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

Abstract

This invention discloses a structural design method, program product, and flexible, special-shaped catheter robot. The goal is to provide an efficient solution for the special-shaped design of catheter robot structures through topology optimization. The structural design method includes modeling and initial meshing the catheter robot, establishing a mathematical representation of topology optimization, solving the mathematical model using a specific optimization algorithm, further optimizing the design until convergence, and outputting the optimized pseudo-density matrix or vector at the current moment. This invention incorporates topology optimization design concepts into the design of the catheter robot, enhancing its flexibility and cost-effectiveness by designing mesh holes in the catheter robot.

Description

Technical Field

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

[0002] Medical catheter robotics offer significant advantages in improving surgical precision and safety, reducing physician workload, enhancing surgical efficiency, improving the patient experience, and driving innovation and development in medical technology. For example, transcatheter mitral valve edge-to-edge repair (TEER) is a procedure in which traditional instruments are complex, inefficient, and rely on the coordinated efforts of multiple personnel. Catheter robotics, which fully consider both medical objectives and treatment efficiency, are advanced tools in clinical practice.

[0003] Surgical catheter robots should meet the deformation requirements of the treatment while minimizing patient trauma, while also being as lightweight as possible to avoid placing additional burdens on 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 requires high precision, usually requiring a delivery range of 0-800mm and an operating accuracy of less than 1mm. Traditional catheter robots are dense, thin-walled, and versatile. However, in the face of different surgical working environments, it is necessary to use efficient methods to design catheter robot structures that better match them.

[0004] For example, transcatheter mitral valve edge-to-edge repair (TEER) requires a catheter robot to flatten and expand significantly. This can be achieved by designing the catheter robot as a multi-stiffness grid. By incorporating varying grid holes into an otherwise dense material, the robot improves its performance while also saving material and achieving economic benefits. The grid holes reduce the stiffness of the raw material, making it more flexible and accommodating multi-dimensional bending. Furthermore, the grid holes allow for the release of material deformation, preventing plastic deformation or damage to the flexible robot. Currently, there is no method for designing custom-shaped catheter robots based on optimal passage conditions. Summary of the Invention

[0005] To address the challenges of existing technologies, this paper proposes a structural design method, program product, and flexible, custom-shaped catheter robot. These methods aim to provide an efficient solution for custom-shaped catheter robot structures through topology optimization. This method generates matching design tasks based on the catheter robot's operating environment, resulting in a designed catheter robot with improved 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: Create a virtual model of the catheter robot to be designed and implement 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, magnitude, and location of the external force it is subjected to; determine the ultimate strain energy of the catheter robot manufacturing material ;

[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 The multi-directional strain vector at each element, Indicates the The element elastic (stiffness) matrix at each element, For the reduction of this term, their product is represented by 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 Propose constraints, not greater than the maximum allowable value ; is the stiffness of the material at any position in the specified direction, Indicates 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, solution and post-processing: Use optimization algorithm to solve the mathematical description model of step S3 to obtain , 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 optimization 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, a finite element simulation is performed for each individual based on a pseudo-density vector and known stress conditions to solve for the strain condition of each unit and calculate the strain energy at each unit location; the optimization algorithm described in step S3 is implemented using strain energy as the optimization metric. During the iterative process of the optimization algorithm, when all meshes meet the requirement that the strain energy does not exceed the limit, the iterative conditions are compared. If it is found that the optimization results converge after a certain iteration, the optimization design is executed; otherwise, the inverse of this 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 ;

[0022] Step S34, otherwise, refer to Optimize the design according to different optimization algorithms until convergence.

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

[0024] Step S51: Use 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 the 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 provides a Heaviside function as follows:

[0028]

[0029] in, is the threshold, To avoid the instability of the iterative process caused by the drastic change of volume fraction before and after filtration, the optimization 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 calculated .

[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 Heaviside function; When , the Heaviside function loses its effect; The larger it is, the closer it 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 indicates the presence or absence of material at the grid; the design calculation results are input into the manufacturing equipment to produce 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 is run 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. This invention introduces the concept of topological optimization into the design of the catheter robot. By designing the grid holes of the catheter robot, its flexibility and economic benefits are improved.

[0040] 2. The structural design method of the present invention uses the ultimate strain energy density as the optimization target and specifies a simple replacement condition for the practical requirement of "continuous passive deformation of materials". Therefore, it has the advantage of allowing the realization of special-shaped designs based on specific tasks and the use of different materials.

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

[0042] Figure 1 This 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 deployable 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] 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 the design space and identification of application scenarios: A virtual model of the thin-walled catheter robot to be designed is created to determine the envelope geometry required to complete its function. This is the design process for a traditional catheter robot.

[0050] b. Determine the minimum design resolution (i.e., mesh size) that can be used for special-shaped designs based on the minimum resolution of the additive manufacturing method and actual requirements;

[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 corresponding values ​​to them. 、 、…… . 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, that is, it 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 originally dense catheter robot has been designed into a grid form. In this case, the optimization variable is discontinuous, making it difficult to derive it and thus conveniently achieve optimization. Therefore, the constraint condition is relaxed to: To ensure the optimization results, To be 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 this invention is to enable the design of custom-shaped catheter robot structures to meet diverse application requirements. To ensure that the designed hole shape meets these requirements, mathematical abstraction of the application requirements should be performed in this step. For example, transcatheter mitral valve edge-to-edge repair (TEER) requires the catheter robot to achieve flattening and large-scale expansion. This requires that the local maximum strain energy of the catheter robot does not exceed the ultimate strain energy of the material used. Exceeding this limit indicates material failure.

[0053] e. Identify the ultimate application scenarios of the catheter robot and determine the form, magnitude, and location of the external forces it is subjected to; determine the ultimate strain energy of the catheter robot's manufacturing materials. .

[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-density) as described above; the optimization goal is to minimize .in, Indicates the The multi-directional strain vector at each element, Indicates the The element elastic (stiffness) matrix at each element, Used to reduce this item. 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, Is the material's ultimate strain energy density. It is generally believed that before the material's strain energy approaches this value, the material has already been damaged in the usage scenario and cannot achieve passive continuous deformation. Putting constraints on strain energy means achieving 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 in accordance with 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 proposed in (2), a variety of algorithms can be used to solve it, including but not limited to genetic algorithm, annealing algorithm, particle swarm optimization algorithm, MMA algorithm, GCMMA algorithm, etc. The basic method is:

[0061] a.1 Randomly Take samples;

[0062] a.2 Solve 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 Optimize the design according to different optimization algorithms until convergence.

[0065] b. As mentioned above, The meaning is clear when the value of is 0 or 1. However, in the description of the present invention, The value of can be anywhere between 0 and 1, so post-processing of the optimization results is necessary based on accuracy and manufacturing requirements to avoid result fluctuations and local optimal solutions. For example, within a portion of the design domain, a filter can be used to perform filtering operations, with the output used as the design result for that region, and the mean value of x within the region can be used to determine the final value of the pseudo-density. The present invention implements this process using the volume-preserving Heaviside filtering method.

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

[0067] Example 1

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

[0069] Step S1: Create a virtual model of the catheter robot to be designed and implement 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 that grid. As an example, a catheter robot is used for transcatheter mitral valve edge-to-edge repair. Its geometric dimensions are preliminarily calibrated, and the minimum size of the design unit grid is determined to be 0.1 mm.

[0070] Step S2: Using the maximum strain energy as the optimization index, establish the mathematical description of the topology 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 location 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 the 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 The multi-directional strain vector at each element, Indicates the The element elastic (stiffness) matrix at each element, For the reduction of this term, their product is represented by 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 Propose constraints, not greater than the maximum allowable value ; is the stiffness of the material at any position in the specified direction, Indicates 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 material consumption 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, solution and post-processing: Use optimization algorithm to solve the mathematical description model of step S3 to obtain , 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 to a random sample between 0 and 1, and the next step is executed to check whether the result converges. If it converges, the loop ends; otherwise, according to the comfort level, the generation, exchange, and mutation operations of the genetic algorithm are implemented, and the probability is set to 0.5%, and then the next step is executed;

[0077] For each individual, finite element simulation calculations are performed based on the pseudo-density vector and the known stress conditions to solve the strain conditions of each unit and calculate the strain energy at each unit position; the optimization algorithm described in step S3 is implemented with strain energy as the optimization indicator; during 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. 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 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, To avoid the instability of the iterative process caused by the drastic change of volume fraction before and after filtration, the optimization 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 calculated The Heaviside filtering method given here is not continuous. In order to capture as many possibilities as possible in the initial optimization stage while avoiding 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 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 the post-processing step for final processing to give the optimization result.

[0089] The purpose of using the Heaviside function is to avoid design gridding and the appearance of designs that do not meet the 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 of each iteration must be processed with 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. The grid structure design of the flexible, special-shaped catheter robot employs the structural design method for the flexible, special-shaped catheter robot described in Example 1. The output pseudo-density value indicates the presence or absence of material at that grid point. The design calculation results are input into a manufacturing device to produce the flexible, special-shaped catheter robot. The manufacturing device is preferably an additive manufacturing or 3D printing device.

[0095] The structural design method for the flexible, special-shaped catheter robot described above can be embodied in the form of a computer program product or a software functional unit. If the structural design method for the flexible, special-shaped catheter robot described above is implemented as 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 portion that contributes to the prior art, or the portion of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing an electronic system (which can be a personal computer, server, or network system, etc.) to perform all or part of the steps of the method described in various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[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 using electronic hardware or 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. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0097] In summary, the present invention provides a structural design method, program product, and flexible, special-shaped catheter robot for a flexible, special-shaped catheter robot. These methods aim to provide an efficient solution for the special-shaped design of catheter robot structures through a topology optimization design approach. The structural design method includes modeling and initial meshing the catheter robot, establishing a mathematical representation for topology optimization, solving the mathematical model according to a specific optimization algorithm, further optimizing the design until convergence, and outputting the optimized pseudo-density matrix or vector at the current moment. This invention incorporates topology optimization design concepts into the design of the catheter robot, enhancing its flexibility and cost-effectiveness by designing mesh holes within the catheter robot.

[0098] Those skilled in the art should understand that they can implement variations by combining the prior art with the above embodiments, which will not be described in detail here. Such variations do not affect the essence 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-mentioned 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 that do not depart 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 performing 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, magnitude, and location of the external force it is subjected to; determine the ultimate strain energy of the catheter robot manufacturing material ; 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 The multi-directional strain vector at each element, Indicates the The element elastic / stiffness matrix at each element, For the reduction of this term, their product is represented by 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 Propose constraints, not greater than the maximum allowable value ; is the stiffness of the material at any position in the specified direction, Indicates 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, solution and post-processing: Use optimization algorithm to solve the mathematical description model of step S3 to obtain , 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 optimization 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, a finite element simulation calculation is performed on each individual based on the pseudo-density vector and the known stress conditions to solve the strain conditions of each unit and calculate the strain energy at each unit position; the optimization algorithm described in step S3 is implemented with strain energy as the optimization indicator; during 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. 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, characterized in that: The basic method of step S3 includes the following steps: Step S31, randomly Take samples; 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 ; Step S34, otherwise, refer to Optimize the design 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: Use 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 the 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, To avoid the instability of the iterative process caused by the drastic change of volume fraction before and after filtration, the optimization 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 calculated .

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 Heaviside function; When , the Heaviside function loses its effect; The larger it is, the closer it is to the original Heaviside step function.

8. Flexible special-shaped catheter robot, characterized in that: Its 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 produce 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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