Piezoelectric actuating double-shaft micro-nano manipulator for medical equipment and optimization topology method

Abstract

The piezoelectric actuation double-shaft micro-nano operation instrument comprises a flexible driving frame, a driving mechanism and a mounting base, the mounting base is of an inverted-L-shaped structure, the driving mechanism is mounted on the mounting base, the output end of the driving mechanism is connected with the flexible driving frame, and the output end of the driving mechanism is connected with the flexible driving frame. The flexible driving frame comprises a driving table, a y-axis supporting piece and x-axis connecting pieces which are integrally formed, the section of the driving table is of an inverted triangle structure, the section of the y-axis supporting piece is of a shawl-leaf-shaped structure, one ends of the three x-axis connecting pieces are connected with one another, and the other ends of the three x-axis connecting pieces are connected with one another. The other ends of the three x-axis connecting pieces are connected with the driving table, the y-axis supporting piece and the mounting base correspondingly, power of the driving mechanism is output to one ends of the three x-axis connecting pieces and the bottom of the y-axis supporting piece, and the top of the y-axis supporting piece is connected with the bottom of the driving table. According to the device, complete decoupling movement can be realized, so that the positioning precision and stability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-precision micro-nano manipulation of medical devices, and in particular to a piezoelectrically actuated dual-axis micro-nano manipulator for medical devices and a topology optimization method thereof. Background Art

[0002] With the rapid development of minimally invasive surgery and precision medical technology, the limitations of traditional surgical tools and equipment in micro-nano-level operation accuracy and control stability have become increasingly prominent, and it is difficult to meet the increasingly complex and sophisticated medical needs. Existing operating instruments generally have deficiencies in positioning accuracy, response speed, and system stability, especially in the fields of cell manipulation, tissue repair, and micro-device assembly. Therefore, it is urgent to develop a micro-nano manipulator with high precision, fast response, and excellent stability to meet the operating requirements of modern precision medical devices and promote the further development of minimally invasive surgery, precision diagnosis and treatment, and biomedicine.

[0003] Traditional rigid mechanism operating instruments have inherent defects such as friction, clearance and assembly errors, which make it difficult to achieve high-precision operation and cannot meet the stringent requirements of minimally invasive surgery. In contrast, flexible mechanisms can effectively avoid the above defects by transmitting motion through the elastic deformation of flexible joints. Combined with piezoelectric actuators with high bandwidth and high precision, flexible mechanisms can achieve precise positioning with nanometer-level resolution and fast response. Therefore, flexible mechanisms based on piezoelectric drive have become an ideal choice for building high-performance XY nanomanipulators.

[0004] However, in previous studies, the design of nanomanipulators based on complex series and parallel structures usually found it difficult to fully and effectively establish the coupling relationship between the rigid body and the flexible hinge in the flexible mechanism. The existence of this coupling relationship not only complicates the kinematic analysis, but also limits the improvement of the performance of the dual-axis micro-nano manipulator system, becoming the main bottleneck for further optimization of the design.

[0005] In order to solve the above problems, the present invention proposes to combine the finite element analysis method with the flexible mechanism design theory, give full play to the advantages of the topology optimization method in structural optimization, and design a piezoelectrically actuated two-axis micro-nano manipulator with completely decoupled motion. The introduction of the topology optimization method effectively solves the performance bottleneck caused by the coupling relationship in the flexible mechanism, and realizes motion decoupling, stiffness enhancement and dynamic performance improvement through global optimization of the structure. The present invention not only overcomes the limitations of traditional design methods and provides a new solution for micro-nano manipulators, but also provides important theoretical references and technical guidance for the topology optimization design of medical devices, precision engineering and flexible mechanisms.

[0006] In summary, the present invention solves the problem of insufficient precision of traditional rigid mechanism operating instruments through flexible mechanism design, and solves the technical difficulties of flexible mechanism in coupling relationship and structural performance optimization through topological optimization method. This innovative design has significant academic value and practical application potential, and can provide reliable technical support for minimally invasive surgery and precision medicine. Summary of the invention

[0007] In view of the deficiencies of the prior art, the present invention proposes a piezoelectrically actuated two-axis micro-nano manipulator for medical devices and a topology optimization method thereof, which can achieve completely decoupled motion, thereby improving the accuracy and stability of positioning.

[0008] In order to solve the above technical problems, the technical solution of the present invention is:

[0009] A piezoelectrically actuated biaxial micro-nano manipulator for medical equipment comprises a flexible drive frame, a drive mechanism and a mounting base, wherein the mounting base is an inverted L-shaped structure, the drive mechanism is mounted on the mounting base, the output end of the drive mechanism is connected to the flexible drive frame, the flexible drive frame comprises an integrally formed drive platform, a y-axial support member and an x-axial connecting member, the cross section of the drive platform is an inverted triangle structure, the cross section of the y-axial support member is a lanceolate leaf-shaped structure, one end of three x-axial connecting members are connected to each other, and the other ends of the three x-axial connecting members are respectively connected to the drive platform, the y-axial support member and the mounting base, the drive mechanism outputs power to one end of the three x-axial connecting members and the bottom of the y-axial support member, and the top of the y-axial support member is connected to the bottom of the drive platform.

[0010] In the above technical solution, the top surface of the driving platform with an inverted triangle structure serves as the output end, and acts on the y-axial support member and the x-axial connecting member respectively through the driving mechanism, thereby realizing y-axial and x-axial movements, and a flexible driving frame made of flexible material is used, so that the driving platform has decoupled movement.

[0011] Preferably, the mounting base includes a base body, the base body is an inverted L-shaped structure, and a first mounting platform, a first connecting platform, a second connecting platform and a second mounting platform are integrally formed on the base body, and the first mounting platform, the first connecting platform, the second connecting platform and the second mounting platform are arranged in a stepped manner from top to bottom.

[0012] Preferably, the driving mechanism includes an x-axial piezoelectric actuator and a y-axial piezoelectric actuator, and the x-axial piezoelectric actuator and the y-axial piezoelectric actuator are respectively mounted on a first mounting platform and a second mounting platform, and the power of the x-axial piezoelectric actuator is output to the connecting ends of three x-axial connecting members, and the power of the y-axial piezoelectric actuator is output to the bottom of the y-axial support member.

[0013] In the above technical solution, the x-axial piezoelectric actuator and the y-axial piezoelectric actuator are placed at two input ends of the flexible driving frame, and the x-axial piezoelectric actuator and the y-axial piezoelectric actuator are pre-tightened accordingly by two pre-tightening screws.

[0014] Among them, the x-axis piezoelectric actuator and the y-axis piezoelectric actuator are orthogonally distributed and keep the same direction with the corresponding output end. When the two piezoelectrics are excited, the output end of the flexible drive frame has decoupled motion, which can realize not only the motion in the x-axis direction, but also the motion in the y-axis direction.

[0015] Preferably, the connecting ends of the three x-axial connecting members are fixedly connected to an x-axial connecting portion, the x-axial connecting portion is a rectangular structure, and the power output end of the x-axial piezoelectric actuator is fixedly connected to one side of the x-axial connecting portion.

[0016] Preferably, a y-axial connecting portion is fixedly connected to the bottom of the y-axial supporting member, and a power output end of the y-axial piezoelectric actuator is fixedly connected to the bottom side of the y-axial connecting portion.

[0017] Preferably, a longitudinal flexible hinge is provided between the x-axial connection part and the first connecting platform, and the longitudinal flexible hinge comprises a plurality of flexible vertical plates arranged in parallel, the flexible vertical plates are integrally formed with the x-axial connection part, and the flexible vertical plates are fixedly connected to the horizontal surface of the first connecting platform.

[0018] In the above technical solution, the flexible vertical plates are parallel to each other, thereby ensuring that the flexible driving frame has a certain stability when moving.

[0019] Preferably, a transverse flexible hinge is arranged between the y-axial connecting part and the second connecting platform, and the transverse flexible hinge includes a plurality of flexible horizontal plates arranged in parallel, one end of the flexible vertical plate is integrally formed with the y-axial connecting part, and the other end of the flexible vertical plate is fixedly connected to the side wall of the second connecting platform.

[0020] Preferably, the other end of the uppermost x-axial connecting member is fixedly connected to the corner end of the driving platform, the other end of the middle x-axial connecting member is fixedly connected to the middle position of one side of the y-axial supporting member, and the other end of the lowermost x-axial connecting member is fixedly connected to the first connecting platform.

[0021] Preferably, the driving platform and the y-axial support are both provided with a plurality of hollow holes.

[0022] In the above technical solution, the flexibility of the flexible driving frame is increased by setting the hollow holes, and the manufacturing materials of the flexible driving frame are reduced, thereby reducing the cost.

[0023] Preferably, the mounting base is provided with a plurality of threaded holes, through which the operating instrument is fixed with bolts.

[0024] The present invention also discloses a topology optimization method for a piezoelectrically actuated biaxial micro-nano manipulator for medical devices, comprising the following steps:

[0025] Step 1: Define the FTS mechanism optimization problem;

[0026] Step 2: Define the initial design domain and boundary conditions;

[0027] Step 3: Determine the finite element mesh, define the element type, and establish the element stiffness and mass model;

[0028] Step 4: Pre-processing to form a finite element model;

[0029] Step 5: Define the objective function and constraints;

[0030] Step 6: Theoretically solve the stability problem (density filtering);

[0031] Step 7: MMA optimization algorithm;

[0032] Step 8: Determine whether the optimization process converges, otherwise repeat the finite element analysis, update the material density, density filtering and MMA optimization algorithm until the convergence conditions of the objective function and constraint function are met;

[0033] Step 9: Output the optimal result; after convergence, output the optimal material distribution and structural topology layout, including the optimal material density, structural geometry and response results.

[0034] The present invention has the following characteristics and beneficial effects:

[0035] By adopting the above technical scheme, the present invention realizes planar motion in the x- and y-directions by driving a piezoelectric actuator, and has the advantages of compact structure, large driving force, and fast response speed. It takes a topological flexible mechanism as the main body and two straight parallel flexible hinges at two input ends as the guiding mechanism, and can effectively seek the best mechanism configuration and parameters, so that the mechanism performance can be improved to the optimal level. The dual-axis micro-nano manipulator of the present invention has the advantages of reasonable structural design, compactness, small size, relatively large motion stroke, relatively high frequency, and high positioning accuracy.

[0036] The present invention proposes to combine the finite element analysis method with the flexible mechanism design theory, give full play to the advantages of the topology optimization method in structural optimization, and design a piezoelectrically actuated two-axis micro-nano manipulator with completely decoupled motion. The introduction of the topology optimization method effectively solves the performance bottleneck caused by the coupling relationship in the flexible mechanism, and realizes motion decoupling, stiffness enhancement and dynamic performance improvement through global optimization of the structure. The present invention not only overcomes the limitations of traditional design methods and provides a new solution for micro-nano manipulators, but also provides important theoretical references and technical guidance for the topology optimization design of medical devices, precision engineering and flexible mechanisms.

[0037] In summary, the present invention realizes high-precision two-degree-of-freedom motion control, improves the accuracy and stability of the positioning system during the motion process, and brings significant technological progress and application prospects to related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0039] Figure 1 The figure is a schematic structural diagram of an embodiment of a piezoelectrically actuated dual-axis micro-nano manipulator for medical devices according to the present invention.

[0040] Figure 2 It is the design domain of a topology optimization method for a piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to an embodiment of the present invention.

[0041] Figure 3 It is a flow chart of a topology optimization method for a piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to an embodiment of the present invention;

[0042] Figure 4 The diagram is a density profile and stress distribution diagram of a piezoelectrically actuated dual-axis micro-nano manipulator for medical devices according to an embodiment of the present invention.

[0043] Figure 5 It is a two-direction deformation diagram of a piezoelectrically actuated dual-axis micro-nano manipulator for medical devices according to an embodiment of the present invention;

[0044] Figure 6 It is a two-dimensional schematic diagram of a plane profile of a piezoelectrically actuated dual-axis micro-nano manipulator for medical devices according to an embodiment of the present invention;

[0045] Figure 7The present invention discloses a motion trajectory of a piezoelectrically actuated dual-axis micro-nano manipulator for medical devices.

[0046] In the figure, 1-flexible driving frame, 101-x axial connection part, 102-driving platform, 103-y axial support member, 104-x axial connection member, 105-hollow hole, 106-y axial connection part;

[0047] 2-y-axis piezoelectric actuator;

[0048] 3-mounting base, 301-base body, 302-threaded hole, 303-first mounting platform, 304-first connecting platform, 305-second connecting platform, 306-second mounting platform;

[0049] 4-longitudinal flexible hinge, 5-x-axial piezoelectric actuator, 6-lateral flexible hinge. DETAILED DESCRIPTION

[0050] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0052] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0053] Example 1

[0054] This embodiment provides a piezoelectrically actuated dual-axis micro-nano manipulator for medical devices, such as Figure 1 As shown, it includes a flexible driving frame 1, a driving mechanism and a mounting base 3, wherein the mounting base 3 is an inverted L-shaped structure, the driving mechanism is mounted on the mounting base 3, and the output end of the driving mechanism is connected to the flexible driving frame 1.

[0055] Specifically, the flexible driving frame 1 includes an integrally formed driving platform 102, a y-axial support member 103 and an x-axial connecting member 104. The mounting base 3 includes a base body 301, the base body 301 is an inverted L-shaped structure, and a first mounting platform 303, a first connecting platform 304, a second connecting platform 305 and a second mounting platform 306 are integrally formed on the base body 301, and a plurality of threaded holes 302 are provided on the mounting base 3. The first mounting platform 303, the first connecting platform 304, the second connecting platform 305 and the second mounting platform 306 are arranged in a stepped manner from top to bottom. The driving mechanism includes an x-axial piezoelectric actuator 5 and a y-axial piezoelectric actuator 2, wherein the x-axial piezoelectric actuator 5 and the y-axial piezoelectric actuator 2 are pre-tightened and mounted on the first mounting platform 303 and the second mounting platform 306 by pre-tightening screws.

[0056] Furthermore, the cross section of the driving platform 102 is an inverted triangle structure, and the top surface of the driving platform 102 is a horizontal plane, which serves as a power output end for installing a third-party driving component. The cross section of the y-axial support member 103 is a lanceolate leaf-shaped structure, and a plurality of hollow holes 105 are provided on the driving platform 102 and the y-axial support member 103. One end of the three x-axial connectors 104 is connected to each other, and the connecting ends of the three x-axial connectors 104 are fixedly connected to an x-axial connecting portion 101, which is a rectangular body structure, and the power output end of the x-axial piezoelectric actuator 5 is fixedly connected to one side of the x-axial connecting portion 101. The other end of the uppermost x-axial connector 104 is fixedly connected to the corner end of the driving platform 102, the other end of the middle x-axial connector 104 is fixedly connected to the middle position of one side of the y-axial support 103, and the other end of the lowermost x-axial connector 104 is fixedly connected to the first connecting platform 304. The power of the x-axial piezoelectric actuator 5 is output to the connection ends of the three x-axial connectors 104 to achieve x-axial output. The bottom of the y-axial support 103 is fixedly connected with a y-axial connecting portion 106, and the power output end of the y-axial piezoelectric actuator 2 is fixedly connected to the bottom side of the y-axial connecting portion 106. The power of the y-axial piezoelectric actuator 2 is output to the bottom of the y-axial support 103 to achieve y-axial output.

[0057] It can be understood that the x-axis piezoelectric actuator 5 and the y-axis piezoelectric actuator 2 are orthogonally distributed and keep consistent with the direction of the corresponding output end. When the x-axis piezoelectric actuator 5 and the y-axis piezoelectric actuator 2 are excited, the output end of the flexible driving frame 1 has a decoupled motion, which can not only realize the motion in the x-axis direction, but also realize the motion in the y-axis direction. The output end of the driving platform 102 is located at the upper right corner, and there is a certain displacement amplification and corresponding decoupling from the input end to the output end.

[0058] In a further configuration of this embodiment, a longitudinal flexible hinge 4 is provided between the x-axial connecting portion 101 and the first connecting platform 305, and the longitudinal flexible hinge 4 includes a plurality of parallel flexible vertical plates, the flexible vertical plates are integrally formed with the x-axial connecting portion 101, and the flexible vertical plates are fixedly connected to the horizontal surface of the first connecting platform 305. A transverse flexible hinge 6 is provided between the y-axial connecting portion 106 and the second connecting platform 306, and the transverse flexible hinge 6 includes a plurality of parallel flexible horizontal plates, one end of the flexible vertical plates is integrally formed with the y-axial connecting portion 106, and the other end of the flexible vertical plates is fixedly connected to the side wall of the second connecting platform 306.

[0059] It can be understood that there is a certain gap between the longitudinal flexible hinge 4 formed by the flexible vertical plate at the input end and the flexible driving frame 1 to ensure that there is no interference during the movement and to ensure that the guide mechanism has a certain stability.

[0060] The working principle of the embodiment of the present invention is as follows:

[0061] (1) When a driving signal is only provided to piezoelectric stack 1 and no driving signal is applied to piezoelectric stack 2, piezoelectric stack 2 will not work and only piezoelectric stack 1 will move. On the contrary, when a driving signal is only provided to piezoelectric stack 2 and no driving signal is applied to piezoelectric stack 1, piezoelectric stack 1 will stop working and only piezoelectric stack 2 will move. Under open-loop conditions, piezoelectric stack 1 and piezoelectric stack 2 perform linear motion separately to achieve motion control with large stroke, low precision and low bandwidth. This mode is suitable for application scenarios that require a large stroke but not high tracking accuracy.

[0062] (2) When the piezoelectric stack 1 provides a driving signal and the piezoelectric stack 2 also provides a driving signal, the piezoelectric stack 1 and the piezoelectric stack 2 move simultaneously. Under closed-loop control, the piezoelectric stack 1 and the piezoelectric stack 2 move linearly to achieve motion control with a large stroke, low precision and low bandwidth. This mode is suitable for applications with high precision requirements but small stroke requirements.

[0063] The micro-nano manipulator of the present invention can flexibly select working modes according to specific application scenarios, and realize decoupled motion in different directions or high-precision linkage control. This feature makes the micro-nano manipulator widely applicable in multiple application fields, and promotes the progress of related technologies and the possibility of their practical application.

[0064] Through the above technical solution, the piezoelectrically actuated two-axis micro-nano manipulator with fully decoupled motion of the present invention can effectively seek the best mechanism configuration-parameters, thereby achieving the best mechanism performance.

[0065] Example 2

[0066] This embodiment also provides a topology optimization method for a piezoelectrically actuated dual-axis micro-nano manipulator for medical devices.

[0067] Understandably, the topology optimization problem of micro-nano manipulator is described as follows:

[0068] In view of the basic performance requirements of micro-nano manipulators with large travel, high frequency response and high positioning accuracy in the current field of precision medical equipment, it is urgent to develop a micro-nano manipulator with high precision, fast response and excellent stability to meet the operation requirements of modern precision medical equipment and promote the further development of minimally invasive surgery, precision diagnosis and treatment, and biomedicine.

[0069] See also Figure 2 As shown, by integrating the kinematic characteristics of the mechanism design and the elastic mechanical characteristics of the structure design, the present invention proposes a topological optimization design of a micro-nano manipulator with general significance, using the eigenvalue λ i The maximum is taken as the objective function, while the constraints such as motion coupling and global stress are considered as the design indicators of the micro-nano manipulator.

[0070] At present, the optimization theory algorithms for structural topology optimization design mainly include: Optimality criteria method (OC) and method of moving asymptotes (MMA). The optimization criteria method is usually more suitable for solving problems with single objective functions and single constraints, and its calculation speed is faster. However, when faced with complex problems such as multiple objective functions and multiple constraints, the MMA method becomes a more suitable choice because it can deal with different types of optimization problems in a unified modeling form. Therefore, the MMA method is used in the present invention to solve the topology optimization design problem of micro-nano manipulators. Among them, the basic flow chart of the corresponding planar biaxial micro-nano manipulator topology optimization method is as follows Figure 3 See Figure 3 As shown, the specific steps of the topology optimization method of the dual-axis micro-nano manipulator are as follows:

[0071] Step 1: Define the FTS mechanism optimization problem, and use the eigenvalue λ by integrating the kinematic characteristics of the mechanism design and the elastic mechanical characteristics of the structure design. i The maximum is taken as the objective function, and the constraints such as motion coupling and global stress are considered as the design indicators of the micro-nano manipulator. The corresponding specific optimization mathematical model can be expressed as follows:

[0072]

[0073] In the formula, represents the set of design variables, n represents the total number of unit design variables, V represents the material usage volume, V * represents the upper limit of the material volume, and U represents the global displacement matrix caused by the external load vector F of the node. K and M are the global stiffness matrix and the global structural mass matrix respectively. Φ m is the mth-order eigenvalue λ m The associated feature vector.

[0074] It should be noted that, strictly speaking, KU = F and (K-λ m M)·Φ m =0 is a necessary equation used to analyze structural performance in optimization problems. It is not a direct constraint condition itself, but is used to calculate the objective function.

[0075] Step 2: Define the initial design domain and boundary conditions. The initial design domain determines the optimized structural geometry and size, while the boundary conditions include input drives, output requirements, and fixed nodes.

[0076] Step 3: Determine the finite element mesh, define the element type and establish the element stiffness and mass model. Therefore, the element stiffness matrix k e and the mass matrix m e The models can be expressed as:

[0077] k e =t∫∫B T DBdxdy (2)

[0078] m e =ρ0t∫∫N T Ndxdy (3)

[0079] Where N is the shape function matrix of the unit, B is the strain (geometry) matrix of the unit, D is the constitutive matrix of the unit solid material, ρ0 is the unit physical density of the material, and t is the unit thickness.

[0080] Step 4: Pre-processing to form a finite element model. In order to obtain the overall stiffness matrix K and the mass matrix M, first convert the local unit stiffness matrix k e and the local element mass matrix me Transformed into the global element stiffness matrix K e and the global mass matrix M e , and finally K e and M e The K and M of the structure are obtained by grouping. Therefore, based on the SIMP interpolation model, K and M can be expressed as:

[0081]

[0082] In the formula, E min and E0 represent the preset Young's modulus of the empty cell and the Young's modulus of the solid material, respectively. K expresses the design variable of the i-th unit, with a value of (0,1], p1 and p2 represent the penalty factors of the two models for the intermediate density material. In order to ensure that the intermediate density unit can converge to the 0 / 1 solution well, p1 = 3 and p2 = 1 are usually taken. s Represents the global stiffness matrix for a spring of known stiffness s.

[0083] Step 5: Define the objective function and constraints to quantitatively evaluate the performance of different topologies. The objective and constraint functions use the finite element method as the mechanism analysis theory and are optimized through optimization theory. The goal of topology optimization is usually to make the structure have the best performance while satisfying the constraints, for example:

[0084]

[0085] In the formula, and * They represent the maximum allowable output and input coupling constraint indicators, σ * represents the global maximum stress constraint index;

[0086] Step 6: Solve the stability problem through density transition theory. The final optimized topology is extracted from the optimization results through corresponding filtering techniques to obtain the actual processing design. This step ensures that the final topology meets the requirements of manufacturing and practical applications. The goal of this process is to automatically find the best structural topology by optimizing the design variables to meet the given performance indicators and constraints.

[0087] Step 7: MMA optimization algorithm;

[0088] Step 8: Determine whether the optimization process converges, otherwise repeat the finite element analysis, update the material density, density filtering and MMA optimization algorithm until the convergence conditions of the objective function and constraint function are met;

[0089] Step 9: Output the optimal result; after convergence, output the optimal material distribution and structural topology layout, including the optimal material density, structural geometry and response results.

[0090] The above is a topology optimization design layout optimization process based on the SIMP method to build a mathematical model for topology optimization of a dual-axis micro-nano manipulator. This process involves defining the initial design domain and boundary conditions, determining the finite element mesh and unit type, determining material properties, performing finite element analysis, calculating stiffness and mass matrices, defining objective functions and constraints, updating material density, applying density filtering, using the MMA optimization algorithm for topology optimization, performing convergence testing and iterative optimization, and finally outputting the optimal result. Through the above process, the dual-axis micro-nano manipulator of the present invention can be effectively designed, see Figure 4 shown.

[0091] See also Figure 3 As shown, the present invention provides deformation density diagrams of plane motion in x- and y-directions, which is used to prove that the plane motion in x- and y-directions has a decoupling effect. It can be seen from the figure that the deformation of the output end is related to the driving direction and does not cause disturbances in other directions. At the same time, it also proves the correctness of the motion coupling model design theory.

[0092] See also Figure 4 and Figure 1 As shown, two-dimensional and three-dimensional images of the piezoelectrically actuated dual-axis micro-nano manipulator are given respectively.

[0093] Finally, the present invention shows through the Lissajous diagram that the output end can realize complex motion, wherein if A1=20, A2=20, and f1=10, f2=9.5 harmonic superposition signals are selected as the drive of the two axes, the two-sine formula can be used when the two axes move simultaneously:

[0094]

[0095] See Figure 7 As shown in the figure, it is a Lissajous figure synthesized by two sinusoidal signals. In the process of realizing two-axis driving, the output end can generate corresponding motion trajectories. Therefore, when the piezoelectric is stimulated by different signals, different related signals can be generated.

[0096] In the above technical solution, the finite element analysis method and the flexible mechanism design theory are combined to give full play to the advantages of the topology optimization method in structural optimization, and a piezoelectrically actuated two-axis micro-nano manipulator with completely decoupled motion is designed. The introduction of the topology optimization method effectively solves the performance bottleneck caused by the coupling relationship in the flexible mechanism, and realizes motion decoupling, stiffness enhancement and dynamic performance improvement through global optimization of the structure. The present invention not only overcomes the limitations of traditional design methods and provides a new solution for micro-nano manipulators, but also provides important theoretical references and technical guidance for the topology optimization design of medical devices, precision engineering and flexible mechanisms.

[0097] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments including components are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A piezoelectrically actuated biaxial micro-nano manipulator for medical devices, characterized in that: The invention comprises a flexible driving frame (1), a driving mechanism and a mounting base (3); the mounting base (3) is in an inverted L-shaped structure; the driving mechanism is mounted on the mounting base (3); the output end of the driving mechanism is connected to the flexible driving frame (1); the flexible driving frame (1) comprises an integrally formed driving platform (102), a y-axial support member (103) and an x-axial connecting member (104); the cross section of the driving platform (102) is in an inverted triangle structure; the y-axial support member (103) is in an inverted triangle structure; The cross-section is a lanceolate leaf-like structure, one end of the three x-axial connecting members (104) are connected to each other, and the other ends of the three x-axial connecting members (104) are respectively connected to the driving platform (102), the y-axial supporting member (103) and the mounting base (3), the power of the driving mechanism is output to one end of the three x-axial connecting members (104) and the bottom of the y-axial supporting member (103), and the top of the y-axial supporting member (103) is connected to the bottom of the driving platform (102).

2. The piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to claim 1, characterized in that: The mounting base (3) comprises a base body (301), the base body (301) is an inverted L-shaped structure, and a first mounting platform (303), a first connecting platform (304), a second connecting platform (305) and a second mounting platform (306) are integrally formed on the base body (301), and the first mounting platform (303), the first connecting platform (304), the second connecting platform (305) and the second mounting platform (306) are arranged in a stepped manner from top to bottom.

3. The piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to claim 2, characterized in that: The driving mechanism comprises an x-axial piezoelectric actuator (5) and a y-axial piezoelectric actuator (2), wherein the x-axial piezoelectric actuator (5) and the y-axial piezoelectric actuator (2) are respectively mounted on a first mounting platform (303) and a second mounting platform (306), wherein the power of the x-axial piezoelectric actuator (5) is output to the connecting ends of three x-axial connecting members (104), and the power of the y-axial piezoelectric actuator (2) is output to the bottom of the y-axial supporting member (103).

4. The piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to claim 3, characterized in that: The connection ends of the three x-axial connecting members (104) are fixedly connected to an x-axial connecting portion (101), the x-axial connecting portion (101) is in a rectangular structure, and the power output end of the x-axial piezoelectric actuator (5) is fixedly connected to one side of the x-axial connecting portion (101).

5. The piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to claim 3, characterized in that: The bottom of the y-axial support member (103) is fixedly connected to a y-axial connecting portion (106), and the power output end of the y-axial piezoelectric actuator (2) is fixedly connected to the bottom side of the y-axial connecting portion (106).

6. The piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to claim 4, characterized in that: A longitudinal flexible hinge (4) is provided between the x-axial connecting portion (101) and the first connecting platform (305), and the longitudinal flexible hinge (4) comprises a plurality of flexible vertical plates arranged in parallel, the flexible vertical plates are integrally formed with the x-axial connecting portion (101), and the flexible vertical plates are fixedly connected to the horizontal surface of the first connecting platform (305).

7. The piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to claim 5, characterized in that: A transverse flexible hinge (6) is provided between the y-axial connecting portion (106) and the second connecting platform (306), and the transverse flexible hinge (6) comprises a plurality of flexible transverse plates arranged in parallel, one end of the flexible vertical plate is integrally formed with the y-axial connecting portion (106), and the other end of the flexible vertical plate is fixedly connected to the side wall of the second connecting platform (306).

8. The piezoelectrically actuated dual-axis micro-nano manipulator for medical devices according to claim 1, characterized in that: The other end of the uppermost x-axial connecting member (104) is fixedly connected to the corner end of the driving platform (102), the other end of the middle x-axial connecting member (104) is fixedly connected to the middle position of one side of the y-axial supporting member (103), and the other end of the lowermost x-axial connecting member (104) is fixedly connected to the first connecting platform (304).

9. The piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to claim 1, characterized in that: The driving platform (102) and the y-axial support member (103) are both provided with a plurality of hollow holes (105).

10. The piezoelectrically actuated dual-axis micro-nano manipulator for medical devices according to claim 1, characterized in that: The mounting base (3) is provided with a plurality of threaded holes (302).

11. A topology optimization method for a piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to any one of claims 1 to 10, characterized in that: The steps include: Step 1: Define the FTS mechanism optimization problem, which is expressed as follows: KU=F;(K-λ m M)·Φ m =0 i=1,2,…,n; j=1,2,…,n; i≠j In the formula, represents the set of design variables, n represents the total number of unit design variables, V represents the material usage volume, V * represents the upper limit of the material volume; U represents the global displacement matrix caused by the external load vector F of the node, K and M are the global stiffness matrix and the global structural mass matrix respectively, Φ m is the mth-order eigenvalue λ m The associated eigenvector; Step 2: Define the initial design domain and boundary conditions; Step 3: Determine the finite element mesh, define the element type and establish the element stiffness and mass model. Therefore, the element stiffness matrix k e and the mass matrix m e The models can be expressed as: k e =t∫∫B T DBdxdy m e =ρ0t∫∫N T Ndxdy Where N represents the shape function matrix of the unit, B represents the strain (geometry) matrix of the unit, D represents the constitutive matrix of the unit entity material, ρ0 is the unit physical density of the material, and t represents the unit thickness; Step 4: Pre-processing to form a finite element model; Step 5: Define the objective function and constraints; v i，j ≤c * ;s max ≤σ * and v * They represent the maximum allowable output and input coupling constraint indicators, σ * represents the global maximum stress constraint index; Step 6: Solve the stability problem through density transition theory; Step 7: MMA optimization algorithm; Step 8: Determine whether the optimization process converges, otherwise repeat the finite element analysis, update the material density, density filtering and MMA optimization algorithm until the convergence conditions of the objective function and constraint function are met; Step 9: Output the optimal result; after convergence, output the optimal material distribution and structural topology layout, including the optimal material density, structural geometry and response results.

12. The topology optimization method for a piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to claim 11, characterized in that: In step 2, the initial design domain includes determining the optimized geometry and size, and the boundary conditions include input drive, output demand and fixed nodes.

13. The topology optimization method for a piezoelectrically actuated biaxial micro-nano manipulator for medical devices according to claim 11, characterized in that: In step 4, the pre-processing method is: in order to obtain the overall stiffness matrix K and the mass matrix M, firstly transform the local unit stiffness matrix k e and the local element mass matrix m e Transformed into the global element stiffness matrix K e and the global mass matrix M e , and finally K e and M e The K and M of the structure are obtained by grouping. Therefore, based on the SIMP interpolation model, K and M can be expressed as: In the formula, E min and E0 represent the preset Young's modulus of the empty cell and the Young's modulus of the solid material, respectively. expresses the design variable of the i-th unit, p1 and p2 represent the penalty factors of the two models for the intermediate density material, K s Represents the global stiffness matrix for a spring of known stiffness s.

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