Two-degree-of-freedom rigidity-variable compliant positioning platform

Abstract

The utility model discloses a two-degree-of-freedom rigidity-variable compliant positioning platform, which comprises a base platform, a movable platform, an X-direction input mechanism, a Y-direction input mechanism, an X-direction rigidity-variable mechanism, a Y-direction rigidity-variable mechanism and a guide mechanism, wherein the guide mechanism is used for controlling the movement directions of the X-direction input mechanism, the Y-direction input mechanism, the X-direction rigidity-variable mechanism and the Y-direction rigidity-variable mechanism. When the X-direction input mechanism or the Y-direction input mechanism is driven by a motor to generate displacement in the X-axis direction or the Y-axis direction, the displacement is transmitted to the variable-rigidity mechanism through the guide mechanism and the movable platform, rigidity change on the X-direction variable-rigidity mechanism or the Y-direction variable-rigidity mechanism is caused, rigidity adjustment in the two-degree-of-freedom direction is completed, the overall structure is compact, a control system is simple, and cost is low. And the variable stiffness degree is high.

Description

Technical Field

[0001] The utility model relates to the technical field of precision micro-positioning, and in particular to a two-degree-of-freedom variable stiffness compliant positioning platform. Background Technique

[0002] A flexible mechanism is a mechanism that relies on the flexibility of component elements to output motion or force, and has the advantages of compact structure, light weight, no clearance, no friction, etc. For a variable stiffness mechanism, it is mainly divided into an active variable stiffness mechanism and a passive variable stiffness mechanism. The stiffness of the former can be actively adjusted artificially, and the stiffness of the latter changes with the change of load, and the stiffness change is achieved by changing the structural acting force or changing the material stiffness. The variable stiffness compliant mechanism obtained by combining the variable stiffness mechanism and the flexible mechanism combines the advantages of both, and has been widely used in many technical fields, such as micro-nano coordinate measurement, precision machining, mobile phone screen production and other fields. In the existing technology, for example, a series-type flexible two-degree-of-freedom precision motion platform disclosed in CN216216591U adopts a series-type double-parallelogram flexible guiding mechanism and a parallel-type double-parallelogram flexible guiding mechanism, and is combined with components such as a motion platform and a support frame. The overall structure is compact and can be used for positioning or tracking requirements in a narrow space, or can also be used as the last stage of a multi-stage motion platform to achieve high-precision motion compensation. Although this device realizes two-degree-of-freedom precision positioning through a compliant mechanism, the stiffness in each direction cannot be changed, and the application scenarios are limited. Content of the Utility Model

[0003] The purpose of the utility model is to solve the problem of stiffness adjustment of the compliant mechanism precision positioning platform in two degrees of freedom, and provides a two-degree-of-freedom variable stiffness compliant positioning platform. Through the cooperation of the X-direction input mechanism, the Y-direction input mechanism, the X-direction variable stiffness mechanism, the Y-direction variable stiffness mechanism and the guiding mechanism in the X-axis direction and the Y-axis direction, variable stiffness precision positioning in two degrees of freedom is realized.

[0004] To solve the above technical problems, the technical solution adopted by the utility model is:

[0005] A two-degree-of-freedom variable stiffness compliant positioning platform is provided, including a base, a moving platform, an X-direction input mechanism, a Y-direction input mechanism, an X-direction variable stiffness mechanism, a Y-direction variable stiffness mechanism, and a guiding mechanism for controlling the movement directions of the X-direction input mechanism, the Y-direction input mechanism, the X-direction variable stiffness mechanism, and the Y-direction variable stiffness mechanism; the X-direction input mechanism, the Y-direction input mechanism, the X-direction variable stiffness mechanism, and the Y-direction variable stiffness mechanism are all connected to the guiding mechanism, the guiding mechanism is connected to the base, one side of the moving platform in the X-axis direction is connected with the X-direction input mechanism, and the other side is connected with the X-direction variable stiffness mechanism. One side of the moving platform in the Y-axis direction is connected with the Y-direction input mechanism, and the other side is connected with the Y-direction variable stiffness mechanism.

[0006] For the two-degree-of-freedom variable stiffness compliant positioning platform of the present utility model, displacement is input in the X-axis direction through the X-direction input mechanism. The X-direction input mechanism moves along the X-axis direction under the action of the guiding mechanism and transmits the displacement to the moving platform. On the other side of the moving platform in the X-axis direction, there is an X-direction variable stiffness mechanism. The moving platform transmits the displacement of the X-direction input mechanism to the X-direction variable stiffness mechanism, and the X-direction variable stiffness mechanism adjusts its own stiffness according to the magnitude of the input displacement, thereby achieving variable stiffness in the X-axis direction. The base is internally connected to the guiding mechanism, which can protect the overall structure of the positioning platform and increase the working stability. The working mechanism in the Y-axis direction is the same as that in the X-axis direction. In actual application, through the cooperation of the mechanisms in the X-axis direction and the Y-axis direction, automatic stiffness adjustment in two degrees of freedom can be achieved.

[0007] Furthermore, the X-direction variable stiffness mechanism and the Y-direction variable stiffness mechanism have the same structure, both including a T-shaped block, an I-shaped column, a rigid block, and a fixed block; there is a gap between the T-shaped block and the I-shaped column, and there is a gap between the I-shaped column and the rigid block; the T-shaped block and the I-shaped column are connected by a first flexible hinge, the I-shaped column and the fixed block are connected by a second flexible hinge, and the rigid block and the fixed block are connected by a third flexible hinge; there is a fixing hole on the fixed block. The X-direction variable stiffness mechanism and the Y-direction variable stiffness mechanism are set to have the same structure, enabling the compliant positioning platform to achieve the same range of automatic variable stiffness in two degrees of freedom. The variable stiffness process in the X-direction is mainly divided into three stiffness stages. When the moving platform just transmits the displacement of the X-direction input mechanism to the X-direction variable stiffness mechanism, since there is a gap between the T-shaped block and the I-shaped column and they have not come into contact yet, this is the first stiffness stage, and the mechanism stiffness is determined by the first flexible hinge connecting the T-shaped block and the I-shaped column. When the input displacement gradually increases until the T-shaped block and the I-shaped block have come into contact, but there is still a gap between the I-shaped column and the rigid block, at this time, the mechanism stiffness changes from the first stiffness stage to the second stiffness stage, and the mechanism stiffness is determined by the second flexible hinge connecting the I-shaped column and the fixed block and the guiding mechanism. When the input displacement further increases, that is, the gap between the I-shaped column and the rigid block continuously decreases until the I-shaped column and the rigid block come into contact, it enters the third stiffness stage of the variable stiffness mechanism, and the mechanism stiffness is determined by the third flexible hinge connecting the rigid block and the fixed block and the guiding mechanism. The two-degree-of-freedom variable stiffness compliant positioning platform can be connected to an actuator such as a fast tool servo mechanism. The fixing hole is connected to the connecting component on the actuator to ensure that the overall position does not shift during the working process of the variable stiffness mechanism, only the internal structure changes, and only the mechanism stiffness changes.

[0008] Furthermore, the gaps between the T-shaped block and the I-shaped column and between the I-shaped column and the rigid block are both 0.5 - 1.0 mm. By adjusting the gaps between the T-shaped block and the I-shaped column and between the I-shaped column and the rigid block, the stiffness change range and change speed in the variable stiffness stage can be controlled. When the gaps are controlled within 0.5 - 1.0 mm, the response speed of the compliant positioning platform can be relatively fast, while ensuring a stable stiffness change without sudden changes.

[0009] Furthermore, the X-direction input mechanism and the Y-direction input mechanism have the same structure, and both are hollow structures inside. Inside the input mechanism, several fourth flexible hinges are provided in the X-axis direction or the Y-axis direction. The same structure of the X-direction input mechanism and the Y-direction input mechanism enables stable displacement and the same input speed in two degrees of freedom. The hollow X-direction input mechanism and Y-direction input mechanism reduce their own mass while the flexible hinges ensure a certain strength, which can improve the overall natural frequency and stability of the mechanism.

[0010] Furthermore, both the X-direction input mechanism and the Y-direction input mechanism are connected to a voice coil motor or a piezoelectric ceramic actuator. The voice coil motor has characteristics such as high acceleration, high speed, and fast response, and is widely used in high-precision positioning systems. The piezoelectric ceramic actuator has high displacement resolution, small volume, fast response, large output force, and does not generate heat. When combined with the flexible variable stiffness mechanism, it can improve its inherent hysteresis, creep and other problems and enhance its positioning accuracy.

[0011] Furthermore, the guiding mechanism includes a first flexible member, a first guiding beam, a second flexible member, and a third flexible member. The first flexible member and the second flexible member are connected by the first guiding beam and the third flexible member; both the first flexible member and the second flexible member are connected to the X-direction input mechanism, the Y-direction input mechanism, the X-direction variable stiffness mechanism, and the Y-direction variable stiffness mechanism. When the X-direction input mechanism or the Y-direction input mechanism inputs displacement to the guiding mechanism, the first flexible member bends first, and the first guiding beam and the third flexible member transfer the displacement to the second flexible member, causing the second flexible member to bend and controlling the overall movement direction of the X-direction input mechanism or the Y-direction input mechanism. During the X-direction variable stiffness mechanism or the Y-direction variable stiffness mechanism process, the first flexible member, the first guiding beam, the second flexible member, and the third flexible member not only control its movement direction, but also their own stiffness will affect the variable stiffness range.

[0012] Furthermore, both the first flexible member and the second flexible member are in a shape of a several-character bend structure, and the third flexible member is in an M-shaped bend structure. The first flexible member and the second flexible member in the shape of a several-character bend structure are connected by a straight first guiding beam and an M-shaped third guiding beam. Compared with the traditional double-parallelogram guiding beam, the several-character bend structure and the M-shaped bend structure can provide a larger output stroke in a smaller space.

[0013] Furthermore, the moving platform is connected to the X-direction input mechanism, the Y-direction input mechanism, the X-direction variable stiffness mechanism, and the Y-direction variable stiffness mechanism by fifth flexible hinges. Connecting the moving platform to the X-direction input mechanism, the Y-direction input mechanism, the X-direction variable stiffness mechanism, and the Y-direction variable stiffness mechanism through the fifth flexible hinges can stably transmit displacement and make the stiffness change of the X-direction variable stiffness mechanism and the Y-direction variable stiffness mechanism smoother.

[0014] Furthermore, there are at least two groups of the fifth flexible hinges and they are parallel to each other. Two or more groups of parallel fifth flexible hinges form multiple parallelogram structures, which can improve the overall motion stability and positioning accuracy of the device.

[0015] Furthermore, the base is arranged outside the guiding mechanism, and there are several positioning and mounting holes on the base. The base is located outside the guiding mechanism, which can protect the X-direction input mechanism, the Y-direction input mechanism, the X-direction variable stiffness mechanism, the Y-direction variable stiffness mechanism, the moving platform and the guiding mechanism. By cooperating with the connecting components on the actuator through the positioning and mounting holes, the relative positions of the two-degree-of-freedom variable stiffness compliant positioning platform and the actuator can be fixed, avoiding the position deviation of the compliant positioning platform during the working process.

[0016] Compared with the prior art, the utility model has the following beneficial effects: 1. It realizes the stiffness adjustment in two degrees of freedom, the device structure is simple, and the manufacturing difficulty is low; 2. The variable stiffness range can be adjusted, and it has many application scenarios; 3. The control system is simple, and only the displacement inputs on the X-direction input mechanism and the Y-direction input mechanism need to be controlled to complete the variable stiffness in two degrees of freedom. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present utility model. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Structural schematic diagram of the two-degree-of-freedom variable stiffness compliant positioning platform for Embodiment 1;

[0019] Figure 2 Stereogram of the two-degree-of-freedom variable stiffness compliant positioning platform;

[0020] Figure 3 Structural schematic diagram of the variable stiffness mechanism;

[0021] Figure 4 Structural schematic diagram of the X-direction input mechanism and the guiding mechanism;

[0022] Figure 5Schematic structural diagram of the two-degree-of-freedom variable stiffness compliant positioning platform in the second embodiment;

[0023] Figure 6 Schematic structural diagram of the two-degree-of-freedom variable stiffness compliant positioning platform in the third embodiment;

[0024] Explanation of reference numerals:

[0025] 1. Base; 11. Positioning and mounting hole; 2. Moving platform; 21. Fifth flexible hinge; 31. X-direction input mechanism; 311. Fourth flexible hinge; 32. Y-direction input mechanism; 41. X-direction variable stiffness mechanism; 411. T-shaped block; 412. I-shaped column; 413. Rigid block; 414. Fixed block; 415. First flexible hinge; 416. Second flexible hinge; 417. Third flexible hinge; 418. Fixed hole; 42. Y-direction variable stiffness mechanism; 5. Guiding mechanism; 51. First flexible member; 52. First guiding beam; 53. Second flexible member; 54. Third flexible member. Detailed implementation manners

[0026] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0027] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0028] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined. In addition, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0029] The technical solutions in the embodiments of the present utility model will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0030] Embodiment 1

[0031] As Figure 1 、 Figure 2 shown, the two-degree-of-freedom variable stiffness compliant positioning platform in this embodiment includes a base 1, a moving platform 2, an X-direction input mechanism 31, a Y-direction input mechanism 32, an X-direction variable stiffness mechanism 41, a Y-direction variable stiffness mechanism 42, and a guiding mechanism 5 for controlling the moving directions of the X-direction input mechanism 31, the Y-direction input mechanism 32, the X-direction variable stiffness mechanism 41, and the Y-direction variable stiffness mechanism 42; the X-direction input mechanism 31, the Y-direction input mechanism 32, the X-direction variable stiffness mechanism 41, and the Y-direction variable stiffness mechanism 42 are all connected to the guiding mechanism 5, the guiding mechanism 5 is connected to the base 1, one side of the moving platform 2 in the X-axis direction is connected to the X-direction input mechanism 31, and the other side is connected to the X-direction variable stiffness mechanism 41, one side of the moving platform 2 in the Y-axis direction is connected to the Y-direction input mechanism 32, and the other side is connected to the Y-direction variable stiffness mechanism 42.

[0032] As Figure 3As shown, the X-direction variable stiffness mechanism 414 includes a T-shaped block 411, an I-shaped column 412, a rigid block 413, and a fixed block 414. There is a gap between the T-shaped block 411 and the I-shaped column 412 in the X-axis direction, and there is a gap between the I-shaped column 412 and the rigid block 413 in the X-axis direction. The gap between the T-shaped block 411 and the I-shaped column 412 and the gap between the I-shaped column 412 and the rigid block 413 should be controlled within 0.5 - 1.0 mm. In this embodiment, to balance the corresponding speed and the smoothness of stiffness change, the gap is set to 0.8 mm. The T-shaped block 411 and the I-shaped column 412 are connected in the Y-axis direction through a first flexible hinge 415, the I-shaped column 412 and the fixed block 414 are connected in the Y-axis direction through a second flexible hinge 416, and the rigid block 413 and the fixed block 414 are connected in the Y-axis direction through a third flexible hinge 417. There is a fixing hole 418 on the fixed block 414. The number and the self-stiffness of the third flexible hinge should be greater than those of the second flexible hinge to ensure that as the input displacement increases, the stiffness of the X-direction variable stiffness mechanism can increase synchronously to achieve automatic variable stiffness. The X-direction input mechanism 31 and the Y-direction input mechanism 32 have the same structure, and the X-direction variable stiffness mechanism 41 and the Y-direction variable stiffness mechanism 42 have the same structure. Therefore, during the working process, the variable stiffness process in the X direction is the same as that in the Y direction, both being divided into a first stiffness stage, a second stiffness stage, and a third stiffness stage. The two-degree-of-freedom variable stiffness compliant positioning platform can be connected to an actuator such as a fast tool servo mechanism. The fixing hole 418 cooperates with the connecting component on the actuator to facilitate connection methods such as bolt connection and riveting, and to fix the relative position between the two-degree-of-freedom variable stiffness compliant positioning platform and the actuator.

[0033] Taking the variable stiffness process in the X-axis direction as an example, the X-direction input mechanism 31 generates a displacement in the X-axis direction, driving the moving platform 2 to move in the X-axis direction and transmitting the displacement of the X-direction input mechanism 31 to the X-direction variable stiffness mechanism 41. When the X-direction variable stiffness mechanism 41 just starts to displace, since there is a gap between the T-shaped block 411 and the I-shaped column 412, the T-shaped block 411 and the I-shaped column 412 are not in contact yet, and the overall stiffness of the mechanism is determined by the first flexible hinge 415, that is, the first stiffness stage; when the displacement gradually increases, the T-shaped block 411 and the I-shaped column 412 come into contact with each other. At this time, the first flexible hinge 415 fails, while the guiding mechanism 5 and the second flexible hinge 416 bend, and the overall stiffness of the mechanism is jointly determined by the guiding mechanism 5 and the second flexible hinge 416, that is, the second stiffness stage; as the displacement continues to increase until the I-shaped column 412 contacts the rigid block 413, at this time the second flexible hinge 416 loses its function, and the overall stiffness of the mechanism is determined by the guiding mechanism 5 and the third flexible hinge 417. Since the number and its own stiffness of the third flexible hinge 417 are both greater than those of the second flexible hinge 416, the overall stiffness of the mechanism further increases at this time, that is, the third stiffness stage. By changing the number, arrangement mode and its own stiffness of the first flexible hinge 415, the second flexible hinge 416 and the third flexible hinge 417, the stiffness change range of the three stiffness stages can be adjusted.

[0034] As Figure 4 shown, the guiding mechanism 5 includes a first flexible member 51, a first guiding beam 52, a second flexible member 53 and a third flexible member 54. The first flexible member 51 and the second flexible member 53 are connected by the first guiding beam 52 and the third flexible member 54. The first flexible member 51 and the second flexible member 53 are in a "Ji" shape, and the third flexible member 54 is in an M shape. The base 1 is arranged outside the guiding mechanism 5, and a number of positioning and mounting holes 11 are provided on the base 1. The base 1 can protect the overall structure of the two-degree-of-freedom variable stiffness compliant positioning platform and cooperate with the connecting components on the actuator through the fixed mounting holes 11, so as to ensure that the positioning platform will not shift in the overall position during the working process.

[0035] When the X-direction input mechanism 31 or the Y-direction input mechanism 32 inputs displacement to the guiding mechanism 5, the first flexible member 51 first bends, and the displacement is transmitted to the second flexible member 53 through the first guiding beam 52 and the third flexible member 54, causing the second flexible member 53 to bend. Different from the traditional double parallelogram guiding beam, on the one hand, the guiding mechanism 5 in this embodiment can provide a larger output stroke in a smaller space through its special shape design. On the other hand, it also affects the stiffness change range of the X-direction variable stiffness mechanism 41 and the Y-direction variable stiffness mechanism 42 through the stiffness of the first flexible member 51, the first guiding beam 52, the second flexible member 53 and the third flexible member 54. The stiffness of the two-degree-of-freedom variable stiffness compliant positioning platform can be changed by changing the material selection of the guiding beam and the flexible member. Each structure in this embodiment is made of Al-7075-T6 material, with low manufacturing difficulty and production cost. Only one control system is required to control the displacement of the X-direction input mechanism 31 and the Y-direction input mechanism 32 to achieve stiffness change in two degrees of freedom, and the operating system is simple.

[0036] Embodiment 2

[0037] As Figure 5 shown, this embodiment is similar to Embodiment 1. The difference is that the X-direction input mechanism 31 and the Y-direction input mechanism 32 in this embodiment have the same structure and are both hollow structures. Inside the X-direction input mechanism 31, a number of fourth flexible hinges 311 are provided in the X-axis direction, and inside the Y-direction input mechanism 32, a number of fourth flexible hinges 311 are provided in the Y-axis direction. Using flexible hinges instead of solid structures can reduce the overall weight of the mechanism, while ensuring a certain strength and reducing production costs. The fourth flexible hinges 311 should be kept parallel and can be arranged along the X-axis direction or the Y-axis direction. The fourth flexible hinges 311 forming a parallelogram structure can make the internal structure of the X-direction input mechanism 31 and the Y-direction input mechanism 32 stable, with uniform displacement of each part, and ensure the stability of displacement input. In this embodiment, a voice coil motor or a piezoelectric ceramic actuator is connected to the X-direction input mechanism 31 and the Y-direction input mechanism 32. The voice coil motor has a fast response speed and can provide displacement input with high acceleration and high speed; the piezoelectric ceramic actuator has a high displacement resolution, small volume, large output force, and does not generate heat. When connected to the input mechanism 3 in this embodiment and cooperating with the flexible hinge, it can make the X-direction input mechanism 31 and the Y-direction input mechanism 32 generate smooth, stable and fast displacement input, ensuring the accuracy and response speed of the two-degree-of-freedom variable stiffness compliant positioning platform.

[0038] Embodiment 3

[0039] As Figure 6As shown, this embodiment is similar to Embodiment 1, except that in this embodiment, the moving platform 2 is connected to the X-direction input mechanism 31, the Y-direction input mechanism 32, the X-direction variable stiffness mechanism 41, and the Y-direction variable stiffness mechanism 42 by a plurality of fifth flexible hinges 21, and the plurality of fifth flexible hinges 21 are arranged in parallel. The plurality of fifth flexible hinges 21 arranged in parallel will form a plurality of parallelogram structures at the joints of the moving platform 2 with the X-direction input mechanism 31, the Y-direction input mechanism 32, the X-direction variable stiffness mechanism 41, and the Y-direction variable stiffness mechanism 42, increasing the stability of the movement of the moving platform 2 and improving the overall accuracy of the positioning platform.

[0040] Only some exemplary embodiments of the present invention have been described by way of illustration above. Undoubtedly, for those of ordinary skill in the art, the described embodiments can be modified in various different ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

[0041] Although the present invention uses terms such as base, variable stiffness mechanism, input mechanism, guiding mechanism, moving platform, and flexible hinge more frequently, the possibility of using other terms is not excluded. These terms are only used to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A two-degree-of-freedom variable-rigidity compliant positioning platform, characterized in that: The invention comprises a base (1), a moving platform (2), an X-direction input mechanism (31), a Y-direction input mechanism (32), an X-direction variable stiffness mechanism (41), a Y-direction variable stiffness mechanism (42), and a guide mechanism (5) for controlling the movement direction of the X-direction input mechanism (31), the Y-direction input mechanism (32), the X-direction variable stiffness mechanism (41), and the Y-direction variable stiffness mechanism (42); the X-direction input mechanism (31), the Y-direction input mechanism (32), the X-direction variable stiffness mechanism (41), and the Y-direction variable stiffness mechanism (42) are all connected to the guide mechanism (5); the guide mechanism (5) is connected to the base (1); one side of the moving platform (2) in the X-axis direction is connected to the X-direction input mechanism (31), and the other side is connected to the X-direction variable stiffness mechanism (41); one side of the moving platform (2) in the Y-axis direction is connected to the Y-direction input mechanism (32), and the other side is connected to the Y-direction variable stiffness mechanism (42).

2. A two-degree-of-freedom variable-rigidity compliant positioning platform according to claim 1, characterized in that: The X-axis variable stiffness mechanism (41) and the Y-axis variable stiffness mechanism (42) have the same structure, and both comprise a T-shaped block (411), an I-shaped column (412), a rigid block (413), and a fixed block (414); a gap is provided between the T-shaped block (411) and the I-shaped column (412), and a gap is provided between the I-shaped column (412) and the rigid block (413); the T-shaped block (411) and the I-shaped column (412) are connected via a first flexible hinge (415), the I-shaped column (412) and the fixed block (414) are connected via a second flexible hinge (416), and the rigid block (413) and the fixed block (414) are connected via a third flexible hinge (417); and a fixing hole (418) is provided on the fixed block (414).

3. A two-degree-of-freedom variable-rigidity compliant positioning platform according to claim 2, characterized in that: The gap between the T-shaped block (411) and the I-shaped column (412) and the gap between the I-shaped column (412) and the rigid block (413) are both 0.5 to 1.0 mm.

4. The two-degree-of-freedom variable-rigidity compliant positioning platform according to claim 1, characterized in that: The X-direction input mechanism (31) and the Y-direction input mechanism (32) have the same structure, both of which are hollow structures inside. A plurality of fourth flexible hinges (311) are provided inside the input mechanism (3) in the X-axis direction or the Y-axis direction.

5. The two-degree-of-freedom variable-rigidity compliant positioning platform according to claim 4, characterized in that: The X-direction input mechanism (31) and the Y-direction input mechanism (32) are both connected to a voice coil motor or a piezoelectric ceramic driver.

6. A two-degree-of-freedom variable-rigidity compliant positioning platform according to any one of claims 1 to 5, characterized in that: The guide mechanism (5) comprises a first flexible member (51), a first guide beam (52), a second flexible member (53) and a third flexible member (54); the first flexible member (51) and the second flexible member (53) are connected via the first guide beam (52) and the third flexible member (54); the first flexible member (51) and the second flexible member (53) are both connected to an X-direction input mechanism (31), a Y-direction input mechanism (32), an X-direction variable stiffness mechanism (41) and a Y-direction variable stiffness mechanism (42).

7. The two-degree-of-freedom variable-rigidity compliant positioning platform according to claim 6, characterized in that: The first flexible member (51) and the second flexible member (53) are both of an X-shaped bending structure, and the third flexible member (54) is of an M-shaped bending structure.

8. A two-degree-of-freedom variable-rigidity compliant positioning platform according to any one of claims 1 to 5, characterized in that: A fifth flexible hinge (21) is connected between the moving platform (2) and the X-direction input mechanism (31), the Y-direction input mechanism (32), the X-direction variable stiffness mechanism (41), and the Y-direction variable stiffness mechanism (42).

9. The two-degree-of-freedom variable-rigidity compliant positioning platform according to claim 8, characterized in that: The fifth flexible hinges (21) are at least two groups and are parallel to each other.

10. The two-degree-of-freedom variable-rigidity compliant positioning platform according to claim 1, characterized in that: The base (1) is arranged outside the guide mechanism (5), and a plurality of positioning and mounting holes (11) are provided on the base (1).

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