High-precision positioning platform based on flexible kinematic pair

Abstract

According to the high-precision positioning platform based on the flexible kinematic pair, high-precision positioning can be achieved, the overall structure of the platform is simplified, occupied space is reduced, and convenience of maintenance and troubleshooting is greatly improved. The bending of the flexible rod is converted into the translation of the rigid piece, so that the three translation degrees of freedom required by the platform are realized, and the purpose of replacing a branched chain by a single kinematic pair is achieved; a single kinematic pair is adopted in the X direction and the Y direction to replace a traditional multi-branch-chain structure, and therefore the platform structure is simplified. The second flexible branch chain and the four flexible kinematic pairs are arranged in a cross-shaped symmetrical mode, and flexible rods in the flexible kinematic pairs are connected in series reversely and arranged symmetrically. Two homonymous drivers are arranged on the same axis, and the two homonymous drivers are made to move in the same direction with the same displacement and force through synchronous control so as to achieve synchronous driving.

Description

Technical Field

[0001] The invention relates to the technical field of flexible mechanisms, and in particular to a high-precision positioning platform based on a flexible kinematic pair. Background Art

[0002] With the continuous advancement of micro-nano technology, micro-nano precision positioning platforms play an increasingly important role in many fields such as precision machining and precision measurement, microelectronics engineering, bioengineering, and nanoscience and technology. The spatial translation precision positioning platform based on the micro-nano precision positioning platform is widely used in application scenarios such as three-dimensional scanning of atomic force microscopes, micro-nano operations, and advanced sensing systems. In order to meet the high requirements of micro-nano technology, flexible mechanisms are usually used as transmission devices for precision positioning platforms. Unlike traditional rigid mechanisms that achieve motion and function through kinematic pairs and connecting rods, flexible mechanisms use the elastic deformation of materials to transmit motion. Since these mechanisms use an integrated flexible structure, assembly errors, friction, wear, clearance and other problems are avoided, thereby extending the life of the mechanism and improving accuracy. With the continuous improvement of the theory of flexible mechanism configuration design, new spatial translation precision positioning platforms continue to emerge. The main research directions of these new platforms include large travel, high precision, compact structure and motion decoupling.

[0003] Among the existing technical solutions for spatial translation precision positioning platforms, such as the patent with application number CN201910991939.1, a high-precision flexible micro-positioning platform based on a flexible rod is disclosed, which adopts multiple kinematic pairs in parallel to form a branch chain, and the entire platform is formed by multiple branches in parallel to achieve functions such as large stroke, high precision and motion decoupling. The design of multiple kinematic pairs in parallel to form a branch chain and multiple branches in parallel greatly improves the accuracy and stroke capacity of the platform; however, this also leads to the complexity and bulkiness of the platform structure, bringing about a large space occupancy problem. When the platform fails, due to the complexity of multiple branches, the process of troubleshooting and locating the problem structure becomes time-consuming and difficult. These structural shortcomings limit the widespread application of existing platforms in application scenarios where space is limited and there is a high demand for rapid maintenance. Summary of the invention

[0004] In order to solve the problems that the existing micro-positioning platform based on flexible kinematic pairs occupies a large space due to its complex and bloated structure, and troubleshooting and positioning are time-consuming and labor-intensive, the present invention provides a high-precision positioning platform based on flexible kinematic pairs, which can not only achieve high-precision positioning, but also simplifies the overall structure of the platform, reduces space occupancy, and greatly 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 a flexible kinematic pair, comprising: a base, a moving platform and a rigid frame, characterized in that it also comprises: four flexible kinematic pairs, a second flexible branch chain, a piezoelectric ceramic actuator and an electromagnetic driver; The rigid frame is arranged on the base, the flexible motion pair and the second flexible branch chain are arranged above the base, and the flexible motion pair is located in the inner cavity of the rigid frame; four flexible motion pairs are distributed around the moving platform in a cross-symmetrical manner; the second flexible branch chain is arranged below the moving platform and the flexible motion pair; The end of each of the flexible motion pairs is connected to the moving platform; the head ends of two of the flexible motion pairs are connected to the piezoelectric ceramic actuator in the X direction, and the head ends of the other two flexible motion 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 directions based on the piezoelectric ceramic actuator; The second flexible branch chain includes a driving pair and a passive pair; the driving pair of the second flexible branch chain is arranged on the base, and the passive pair is arranged on the driving pair and is not directly connected to the driving pair; the passive pair of the second flexible branch chain is connected to the moving platform; The electromagnetic driver in the Z direction is arranged on the mounting bracket of the base, and the driving end of the electromagnetic driver is connected to the second flexible branch chain to drive the moving platform to move along the Z axis direction.

[0006] It is further characterized by: The flexible kinematic pair comprises: ten mutually parallel flexible rods, two rigid connecting members 1, two rigid connecting members 2, one rigid connecting member 3 and a kinematic pair frame; The motion sub-frame is a concave frame structure, including a frame straight plate and two L-shaped frame folding plates; one end of the frame folding plate is connected to the frame straight plate, and the other end is an edge plate bent toward the inside of the frame, and the edge plate is parallel to the center line of the frame straight plate; the two frame folding plates are symmetrically arranged on both sides of the center line of the frame straight plate; The flexible rod, the first rigid connector, the second rigid connector, and the third rigid connector are all arranged in the inner cavity of the motion sub-frame; The two rigid connectors are symmetrically arranged based on the center line of the frame straight plate; four flexible rods are arranged on the end surface of each rigid connector away from the frame straight plate, and the four flexible rods are respectively located at the four vertices of the rectangle; at the same time, one more flexible rod is arranged at the midpoint position of the adjacent sides of the two rectangles, which are recorded as midpoint flexible rods; The installation positions of the flexible rods on the two rigid connectors are symmetrically arranged based on the center line of the frame straight plate; One end of the two midpoint flexible rods away from the rigid connecting member 1 is fixedly connected to the rigid connecting member 3 at the same time; The two rigid connectors 2 are respectively arranged in parallel and symmetrically on both sides of the rigid connector 3; and each rigid connector 2 is respectively and simultaneously connected to two flexible rods located on adjacent sides of the rectangle on the end surface facing the frame straight plate; In the two rectangles formed by the flexible rods, two flexible rods on the sides closest to the frame folding plates are connected to the edge plates of the adjacent frame folding plates; The second rigid connector constitutes the end of the flexible motion pair, and its end surface away from the frame straight plate is fixedly connected to the moving platform; the third rigid connector constitutes the head end of the flexible motion pair, and its end surface adjacent to the frame straight plate is fixedly connected to the piezoelectric ceramic actuator; The rigid connector 1 is a plate-shaped connector, and the rigid connector 2 and the rigid connector 3 are rectangular parallelepiped structures; the rigid connector 2 and the rigid connector 3 are arranged in a "three" shape, and a gap is left between the rigid connector 2 and the rigid connector 3, and the top surface of the rigid connector 2 is higher than the top surface of the rigid connector 3; The piezoelectric ceramic actuator is fixed on the motion pair frame, and the driving ends of the X-direction piezoelectric ceramic actuator and the Y-direction piezoelectric ceramic actuator are respectively connected to the rigid connecting parts in the X-direction and Y-direction motion pairs; The rigid connecting member 4 is a square-shaped structure, and the four rigid connecting members 4 are respectively fixed to the return bottom plate of the base; The second flexible branch chain comprises: a double four-bar flexible module, a connecting module and four four-bar flexible modules; the four four-bar flexible modules constitute a driving pair of the second flexible branch chain; the double four-bar flexible module constitutes a passive pair of the second flexible branch chain; The double four-rod type flexible module comprises: eight second flexible rods arranged longitudinally, rigid connector six, rigid connector seven and rigid connector eight in a square frame structure; The lower ends of the eight second flexible rods are respectively fixed to the four inflection points of the square rigid connector 6 and the four midpoints of the four sides; 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 7, and the upper ends of the four second flexible rods located at the midpoints are fixed to the connection module through the rigid connector 8; The four four-rod flexible modules are distributed around the connection module in a rectangular shape; The four-rod type flexible module comprises four first flexible rods, a rigid connector four and a rigid connector five; the four first flexible rods in the four-rod type flexible module are all arranged horizontally and distributed in a rectangular shape, one end of the four first flexible rods is fixedly connected to the base through the rigid connector four, and the other end is fixedly connected to the connection module through the rigid connector five; the driving end of the electromagnetic driver is fixedly connected to the bottom surface of the connection module; The connection modules include: a square module and a cross module; The cross-shaped module is fixedly connected to the top surface of the square module; the four four-rod flexible modules are distributed in a rectangular shape around the square module; the rigid connector 5 is a square plate-shaped structure, fixedly connected 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-shaped structure, and its top surface is higher than the rigid connector eight, and is arranged in a cross shape 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, and the top surface of the rigid connector 7 is higher than the top surface of the rigid connector 8; The driving end of the electromagnetic driver is fixedly connected to the bottom surface of the square module; In the flexible kinematic pair, the 10 flexible rods, the rigid connector 1, the rigid connector 2 and the rigid connector 3 are made as one piece; The base comprises: a horizontally arranged circular bottom plate and four longitudinally arranged pillars; the pillars are made integrally with the circular bottom plate; The four pillars are distributed in a rectangular shape, the middle and lower ends of the pillars are fixedly connected to the circular bottom plate, and the rigid frame is fixedly connected to the four pillars; The piezoelectric ceramic actuator comprises: 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 same-direction drivers.

[0007] The application provides a high-precision positioning platform based on a flexible kinematic pair, which realizes the three translational degrees of freedom required by the platform 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; it adopts a single kinematic pair in the X and Y directions to replace the traditional multi-branch chain structure, thereby simplifying the platform structure, reducing space occupancy, and greatly improving the convenience of maintenance and troubleshooting; the second flexible branch chain and the four flexible kinematic pairs are arranged in a cross-symmetrical manner, and the flexible rods in the flexible kinematic pairs are arranged in reverse series and symmetrically, which effectively offsets the parasitic motion and reduces the coupled displacement and associated rotation; two same-direction drives are arranged on the same axis, and through synchronous control, they are made to move in the same direction with the same displacement and force to achieve synchronous drive, thereby improving the accuracy of the platform in unidirectional movement. The technical solution of the 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram of the overall structure of the present invention at a right isometric viewing angle; Figure 2 It is a schematic diagram of the overall structure of the top view projection of the orthogonal isometric viewing angle of the present invention; Figure 3 It is a schematic diagram of the main structure of the present invention in a positive three-axis viewing angle; Figure 4 It is a schematic diagram of a partial cross-sectional structure of a flexible kinematic pair; Figure 5 It is the Z-direction motion trend diagram of the flexible kinematic pair; Figure 6 It is the X-direction motion trend diagram of the flexible kinematic pair; Figure 7 It is the Y-direction motion trend diagram of the flexible kinematic pair; Figure 8 This is an exploded view of the second flexible branch.

[0009] Among them: 1-base; 11-retractable bottom plate; 12-pillar; 13-mounting bracket; 2-moving platform; 3-rigid frame; 4-flexible kinematic pair; 41-flexible rod; 42-rigid connector 1; 43-rigid connector 2; 44-rigid connector 3; 45-kinematic pair frame; 5-second flexible branch chain; 51-double four-rod flexible module; 511-second flexible rod; 512-rigid connector six; 513-rigid connector seven; 514-rigid connector eight; 521-square module; 522-cross module; 53-four-rod flexible module; 531-first flexible rod; 532-rigid connector four; 533-rigid connector five; 6-Piezoelectric ceramic actuator; 7-Z-axis electromagnetic drive. DETAILED DESCRIPTION

[0010] like Figure 1 to Figure 8 As shown, the present application includes a high-precision positioning platform based on a flexible motion pair, which includes: a base 1, a moving platform 2, a rigid frame 3, four flexible motion pairs 4, a second flexible branch 5, a piezoelectric ceramic actuator 6 and an electromagnetic drive 7.

[0011] The rigid frame 3 is arranged on the base 1, the flexible motion pair 4 and the second flexible branch chain 5 are arranged above the base 1, and the flexible motion pair 4 is located in the inner cavity of the rigid frame 3; the four flexible motion pairs 4 are distributed around the moving platform 2 in a cross-symmetrical manner; the second flexible branch chain 5 is arranged below the moving platform 2 and the flexible motion pair 4.

[0012] The end of each flexible motion pair 4 is connected to the moving platform 2; the head ends of two flexible motion pairs 4 are connected to the piezoelectric ceramic actuator 6 in the X direction, and the head ends of the other two flexible motion pairs 4 are connected to the piezoelectric ceramic actuator 6 in the Y direction. The piezoelectric ceramic actuator drives the moving platform to move along the X-axis and Y-axis directions.

[0013] The second flexible branch chain 5 includes a driving pair and a passive pair; the driving pair of the second flexible branch chain 5 is arranged on the base 1, and the passive pair is arranged on the driving pair and is not directly connected to the driving pair; the passive pair of the second flexible branch chain 5 is connected to the moving platform 2; 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 driver 7 in the Z direction is arranged at the center point of the mounting bracket 13 of the base 1, and the driving end of the electromagnetic driver 7 is connected to the second flexible branch chain 5 to drive the moving platform to move along the Z axis direction.

[0014] like Figure 2 As shown, the base 1 includes: a horizontally arranged circular bottom plate 11 and four longitudinally arranged pillars 12. The four pillars 12 are distributed in a rectangular shape, and the middle and lower ends of the pillars 12 are fixed to the circular bottom plate 11, and the rigid frame 3 is fixed to the four pillars 12. The pillars 12 are made integrally with the circular bottom plate 11, and threaded holes are opened on the top surfaces of the pillars 12. Through holes are opened on the rigid frame 3 corresponding to the threaded holes, and screws are passed through the through holes and screwed into the threaded holes to fix the rigid frame 3 and the pillars 12.

[0015] like Figure 4 As shown, the flexible kinematic pair 4 includes: ten mutually parallel flexible rods 41, two rigid connecting members 1 42, two rigid connecting members 2 43, one rigid connecting member 3 44 and a kinematic pair frame 45.

[0016] The motion sub-frame 45 is a concave-shaped frame structure, including: a frame straight plate 451 and two L-shaped frame folding plates 452; one end of the frame folding plate 452 is connected to the frame straight plate 451, and the other end is an edge plate bent toward the inside of the frame, and the edge plate is parallel to the center line L of the frame straight plate 451; the two frame folding plates 452 are symmetrically arranged on both sides of the center line L of the frame straight plate 451. In specific implementation, the frame straight plate 451 and the two L-shaped frame folding plates 452 are integrally formed.

[0017] The flexible rod 41 , the rigid connecting piece 1 42 , the rigid connecting piece 2 43 , and the rigid connecting piece 3 44 are all arranged in the inner cavity of the moving sub-frame 45 .

[0018] The two rigid connectors 42 are symmetrically arranged based on the center line L of the frame straight plate 451; the rigid connector 42 is adjacent to the frame straight plate 451, but the two are not directly connected; Four flexible rods 41 are respectively arranged on the end surface of each rigid connecting member 42 away from the frame straight plate 451, and the four flexible rods 41 are respectively located at the four vertices of the rectangle; at the same time, one more flexible rod 41 is respectively arranged at the midpoint position of the adjacent sides of the two rectangles, which are recorded as: midpoint flexible rods; The installation positions of the flexible rods 41 on the two rigid connecting members 42 are symmetrically arranged based on the center line L of the frame straight plate 451; One end of the two midpoint flexible rods 41 away from the rigid connecting member 1 42 is fixedly connected to the rigid connecting member 3 44 respectively; Two rigid connectors 43 are respectively arranged parallel and symmetrically on both sides of the rigid connector 44; and each rigid connector 43 is connected to two flexible rods 41 located on adjacent sides of the rectangle on the end surface facing the frame straight plate 451; In the two rectangles formed by the flexible rods 41 , the two flexible rods 41 on the sides closest to the frame folding plates 452 are connected to the edge plates of the adjacent frame folding plates 452 .

[0019] The rigid connector 2 43 constitutes the end of the flexible motion pair 4, and the end face of the rigid connector 2 43 away from the frame straight plate 451 is fixedly connected to the moving platform 2; the rigid connector 3 44 constitutes the head end of the flexible motion pair 4, and the end face of the rigid connector 3 44 adjacent to the frame straight plate 451 is fixedly connected to the piezoelectric ceramic actuator 6.

[0020] The rigid connector 1 42 is a plate-shaped connector, and the rigid connector 2 43 and the rigid connector 3 44 are rectangular structures; the rigid connector 2 43 and the rigid connector 3 44 are arranged in a three-shaped shape; the driving ends of the X-direction piezoelectric ceramic actuator 6 and the Y-direction piezoelectric ceramic actuator 6 are respectively connected to the rigid connector 3 44 in the X-direction and Y-direction motion pairs.

[0021] When installing, Figure 4 As shown, the top surface of the second rigid connector 43 is higher than the top surface of the third rigid connector 44. The second rigid connector 43 is connected to the moving platform, and the third rigid connector 44 is connected to the driver. When a specific movement occurs, the force of the electric ceramic actuator 6 in the X direction or the Y direction is transmitted to the third rigid connector 44, and then transmitted to the moving platform 2 through a series of rigid connectors and flexible rods to achieve movement in the X direction or the Y direction; the top surface of the second rigid connector 43 is set to be higher than the top surface of the third rigid connector 44, leaving a certain activity space for the third rigid connector 44, preventing the third rigid connector 44 from directly colliding with the moving platform 2 when being driven by the driver, ensuring effective force transmission, and then ensuring the precise movement of the moving platform 2.

[0022] There is a gap between the rigid connector 2 43 and the rigid connector 3 44. When the flexible motion pair 4 acts as a passive pair and the force of the moving platform 2 is transmitted from the rigid connector 3 44 to the flexible motion pair 4, a gap is left between the rigid connector 2 43 and the rigid connector 3 44 to prevent direct collision between the two, thereby ensuring the precise movement of the moving platform 2.

[0023] One end of the piezoelectric ceramic actuator 6 is fixed on the moving sub-frame 45 , and the driving end of the piezoelectric ceramic actuator 6 is connected to the rigid connecting member 3 44 .

[0024] In the flexible kinematic pair, 10 flexible rods 41, a rigid connector 1 42, a rigid connector 2 43 and a rigid connector 3 44 are integrally formed.

[0025] The piezoelectric ceramic actuator 6 in the present application includes an X-direction piezoelectric ceramic actuator 6 and a Y-direction piezoelectric ceramic actuator 6. In specific implementation, in order to ensure that a single kinematic pair replaces a branch chain to realize multi-axis drive in the present application, a piezoelectric ceramic actuator that can withstand a slight lateral load is selected to limit the undesired movement of the rigid connection member 3 44; so that the driver can be directly connected to the flexible kinematic pair, when the flexible kinematic pair is used as a passive pair, the piezoelectric ceramic actuator that can withstand a slight lateral load can ensure that the deformation of the flexible kinematic pair will not cause undesired movement of the rigid connection member 3 44 and thus affect the driving accuracy.

[0026] In the specific driving, the two piezoelectric ceramic actuators arranged in the same coordinate axis direction in the present application are same-direction drivers. Through synchronous control, they are made to move in the same direction with the same displacement and force to achieve synchronous driving, thereby improving the accuracy of the platform moving in a single direction.

[0027] like Figure 8 As shown, the second flexible branch chain 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 chain 5; the double four-bar flexible module 51 constitutes the passive pair of the second flexible branch chain 5; The double four-rod type flexible module 51 includes: eight second flexible rods 511 arranged longitudinally, a rigid connection member six 512, a rigid connection member seven 513 and a rigid connection member eight 514 in a square frame structure; The lower ends of the eight second flexible rods 511 are respectively fixed to the four inflection points of the square rigid connector six 512 and the four midpoints of the four sides; 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 connection module 52 through the rigid connector eight 514.

[0028] Four four-rod type flexible modules 53 are distributed around the connection module 52 in a rectangular shape; The four-rod type flexible module 53 includes four first flexible rods 531, a rigid connector four 532 and a rigid connector five 533; the four first flexible rods 531 in the four-rod type flexible module 53 are all horizontally arranged and distributed in a rectangular shape, one end of the four first flexible rods 531 is fixedly connected to the base 1 through the rigid connector four 532, and the other end is fixedly connected to the connection module 52 through the rigid connector five 533; the driving end of the electromagnetic driver 7 is fixedly connected to the bottom surface of the connection module 52.

[0029] The connection module 52 includes: a square module 521 and a cross module 522; The cross-shaped module 522 is fixedly connected to the top surface of the square module 521; the four four-rod flexible modules 53 are distributed in a rectangular shape around the square module 521; the rigid connecting member 533 is a square plate-shaped structure, fixedly connected to the four sides of the square module 521.

[0030] The cross-shaped module 522 extends into the inner cavity of the double four-rod flexible module 51; the rigid connector eight 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 seven 513 is a square structure, its top surface is higher than the rigid connector eight 514, and is arranged in a cross shape with the rigid connector eight 514.

[0031] A gap is left between the rigid connector seven 513 and the rigid connector eight 514. The rigid connector seven 513 is fixed to the bottom surface of the moving platform 2 by screws. The top surface of the rigid connector seven 513 is higher than the top surface of the rigid connector eight 514.

[0032] The driving end of the electromagnetic driver 7 is fixedly connected to the bottom surface of the square module 521 .

[0033] The four rigid connecting members 532 are of a square structure, and the four rigid connecting members 532 are respectively fixed to the circular bottom plate 11 of the base 1 by screws.

[0034] The three drivers in the present application: the X-axis piezoelectric ceramic actuator 6, the Y-axis piezoelectric ceramic actuator 6, and the Z-axis electromagnetic driver 7, respectively control the translational motion of the mechanism in three directions in space, ensuring that the various motions are independent of each other and there is no motion coupling.

[0035] In the present 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 branched chain structure in the traditional structure, and the flexible kinematic pair 4 is directly connected to the driving structure.

[0036] Combination Figure 4 , Figure 5 As shown, when the flexible motion pair 4 is used as the driving pair, the piezoelectric ceramic actuator 6 inputs displacement to transmit force to the rigid connection member 3 44, the rigid connection member 3 44 transmits force to the rigid connection member 1 42 through the two middle flexible rods 41 connected thereto, the rigid connection member 1 42 transmits force to the rigid connection member 2 43 through the four outer flexible rods 41 connected thereto, and finally transmits force to the moving platform 2, and the bending deformation generated by the four outer flexible rods 41 connected to the rigid connection member 1 42 is converted into the platform of the moving platform 2 to realize the movement in the X-axis and Y-axis directions, for details, refer to Figure 5 In the direction of the red arrow. Rigid connector 2 43 along Figure 5 When moving in the direction of the red arrow, all the flexible rods 41 distributed between the rigid connector 2 43 and the frame straight plate 451 are symmetrically arranged about the rigid connector 3 44, so that the rigid connector 2 43 reduces the movement of the front, back, left and right during the movement, thereby improving the output accuracy of the moving platform 2 connected to the rigid connector 2 43.

[0037] When the moving platform moves along the Z-axis, the flexible motion pair 4 will act as a passive pair; when the moving platform moves along the X-axis or Y-axis, the flexible motion pair 4 in the perpendicular Y-axis or X-axis direction will also act as a passive pair. In the flexible motion structure, the passive pair is mainly used to provide flexibility and buffering to allow certain degrees of freedom to move while limiting or adjusting other degrees of freedom. Figure 4 , Figure 6 , Figure 7 As shown, the input displacement of the moving platform 2 transmits the force to the rigid connector 2 43, and the rigid connector 2 43 transmits the force to the rigid connector 1 42 through the four middle flexible rods 41 connected to it, and the rigid connector 1 42 transmits the force to the four outer flexible rods 41 connected to it. Since the undesired movement of the rigid connector 3 44 is suppressed, the force is also transmitted to the two middle flexible rods 41 connected to it, and finally causes the corresponding flexible rods 41 to deform with the moving platform. The moving direction of the moving platform is referred to Figure 6 The b direction and Figure 7 The c direction in . Figure 6 and Figure 7The a direction in the figure is perpendicular to the plane where the frame straight plate 451 is located, and the a direction, the b direction, and the c direction are perpendicular to each other.

[0038] The two rigid connectors 43 of the same flexible motion pair 4 are connected to the moving platform 2 at the same time, so the two rigid connectors 43 move synchronously. Figure 6 When moving in the b direction, the rigid connector 1 42 and the rigid connector 2 43 are connected to the two ends of the flexible rod 41 respectively. The multiple groups of structures connected in series by the rigid connector 1 42, the rigid connector 2 43 and the flexible rod 41 are m1~m6 in the figure, and the structures of m1~m6 are the same. Among them, m1 and m5 are in the same direction and opposite to m3 at the same time. m1, m3 and m5 constitute a reverse series structure; m2, m4 and m6 constitute another group of reverse series structures. In this application, the parasitic motion is offset by the symmetrical deformation of the structures in the two directions in the same plane in the opposite directions. For example, when the rigid connector 2 43 moves in the b direction, the deformation of m3 in the a direction and the deformation of m1 and m5 in the a direction are symmetrical and can offset each other, so the movement of the moving platform 2 along the a direction can be reduced. At the same time, the two groups of reverse series structures are symmetrically arranged in parallel with the rigid connector 3 44 as the midline, which reduces the movement of the moving platform 2 in the c direction and improves the accuracy of the moving platform 2.

[0039] When the rigid connecting member 43 acts as a passive pair along Figure 7 When the middle c direction moves, the multiple groups of structures connected in series, which are composed of the rigid connector 1 42, the rigid connector 2 43 and the flexible rod 41, are n1~n4 in the figure, and the structures of n1~n4 are the same. Among them, n1 and n2 have the same and reverse structures, forming a reverse series structure; n3 and n4 form another group of reverse series structures. When the rigid connector 2 43 moves in the c direction, the deformations of n1 and n2 in the a direction offset each other, and the deformations of n3 and n4 in the a direction offset each other, thereby reducing the movement of the two rigid connectors 2 43 in the a direction and improving the movement accuracy of the moving platform 2. At the same time, the two groups of reverse series structures are symmetrically arranged in parallel based on the midline L to reduce the movement of the moving platform 2 in the b direction.

[0040] At the same time, in the same flexible joint 4, Figure 6 The two reverse series structures shown in Figure 7The two sets of reverse series structures in the figure are actually highly integrated on the flexible motion based on the principle of cross connection. The flexible motion pair 4 of the present application arranges 10 flexible rods, rigid connector 1, rigid connector 2 and rigid connector 3 symmetrically, in reverse series, and the driver is directly connected to the motion pair. All structures are highly integrated on one motion pair to obtain a new motion pair, thereby simplifying the platform structure, reducing space occupancy, and greatly improving the convenience of maintenance and troubleshooting.

[0041] The Z-direction electromagnetic driver 7 inputs displacement to transfer force to the square module 521, the square module 521 transfers it to the cross-shaped module 522, the cross-shaped module 522 transfers it to the rigid connector eight 514, the rigid connector eight 514 transfers it to the rigid connector six 512 through the four second flexible rods 511 in the middle, the rigid connector six 512 transfers it to the rigid connector seven 513 through the four second flexible rods 511 outside, and finally transfers it to the moving platform 2. Specifically, the Z-direction electromagnetic driver 7 gives an upward driving force, and the moving platform 2 realizes upward movement; the Z-direction electromagnetic driver 7 gives a downward driving force, and the moving platform 2 realizes downward movement. Specific motion trend diagram class flexible motion pair 4. The first flexible rod 531 in the driving pair 53 is the main component of the driving pair, and is symmetrically arranged around the moving platform 2 in a cross shape. In the flexible motion structure, the driving pair is used to provide freedom of movement, stability and precision. During the force transmission process, the first flexible rod 531 deforms to ensure that the Z-direction force given by the Z-direction electromagnetic driver 7 can be accurately transmitted in the flexible structure, thereby realizing the precise movement of the moving platform.

[0042] like Figure 3 As shown, in the present application, the four flexible kinematic pairs 4 and the four four-bar flexible modules 53 in the second flexible branch chain 5 are all 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 geometric shape of the mechanism is symmetrical, the parasitic motion caused by deformation on any one side will be offset by the same deformation on the other side, thereby reducing undesirable motion and coupling effects, and can also reduce undesirable rotation generated by the mechanism during movement.

[0043] After using the technical solution of the present invention, the positioning platform not only has a large motion range and excellent structural processability through an optimized flexible structure design, but also effectively eliminates the motion coupling phenomenon and significantly improves the positioning accuracy. At the same time, the application simplifies the overall structure of the platform, reduces space occupancy, 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, the moving platform and the rigid frame are characterized in that they also include: four flexible kinematic pairs, a second flexible branch chain, a piezoelectric ceramic actuator and an electromagnetic driver; The rigid frame is arranged on the base, the flexible motion pair and the second flexible branch chain are arranged above the base, and the flexible motion pair is located in the inner cavity of the rigid frame; four flexible motion pairs are distributed around the moving platform in a cross-symmetrical manner; the second flexible branch chain is arranged below the moving platform and the flexible motion pair; The end of each of the flexible motion pairs is connected to the moving platform; the head ends of two of the flexible motion pairs are connected to the piezoelectric ceramic actuator in the X direction, and the head ends of the other two flexible motion 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 directions based on the piezoelectric ceramic actuator; The second flexible branch chain includes a driving pair and a passive pair; the driving pair of the second flexible branch chain is arranged on the base, and the passive pair is arranged on the driving pair and is not directly connected to the driving pair; the passive pair of the second flexible branch chain is connected to the moving platform; The electromagnetic driver in the Z direction is arranged on the mounting bracket of the base, and the driving end of the electromagnetic driver is connected to the second flexible branch chain to drive the moving platform to move along the Z axis direction.

2. According to claim 1, a high-precision positioning platform based on a flexible kinematic pair is characterized in that: The flexible kinematic pair comprises: ten mutually parallel flexible rods, two rigid connecting members 1, two rigid connecting members 2, one rigid connecting member 3 and a kinematic pair frame; The motion sub-frame is a concave frame structure, including a frame straight plate and two L-shaped frame folding plates; one end of the frame folding plate is connected to the frame straight plate, and the other end is an edge plate bent toward the inside of the frame, and the edge plate is parallel to the center line of the frame straight plate; the two frame folding plates are symmetrically arranged on both sides of the center line of the frame straight plate; The flexible rod, the first rigid connector, the second rigid connector and the third rigid connector are all arranged in the inner cavity of the motion sub-frame; The two rigid connectors are symmetrically arranged based on the center line of the frame straight plate; four flexible rods are arranged on the end surface of each rigid connector away from the frame straight plate, and the four flexible rods are respectively located at the four vertices of the rectangle; at the same time, one more flexible rod is arranged at the midpoint position of the adjacent sides of the two rectangles, which are recorded as midpoint flexible rods; The installation positions of the flexible rods on the two rigid connectors are symmetrically arranged based on the center line of the frame straight plate; One end of the two midpoint flexible rods away from the rigid connecting member 1 is fixedly connected to the rigid connecting member 3 at the same time; The two rigid connectors 2 are respectively arranged in parallel and symmetrically on both sides of the rigid connector 3; and each rigid connector 2 is respectively and simultaneously connected to two flexible rods located on adjacent sides of the rectangle on the end surface facing the frame straight plate; In the two rectangles formed by the flexible rods, two flexible rods on the sides closest to the frame folding plates are connected to the edge plates of the adjacent frame folding plates; The second rigid connector constitutes the end of the flexible motion pair, and its end surface away from the frame straight plate is fixedly connected to the moving platform; the third rigid connector constitutes the head end of the flexible motion pair, and its end surface adjacent to the frame straight plate is fixedly connected to the piezoelectric ceramic actuator.

3. According to claim 2, a high-precision positioning platform based on a flexible kinematic pair is characterized in that: The rigid connector one is a plate-shaped connector, and the rigid connector two and the rigid connector three are rectangular structures; the rigid connector two and the rigid connector three are arranged in a three-shape, and a gap is left between the rigid connector two and the rigid connector three, and the top surface of the rigid connector two is higher than the top surface of the rigid connector three.

4. According to claim 2, a high-precision positioning platform based on a flexible kinematic pair is characterized in that: The piezoelectric ceramic actuator is fixed on the motion pair frame, and the driving ends of the X-direction piezoelectric ceramic actuator and the Y-direction piezoelectric ceramic actuator are respectively connected to the rigid connecting parts in the X-direction and Y-direction motion pairs.

5. According to claim 2, a high-precision positioning platform based on a flexible kinematic pair is characterized in that: The rigid connecting member four is a square-shaped structure, and the four rigid connecting members four are respectively fixed to the circular bottom plate of the base.

6. According to claim 1, a high-precision positioning platform based on a flexible kinematic pair is characterized in that: The second flexible branch chain comprises: a double four-bar flexible module, a connecting module and four four-bar flexible modules; the four four-bar flexible modules constitute a driving pair of the second flexible branch chain; the double four-bar flexible module constitutes a passive pair of the second flexible branch chain; The double four-rod type flexible module comprises: eight second flexible rods arranged longitudinally, rigid connector six, rigid connector seven and rigid connector eight in a square frame structure; The lower ends of the eight second flexible rods are respectively fixed to the four inflection points of the square rigid connector 6 and the four midpoints of the four sides; 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 7, and the upper ends of the four second flexible rods located at the midpoints are fixed to the connection module through the rigid connector 8; The four four-rod flexible modules are distributed around the connection module in a rectangular shape; The four-rod type flexible module includes four first flexible rods, a rigid connector four and a rigid connector five; the four first flexible rods in the four-rod type flexible module are horizontally arranged and distributed in a rectangular shape, one end of the four first flexible rods is fixedly connected to the base through a rigid connector four, and the other end is fixedly connected to the connection module through a rigid connector five; the driving end of the electromagnetic driver is fixedly connected to the bottom surface of the connection module.

7. The high-precision positioning platform based on a flexible kinematic pair according to claim 6, characterized in that: The connection modules include: a square module and a cross module; The cross-shaped module is fixedly connected to the top surface of the square module; the four four-rod flexible modules are distributed in a rectangular shape around the square module; the rigid connector 5 is a square plate-shaped structure, fixedly connected 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-shaped structure, and its top surface is higher than the rigid connector eight, and is arranged in a cross shape 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, and the top surface of the rigid connector 7 is higher than the top surface of the rigid connector 8; The driving end of the electromagnetic driver is fixedly connected to the bottom surface of the square module.

8. According to claim 2, a high-precision positioning platform based on a flexible kinematic pair is characterized in that: In the flexible kinematic pair, the 10 flexible rods, the rigid connector 1, the rigid connector 2 and the rigid connector 3 are made as one piece.

9. The high-precision positioning platform based on a flexible kinematic pair according to claim 1, characterized in that: The base comprises: a horizontally arranged circular bottom plate and four longitudinally arranged pillars; the pillars are made integrally with the circular bottom plate; The four pillars are distributed in a rectangular shape, the middle and lower ends of the pillars are fixedly connected to the circular bottom plate, and the rigid frame is fixedly connected to the four pillars.

10. The high-precision positioning platform based on a flexible kinematic pair according to claim 1, characterized in that: 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 same-direction drivers.

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