A high-precision positioning platform based on flexible kinematic pair

Abstract

The application provides a high-precision positioning platform based on a flexible kinematic pair, which can realize high-precision positioning, simplify the overall structure of the platform, reduce the space occupation, and greatly improve the convenience of maintenance and troubleshooting. The three translational degrees of freedom required by the platform are realized by converting the bending of the flexible rod into the translation of the rigid part, so as to achieve the purpose of replacing the branch chain with a single kinematic pair. The single kinematic pair is used to replace the traditional multi-branch chain structure in the X and Y directions, so as to simplify the platform structure. The second flexible branch chain and the four flexible kinematic pairs are arranged in a cross-symmetric manner, the flexible rods in the flexible kinematic pairs are arranged in a reverse series and symmetric manner, two same-direction drives are arranged on the same axis, and synchronous control is performed to make them move in the same direction with the same displacement and force to realize synchronous driving.

Description

Technical Field

[0001] This invention relates to the field of flexible mechanism technology, specifically a high-precision positioning platform based on flexible kinematic pairs. Background Technology

[0002] With the continuous advancement of micro- and nano-technology, micro- and nano-scale precision positioning platforms are playing an increasingly important role in many fields such as precision machining and measurement, microelectronics engineering, bioengineering, and nanoscience and technology. Spatial translational precision positioning platforms based on micro- and nano-scale precision positioning platforms are widely used in applications such as 3D scanning of atomic force microscopes, micro- and nano-manipulation, and advanced sensing systems. To meet the high requirements of micro- and nano-technology, flexible mechanisms are typically used as the transmission devices for precision positioning platforms. Unlike traditional rigid mechanisms that achieve motion and function through kinematic pairs and linkages, flexible mechanisms utilize the elastic deformation of materials to transmit motion. Because these mechanisms employ an integrated flexible structure, problems such as assembly errors, friction, wear, and gaps are avoided, thereby extending the lifespan of the mechanism and improving accuracy. With the continuous improvement of the design theory of flexible mechanism configurations, new types of spatial translational precision positioning platforms are constantly emerging. The main research directions of these new platforms include characteristics such as large stroke, high precision, compact structure, and motion decoupling.

[0003] Existing spatial translational precision positioning platform technologies, such as the patent application number CN201910991939.1, disclose a high-precision flexible micro-positioning platform based on flexible rods. This platform employs multiple kinematic pairs connected in parallel to form branches, and these branches are then connected in parallel to form the entire platform, achieving functions such as large stroke, high precision, and motion decoupling. This design of multiple kinematic pairs connected in parallel to form branches significantly improves the platform's accuracy and stroke capacity; however, it also leads to the complexity and bulkiness of the platform structure, resulting in significant space occupation. When the platform malfunctions, the complexity of the multiple branches makes troubleshooting and locating the problematic structure time-consuming and difficult. These structural drawbacks limit the widespread application of existing platforms in space-constrained scenarios and applications requiring rapid maintenance. Summary of the Invention

[0004] To address the problems of existing micro-positioning platforms based on flexible kinematic pairs, which suffer from large space requirements due to complex and bulky structures, as well as time-consuming and labor-intensive troubleshooting and positioning, this invention provides a high-precision positioning platform based on flexible kinematic pairs. This platform not only achieves high-precision positioning but also simplifies the overall structure, reduces space requirements, and significantly improves the convenience of maintenance and troubleshooting.

[0005] The technical solution of the present invention is as follows: a high-precision positioning platform based on flexible kinematic pairs, comprising: a base, a moving platform and a rigid frame, characterized in that it further comprises: four flexible kinematic pairs, a second flexible branch, a piezoelectric ceramic actuator and an electromagnetic actuator;

[0006] The rigid frame is mounted on the base, the flexible kinematic pair and the second flexible branch are mounted above the base, and the flexible kinematic pair is located inside the rigid frame cavity; the four flexible kinematic pairs are distributed in a cross-shaped symmetrical manner around the moving platform; the second flexible branch is located below the moving platform and the flexible kinematic pair;

[0007] The end of each of the flexible kinematic pairs is connected to the moving platform; the beginning ends of two of the flexible kinematic pairs are connected to the piezoelectric ceramic actuator in the X direction, and the beginning ends of the other two flexible kinematic pairs are connected to the piezoelectric ceramic actuator in the Y direction; the moving platform is driven to move along the X-axis and Y-axis based on the piezoelectric ceramic actuator;

[0008] The second flexible branch includes a driving pair and a passive pair; the driving pair of the second flexible branch is disposed on the base, and the passive pair is disposed on the driving pair but not directly connected to the driving pair; the passive pair of the second flexible branch is connected to the moving platform.

[0009] The electromagnetic actuator in the Z-direction is mounted on the mounting bracket of the base, and the driving end of the electromagnetic actuator is connected to a second flexible branch, driving the moving platform to move along the Z-axis.

[0010] Its further features are:

[0011] The flexible kinematic pair includes: ten parallel flexible rods, two rigid connectors one, two rigid connectors two, one rigid connector three, and a kinematic pair frame;

[0012] The motion pair frame is a U-shaped frame structure, including a straight frame plate and two L-shaped frame folded plates; one end of the frame folded plate is connected to the straight frame plate, and the other end is an edge plate bent inwards towards the frame, and the edge plate is parallel to the center line of the straight frame plate; the two frame folded plates are symmetrically arranged on both sides of the center line of the straight frame plate.

[0013] The flexible rod, rigid connector one, rigid connector two, and rigid connector three are all disposed in the inner cavity of the kinematic pair frame;

[0014] Two rigid connectors are symmetrically arranged based on the centerline of the frame plate; four flexible rods are respectively arranged on the end face of each rigid connector away from the frame plate, and the four flexible rods are respectively located at the four vertices of the rectangle; at the same time, another flexible rod is arranged at the midpoint of the adjacent sides of the two rectangles, denoted as the midpoint flexible rod;

[0015] The installation positions of the flexible rods on the two rigid connectors are symmetrically arranged based on the center line of the frame plate;

[0016] The ends of the two midpoint flexible rods that are furthest from the rigid connector one are simultaneously fixedly connected to the rigid connector three;

[0017] Two rigid connectors are arranged parallel and symmetrically on both sides of the rigid connector; and each rigid connector is simultaneously connected to two flexible rods located on adjacent sides of the rectangle on the end face of the frame plate.

[0018] In two rectangles formed by flexible rods, the two flexible rods on the side closest to the frame folding plate are connected to the edge plate of the adjacent frame folding plate;

[0019] The second rigid connector forms the end of the flexible kinematic pair, and its end face away from the frame plate is fixedly connected to the moving platform; the third rigid connector forms the beginning of the flexible kinematic pair, and its end face adjacent to the frame plate is fixedly connected to the piezoelectric ceramic actuator.

[0020] The first rigid connector is a plate-shaped connector, and the second and third rigid connectors are cuboid structures. The second and third rigid connectors are arranged in a triangular shape, and there is a gap between the second and third rigid connectors. The top surface of the second rigid connector is higher than the top surface of the third rigid connector.

[0021] The piezoelectric ceramic actuator is fixed on the kinematic pair frame, and the driving ends of the X-axis piezoelectric ceramic actuator and the Y-axis piezoelectric ceramic actuator are respectively connected to the rigid connecting member three in the X-axis and Y-axis kinematic pairs;

[0022] The four rigid connectors are block-shaped structures, and the four rigid connectors are respectively fixed to the U-shaped base plate of the base.

[0023] The second flexible branch includes: a dual four-bar flexible module, a connecting module, and four four-bar flexible modules; the four four-bar flexible modules constitute the driving pair of the second flexible branch; the dual four-bar flexible modules constitute the passive pair of the second flexible branch.

[0024] The double four-bar flexible module includes: eight longitudinally arranged second flexible bars, and rigid connectors six, seven, and eight in a square frame structure;

[0025] The lower ends of the eight second flexible rods are respectively fixed to the four inflection points and the four midpoints of the four sides of the square rigid connector six; the upper ends of the four second flexible rods located at the inflection points are respectively fixed to the moving platform through the rigid connector seven, and the upper ends of the four second flexible rods located at the midpoints are fixed to the connecting module through the rigid connector eight.

[0026] The four four-bar flexible modules are arranged in a rectangular pattern around the connecting module;

[0027] The four-bar flexible module includes four first flexible bars, a rigid connector four, and a rigid connector five. The four first flexible bars in the four-bar flexible module are all horizontally arranged and rectangularly distributed. One end of each of the four first flexible bars is fixed to the base through the rigid connector four, and the other end is fixed to the connecting module through the rigid connector five. The driving end of the electromagnetic actuator is fixed to the bottom surface of the connecting module.

[0028] The connection module includes: a square module and a cross-shaped module;

[0029] The cross-shaped module is fixed to the top surface of the square module; the four four-bar flexible modules are arranged in a rectangle around the square module; the rigid connector five is a square plate structure and is fixed to the four sides of the square module.

[0030] The cross-shaped module extends into the inner cavity of the double four-bar flexible module; the rigid connector eight is a cross-shaped plate structure and its center is fixed to the center of the top surface of the cross-shaped module by screws; the rigid connector seven is a square structure, its top surface is higher than that of the rigid connector eight, and it is arranged in a star-shaped pattern with the rigid connector eight.

[0031] A gap is left between the rigid connector 7 and the rigid connector 8. The rigid connector 7 is fixed to the bottom surface of the moving platform by screws. The top surface of the rigid connector 7 is higher than the top surface of the rigid connector 8.

[0032] The drive end of the electromagnetic driver is fixedly connected to the bottom surface of the square module;

[0033] In the flexible kinematic pair, the 10 flexible rods, the first rigid connector, the second rigid connector, and the third rigid connector are integrally formed;

[0034] The base includes: a horizontally arranged U-shaped base plate and four longitudinally arranged pillars; the pillars are integrally formed with the U-shaped base plate;

[0035] The four pillars are arranged in a rectangular shape, and the lower middle end of each pillar is fixed to the U-shaped base plate. The rigid frame is fixed to the four pillars.

[0036] The piezoelectric ceramic actuator includes: two piezoelectric ceramic actuators in the x-axis direction and two piezoelectric ceramic actuators in the y-axis direction; the two piezoelectric ceramic actuators arranged in the same coordinate axis direction are co-directional actuators.

[0037] This application provides a high-precision positioning platform based on flexible kinematic pairs. By converting the bending of a flexible rod into the translation of a rigid component, it achieves the required three translational degrees of freedom for the platform, thus replacing branches with single kinematic pairs. In the X and Y directions, it uses single kinematic pairs instead of the traditional multi-branch structure, simplifying the platform structure, reducing space occupation, and significantly improving the convenience of maintenance and troubleshooting. The second flexible branch and four flexible kinematic pairs are arranged in a cross-symmetrical manner. The flexible rods in the flexible kinematic pairs are arranged in reverse series and symmetrically, effectively offsetting parasitic motion and reducing coupled displacement and accompanying rotation. Two co-directional drives are set on the same axis, and synchronous control enables them to move in the same direction with the same displacement and force to achieve synchronous drive, thereby improving the accuracy of the platform's movement in one direction. The technical solution of this application not only ensures that the platform is more compact and concise while achieving high precision and large stroke, but also significantly improves the positioning accuracy and reliability of the platform. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the isometric field of view of the present invention;

[0039] Figure 2 This is a schematic diagram of the overall structure of the top-view projection of the isometric view of the present invention.

[0040] Figure 3 This is a schematic diagram of the main structure of the present invention from a positive three-axis perspective;

[0041] Figure 4 A partial cross-sectional structural diagram of a flexible kinematic pair;

[0042] Figure 5 The Z-axis motion trend diagram of the flexible kinematic pair;

[0043] Figure 6 This is a diagram showing the X-axis motion trend of a flexible kinematic pair.

[0044] Figure 7 The Y-axis motion trend diagram of the flexible kinematic pair;

[0045] Figure 8 This is an exploded view of the second flexible branch.

[0046] Wherein: 1-base; 11-U-shaped base plate; 12-support column; 13-mounting bracket; 2-moving platform; 3-rigid frame;

[0047] 4- Flexible kinematic pair; 41- Flexible rod; 42- Rigid connector one; 43- Rigid connector two; 44- Rigid connector three; 45- Kinematic pair frame;

[0048] 5 - Second flexible branch; 51 - Double four-bar flexible module; 511 - Second flexible bar; 512 - Rigid connector six; 513 - Rigid connector seven; 514 - Rigid connector eight; 521 - Square module; 522 - Cross-shaped module; 53 - Four-bar flexible module; 531 - First flexible bar; 532 - Rigid connector four; 533 - Rigid connector five;

[0049] 6-Piezoelectric ceramic actuator; 7-Z-axis electromagnetic actuator. Detailed Implementation

[0050] like Figures 1-8 As shown, this application includes a high-precision positioning platform based on flexible kinematic pairs, which includes: a base 1, a moving platform 2, a rigid frame 3, four flexible kinematic pairs 4, a second flexible branch 5, a piezoelectric ceramic actuator 6, and an electromagnetic actuator 7.

[0051] The rigid frame 3 is mounted on the base 1, the flexible kinematic pair 4 and the second flexible branch 5 are mounted above the base 1, and the flexible kinematic pair 4 is located inside the rigid frame 3; the four flexible kinematic pairs 4 are distributed in a cross-shaped symmetrical manner around the moving platform 2; the second flexible branch 5 is mounted below the moving platform 2 and the flexible kinematic pair 4.

[0052] Each flexible kinematic pair 4 has its end connected to the moving platform 2; the beginning ends of two of the flexible kinematic pairs 4 are connected to piezoelectric ceramic actuators 6 in the X direction, and the beginning ends of the other two flexible kinematic pairs 4 are connected to piezoelectric ceramic actuators 6 in the Y direction. The moving platform is driven to move along the X and Y axes based on the piezoelectric ceramic actuators.

[0053] The second flexible branch 5 includes a driving pair and a passive pair; the driving pair of the second flexible branch 5 is disposed on the base 1, and the passive pair is disposed on the driving pair but not directly connected to the driving pair; the passive pair of the second flexible branch 5 is connected to the moving platform 2.

[0054] like Figure 1 As shown, the mounting bracket 13 is a cross-shaped bracket, and its center point is also the center point of the base 1. The electromagnetic actuator 7 in the Z direction is set at the center point of the mounting bracket 13 of the base 1. The driving end of the electromagnetic actuator 7 is connected to the second flexible branch 5, driving the moving platform to move along the Z-axis.

[0055] like Figure 2As shown, the base 1 includes a horizontally arranged U-shaped base plate 11 and four longitudinally arranged support columns 12. The four support columns 12 are rectangularly distributed, and the lower middle ends of the support columns 12 are fixed to the U-shaped base plate 11. The rigid frame 3 is fixed to the four support columns 12. The support columns 12 and the U-shaped base plate 11 are integrally formed. The top surface of the support column 12 has threaded holes, and the rigid frame 3 has through holes corresponding to the threaded holes. Screws pass through the through holes and are screwed into the threaded holes to fix the rigid frame 3 to the support columns 12.

[0056] like Figure 4 As shown, the flexible kinematic pair 4 includes: ten parallel flexible rods 41, two rigid connectors 42, two rigid connectors 43, one rigid connector 44, and a kinematic pair frame 45.

[0057] The motion sub-frame 45 is a U-shaped frame structure, including: a straight frame plate 451 and two L-shaped frame folded plates 452; one end of the frame folded plate 452 is connected to the straight frame plate 451, and the other end is an edge plate bent inwards towards the frame, with the edge plate parallel to the center line L of the straight frame plate 451; the two frame folded plates 452 are symmetrically arranged on both sides of the center line L of the straight frame plate 451. In practice, the straight frame plate 451 and the two L-shaped frame folded plates 452 are integrally formed.

[0058] Flexible rod 41, rigid connector 1 42, rigid connector 2 43, and rigid connector 3 44 are all located in the inner cavity of the kinematic pair frame 45.

[0059] Two rigid connectors 42 are symmetrically arranged based on the centerline L of the frame plate 451; the rigid connectors 42 are adjacent to the frame plate 451, but the two are not directly connected.

[0060] On the end face of each rigid connector 42 away from the frame plate 451, four flexible rods 41 are respectively provided, and the four flexible rods 41 are respectively located at the four vertices of the rectangle; at the same time, a flexible rod 41 is provided at the midpoint of the adjacent sides of the two rectangles, denoted as: midpoint flexible rod.

[0061] The installation positions of the flexible rods 41 on the two rigid connectors 42 are symmetrically arranged based on the center line L of the frame plate 451;

[0062] The ends of the two midpoint flexible rods 41 that are away from the rigid connector 42 are respectively fixedly connected to the rigid connector 44.

[0063] Two rigid connectors 43 are arranged parallel and symmetrically on both sides of the rigid connector 44; and on the end face of each rigid connector 43 facing the frame plate 451, two flexible rods 41 located on adjacent sides of the rectangle are connected at the same time.

[0064] In the two rectangles formed by the flexible rods 41, the two flexible rods 41 on the side closest to the frame folded plate 452 are connected to the edge plate of the adjacent frame folded plate 452.

[0065] Rigid connector 2 43 forms the end of flexible kinematic pair 4, and the end face of rigid connector 2 43 away from the frame plate 451 is fixedly connected to the moving platform 2; rigid connector 3 44 forms the beginning of flexible kinematic pair 4, and the end face of rigid connector 3 44 adjacent to the frame plate 451 is fixedly connected to the piezoelectric ceramic actuator 6.

[0066] Rigid connector 1 42 is a plate-shaped connector, and rigid connector 2 43 and rigid connector 3 44 are cuboid structures; rigid connector 2 43 and rigid connector 3 44 are arranged in a triangular shape; the driving ends of the X-direction piezoelectric ceramic actuator 6 and the Y-direction piezoelectric ceramic actuator 6 are respectively connected to rigid connector 3 44 in the X-direction and Y-direction kinematic pairs.

[0067] During the specific installation, such as Figure 4 As shown, the top surface of rigid connector 2 43 is higher than the top surface of rigid connector 3 44. Rigid connector 2 43 is connected to the moving platform, and rigid connector 3 44 is connected to the driver. When a specific movement occurs, the force of the electro-ceramic actuator 6 in the X or Y direction is transmitted to rigid connector 3 44, and then transmitted to the moving platform 2 through a series of rigid connectors and flexible rods, realizing movement in the X or Y direction. Setting the top surface of rigid connector 2 43 to be higher than the top surface of rigid connector 3 44 provides a certain amount of room for rigid connector 3 44 to move, preventing rigid connector 3 44 from directly colliding with the moving platform 2 when driven by the driver, ensuring effective force transmission, and thus ensuring the precise movement of the moving platform 2.

[0068] A gap is left between rigid connector 2 43 and rigid connector 3 44. When the flexible kinematic pair 4 acts as a passive pair, and the force of the moving platform 2 is transmitted to the flexible kinematic pair 4 through rigid connector 3 44, the gap between rigid connector 2 43 and rigid connector 3 44 prevents direct collision between the two, thereby ensuring the precise movement of the moving platform 2.

[0069] One end of the piezoelectric ceramic actuator 6 is fixed on the kinematic pair frame 45, and the driving end of the piezoelectric ceramic actuator 6 is connected to the rigid connector 44.

[0070] In the flexible kinematic pair, 10 flexible rods 41, rigid connector 1 42, rigid connector 2 43 and rigid connector 3 44 are made as a single unit.

[0071] The piezoelectric ceramic actuator 6 in this application includes an X-axis piezoelectric ceramic actuator 6 and a Y-axis piezoelectric ceramic actuator 6. In specific implementation, in order to ensure that multi-axis drive is achieved by replacing branches with a single kinematic pair in this application, a piezoelectric ceramic actuator capable of withstanding a slight lateral load is selected to limit the undesired movement of the rigid connector 44; this allows the actuator to be directly connected to the flexible kinematic pair. When the flexible kinematic pair acts as a passive pair, the piezoelectric ceramic actuator capable of withstanding a slight lateral load can ensure that the deformation of the flexible kinematic pair will not cause the undesired movement of the rigid connector 44, thereby affecting the accuracy of the drive.

[0072] In practical driving, the two piezoelectric ceramic actuators arranged in the same coordinate axis direction in this application are co-directional actuators. Synchronous control enables them to move in the same direction with the same displacement and force to achieve synchronous driving, thereby improving the accuracy of the platform's movement in one direction.

[0073] like Figure 8 As shown, the second flexible branch 5 includes: a double four-bar flexible module 51, a connecting module 52, and four four-bar flexible modules 53; the four four-bar flexible modules 53 constitute the driving pair of the second flexible branch 5; the double four-bar flexible module 51 constitutes the passive pair of the second flexible branch 5.

[0074] The double four-bar flexible module 51 includes: eight longitudinally arranged second flexible bars 511, a rigid connector six 512 with a square frame structure, a rigid connector seven 513 and a rigid connector eight 514;

[0075] The lower ends of the eight second flexible rods 511 are respectively fixed to the four inflection points and the four midpoints of the four sides of the square rigid connector six 512; the upper ends of the four second flexible rods 511 located at the inflection points are respectively fixed to the moving platform 2 through the rigid connector seven 513, and the upper ends of the four second flexible rods 511 located at the midpoints are fixed to the connecting module 52 through the rigid connector eight 514.

[0076] Four four-bar flexible modules 53 are arranged in a rectangular shape around the connecting module 52;

[0077] The four-bar flexible module 53 includes four first flexible bars 531, a rigid connector four 532, and a rigid connector five 533. The four first flexible bars 531 in the four-bar flexible module 53 are all horizontally arranged and rectangularly distributed. One end of the four first flexible bars 531 is fixed to the base 1 through the rigid connector four 532, and the other end is fixed to the connecting module 52 through the rigid connector five 533. The driving end of the electromagnetic driver 7 is fixed to the bottom surface of the connecting module 52.

[0078] The connecting module 52 includes: a square module 521 and a cross-shaped module 522;

[0079] The cross-shaped module 522 is fixed to the top surface of the square module 521; four four-bar flexible modules 53 are rectangularly distributed around the square module 521; the rigid connector 533 is a square plate structure and is fixed to the four sides of the square module 521.

[0080] The cross-shaped module 522 extends into the inner cavity of the double four-bar flexible module 51; the rigid connector 8 514 is a cross-shaped plate structure and its center is fixed to the center of the top surface of the cross-shaped module 522 by screws; the rigid connector 7 513 is a square structure, its top surface is higher than the rigid connector 8 514, and it is arranged in a star-shaped pattern with the rigid connector 8 514.

[0081] There is a gap between rigid connector 7 513 and rigid connector 8 514. Rigid connector 7 513 is fixed to the bottom surface of the moving platform 2 by screws. The top surface of rigid connector 7 513 is higher than the top surface of rigid connector 8 514.

[0082] The drive end of the electromagnetic actuator 7 is fixedly connected to the bottom surface of the square module 521.

[0083] The rigid connector 4532 has a square structure, and the four rigid connectors 4532 are respectively fixed to the U-shaped base plate 11 of the base 1 by screws.

[0084] The three actuators in this application—the X-axis piezoelectric ceramic actuator 6, the Y-axis piezoelectric ceramic actuator 6, and the Z-axis electromagnetic actuator 7—control the translational motion of the mechanism in three directions in space, respectively, ensuring that each motion is independent of the others and there is no motion coupling.

[0085] In this application, in order to simplify the system structure, a single kinematic pair is used in the X and Y directions of the moving platform to replace the branch structure in the traditional structure, and the flexible kinematic pair 4 is directly connected to the driving structure.

[0086] Combination Figure 4 , Figure 5 As shown, when the flexible kinematic pair 4 acts as the driving pair, the piezoelectric ceramic actuator 6 transmits the force to the rigid connector 3 44 through the input displacement. The rigid connector 3 44 transmits the force to the rigid connector 1 42 through the two intermediate flexible rods 41 connected to it. The rigid connector 1 42 transmits the force to the rigid connector 2 43 through the four outer flexible rods 41 connected to it, and finally to the moving platform 2. The bending deformation generated by the four outer flexible rods 41 connected to the rigid connector 1 42 is converted into the platform of the moving platform 2, realizing the movement in the X and Y axis directions. For details, refer to... Figure 5 The direction of the red arrow in the middle. Rigid connector 2 43 along... Figure 5When moving in the direction of the red arrow, all the flexible rods 41 distributed between the rigid connector 2 43 and the frame plate 451 are symmetrically arranged about the rigid connector 3 44, which reduces the forward, backward and left and right movement of the rigid connector 2 43 during the movement, thereby improving the output accuracy of the moving platform 2 connected to the rigid connector 2 43.

[0087] When the moving platform moves along the Z-axis, flexible kinematic pair 4 acts as a passive pair; when the moving platform moves along the X-axis or Y-axis, the flexible kinematic pair 4 in the perpendicular Y-axis or X-axis direction also acts as a passive pair. In flexible kinematic structures, passive pairs are mainly used to provide compliance and cushioning, allowing movement in some degrees of freedom while restricting or adjusting other degrees of freedom. Figure 4 , Figure 6 , Figure 7 As shown, the input displacement of the moving platform 2 transmits force to rigid connector 2 43. Rigid connector 2 43, through its four central flexible rods 41, transmits the force to rigid connector 1 42. Rigid connector 1 42 then transmits the force to its four outer flexible rods 41. Since the undesired movement of rigid connector 3 44 is suppressed, the force is also transmitted to its two central flexible rods 41, ultimately causing the corresponding flexible rods 41 to deform with the moving platform. The direction of movement of the moving platform is referenced... Figure 6 The b direction and Figure 7 The c-direction in the middle. Figure 6 and Figure 7 The direction a is perpendicular to the plane where the frame plate 451 is located, and the directions a, b, and c are perpendicular to each other.

[0088] Two rigid connectors 43 of the same flexible kinematic pair 4 are simultaneously connected to the moving platform 2, so the two rigid connectors 43 move synchronously. When the rigid connector 43 acts as a passive pair along... Figure 6During the movement in the b-direction, rigid connector 1 42 and rigid connector 2 43 are respectively connected to the two ends of the flexible rod 41. Multiple sets of structures connected in series by rigid connector 1 42, rigid connector 2 43, and the flexible rod 41 are shown as m1~m6 in the figure, and m1~m6 have identical structures. Specifically, m1 and m5 are in the same direction and opposite to m3, forming a reverse series structure; m2, m4, and m6 form another set of reverse series structures. In this application, parasitic motion is counteracted by the symmetrical deformation of the structures in opposite directions within the same plane in each set of reverse series structures. For example, when rigid connector 2 43 moves in the b-direction, the deformation of m3 in the a-direction is symmetrical with the deformation of m1 and m5 in the a-direction, and they can cancel each other out, thus reducing the movement of the moving platform 2 along the a-direction. Simultaneously, the two sets of reverse series structures are symmetrically connected in parallel with rigid connector 3 44 as the centerline, reducing the movement of the moving platform 2 in the c-direction and improving the accuracy of the moving platform 2.

[0089] When rigid connector 243 acts as a passive pair along Figure 7 When moving in the c-direction, multiple sets of structures connected in series, consisting of rigid connector 42, rigid connector 43, and flexible rod 41, are shown as n1~n4 in the figure. n1~n4 have identical structures. Specifically, n1 and n2 have identical but opposite structures, forming a reverse series structure; n3 and n4 form another reverse series structure. When rigid connector 43 moves in the c-direction, the deformations of n1 and n2 in the a-direction cancel each other out, as do the deformations of n3 and n4 in the a-direction. This reduces the movement of the two rigid connectors 43 in the a-direction, improving the movement accuracy of the moving platform 2. Simultaneously, the two sets of reverse series structures are symmetrically arranged in parallel based on the centerline L, reducing the movement of the moving platform 2 in the b-direction.

[0090] Meanwhile, within the same flexible kinematic pair 4, Figure 6 The two sets of reverse series structures shown are Figure 7 The two sets of reverse-connected structures are actually highly integrated into the flexible motion based on the principle of cross-connection. The flexible motion pair 4 of this application integrates 10 flexible rods, rigid connector one, rigid connector two, and rigid connector three in a symmetrical arrangement, reverse-connected series, and with the actuator directly connected to the motion pair. All the structures are highly integrated into one motion pair to obtain a new type of motion pair, thereby simplifying the platform structure, reducing space occupation, and greatly improving the convenience of maintenance and troubleshooting.

[0091] The Z-axis electromagnetic actuator 7 inputs displacement and transmits force to the square module 521, which in turn transmits it to the cross-shaped module 522. The cross-shaped module 522 then transmits the force to the rigid connector 8 514. The rigid connector 8 514 transmits the force through four central second flexible rods 511 to the rigid connector 6 512, which in turn transmits it through four external second flexible rods 511 to the rigid connector 7 513, and finally to the moving platform 2. Specifically, the Z-axis electromagnetic actuator 7 provides an upward driving force, causing the moving platform 2 to move upward; the Z-axis electromagnetic actuator 7 provides a downward driving force, causing the moving platform 2 to move downward. The specific motion trend is similar to the flexible motion pair 4. The first flexible rod 531 in the drive pair 53, as the main component of the drive pair, is symmetrically arranged around the moving platform 2 in a cross shape. In the flexible motion structure, the drive pair provides motion freedom, stability, and precision. During force transmission, the first flexible rod 531 deforms, ensuring that the Z-axis force from the Z-axis electromagnetic actuator 7 is accurately transmitted within the flexible structure, thereby achieving precise movement of the moving platform.

[0092] like Figure 3 As shown in this application, the four flexible kinematic pairs 4 and the four four-bar flexible modules 53 in the second flexible branch 5 are arranged in a cross-symmetrical manner with the moving platform 2 as the center. This symmetrical arrangement can achieve uniformity of force and deformation, thereby eliminating parasitic motion. When the geometry of the mechanism is symmetrical, parasitic motion caused by deformation on any side will be canceled out by the same deformation on the other side, thereby reducing undesirable motion and coupling effects, and also reducing undesirable rotation generated by the mechanism during motion.

[0093] By using the technical solution of this invention, the positioning platform, through its optimized flexible structural design, not only possesses a large motion stroke and excellent structural manufacturability, but also effectively eliminates motion coupling phenomena, significantly improving positioning accuracy. Simultaneously, this application simplifies the overall structure of the platform, reduces space occupation, and greatly improves the convenience of maintenance and troubleshooting.

Claims

1. A high-precision positioning platform based on a flexible kinematic pair, comprising: The base, moving platform, and rigid frame are characterized in that they further include: four flexible kinematic pairs, a second flexible branch, a piezoelectric ceramic actuator, and an electromagnetic actuator; The rigid frame is mounted on the base, the flexible kinematic pair and the second flexible branch are mounted above the base, and the flexible kinematic pair is located inside the rigid frame cavity; the four flexible kinematic pairs are distributed in a cross-shaped symmetrical manner around the moving platform; the second flexible branch is located below the moving platform and the flexible kinematic pair; The end of each of the flexible kinematic pairs is connected to the moving platform; the beginning ends of two of the flexible kinematic pairs are connected to the piezoelectric ceramic actuator in the X direction, and the beginning ends of the other two flexible kinematic pairs are connected to the piezoelectric ceramic actuator in the Y direction; the moving platform is driven to move along the X-axis and Y-axis based on the piezoelectric ceramic actuator; The second flexible branch includes a driving pair and a passive pair; the driving pair of the second flexible branch is disposed on the base, and the passive pair is disposed on the driving pair but not directly connected to the driving pair; the passive pair of the second flexible branch is connected to the moving platform. The electromagnetic actuator in the Z-direction is mounted on the mounting bracket of the base, and the driving end of the electromagnetic actuator is connected to the second flexible branch, driving the moving platform to move along the Z-axis. The second flexible branch is arranged in a cross-symmetrical manner; The flexible kinematic pair includes: ten parallel flexible rods, two rigid connectors one, two rigid connectors two, one rigid connector three, and a kinematic pair frame; The motion pair frame is a U-shaped frame structure, including a straight frame plate and two L-shaped frame folded plates; one end of the frame folded plate is connected to the straight frame plate, and the other end is an edge plate bent inwards towards the frame, and the edge plate is parallel to the center line of the straight frame plate; the two frame folded plates are symmetrically arranged on both sides of the center line of the straight frame plate. The flexible rod, rigid connector one, rigid connector two, and rigid connector three are all disposed in the inner cavity of the kinematic pair frame; Two rigid connectors are symmetrically arranged based on the centerline of the frame plate; four flexible rods are respectively arranged on the end face of each rigid connector away from the frame plate, and the four flexible rods are respectively located at the four vertices of the rectangle; at the same time, another flexible rod is arranged at the midpoint of the adjacent sides of the two rectangles, denoted as the midpoint flexible rod; The installation positions of the flexible rods on the two rigid connectors are symmetrically arranged based on the center line of the frame plate; The ends of the two midpoint flexible rods that are furthest from the rigid connector one are simultaneously fixedly connected to the rigid connector three; Two rigid connectors are arranged parallel and symmetrically on both sides of the rigid connector; and each rigid connector is simultaneously connected to two flexible rods located on adjacent sides of the rectangle on the end face of the frame plate. In two rectangles formed by flexible rods, the two flexible rods on the side closest to the frame folding plate are connected to the edge plate of the adjacent frame folding plate; The second rigid connector forms the end of the flexible kinematic pair, and its end face away from the frame plate is fixedly connected to the moving platform; the third rigid connector forms the beginning of the flexible kinematic pair, and its end face adjacent to the frame plate is fixedly connected to the piezoelectric ceramic actuator. Two piezoelectric ceramic actuators are set on the same axis and drive in the same direction; The piezoelectric ceramic actuator includes: two piezoelectric ceramic actuators in the x-axis direction and two piezoelectric ceramic actuators in the y-axis direction; the two piezoelectric ceramic actuators arranged in the same coordinate axis direction are co-directional actuators.

2. The high-precision positioning platform based on flexible kinematic pairs according to claim 1, characterized in that: The first rigid connector is a plate-shaped connector, and the second and third rigid connectors are cuboid structures. The second and third rigid connectors are arranged in a triangular shape, and there is a gap between the second and third rigid connectors. The top surface of the second rigid connector is higher than the top surface of the third rigid connector.

3. The high-precision positioning platform based on a flexible kinematic pair according to claim 1, characterized in that: The piezoelectric ceramic actuator is fixed on the kinematic pair frame, and the drive ends of the X-axis piezoelectric ceramic actuator and the Y-axis piezoelectric ceramic actuator are respectively connected to the rigid connecting member three in the X-axis and Y-axis kinematic pairs.

4. The high-precision positioning platform based on a flexible kinematic pair according to claim 1, characterized in that: The four rigid connectors are block-shaped structures, and the four rigid connectors are respectively fixed to the U-shaped base plate of the base.

5. The high-precision positioning platform based on a flexible kinematic pair according to claim 1, characterized in that: The second flexible branch includes: a dual four-bar flexible module, a connecting module, and four four-bar flexible modules; the four four-bar flexible modules constitute the driving pair of the second flexible branch; the dual four-bar flexible modules constitute the passive pair of the second flexible branch. The double four-bar flexible module includes: eight longitudinally arranged second flexible bars, and rigid connectors six, seven, and eight in a square frame structure; The lower ends of the eight second flexible rods are respectively fixed to the four inflection points and the four midpoints of the four sides of the square rigid connector six; the upper ends of the four second flexible rods located at the inflection points are respectively fixed to the moving platform through the rigid connector seven, and the upper ends of the four second flexible rods located at the midpoints are fixed to the connecting module through the rigid connector eight. The four four-bar flexible modules are arranged in a rectangular pattern around the connecting module; The four-bar flexible module includes four first flexible bars, a rigid connector four, and a rigid connector five. The four first flexible bars in the four-bar flexible module are all horizontally arranged and rectangularly distributed. One end of each of the four first flexible bars is fixed to the base through the rigid connector four, and the other end is fixed to the connecting module through the rigid connector five. The driving end of the electromagnetic actuator is fixed to the bottom surface of the connecting module.

6. The high-precision positioning platform based on a flexible kinematic pair according to claim 5, characterized in that: The connection module includes: a square module and a cross-shaped module; The cross-shaped module is fixed to the top surface of the square module; the four four-bar flexible modules are arranged in a rectangle around the square module; the rigid connector five is a square plate structure and is fixed to the four sides of the square module. The cross-shaped module extends into the inner cavity of the double four-bar flexible module; the rigid connector eight is a cross-shaped plate structure and its center is fixed to the center of the top surface of the cross-shaped module by screws; the rigid connector seven is a square structure, its top surface is higher than that of the rigid connector eight, and it is arranged in a star-shaped pattern with the rigid connector eight. A gap is left between the rigid connector 7 and the rigid connector 8. The rigid connector 7 is fixed to the bottom surface of the moving platform by screws. The top surface of the rigid connector 7 is higher than the top surface of the rigid connector 8. The drive end of the electromagnetic driver is fixedly connected to the bottom surface of the square module.

7. The high-precision positioning platform based on a flexible kinematic pair according to claim 1, characterized in that: In the flexible kinematic pair, the 10 flexible rods, the first rigid connector, the second rigid connector, and the third rigid connector are integrally formed.

8. The high-precision positioning platform based on a flexible kinematic pair according to claim 1, characterized in that: The base includes: a horizontally arranged U-shaped base plate and four longitudinally arranged pillars; the pillars are integrally formed with the U-shaped base plate; The four pillars are arranged in a rectangular shape, with the lower middle ends of the pillars fixed to the U-shaped base plate, and the rigid frame fixed to the four pillars.

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