the motion deformation cloud diagrams of the motion platform in the X or Y direction.

[0029] Figure 8(a) and Figure 8(b) show the motion deformation cloud diagrams of the motion platform in the Z-direction.

[0030] Figure 9 Typical working principle diagram of a flexible passive module;

[0031] Figure 10 Working principle diagram of a flexible passive module with parasitic compensation function;

[0032] Among them, 1-AM active module, 2-PM passive module, 3-worktable, 4-drive element, 5-parasitic compensation module;

[0033] 101-Leaf spring; 102-Main frame; 1021-Top beam; 1022-Bottom beam; 1023-Connecting column; 104-Driven component;

[0034] 201 - Prism structure, 202 - Notch-type flexible hinge. Detailed Implementation

[0035] 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.

[0036] 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.

[0037] Glossary section:

[0038] "Over-constraint" refers to the application of multiple constraints in the same direction of the same degree of freedom.

[0039] "Three-dimensional" refers to the three dimensions formed by the X, Y, and Z directions.

[0040] "Spatial decoupling" means that motions in different degrees of freedom do not interfere with each other and can move independently.

[0041] "Parasitic movement" refers to movement in a non-functional direction, that is, unnecessary movement that is not desired.

[0042] "Parasitic compensation" refers to the fact that since compliant mechanisms generate motion through the deformation of materials, they are more prone to generating unnecessary motion compared to rigid mechanisms. This is one of the major challenges in the design of flexible mechanisms. Therefore, parasitic compensation is to reduce or even eliminate non-functional motion as much as possible through various methods.

[0043] The following description, with reference to the accompanying drawings, illustrates the spatially over-constrained compliant positioning platform with three-dimensional parasitic compensation disclosed in this embodiment: This embodiment discloses a three-axis translational motion platform to achieve spatial decoupling and high-precision spatial positioning. A constraint flow-based synthesis method can obtain the allowable constraints constraining the compliant modules. This embodiment synthesizes a three-axis translational mechanism by developing this method. For example... Figure 1 As shown, the topology consists of a drive module (AM) and a passive module (PM). The former is used to implement driven motion, and the latter is used to implement decoupled motion. According to the scheme requirements, [the following will be implemented]... Figure 1 The basic configuration of the three-axis translation mechanism shown is divided into three compliant functional units between the motion platform and the ground. This embodiment employs a series design of active and passive modules to create the functional elements of the three-axis translation motion platform. To achieve spatial decoupling and high-precision motion, the active module consists of multiple parallel leaf springs, improving accuracy by reducing parasitic motion. The passive module consists of prisms and multi-axis notched flexible hinges, achieving greater deflection by reducing stress concentration.

[0044] All flexible elements primarily achieve motion, force, and energy transfer through their own elastic deformation. For detailed analysis, specific analytical models have been proposed to describe the mechanical behavior of the corresponding flexural elements. Considering spatial mechanisms composed of flexural elements with various cross-sections, traditional calculation methods inevitably lead to complex computational processes.

[0045] To address the problem of multi-axis decoupling in space, this embodiment proposes a flexible micro / nano positioning and motion device that combines multi-axis motion decoupling with micro / nano positioning capabilities. (Refer to...) Figure 1 The compliant positioning platform consists of an AM active module 1, a PM passive module 2, and a worktable 3. AM active modules 1 and PM passive modules 2 are respectively installed on the four sides and bottom of the worktable 3. The AM active module 1 is located at the center of the four sides and bottom. The upper part of the AM active module 1 is connected to the first end of two first prism structures via two first notch-type flexible hinges, and the lower part is connected to the first end of two second prism structures via two second notch-type flexible hinges. Four connecting rods extend from the four corners of the worktable's sides, each connecting rod being connected to the second end of a third prism structure via a third notch-type flexible hinge. The second ends of the first, second, and third prism structures located on the outer side of the same side or bottom are connected to the same parasitic compensation module 5 via a fourth notch-type flexible hinge.

[0046] Furthermore, among the four sides, the AM active module 1 and PM passive module 2 on the left and right sides realize the movement of the worktable in the X direction, the AM active module 1 and PM passive module 2 on the front and rear sides realize the movement of the worktable in the X direction, and the AM active module 1 and PM passive module 2 on the bottom surface realize the movement of the worktable in the Z direction.

[0047] Furthermore, in this embodiment, the first, second, and third prism structures and connecting rods mentioned above are considered as rigid structures, and the flexibility of each notch-type flexible hinge is much greater than that of the first, second, and third prism structures and connecting rods.

[0048] As a further technical solution, the AM active module 1 and PM passive module 2 corresponding to each surface have the same structure.

[0049] As a further technical solution, the two first prism structures and the two second prism structures located on the same plane are arranged symmetrically from top to bottom.

[0050] As a further technical solution, the four third prism structures located on the same plane are symmetrical about the top and bottom and about the left and right with respect to the center of the worktable.

[0051] As a further technical solution, the active module includes a main frame, within which a driving element is installed.

[0052] As a further technical solution, the main frame includes a top beam 1021, a bottom beam 1022, and a connecting column 1023; one end of the top beam 1021 and the bottom beam 1022 are connected by the connecting column 1023, and the other end of each is connected to the driven member 103 by two leaf springs 101. A space for the driving element 4 is formed between the driven member 103 and the connecting column 1023, meaning the driving element 4 is installed within the main frame to drive the driven member 103.

[0053] As a further technical solution, the driven component 1024 is a rectangular block structure, which is connected to the first ends of two first prism structures through two first notch-type flexible hinges on the top and to the first ends of two second prism structures through two second notch-type flexible hinges on the bottom.

[0054] As a further technical solution, the driving element 4 can be a piezoelectric ceramic.

[0055] As a further technical solution, all the above-mentioned notched flexible hinges have the same structural form, such as... Figure 5 As shown; all the above prism structures have the same structural form, such as Figure 5 As shown.

[0056] It is not difficult to understand that the spatial over-constraint compliant positioning platform with three-dimensional parasitic compensation in this embodiment can also be designed such that AM active module 1 and PM passive module 2 are set on the top surface of the worktable, while no such module is set on the bottom surface of the worktable, and other settings remain unchanged. In this way, the movement of the worktable in the negative Z-axis direction, as well as the movement in the positive and negative X-axis directions and the positive and negative Y-axis directions are realized.

[0057] Furthermore, before the compliant positioning platform can operate, piezoelectric ceramic and other driving components must be added to each AM active module 1, and then assembled, pre-tightened, and grounded. During operation, under the excitation of the driving components, the active module in one axis deforms, simultaneously driving the worktable to move. The deformation of the passive module decouples the movements in other directions. When the driving components stop working, the flexible mechanism returns to its initial state. The specific motion control methods in the three directions are as follows:

[0058] When the active module on the positive X-axis side is activated, the driving element within it begins to drive, and the resulting thrust causes the leaf spring to undergo elastic deformation in the negative X-axis direction. Under the transmission action of the passive module, the connected worktable simultaneously moves in the positive X-axis direction. At this time, under the action of the spatial decoupling mechanism, the functional modules in other directions are not affected.

[0059] When the active module on the X-axis secondary side starts working, that is, the driving element within it begins to drive, and the resulting thrust causes the leaf spring to undergo elastic deformation in the positive X-axis direction. Under the transmission action of the passive module, the connected worktable simultaneously moves in the negative X-axis direction. At this time, under the action of the spatial decoupling mechanism, the functional modules in other directions are not affected.

[0060] When the active module on the positive Y-axis side is activated, the driving element within it begins to drive, and the resulting thrust causes the leaf spring to undergo elastic deformation in the negative Y-axis direction. Under the transmission action of the passive module, the connected worktable simultaneously moves in the positive Y-axis direction. At this time, under the action of the spatial decoupling mechanism, the functional modules in other directions are not affected.

[0061] When the active module on the Y-axis secondary side starts working, that is, the driving element within it begins to drive, and the resulting thrust causes the leaf spring to undergo elastic deformation in the positive Y-axis direction. Under the transmission action of the passive module, the connected worktable simultaneously moves in the negative Y-axis direction. At this time, under the action of the spatial decoupling mechanism, the functional modules in other directions are not affected.

[0062] When the active module on the positive Z-axis side is activated, the driving element within it begins to drive, and the resulting thrust causes the leaf spring to undergo elastic deformation in the negative Z-axis direction. Under the transmission action of the passive module, the connected worktable simultaneously moves in the positive Z-axis direction. At this time, under the action of the spatial decoupling mechanism, the functional modules in other directions are not affected.

[0063] Furthermore, such as Figure 9 , Figure 10 As shown, this embodiment also provides a general working principle diagram of a flexible passive module and a working principle diagram of a flexible passive module with parasitic compensation function proposed in this application; in Figure 9 In this design, the flexible passive module consists of a fixed end, a moving end, and an intermediate connecting rod. During the module's movement, the moving end moves to one side, causing the intermediate connecting rod to tilt to one side. It can be observed that, due to the length limitation of the intermediate connecting rod, the moving end, in addition to translating in the desired direction, also experiences a downward parasitic motion. This demonstrates that the conventional approach significantly impacts the accuracy of the mechanism's end effector. This invention employs... Figure 10 The configuration shown introduces a parasitic compensation module, which allows two sets of reverse-connected connecting rods to cancel each other out during operation, ultimately achieving the effect of parasitic compensation. However, this is only a diagram for ease of description. In this example, eight connecting rods are used in a reasonable spatial arrangement to achieve the purpose of parasitic motion compensation in three-axis space.

[0064] Finally, it should be noted that relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A spatially over-constrained compliant positioning platform with three-dimensional parasitic compensation, comprising a worktable; characterized in that: Active modules are arranged on four sides and the bottom of the workbench; the active modules are arranged at the center of each side, the upper part of each active module is connected with the first end of two first prism structures through two first notched flexible hinges, and the lower part is connected with the first end of two second prism structures through two second notched flexible hinges; four connecting rods are extended from the four corners of the side of the workbench, each connecting rod is connected with the second end of a third prism structure through a third notched flexible hinge; the second end of the first, second and third prism structures located on the same side or the outside of the bottom is connected with the same parasitic compensation module through a fourth notched flexible hinge; The first, second, third and fourth notched flexible hinges, the first, second and third prism structures and the parasitic compensation module form passive modules, and the corresponding active module and passive module on each side of the workbench are completely the same in structure; The two first prism structures and the two second prism structures located on the same side are arranged symmetrically up and down; The four third prism structures located on the same side are symmetrically arranged up and down and left and right relative to the center of the workbench.

2. The spatially over-constrained compliant positioning platform with three-dimensional parasitic compensation of claim 1, wherein, The active module comprises a main frame, and a driving element is arranged in the main frame.

3. The spatially over-constrained compliant positioning platform with three-dimensional parasitic compensation of claim 2, wherein, The main frame comprises a top beam, a bottom beam and a connecting column; one end of the top beam and the bottom beam is connected through the connecting column, and the other end is connected with a driven element through two leaf springs respectively; the driving element installation space is formed between the driven element and the connecting column.

4. The spatially over-constrained compliant positioning platform with three-dimensional parasitic compensation of claim 3, wherein, The driven element is a rectangular block structure, the upper part of which is connected with the first end of two first prism structures through two first notched flexible hinges, and the lower part is connected with the first end of two second prism structures through two second notched flexible hinges.

5. The spatially over-constrained compliant positioning platform with three-dimensional parasitic compensation of claim 3, wherein, The driving element is a piezoelectric ceramic.

6. The spatially over-constrained compliant positioning platform with three-dimensional parasitic compensation of claim 1, wherein, Active modules and passive modules are arranged on the top surface of the workbench, and the bottom surface of the workbench is not arranged.

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