Structural design method of flexible special-shaped catheter robot, program product and flexible special-shaped catheter robot

Abstract

The invention discloses a structural design method of a flexible special-shaped conduit robot, a program product and the flexible special-shaped conduit robot, and aims to provide an efficient solution for special-shaped design of a conduit robot structure through a topological optimization design method. The structural design method comprises the steps of conduit robot modeling and initial gridding, establishing a mathematical expression of topological optimization, solving a mathematical model according to a specific optimization algorithm and further optimizing design until convergence, outputting and optimizing a pseudo-density matrix or vector at the current moment, and the like. According to the method, the topological optimization design thought is introduced into the design of the conduit robot, and the flexibility and economic benefits of the conduit robot are improved by designing the grid holes of the conduit robot.

Description

Technical Field

[0001] The present invention relates to the technical field of medical device design, and more specifically, to a structural design method, a program product and a flexible special-shaped catheter robot. Background Art

[0002] Medical catheter robots have significant advantages in improving surgical accuracy and safety, reducing doctors' workload, improving surgical efficiency, improving patient experience, and promoting innovation and development of medical technology. Taking transcatheter mitral valve edge-to-edge repair (TEER) as an example, traditional instruments are complex to operate, inefficient, and rely on the cooperation of multiple people in this process. Catheter robots fully consider medical purposes and treatment efficiency and are advanced tools in clinical practice.

[0003] The surgical catheter robot should meet the deformation requirements of the treatment while minimizing the trauma to the patient, and at the same time be as lightweight as possible to avoid bringing additional burden to the patient. Generally, the maximum bending angle of the catheter should be greater than 150°, and the operating accuracy should be less than 5°; the catheter delivery range is wide and the precision requirements are high, usually requiring a delivery range of 0~800mm and an operating accuracy of less than 1mm. Traditional catheter robots are dense and thin-walled, and they are versatile. However, in the face of different surgical working environments, it is necessary to use efficient methods to design a catheter robot structure that better matches it.

[0004] For example, transcatheter mitral valve edge-to-edge repair (TEER) requires the catheter robot to achieve functions such as flattening and large-scale expansion. The catheter robot can be designed in the form of a multi-rigidity grid to achieve the above functions: designing grid holes of different sizes on the originally dense material can not only improve the performance of the catheter robot, but also save materials and achieve economic growth: the existence of grid holes reduces the rigidity of the raw material, making it more flexible and able to accommodate multi-dimensional bending; at the same time, the grid holes allow the release of material deformation to avoid plastic deformation or damage to the flexible robot. At present, there is no method for the special-shaped design of catheter robots with the pass condition as the optimization target. Summary of the invention

[0005] Due to the problems existing in the prior art, the present invention proposes a structural design method, a program product and a flexible special-shaped catheter robot, aiming to provide an efficient solution for the special-shaped design of the catheter robot structure through a topological optimization design method. This method can generate matching design tasks according to the working environment of the catheter robot, so that the designed catheter robot has better service performance.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a structural design method for a flexible special-shaped catheter robot, comprising:

[0007] Step S1: Establish a virtual model of the catheter robot to be designed and realize the initial meshing of the model; mark the model meshes and assign values ​​one by one , ,…… ; is the pseudo-density at the i-th grid, and its value indicates the presence or absence of material at the grid;

[0008] Step S2, establish mathematical expression of topology optimization: mathematically abstract the use requirements of the catheter robot, clarify the extreme application scenarios of the catheter robot, determine the form, size and position of the external force it is subjected to; determine the extreme strain energy of the manufacturing material of the catheter robot ;

[0009] A mathematical description model of structural design is established, and the mathematical description is given as follows:

[0010] find: , ,……

[0011] Optimization goal: min:

[0012] st

[0013] Where X is a vector of pseudo-densities; the optimization goal is to minimize ,in, Indicates The multi-directional strain vector at each element, Indicates The element elastic (stiffness) matrix at each element, For the reduction of this term, their product represents the stress-deformation process. The density of strain energy generated at each unit; the requirements for achieving the optimization goal are: / η, η is the safety factor, is the ultimate strain energy density of the material; at the same time, combined with the maximum strain of the material in the usage scenario Put forward constraints, not greater than the maximum allowable value ; is the stiffness of the material at any position in the specified direction, Represents the material unit stiffness when no mesh design is used; through the statics formula Solution , and then get the unit vector ; V represents the total amount of material required when the catheter robot does not use grid design, and V0 represents the material consumption of a single grid when the model grid is designed;

[0014] Step S3, solving and post-processing: using an optimization algorithm to solve the mathematical description model of step S3, and obtaining , and refer to Optimize the design according to different optimization algorithms until convergence;

[0015] Step S4: output the optimized pseudo density vector at the current moment.

[0016] In some embodiments of the first aspect of the present application, in step S3, the optimization algorithm includes but is not limited to one or more of a genetic algorithm, an annealing algorithm, a particle swarm algorithm, a moving asymptote method (MMA) algorithm, and a global convergent moving asymptote method (GCMMA) algorithm.

[0017] In some embodiments of the first aspect of the present application, in step S3, for each individual, a finite element simulation calculation is performed based on a pseudo-density vector and a known force condition, the strain condition of each unit is solved, and the strain energy at each unit position is calculated; the optimization algorithm described in step S3 is implemented with strain energy as the optimization index. During the iteration process of the optimization algorithm, when all grids have met the requirement that the strain energy does not exceed the limit, the iteration conditions are compared and selected. If it is found that: after the iteration reaches a certain generation, the optimization result converges, then the optimization design is executed, otherwise the inverse of the value is used as the fitness, input and the solution step is executed.

[0018] In some embodiments of the first aspect of the present application, the basic method of step S3 includes the following steps:

[0019] Step S31: Randomly Take samples;

[0020] Step S32: Solve complex situations through finite element analysis ,calculate , merge check The size of and the convergence of the calculation results;

[0021] Step S33: If convergence occurs, the calculation is terminated and output is ;

[0022] Step S34, otherwise, refer to The optimization design is performed according to different optimization algorithms until convergence.

[0023] In some embodiments of the first aspect of the present application, the post-processing process comprises the following steps:

[0024] Step S51, using the volume-preserving Heaviside filtering method to filter the design variables to obtain a filtered density value;

[0025] Step S52: updating the physical density according to the filtered density value for subsequent finite element analysis and calculation of objective function, constraint function and sensitivity;

[0026] Step S53: Use the optimization algorithm to update the design variables, and repeat steps S51 and S52 until the convergence condition is met.

[0027] In some embodiments of the first aspect of the present application, the Heaviside filtering gives a Heaviside function as follows:

[0028]

[0029] in, is the threshold value, Variables to be optimized; To avoid the instability of the iteration process caused by the drastic change of volume fraction before and after filtration, the optimization can be calculated The value of is used to maintain the volume fraction before and after optimization, and the optimization objective is introduced as follows:

[0030]

[0031] The parameters that satisfy the volume invariance requirement can be obtained .

[0032] In some embodiments of the first aspect of the present application, the parameter Relax the Heaviside function to a continuous function:

[0033]

[0034] and Different values ​​of will affect the situation of the Heaviside function; When , the Heaviside function loses its effect; The larger it is, the closer its effect is to the original Heaviside step function.

[0035] In the second aspect, the present invention provides a flexible special-shaped catheter robot, whose grid structure design adopts the structural design method of the flexible special-shaped catheter robot as described above, and the output pseudo-density value represents the presence or absence of material at the grid; the design calculation results are input into the manufacturing equipment to manufacture the flexible special-shaped catheter robot.

[0036] In some embodiments of the second aspect of the present application, the manufacturing equipment is additive manufacturing or 3D printing equipment.

[0037] In a third aspect, the present invention provides a computer program product for the structural design of a flexible special-shaped catheter robot; when the computer program product runs on a computer or device, the computer or device executes the structural design method of the flexible special-shaped catheter robot as described above.

[0038] Compared with the prior art, the present invention has the following technical effects:

[0039] 1. The present invention introduces the concept of topological optimization design into the design of the catheter robot, and improves its flexibility and economic benefits by designing the grid holes of the catheter robot.

[0040] 2. The structural design method of the present invention takes the ultimate strain energy density as the optimization target and specifies a simple replacement condition for the practical demand of "continuous passive deformation of materials". Therefore, it has the advantage of allowing special-shaped designs to be realized according to specific tasks and using different materials.

[0041] 3. The structural design method of the present invention and the additive manufacturing technology can be an upstream and downstream relationship, and can give full play to the technical advantages of both. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The figure is a flow chart of structural design of a catheter robot in one embodiment of the present invention.

[0043] Figure 2 This is a structural diagram of the flattened state of a multi-dimensional expandable structure of a multi-stiffness grid in one embodiment of the present invention.

[0044] Figure 3 Schematic diagram of the Heaviside function in one embodiment of the present invention. DETAILED DESCRIPTION

[0045] In the following detailed description, many specific details are set forth to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that well-known algorithms are not shown in detail to avoid obscuring the subject matter of the present invention.

[0046] In addition, the order of execution of actions, steps, etc. in the devices and methods shown in the claims, specifications and drawings can be implemented in any order as long as there is no special explicit limitation on the order and the output of the previous processing is not used in the subsequent processing.

[0047] In order to meet the needs of different surgical environments, the present invention proposes a topology optimization method for realizing the special-shaped design of a flexible catheter robot. The technical solution of the present invention is as follows:

[0048] (1) Preprocessing, mainly including the following steps:

[0049] a. Discretization of design space and clarification of application scenarios: Establish a virtual model of the thin-walled catheter robot to be designed and determine the envelope geometry required to complete its function. This is the design process of a traditional catheter robot.

[0050] b. Determine the minimum design resolution that can be used for special-shaped design, that is, the mesh size in manufacturing, based on the minimum resolution of the additive manufacturing method and actual needs;

[0051] c. Draw a hexagonal grid on the surface of the virtual model designed in a. according to the grid size. Mark the n grids drawn and assign values ​​to them one by one. , ,…… . is called the pseudo density at the i-th grid, and takes a value of 0 or 1, which is the optimization variable in the present invention. When the value is 0 or 1, It has a clear physical meaning, which indicates the presence or absence of material at the grid: Indicates that there is material at this grid. Indicates that the grid is a grid hole. According to certain principles, when the value is 0 or 1, it means that the original dense catheter robot is designed to have a grid form. At this time, the optimization variable is discontinuous, and it is difficult to derive it, and then conveniently achieve optimization. Therefore, the restriction condition is relaxed as follows: To ensure the optimization results, As close to 0 or 1 as possible without causing design ambiguity, the present invention introduces the Heaviside filtering method in the iterative process of the optimization algorithm and the post-processing step to achieve this.

[0052] d. The purpose of the present invention is to realize the special-shaped design of the catheter robot structure to meet different usage requirements. In order to ensure that the form of the designed hole meets this requirement, the usage requirements should be mathematically abstracted in this step. For example, transcatheter mitral valve edge-to-edge repair (TEER) requires the catheter robot to achieve functions such as flattening and large-scale expansion. This requires that the local maximum strain energy of the catheter robot does not exceed the limit strain energy of the material used. Once exceeded, it means that the material fails and is damaged.

[0053] e. Clarify the extreme application scenarios of the catheter robot, determine the form, magnitude, and location of the external forces it is subjected to; determine the extreme strain energy of the catheter robot manufacturing material .

[0054] (2) Establish a mathematical description model and give the following mathematical description:

[0055] find: , ,……

[0056] Optimization goal: min:

[0057] st

[0058] Where X is a vector of optimization variables (pseudo-densities) as described above; the optimization goal is to minimize .in, Indicates The multi-directional strain vector at each element, Indicates The element elastic (stiffness) matrix at each element, Used to reduce this term. Their product represents the process of force deformation. The optimization goal is to minimize the maximum strain energy in the design domain, while requiring / η, η is the safety factor, It is the ultimate strain energy density of the material. It is generally believed that when the strain energy of the material approaches this value, the material has been damaged in the usage scenario and cannot achieve passive continuous deformation. To impose constraints on the strain energy is to achieve continuous passive deformation of the material; at the same time, the maximum strain of the material should be combined with the usage scenario. Put forward constraints, which should not be greater than the maximum allowable value ; can be based on the formula Obtain the stiffness in the specified direction at the corresponding position, where represents the element stiffness value when there is no gap, Used to avoid matrix singularity. After knowing the usage scenario and force conditions, the statics formula can be used Solution , and then query to get the unit vector . Consider the value This is also to avoid the singularity of the matrix.

[0059] (3) Solution and post-processing

[0060] a. For the optimization problem in (2), a variety of algorithms can be used to solve it, including but not limited to genetic algorithm, annealing algorithm, particle swarm algorithm, MMA algorithm, GCMMA algorithm, etc. The basic method is:

[0061] a.1 Randomly Take samples;

[0062] a.2 Solving complex situations through finite element analysis ,calculate , merge check The size of and the convergence of the calculation results;

[0063] a.3 If convergence occurs, the calculation terminates and the output is ;

[0064] a.4 Otherwise, refer to The optimization design is performed according to different optimization algorithms until convergence.

[0065] b. As mentioned above, When the value of is 0 or 1, the meaning is clear. However, in the description of the present invention, The value of can be any value between 0 and 1, so it is necessary to post-process the optimization result according to the accuracy requirements and manufacturing requirements to avoid result oscillation and falling into the local optimal solution. For example, in part of the design domain, a filter is used to perform filtering operations, the output result is used as the design result in the area, and the mean value of x in the area is used to determine the final value of the pseudo-density here. The present invention uses the volume-preserving Heaviside filtering method to achieve this process.

[0066] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0067] Example 1

[0068] See also Figure 1 In this embodiment, Figure 2 Taking the multi-dimensional deployable design of the multi-stiffness grid shown in the figure as an example, a structural design method of a flexible special-shaped catheter robot is provided, comprising the following steps:

[0069] Step S1: Establish a virtual model of the catheter robot to be designed and realize the initial meshing of the model; mark the model meshes and assign values ​​one by one , ,…… ; is the pseudo density at the ith grid, and its value indicates whether there is material at the grid. As an example, the catheter robot is used for transcatheter mitral valve edge-to-edge repair, and its geometric dimensions are preliminarily calibrated to determine that the minimum size of the design unit grid is 0.1 mm.

[0070] Step S2, using the maximum strain energy as the optimization index, establish the mathematical description of topological optimization as described above. Specifically, mathematically abstract the use requirements of the catheter robot, clarify the extreme application scenarios of the catheter robot, determine the form, size, and position of the external force it is subjected to; determine the extreme strain energy of the catheter robot manufacturing material ;

[0071] A mathematical description model of structural design is established, and the mathematical description is given as follows:

[0072] find: , ,……

[0073] Optimization goal: min:

[0074] st

[0075] Where X is a vector of pseudo-densities; the optimization goal is to minimize ,in, Indicates The multi-directional strain vector at each element, Indicates The element elastic (stiffness) matrix at each element, For the reduction of this term, their product represents the stress-deformation process. The density of strain energy generated at each unit; the requirements for achieving the optimization goal are: / η, η is the safety factor, is the ultimate strain energy density of the material; at the same time, combined with the maximum strain of the material in the usage scenario Put forward constraints, not greater than the maximum allowable value ; is the stiffness of the material at any position in the specified direction, Represents the material unit stiffness when no mesh design is used; through the statics formula Solution , and then get the unit vector ; V represents the total amount of material required when the catheter robot does not adopt mesh design, and V0 represents the material consumption of a single mesh when the model mesh is designed.

[0076] Step S3, solving and post-processing: using an optimization algorithm to solve the mathematical description model of step S3, and obtaining , and refer to Optimize the design according to different optimization algorithms until convergence. More specifically, common methods include MMA, GCMMA and other algorithms. Similar algorithms require the derivation of the original equation to solve the sensitivity. Taking into account some specific application scenarios or the difficulty in solving the sensitivity of the objective function to the optimization variable, a more general genetic algorithm is used in this example to solve this problem: set the maximum number of iterations of the population to 50 generations, 200 individuals per generation, and initialize the randomly generated gene vector and the corresponding pseudo-density vector for each individual for the first execution. The pseudo-density vector X can be initialized as a random sample between 0-1, execute the next step, check whether the result converges, and end the loop if it converges; otherwise, according to the comfort level, implement the generation, exchange, and mutation operations of the genetic algorithm, with the probability set to 0.5%, and then execute the next step;

[0077] For each individual, finite element simulation calculation is performed based on the pseudo-density vector and the known stress conditions, the strain conditions of each unit are solved, and the strain energy at each unit position is calculated; the optimization algorithm described in step S3 is implemented with strain energy as the optimization index; in the iterative process of the optimization algorithm, when all grids have met the requirement that the strain energy does not exceed the limit, the iterative conditions are compared and selected, and if it is found that: after a certain generation of iteration, the optimization result converges, post-processing is performed, otherwise the inverse of the value is used as the fitness, input and the solution is performed.

[0078] The following supplements are made to the above loop:

[0079] (1) Application of filtering: Use the volume-preserving Heaviside filtering method to filter the design variables and obtain the filtered density value. The Heaviside function is given as follows:

[0080]

[0081] in, is the threshold value, To avoid the instability of the iteration process caused by the drastic change of volume fraction before and after filtration, the optimization can be calculated. The value of is used to maintain the volume fraction before and after optimization, and the optimization objective is introduced as follows:

[0082]

[0083] The parameters that satisfy the volume invariance requirement can be obtained The Heaviside filter method given here is not continuous. In order to capture as many possibilities as possible in the initial stage of optimization and avoid falling into the local optimal solution, the parameter Relax the Heaviside function to a continuous function.

[0084]

[0085] and Different values ​​of will affect the situation of the Heaviside function. Figure 3 This effect is shown. It can be seen that When , the Heaviside function loses its effect; The larger it is, the closer it is to the original Heaviside step function. It can meet the task requirements.

[0086] (2) Update physical density: Update the physical density according to the filtered density value for subsequent finite element analysis and calculation of objective function, constraint function and sensitivity.

[0087] (3) Optimization iteration: Use the optimization algorithm to update the design variables and repeat the above steps until the convergence conditions are met.

[0088] The above Heaviside function is used in the iterative process of the optimization algorithm and in the post-processing step for final processing to give the optimization result.

[0089] The purpose of using the Heaviside function is to avoid designing grids and avoiding designs that do not meet processing conditions. The Heaviside function is used in two places in the solution and post-processing algorithm of this embodiment:

[0090] 1. During the optimization iteration, the results after each iteration must be processed using the Heaviside function to avoid error accumulation;

[0091] 2. In post-processing, use the Heaviside function to avoid over-gridding of the design results.

[0092] Step S4: Output the optimized pseudo-density matrix or vector at the current moment. More specifically, all meshes with a pseudo-density of 0 are mesh holes, and all meshes with a pseudo-density of 1 are solid materials. The calculation results can be applied to additive design.

[0093] Example 2

[0094] This embodiment provides a flexible special-shaped catheter robot, whose grid structure design adopts the structural design method of the flexible special-shaped catheter robot as described in Example 1, and the output pseudo-density value indicates the presence or absence of material at the grid; the design calculation result is input into a manufacturing device to manufacture the flexible special-shaped catheter robot. The manufacturing device is preferably an additive manufacturing or 3D printing device.

[0095] The structural design method of the above-mentioned flexible special-shaped catheter robot can be embodied in the form of a computer program product or a software functional unit. If the structural design method of the above-mentioned flexible special-shaped catheter robot is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Therefore, the essence of this technical solution or the part that contributes to the prior art or the part of this technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for an electronic system (which can be a personal computer, a server, or a network system, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0096] Those skilled in the art will appreciate that the units, i.e., algorithm steps, of the various examples described in conjunction with this embodiment can be implemented in electronic hardware or in a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0097] In summary, the present invention provides a structural design method, a program product and a flexible special-shaped catheter robot, aiming to provide an efficient solution for the special-shaped design of the catheter robot structure through a topological optimization design method. The structural design method includes the steps of modeling and initial meshing of the catheter robot, establishing a mathematical expression of topological optimization, solving the mathematical model according to a specific optimization algorithm and further optimizing the design until convergence, and outputting the pseudo-density matrix or vector at the current moment. The present invention introduces the concept of topological optimization design into the design of the catheter robot, and improves its flexibility and economic benefits by designing the mesh holes of the catheter robot.

[0098] Those skilled in the art should understand that those skilled in the art can implement variations by combining the prior art and the above embodiments, which will not be described in detail here. Such variations do not affect the essential content of the present invention, and will not be described in detail here.

[0099] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the systems and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A structural design method for a flexible special-shaped catheter robot, characterized in that: include: Step S1, establishing a virtual model of the catheter robot to be designed and realizing initial meshing of the model; Mark the model grids separately and assign values ​​one by one , ,…… ; is the pseudo-density at the i-th grid, and its value indicates the presence or absence of material at the grid; Step S2, establish mathematical expression of topology optimization: mathematically abstract the use requirements of the catheter robot, clarify the extreme application scenarios of the catheter robot, determine the form, size and position of the external force it is subjected to; determine the extreme strain energy of the manufacturing material of the catheter robot ; A mathematical description model of structural design is established, and the mathematical description is given as follows: find: 、 、…… Optimization goal: min: s.t. Where X is a vector of pseudo-densities; the optimization goal is to minimize ,in, Indicates The multi-directional strain vector at each element, Indicates The element elastic (stiffness) matrix at each element, For the reduction of this term, their product represents the stress-deformation process. The density of strain energy generated at each unit; the requirements for achieving the optimization goal are: / η, η is the safety factor, is the ultimate strain energy density of the material; at the same time, combined with the maximum strain of the material in the usage scenario Put forward constraints, not greater than the maximum allowable value ; is the stiffness of the material at any position in the specified direction, Represents the material unit stiffness when no mesh design is used; through the statics formula Solution , and then get the unit vector ; V represents the total amount of material required when the catheter robot does not use grid design, and V0 represents the material consumption of a single grid when the model grid is designed; Step S3, solving and post-processing: using an optimization algorithm to solve the mathematical description model of step S3, and obtaining , and refer to Optimize the design according to different optimization algorithms until convergence; Step S4: output the optimized pseudo density vector at the current moment.

2. The structural design method of the flexible special-shaped catheter robot according to claim 1, characterized in that: In step S3, the optimization algorithm includes but is not limited to one or more of a genetic algorithm, an annealing algorithm, a particle swarm algorithm, a moving asymptote method (MMA) algorithm, and a global convergent moving asymptote method (GCMMA) algorithm.

3. The structural design method of the flexible special-shaped catheter robot according to claim 1 or 2, characterized in that: In step S3, for each individual, finite element simulation calculation is performed based on the pseudo-density vector and the known force conditions, the strain conditions of each unit are solved, and the strain energy at each unit position is calculated; the optimization algorithm described in step S3 is implemented with strain energy as the optimization index; in the iterative process of the optimization algorithm, when all grids have met the requirement that the strain energy does not exceed the limit, the iterative conditions are compared, and if it is found that: after a certain generation of iteration, the optimization result converges, the optimization design is executed, otherwise the inverse of the value is used as the fitness, input and the solution step is executed.

4. The structural design method of the flexible special-shaped catheter robot according to claim 3 is characterized in that: The basic method of step S3 comprises the following steps: Step S31: Randomly Conduct sampling; Step S32: Solve complex situations through finite element analysis ,calculate , merge check The size of and the convergence of the calculation results; Step S33: If convergence occurs, the calculation is terminated and output is ; Step S34, otherwise, refer to The optimization design is performed according to different optimization algorithms until convergence.

5. The structural design method of the flexible special-shaped catheter robot according to claim 3, characterized in that: The post-processing process comprises the following steps: Step S51, using the volume-preserving Heaviside filtering method to filter the design variables to obtain a filtered density value; Step S52: updating the physical density according to the filtered density value for subsequent finite element analysis and calculation of objective function, constraint function and sensitivity; Step S53: Use the optimization algorithm to update the design variables, and repeat steps S51 and S52 until the convergence condition is met.

6. The structural design method of the flexible special-shaped catheter robot according to claim 5, characterized in that: The Heaviside filter gives the Heaviside function as follows: in, is the threshold value, Variables to be optimized; To avoid the instability of the iteration process caused by the drastic change of volume fraction before and after filtration, the optimization can be calculated The value of is used to maintain the volume fraction before and after optimization, and the optimization objective is introduced as follows: The parameters that satisfy the volume invariance requirement can be obtained .

7. The structural design method of the flexible special-shaped catheter robot according to claim 6, characterized in that: Introducing parameters Relax the Heaviside function to a continuous function: and Different values ​​of will affect the situation of the Heaviside function; When , the Heaviside function loses its effect; The larger it is, the closer its effect is to the original Heaviside step function.

8. A flexible special-shaped catheter robot, characterized in that: The grid structure design adopts the structural design method of the flexible special-shaped catheter robot as described in any one of claims 1 to 7, and the output pseudo-density value represents the presence or absence of material at the grid; the design calculation results are input into the manufacturing equipment to manufacture the flexible special-shaped catheter robot.

9. The flexible special-shaped catheter robot according to claim 8, characterized in that: The manufacturing equipment is additive manufacturing or 3D printing equipment.

10. A computer program product, characterized in that Used for the structural design of a flexible special-shaped catheter robot; when the computer program product runs on a computer or device, the computer or device executes the structural design method of a flexible special-shaped catheter robot as described in any one of claims 1 to 7.

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