A large-stroke flexible two-dimensional positioning platform based on S-shaped sheet

Abstract

The application discloses a large-stroke flexible two-dimensional positioning platform based on S-shaped sheets, which comprises a rigid outer frame, a flexible prismatic hinge, a flexible compensation module, a linear driving module and an output dynamic platform, and is arranged in a whole center-symmetrical cross-shaped structure. The flexible prismatic hinge is in an S-shaped sheet structure, and is fixedly connected with the rigid outer frame and the flexible compensation module on two sides, so as to provide driving guidance and balanced stress for the output dynamic platform. The two four-bar structures of the flexible compensation module are synchronously and reversely passively deformed to isolate the interference of parasitic displacement of the output dynamic platform in the working direction of the non-driving module. The application realizes accurate positioning and large-stroke adjustment of the output dynamic platform through isolation of parasitic motion by the flexible compensation module and bending deformation of the S-shaped sheet.

Description

Technical Field

[0001] The present invention belongs to the field of precision optical machinery, and in particular relates to a long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet. Background Art

[0002] In cutting-edge fields such as high-power laser technology, semiconductor lithography, ultra-precision machining and assembly, and nanotechnology, achieving extremely precise positioning and motion control is crucial, creating an urgent need for high-performance precision positioning stage technology. To achieve micro-nano-level positioning accuracy, excellent stability, rigidity, and rapid response, flexible elements are being incorporated into the design of precision positioning platforms. These elements address key issues such as creep, backlash, and wear that can occur with traditional rigid hinge mechanisms during motion, significantly improving overall system performance.

[0003] Currently, most precision positioning platforms tend to use notched flexure hinges as their core flexible components. While these offer significant advantages in submicron and even nanometer-level positioning accuracy, their range of motion is limited to tens of microns, making them difficult to meet requirements for larger travel ranges. On the other hand, while some precision positioning platforms can achieve a wider range of motion, these often suffer from insufficient positioning accuracy, complex structural designs, and bulky designs.

[0004] Therefore, exploring and developing a precision positioning platform that can ensure high-precision positioning, achieve a large range of motion, and maintain a compact structure and rapid response has become a hot topic and challenge in current research. Summary of the Invention

[0005] In order to solve the above problems, the purpose of the present invention is to propose a long-stroke flexible two-dimensional positioning platform based on an S-shaped thin sheet, which realizes the precise positioning and long-stroke adjustment of the output dynamic platform through the isolation of parasitic motion by the flexible compensation module and the bending deformation of the S-shaped thin sheet.

[0006] The technical solutions of the present invention are as follows:

[0007] A long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet is characterized by an overall centrally symmetrical cross-shaped structure, including:

[0008] Rigid outer frame;

[0009] The flexible translation hinge is an I-shaped structure with an S-shaped thin sheet in the middle connection. Its two ends are respectively connected to the rigid outer frame and the flexible compensation module for fixed connection, which is used to provide driving guidance and balanced force for the output dynamic platform.

[0010] The flexible compensation module includes two four-bar structures that can passively deform synchronously and in opposite directions to compensate for the parasitic displacement generated by the output platform movement;

[0011] A linear drive module, used to drive the flexible compensation module and then drive the output moving platform to generate displacement;

[0012] An output dynamic platform, connected to the flexible compensation module, for generating displacement and achieving positioning under the action of the linear drive module;

[0013] The flexible compensation module, used to compensate for parasitic displacements caused by platform motion, includes an output rigid block, a first flexible branch group, a transition rigid block, a second flexible branch group, and a compensation frame. The output rigid block, the transition rigid block, and the first flexible branch group connecting them form a first four-bar structure. The compensation frame is a semi-open frame, accommodating the first four-bar structure. It is divided into opening section 1, opening section 2, a drive section, connection section 1, and connection section 2. Opening sections 1 and 2 of the compensation frame are connected to the transition rigid block via a second flexible branch group, forming a second four-bar structure. The first connection portion of the compensation outer frame is fixed to at least one end of two flexible translation hinges, the other ends of which are fixed to the inner wall of the rigid outer frame. The second connection portion of the compensation outer frame is fixed to at least one end of two flexible translation hinges, the other ends of which are fixed to the inner wall of the rigid outer frame. The drive portion of the compensation outer frame is fixed to the inner wall of the rigid outer frame via a linear drive module. The output rigid block is fixed to the outer wall of the output moving platform. The first and second four-bar structures connected in series by the transition rigid blocks can passively generate deformations of opposite directions and equal degrees along the X-axis of the flexible compensation module coordinate system during platform movement, ensuring that the output rigid block and the compensation outer frame do not experience relative displacement along the Y-axis, thereby offsetting parasitic displacement and improving positioning accuracy.

[0014] Furthermore, the two four-bar structures of the flexible compensation module include a first four-bar structure and a second four-bar structure, which can be staggered in the Y-axis direction of the coordinate system of the flexible compensation module. When the output dynamic platform moves, a larger space can be reserved for the deformation of the first four-bar structure and the second four-bar structure, thereby increasing the ability to compensate for parasitic displacement.

[0015] Furthermore, the linear drive module is fixedly connected to the compensation outer frame drive portion of the flexible compensation module and the rigid outer frame respectively.

[0016] Furthermore, when there are two linear drive modules, their working directions are guaranteed to be perpendicular to each other; when there are four linear drive modules, the linear drive modules with the same working direction need to ensure that the driving displacement and driving direction are the same.

[0017] Furthermore, the performance parameters of the first flexible branch chain group 32 and the second flexible branch chain group 34 should be completely the same when they are designed, and they are centralized flexibility branches, with notches at both ends, and flexible hinges formed inside the notches;

[0018] Furthermore, the flexible translational hinge is equivalent to a conventional linear spring-type flexible hinge, but with additional extension capability. Four such hinges, symmetrically arranged in a parallelogram pattern on either side of the flexible compensation module, provide drive guidance and force balance. Furthermore, the entire structure is coplanar and of uniform thickness, fabricated using a wire-cutting machine.

[0019] When the platform needs to move in a certain direction, during single-direction adjustment, the linear drive module in the corresponding driving direction works and pushes the output dynamic platform to generate displacement through the flexible compensation module. The four translational flexible hinges connected to the driven flexible compensation module deflect and deform together to assist in guiding. At the same time, the translational flexible hinge itself is slightly stretched under force, reducing excessive pulling on the flexible compensation module caused by insufficient length during the offset process.

[0020] At this time, the flexible compensation module in the driving direction (pushed by the linear drive module) does not deform;

[0021] The outer frame of the flexible compensation module does not move in the non-driving direction. However, the first and second four-bar structures, due to the displacement of the output platform, will deform in opposite directions relative to the transition rigid block, but to the same degree. During this deformation, the transition rigid block moves half the output platform's movement in the desired driving direction, accompanied by a parasitic displacement along the Y-axis of the flexible compensation module's coordinate system, close to the output platform. Because the first and second four-bar structures deform to the same degree and are connected in series via the transition rigid block, this parasitic displacement is confined to the transition rigid block and does not further push the output rigid block along the Y-axis of the flexible compensation module's coordinate system, causing displacement of the output platform in the non-driving direction. This effectively isolates the parasitic displacement in the driving direction from that in the non-driving direction, achieving two-dimensional drive decoupling.

[0022] The parallelogram-shaped symmetrical arrangement of four flexible translation hinges provides driving guidance and balanced force, ensuring the smooth operation of the platform.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention achieves high-precision positioning performance over a long travel range while maintaining a compact overall size. The drive module is driven by the flexible compensation module and isolates the displacement interference of the output moving platform in the non-drive module working direction. The flexible compensation module and the bending deformation of the S-shaped sheet enable precise positioning and posture control of the moving platform.

[0025] 2. The present invention uses an S-shaped sheet as a flexible element to increase hinge flexibility and reduce stress concentration. Subsequently, positioning platforms with different workspace properties can be obtained based on the size design of the flexible hinge and the optimization of the kinematic model.

[0026] 3. The flexible compensation module used in the present invention can stagger the arrangement of two series four-bar structures to increase the working range of the positioning platform;

[0027] 4. The present invention is entirely located on the same plane and has the same thickness, and can be integrally processed and formed using a wire cutting machine, thus avoiding overall assembly and transmission errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of this application and should not be regarded as limiting the scope of protection of this application.

[0029] Figure 1 This is a schematic structural diagram of a long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet according to an embodiment of the present invention;

[0030] Figure 2 A three-dimensional diagram of a long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet according to an embodiment of the present invention;

[0031] Figure 3 Schematic diagram of the structure of the flexible translation hinge in the present invention;

[0032] Figure 4 is a schematic diagram of the flexible compensation module in the present invention;

[0033] Figure 5 This is a schematic diagram of an optional flexible compensation module and the first and second four-bar structures according to an embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of a deformation state in a single direction according to an embodiment of the present invention (enlarged scale);

[0035] Figure 7 Schematic diagram of bidirectional deformation state of an embodiment of the present invention (enlarged scale);

[0036] In the picture:

[0037] 1- Rigid outer frame;

[0038] 2-Flexible translation hinge;

[0039] 3- Flexible compensation module: 31- Output rigid block, 32- First flexible branch chain group, 33- Transition rigid block, 34- Second flexible branch chain group, 35- Compensation outer frame, 3511- Opening part 1, 3512- Opening part 2, 352- Driving part, 3531- Connection part 1, 3532- Connection part 2, 36- Second four-bar structure, 37- Second flexible branch chain group;

[0040] 4-Linear drive module;

[0041] 5- Output dynamic platform. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments, but this should not limit the scope of protection of the present invention.

[0043] See also Figure 1 and Figure 2 , Figure 1 This is a structural diagram of a long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet according to an embodiment of the present invention. Figure 2 This is a three-dimensional diagram of a large-stroke flexible two-dimensional positioning platform based on an S-shaped thin sheet according to an embodiment of the present invention. As shown in the figure, a large-stroke flexible two-dimensional positioning platform based on an S-shaped thin sheet has an overall structure arranged in a centrally symmetrical cross shape, including a rigid outer frame 1, a flexible translation hinge 2, a flexible compensation module 3, a linear drive module 4 and an output dynamic platform 5.

[0044] Rigid outer frame 1: As the supporting frame of the entire platform, it is made of high-strength material to ensure the stability and rigidity of the platform.

[0045] like Figure 3 As shown, the flexible translation hinge 2 is an I-shaped hinge with an S-shaped thin plate in the middle. The flexible translation hinge 2 is equivalent to a conventional linear spring-shaped flexible hinge, but has additional extension capacity, which improves the travel and flexibility of the platform. Figure 1 As shown, the four flexible translation hinges 2 located on both sides of the flexible compensation module 3 and arranged symmetrically in a parallelogram form together provide driving guidance and balanced force to ensure the smooth operation of the platform.

[0046] like Figure 4As shown, the flexible compensation module 3, used to compensate for parasitic displacements caused by platform motion, includes an output rigid block 31, a first flexible branch group 32, a transition rigid block 33, a second flexible branch group 34, and a compensation frame 35. The output rigid block 31, the transition rigid block 33, and the first flexible branch group 32 connecting the output rigid block 31 and the transition rigid block 33 form a first four-bar structure 36. The compensation frame 35 is a semi-open frame, accommodating the first four-bar structure 36. The compensation frame 35 is sequentially divided into an opening portion 1 3511, an opening portion 2 3512, a driving portion 352, a connecting portion 1 3531, and a connecting portion 2 3532. The opening portions 1 3511 and 2 3512 of the compensation frame 35 are connected to the transition rigid block 33 via the second flexible branch group 34, forming a second four-bar structure 37. The first connecting portion 3531 of the compensation outer frame 35 is fixed to at least one end of the two flexible translation hinges 2, the other ends of which are fixed to the inner wall of the rigid outer frame 1. The second connecting portion 3532 of the compensation outer frame 35 is fixed to at least one end of the two flexible translation hinges 2, the other ends of which are fixed to the inner wall of the rigid outer frame 1. The driving portion 352 of the compensation outer frame 35 is fixed to the inner wall of the rigid outer frame 1 via the linear drive module 4. The output rigid block 31 is fixed to the outer wall of the output dynamic platform 5. The first four-bar structure 36 and the second four-bar structure 37 connected in series via the transition rigid block 33 can passively generate deformations of opposite directions and equal degrees along the X-axis of the coordinate system of the flexible compensation module 3 during platform movement, ensuring that the output rigid block 31 and the compensation outer frame 35 do not experience relative displacement along the Y-axis, thereby offsetting parasitic displacement and improving positioning accuracy.

[0047] like Figure 5 As shown, the two four-bar structures of the flexible compensation module include a first four-bar structure and a second four-bar structure, which can be staggered in the Y-axis direction of the coordinate system of the flexible compensation module. When the output dynamic platform moves, a larger space can be reserved for the deformation of the first four-bar structure and the second four-bar structure, thereby increasing the ability to compensate for parasitic displacement.

[0048] Linear drive module 4 connects the drive unit 352 of the compensation outer frame 34 to the rigid outer frame 1, thereby limiting the degrees of freedom of the flexible compensation module 3 and providing single-degree-of-freedom displacement drive along the Y-axis of the flexible compensation module's coordinate system. By controlling the displacement of the linear drive module 4 in different working directions, two-dimensional positioning of the platform can be achieved.

[0049] Output platform 5: This is the final actuator of the platform and is fixedly connected to the output rigid block 31 of the flexible compensation module 3. The output platform 5 is displaced by the combined action of the linear drive module 4, the flexible compensation module 3, and the flexible translation hinge 2 to achieve positioning.

[0050] like Figure 6 As shown, when the output moving platform 5 moves, the first four-bar structure 36 and the second four-bar structure 37 of the flexible compensation module 3 will passively generate deformations of opposite directions and the same degree along the X-axis of the coordinate system of the flexible compensation module 3, and ensure that the output rigid block 31 and the compensation outer frame 35 do not generate relative displacement in the Y-axis direction, thereby compensating for the parasitic displacement caused by the deformation of the four-bar structure. At this time, the position of the compensation outer frame 35 in the X-axis direction of the coordinate system of the flexible compensation module 3 remains basically unchanged, avoiding the parasitic displacement and coupling caused by the deformation of the parallel mechanism affecting the input accuracy of the linear drive module at the corresponding position.

[0051] When there are two linear drive modules 4, their working directions must be perpendicular to each other; when there are four linear drive modules 4, the linear drive modules 4 with the same working direction must ensure the same driving displacement and driving direction.

[0052] The performance parameters of the first flexible branch chain group 32 and the second flexible branch chain group 34 should be exactly the same when they are designed. They are centralized flexibility branches, and both ends are provided with notches, and flexible hinges are formed inside the notches.

[0053] The specific working principle and process are as follows:

[0054] The movement direction of the flexible compensation module 3 is jointly constrained by the linear drive module 4 connected thereto and the flexible translation hinges 2 on both sides thereof, retaining the freedom of movement of the compensation outer frame 34 of the flexible compensation module 3 along the Y-axis direction of the coordinate system of the flexible compensation module 3 and controlled by the linear drive module 4;

[0055] like Figure 6As shown, when the single-direction adjustment is working, the linear drive module 4 in the corresponding driving direction works and pushes the output dynamic platform 5 to generate displacement through the flexible compensation module 3, and the four translational flexible hinges 2 connected to the driven flexible compensation module 3 are offset and deformed together to assist in guiding. At the same time, the translational flexible hinge 2 itself is slightly stretched by force, reducing the excessive pulling on the flexible compensation module 3 caused by insufficient length during the offset process, but at this time the flexible compensation module 3 in the driving direction (pushed by the linear drive module 4) does not deform; the compensation outer frame 35 of the flexible compensation module 3 in the non-driving direction does not move, but the first four-bar structure 36 and the second four-bar structure 37 will produce deformations in opposite directions and to the same degree relative to the transition rigid block 33 due to the displacement of the output dynamic platform 5. During this deformation process, the amount of movement of the transition rigid block 33 in the required driving direction is half of the amount of movement of the output movable platform 5, and is accompanied by a parasitic displacement close to the output movable platform 5 along the Y-axis direction of the coordinate system of the flexible compensation module 3. Because the deformation degree of the first four-bar structure 36 and the second four-bar structure 37 are the same, and the two are connected in series through the transition rigid block 33, the parasitic displacement is limited to the transition rigid block 33, and will not further push the output rigid block 31 to move along the Y-axis direction of the coordinate system of the flexible compensation module 3 to cause the displacement of the output movable platform 5 in the non-driving direction, thereby realizing the isolation of the driving direction displacement and the parasitic displacement in the non-driving direction, and realizing decoupling in two-dimensional drive.

[0056] like Figure 7 The simultaneous presence of drive in two directions shown can be viewed as a superposition of drive in a single direction.

[0057] The present invention increases the elongation capacity of the platform by adopting a flexible translation hinge with an S-shaped thin film design, thereby realizing flexible two-dimensional positioning with a large stroke. The S-shaped design not only improves the flexibility of the platform, but also ensures the stability of the platform during movement. The flexible compensation module can produce deformations of opposite directions and the same degree when the platform moves through the first four-bar structure and the second four-bar structure connected in series, effectively compensating for the parasitic displacement caused by the movement of the platform, improving the positioning accuracy of the platform, and avoiding the influence of the deformation of the parallel mechanism on the input accuracy of the linear drive module. The synergistic effect of the linear drive module and the flexible compensation module realizes the transmission of the displacement in the driving direction and the isolation of the drive in the non-driving direction, so that the simultaneous drive in the two directions can be regarded as the superposition of the drive in a single direction, thereby realizing the decoupling of the two-dimensional drive and improving the motion control performance of the platform. The rigid outer frame is made of high-strength material, which ensures the stability and rigidity of the entire platform, enables the platform to withstand large loads and deformations, and ensures the long-term stable operation of the platform.

[0058] In summary, the large-stroke flexible two-dimensional positioning platform based on the S-shaped sheet has significant technical effects such as large stroke, high precision, two-dimensional drive decoupling, stable and reliable structure, and modular design. It is suitable for various application scenarios that require high-precision two-dimensional positioning.

Claims

1. A long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet, characterized in that: The overall centrally symmetrical cross-shaped structure includes: Rigid outer frame; The flexible translation hinge is an I-shaped structure with an S-shaped thin sheet in the middle connection. Its two ends are fixedly connected to the rigid outer frame and the flexible compensation module respectively, and is used to provide driving guidance and balanced force for the output dynamic platform. The flexible compensation module includes two four-bar structures that can passively deform synchronously and in opposite directions to compensate for the parasitic displacement generated by the output platform movement; A linear drive module, used to drive the flexible compensation module and then drive the output moving platform to generate displacement; An output dynamic platform, connected to the flexible compensation module, for generating displacement and achieving positioning under the action of the linear drive module; The flexible compensation module is used to compensate for the parasitic displacement caused by the movement of the platform, and includes an output rigid block, a first flexible branch group, a transition rigid block, a second flexible branch group, and a compensation outer frame; a first four-bar structure composed of the output rigid block, the transition rigid block, and the first flexible branch group connecting the output rigid block and the transition rigid block; the compensation outer frame is a semi-open frame type, used to accommodate the first four-bar structure, and itself is divided into opening part 1, opening part 2, driving part, connection part 1, and connection part 2 in sequence; the opening part 1 and opening part 2 of the compensation outer frame are connected to the transition rigid block through the second flexible branch group to form a second four-bar structure, and the connection part 1 of the compensation outer frame is fixed to at least one end of the two flexible translation hinges The other ends of the two flexible translation hinges are fixed on the inner wall of the rigid outer frame; the second connecting portion of the compensation outer frame is fixed to at least one end of the two flexible translation hinges, and the other ends of the two flexible translation hinges are fixed on the inner wall of the rigid outer frame; the driving portion of the compensation outer frame is fixed to the inner wall of the rigid outer frame through a linear driving module; the output rigid block is fixed on the outer wall of the output dynamic platform, and the first four-bar structure and the second four-bar structure connected in series through the transition rigid block can passively generate deformations in opposite directions and the same degree along the X-axis direction of the flexible compensation module coordinate system when the platform moves, ensuring that the output rigid block and the compensation outer frame do not generate relative displacement in the Y-axis direction, thereby offsetting parasitic displacement and improving positioning accuracy.

2. The long-stroke flexible two-dimensional positioning platform based on the S-shaped sheet according to claim 1 is characterized in that: The two four-bar structures of the flexible compensation module include a first four-bar structure and a second four-bar structure, which are staggered in the Y-axis direction of the coordinate system of the flexible compensation module. When the output movable platform moves, a larger space is reserved for the first four-bar structure and the second four-bar structure to deform in opposite directions but to the same extent, thereby increasing the ability to compensate for the parasitic displacement caused by the movement of the output movable platform.

3. The long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet according to claim 1 is characterized in that: The linear drive module is respectively connected to the drive part and the rigid outer frame of the compensation outer frame of the flexible compensation module, thereby limiting the freedom of the flexible compensation module and providing single-degree-of-freedom displacement drive along the Y-axis of the flexible compensation module coordinate system; by controlling the displacement of the linear drive module in different working directions, the two-dimensional positioning of the platform is achieved.

4. The long-stroke flexible two-dimensional positioning platform based on the S-shaped sheet according to claim 3 is characterized in that: When there are two linear drive modules, their working directions are guaranteed to be perpendicular to each other; when there are four linear drive modules, the linear drive modules with the same working direction need to ensure that the driving displacement and driving direction are the same.

5. The long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet according to claim 1 is characterized in that: The performance parameters of the first flexible branch chain group and the second flexible branch chain group during design should be completely the same, and they are centralized flexibility branches, both ends of which are provided with notches, and flexible hinges are formed inside the notches.

6. The long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet according to claim 1 is characterized in that: The flexible translation hinge is equivalent to a conventional flexible hinge in the form of a straight spring, but has additional elongation capacity, which reduces excessive pulling on the flexible compensation module caused by insufficient length during the offset process; the four flexible translation hinges located on both sides of the flexible compensation module and arranged symmetrically in a parallelogram together provide drive guidance and balanced force.

7. A long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet according to any one of claims 1 to 6, characterized in that: The whole is located on the same plane and has the same thickness, and is processed and formed in an integrated manner using a wire cutting machine.

8. A long-stroke flexible two-dimensional positioning platform based on an S-shaped sheet according to any one of claims 1 to 6, characterized in that: When adjusting in a single direction, the linear drive module in the corresponding driving direction works and pushes the output dynamic platform to generate displacement through the flexible compensation module. The four translational flexible hinges connected to the driven flexible compensation module offset and deform together to assist in guiding. At the same time, the translational flexible hinge itself is slightly stretched by force, reducing the excessive pulling on the flexible compensation module caused by insufficient length during the offset process. However, at this time, the flexible compensation module pushed by the linear drive module in the driving direction does not deform; the compensation module outer frame of the flexible compensation module in the non-driving direction does not move, but the first four-bar structure and the second four-bar structure will produce displacement relative to the transition rigid block due to the displacement of the output dynamic platform. The deformation amounts are opposite and of the same degree. During this deformation process, the movement amount of the transition rigid block in the required driving direction is half of the movement amount of the output moving platform, and is accompanied by a parasitic displacement close to the output moving platform along the Y-axis direction of the coordinate system of the flexible compensation module. Since the deformation degrees of the first four-bar structure and the second four-bar structure are the same and the two are connected in series through the transition rigid block, the parasitic displacement is limited to the transition rigid block and will not further push the output rigid block to move along the Y-axis direction of the coordinate system of the flexible compensation module to cause displacement of the output moving platform in the non-driving direction. Thus, the parasitic displacement in the driving direction and the non-driving direction are isolated, and decoupling in two-dimensional driving is achieved. The simultaneous existence of driving in two directions can be regarded as the superposition of driving in a single direction.

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