Guide wire terminal force feedback simulation system

Abstract

The invention discloses a guide wire terminal force feedback simulation system which comprises a guide wire operation and force feedback system located at a doctor operation end, a guide wire action execution system located at a patient execution end and a medical image processing system. The guide wire operation and force feedback system comprises a damping force device, a linear displacement sensor and an angular displacement sensor; according to the application, remote operation gets rid of the constraint of a rocker, a doctor can also use an actual guide wire to operate at the operation end, on the basis, a damping force device is added, the guide wire at the operation end is clamped to different degrees according to the stress condition, calculated by a medical image processing system, of the tip end of the guide wire in a human body, and the operation efficiency is improved. Therefore, the hand feeling of stress of the guide wire in actual clinical use is accurately simulated in real time, a doctor can simulate the touch experience in a traditional operation more truly, the immersion feeling and the control feeling of operation are improved, touch perception is provided for a remote interventional operation, and the accuracy and the safety of the operation and the operation experience of the doctor are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of guide wire control, and particularly to a guide wire terminal force feedback simulation system. Background Art

[0002] In cardiovascular interventional surgery, as the core tool for precisely guiding instruments to penetrate complex vascular accesses, the real-time modeling of the spatial morphology and mechanical interaction of the guide wire directly affects the surgical safety and operation efficiency.

[0003] Traditional guide wire navigation technologies mainly rely on intraoperative X-ray angiography and the doctor's hand feeling of operating the guide wire for two-dimensional positioning, suffering from problems such as cumulative radiation exposure, low soft tissue contrast, and limited dynamic tracking.

[0004] Currently, remote interventional surgical robots have been developed on the market to solve the radiation problem. Most of these robots only remotely operate the guide wire through a joystick, and install a force sensor at the execution end to detect the contact force between the guide wire and human tissue, and then simulate the hand feeling of the guide wire by adjusting the force of the operating joystick. Operating the guide wire through a joystick is very different from the original operation method of doctors, and the collision force between the guide wire and human tissue simulated by the reaction force of the joystick also has a great difference from the actual collision force. Coupled with the fact that the force sensor at the end of the delivery mechanism cannot well detect the force received by the tip of the guide wire, the hand feeling simulated in this way is very different from the hand feeling of doctors during clinical operations, and it simply cannot meet the doctor's tactile requirements during the interventional surgery process.

[0005] Therefore, it is necessary to develop a guide wire terminal force feedback simulation system to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to design a guide wire terminal force feedback simulation system to solve the above problems.

[0007] The present invention realizes the above purpose through the following technical solutions:

[0008] A guide wire terminal force feedback simulation system, comprising:

[0009] A guide wire operation and force feedback system at the doctor's operation end; the guide wire operation and force feedback system includes a damping force device for simulating the resistance when the guide wire at the execution end advances, a linear displacement sensor for collecting the delivery distance signal of the guide wire, and an angular displacement sensor for collecting the rotation angle signal of the guide wire. The guide wire sequentially passes through the angular displacement sensor, the linear displacement sensor, and the damping force device.

[0010] A wire movement execution system located at the patient execution end; the signal output ends of the linear displacement sensor and the angular displacement sensor are both connected to the signal input end of the wire movement execution system, and the wire movement execution system is used to deliver the actually used wire into the patient's body according to the received signals;

[0011] A medical image processing system; the medical image processing system is used to provide the current position of the wire in the patient's body and the 3D reconstruction model of the CT in the patient's body, and deliver the feedback force after the detected wire tip collides with the blood vessel to the damping force device to simulate the touch feeling of the wire actually entering the patient's body.

[0012] Further, the damping force device includes:

[0013] A single-slider linear guide; the fixed end of the single-slider linear guide is set at a fixed position,

[0014] A slider slot frame; the first end of the slider slot frame is installed on the sliding end of the single-slider linear guide, and the layout direction of the single-slider linear guide is the same as the wire length direction;

[0015] A voice coil motor; the fixed end of the voice coil motor is set at a fixed position, the acting end of the voice coil motor is connected to the middle of the slider slot frame, and the acting direction of the voice coil motor is the same as the layout direction of the single-slider linear guide;

[0016] A double-slider linear guide; the fixed end of the double-slider linear guide is set at a fixed position; the layout direction of the double-slider linear guide is perpendicular to the layout direction of the single-slider linear guide;

[0017] A left slider convex post; a sliding cavity is horizontally arranged inside the second end of the slider slot frame, and the lower end of the left slider convex post is connected to the first slider of the double-slider linear guide;

[0018] A right slider convex post; the lower end of the right slider convex post is connected to the second slider of the double-slider linear guide; the upper ends of the left slider convex post and the right slider convex post are both placed inside the sliding cavity, both the left slider convex post and the right slider convex post form an L shape, a first convex post is vertically arranged above the lower end of the left slider convex post, a second convex post is vertically arranged above the lower end of the right slider convex post, correspondingly, a first sliding slot and a second sliding slot are respectively arranged on both sides of the sliding cavity on the slider slot frame, both the first sliding slot and the second sliding slot are inclined with respect to the wire length direction, the first sliding slot and the second sliding slot are symmetrically distributed based on the wire, the first convex post is in guiding sliding fit with the first sliding slot, and the second convex post is in guiding sliding fit with the second sliding slot;

[0019] A pressure sensor; the pressure sensor is installed inside the upper end of the right slider convex post;

[0020] A first friction plate; the first friction plate is installed inside the upper end of the left slider convex post;

[0021] The second friction plate; the second friction plate is installed on the acting end of the pressure sensor; the first friction plate and the second friction plate are respectively placed on both sides of the guide wire.

[0022] Further, the damping force device further includes a base, and the fixed ends of the single-slider linear guide and the double-slider linear guide are both fixedly installed on the base.

[0023] Further, the damping force device further includes a motor fixing seat, the motor fixing seat is fixedly installed on the base, and the fixed end of the voice coil motor is fixedly installed on the motor fixing seat.

[0024] Further, the damping force device further includes a guide wire catheter seat, a mounting plate, and a guide wire catheter. The mounting plate is installed above the first end of the slider slot frame, the guide wire catheter is installed on the mounting plate, the guide wire catheter seat is installed above the second end of the slider slot frame, and the guide wire is arranged through the guide wire catheter and the guide wire catheter seat.

[0025] Further, the method for obtaining the feedback force after the guide wire tip collides with the blood vessel in the medical image processing system is as follows:

[0026] S1. Obtain the guide wire information;

[0027] S2. Geometric modeling of the guide wire;

[0028] S3. Physical modeling and calculation of the guide wire;

[0029] S4. Guide wire motion prediction;

[0030] S5. Coarse detection: Use a three-dimensional voxel to establish a mask image to obtain whether the front end of the guide wire collides with the blood vessel wall; use the method of S4 for motion prediction according to the collision information;

[0031] S6. Fine detection: Perform collision detection based on the blood vessel wall model, the blood vessel center line, and the kd-tree;

[0032] S7. According to the relationship between the guide wire tip and the blood vessel center line, judge whether the guide wire tip will penetrate the blood vessel wall. If so, enter the next step; if not, enter step S9;

[0033] S8. Calculate the collision feedback force.

[0034] Specifically, step S1 specifically includes: The accurate spatial pose information of the guide wire is obtained through an electromagnetic sensor, and the electromagnetic sensor provides the position ) and the rotation quaternion ( , and is converted to the coordinates in the world coordinate system through a transformation matrix: ( ), and then the guide wire is modeled according to the obtained three-dimensional position coordinates;

[0035] Step S2 specifically includes: describing the guide wire as a three-dimensional curve with coordinates: ; where is an arc length parameterized curve that describes the center line of the guide wire in three-dimensional space, is an orthogonal material frame that is assigned to each point on the center line and contains all the information required to calculate torsion and bending; the material frame satisfies represents the tangent direction of the center line and is perpendicular to each other in pairs, , represents the derivative of ; the curvature vector of the center line ;

[0036] Step S3 specifically includes: physically modeling the tip of the guide wire. Based on the Kirchhoff elastic rod theory, the energy is classified into three categories: , and , and the total energy is:

[0037]

[0038] Since the guide wire is inextensible, excluding the stretching energy of the guide wire and applying a PBD auxiliary constraint to enforce the inextensible property of the guide wire, the total energy is:

[0039]

[0040] The PBD constraint uses the guass-seidel method, processes each edge separately, and converges after more than 5 iterations, which can achieve inextensibility;

[0041] Among them, the bending energy and torsion energy can be calculated by the following formulas:

[0042]

[0043] where represents the length of the guide wire, represents the curvature vector of the curve, represents the first part of the curvature vector, represents the second part of the curvature vector, represents the intrinsic curvature of the tip of the guide wire, represents the bending Young's modulus, represents the radius of the guide wire, represents the shear modulus of elasticity, represents the twist of the guide wire, and D is the differential operator symbol;

[0044] Perform numerical calculations, discretize the guide wire into mass points for calculation. For the bending force, first calculate the curvature of each mass point after discretization. , The calculation depends on two adjacent sides. In the continuous case, the magnitude is , where represents the angle between the two sides. The discrete numerical calculation uses the following formula:

[0045]

[0046] where, represents the number corresponding to each mass point after discretization, ; The discretized expression of the bending energy is:

[0047]

[0048] where ;

[0049] For the calculation of the discrete torsional force, calculate the torsional angle of each point , According to the principle of minimum energy, only the torsional angle of the tip needs to be known. Use the Newton iteration method to solve the following formula:

[0050] Huaxi Jingchuang Medical Technology (Chengdu) Co., Ltd.

[0051] where is the matrix, is the gradient; The calculation method of

[0052]

[0053] where is the rotation rotation matrix, is a symmetric positive definite 2D matrix, matrix The calculation method of

[0054]

[0055] where represents the torsional modulus, The calculation method of

[0056]

[0057] Finally, all , Obtained through the twist angle:

[0058]

[0059] where the scalar , represents the discrete twist;

[0060] Step S4 specifically includes: Using the Lagrangian equation of motion, calculate the bending force of each particle of the guide wire and the twisting force :

[0061]

[0062] Since the time step of the system is very short, numerical instability will not occur. Directly use the semi-implicit integration method to calculate the position change amount at the next moment and the velocity change amount :

[0063]

[0064] where represents the mass, represents the current velocity, represents the current position, represents the magnitude of the current force;

[0065] Step S5 specifically includes: In the rough detection stage, directly obtain whether the front end of the guide wire collides with the blood vessel wall through voxels. If the position value , it indicates a collision. According to the established physical model, predict the movement of the guide wire and update the velocity, displacement, and force state of the next position of the guide wire; if there is no collision, then the next step will continue to move forward in the current state;

[0066] Step S6 specifically includes: Step S6 specifically includes: In the fine detection stage, since the next position is already known, it is necessary to combine the blood vessel centerline and kd-tree to detect whether the blood vessel wall is penetrated. The construction process of the kd-tree will select the dimension with the largest variance each time as the splitting axis:

[0067]

[0068] where represents the mean value of the i-th dimensional data. There are a total of k dimensions and n points. Maximizing the variance ensures the randomness of the data distribution; then, according to the median greed, select the corresponding median of the selected dimension for division:

[0069]

[0070] represents taking the median. The median greedy algorithm ensures the balance of the data volume in the left and right subtrees, making the tree height as low as possible, and achieving a query distance of logarithmic level to the nearest centerline position;

[0071] Steps S7 and S8 specifically include:

[0072] Through the above integral formula and the guidewire model, the displacement information of the next step of the guidewire has been obtained. According to the relationship between the tip of the guidewire and the blood vessel centerline, it can be judged whether the tip of the guidewire will penetrate the blood vessel wall. If penetration occurs, the distance between the tip and the blood vessel wall can be found ; Since different tissues have different elastic coefficients and damping coefficients , the simple spring-damping model is:

[0073]

[0074] Combining the spring-damping system with the structure of the blood vessel wall, the calculation model of the feedback force after collision can be obtained as:

[0075]

[0076] where represents the Young's modulus of the blood vessel wall, represents the contact area between the blood vessel wall and the guidewire in the image, is the thickness of the blood vessel wall.

[0077] Furthermore, the force exerted on the guidewire by the first friction plate and the second friction plate in the guidewire operation and force feedback system is:

[0078]

[0079] where, is the feedback force after the collision between the tip of the guidewire in the human body and the blood vessel, is the friction coefficient between the guidewire material and the contact surfaces of the first friction plate and the second friction plate.

[0080] The beneficial effects of the present invention are as follows:

[0081] This application liberates remote operation from the shackles of joysticks. Doctors can also use actual guidewires for operation at the operation end. On this basis, a damping force device is added. According to the force condition of the tip of the guidewire inside the human body calculated by the medical image processing system, the guidewire at the operation end is clamped to different degrees, so as to accurately simulate the feel of the guidewire force in actual clinical use in real time. This enables doctors to more realistically simulate the tactile experience in traditional surgeries, enhancing the immersion and control sense of operation, providing tactile perception for remote interventional surgeries, and improving the surgical accuracy, safety and doctors' operation experience.

[0082] This application uses an electromagnetic sensor to obtain the real-time position information of the guidewire tip. Based on the obtained point set information and discrete elastic rods, the guidewire is modeled as an inextensible deformable linear object. Its centerline is characterized by an arc-length parameterized three-dimensional curve. The bending and torsion characteristics are described by combining an orthogonal material frame, and the curvature vector and torsion angle are calculated through a discretized particle model to simulate the motion state of the guidewire. The motion trajectory of the guidewire is predicted by a semi-implicit integration method; subsequently, collision detection is performed in combination with the preprocessed blood vessel wall mask image. In this way, due to the existence of the preprocessing structure, the detection is faster than the common bounding box using a tree structure for division; the deformation caused by the guidewire tip to the blood vessel wall is judged using the blood vessel centerline, and a multi-tissue elastic feedback model is constructed in combination with a spring damping system to calculate the corresponding feedback force after collision, so as to realize the simulation of different soft and hard tissue differential mechanical responses; in the rough detection stage of this application, an image mask is used for collision detection, and in the precise detection stage, the centerline is used to judge whether the guidewire tip will penetrate the blood vessel wall. Further, a new model for calculating the feedback force is proposed. Compared with the traditional penalty method, which only uses simple elastic force, it combines the relevant parameters of the blood vessel wall and a linear spring damping system related to the tissue elastic coefficient, thus realizing the simulation of different soft and hard tissue differential mechanical responses, making the speed faster and the calculation more accurate; and the motion state of the particles is solved using the semi-implicit time integration method and the Verlet method, which is fast, numerically stable, and can combine a graph neural network to reduce the accuracy error, with stronger scalability. Brief Description of the Drawings

[0083] Figure 1 It is a schematic structural diagram of the guidewire operation and force feedback system in this application;

[0084] Figure 2 It is a schematic structural diagram of the damping force device in this application;

[0085] Figure 3 It is a right view of the damping force device in this application;

[0086] Figure 4 It is a top view of the damping force device in this application;

[0087] Figure 5This is the front view of the damping force device in this application;

[0088] Figure 6 This is the structural schematic diagram of the double-slider linear guide in this application;

[0089] Figure 7 This is the schematic diagram of the guide wire terminal force feedback simulation system.

[0090] Legend: 1 - Base; 2 - Single-slider linear guide; 3 - Slide block slot frame; 4 - Double-slider linear guide; 5 - Left slider convex post; 6 - Guide wire catheter seat; 7 - Right slider convex post; 8 - Pressure sensor; 9 - Guide wire catheter; 10 - Guide wire; 11 - Voice coil motor; 12 - Motor fixing seat; 13 - Angular displacement operating handle; 14 - Linear displacement sensor; 15 - Angular displacement sensor; 16 - Mounting plate; 17 - Sliding cavity; 18 - First convex post; 19 - First sliding slot; 20 - Second convex post; 21 - Second sliding slot. Detailed implementation manners

[0091] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0092] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0093] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0094] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship when the product of the present invention is usually placed, or the orientation or positional relationship commonly understood by those skilled in the art. It is 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 should not be construed as a limitation to the present invention.

[0095] In addition, terms such as "first" and "second" are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0096] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, terms such as "arrangement" and "connection" should be understood in a broad sense. For example, "connection" 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 an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0097] The following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings.

[0098] As Figure 1 and 7 shown, a guide wire terminal force feedback simulation system includes:

[0099] A guide wire 10 operation and force feedback system at the doctor operation end; the guide wire 10 operation and force feedback system includes a damping force device for simulating the resistance when the guide wire 10 advances at the simulation execution end, a linear displacement sensor 14 for collecting the delivery distance signal of the guide wire 10, and an angular displacement sensor 15 for collecting the rotation angle signal of the guide wire 10. The guide wire 10 passes through the angular displacement sensor 15, the linear displacement sensor 14, and the damping force device in sequence.

[0100] A guide wire 10 action execution system at the patient execution end (the guide wire 10 action execution system can select the execution end of Siemens' Turing system / Minimally Invasive: R-One); the signal output ends of the linear displacement sensor 14 and the angular displacement sensor 15 are both connected to the signal input end of the guide wire 10 action execution system. The guide wire 10 action execution system is used to deliver the actual guide wire 10 into the patient's body according to the received signal.

[0101] A medical image processing system; the medical image processing system is used to provide the current position of the guide wire 10 in the patient's body and the 3D reconstruction model of the CT in the patient's body, and transmit the feedback force after the detected tip of the guide wire 10 collides with the blood vessel to the damping force device through wired / wireless to simulate the touch feeling of the actual guide wire 10 entering the patient's body.

[0102] Through this application, the force simulation between the guide wire 10 and human tissues in remote interventional surgery is realized, which helps doctors better judge the texture, elasticity, resistance and other characteristics of tissues, so as to make more accurate decisions. This makes remote surgery not only feasible, but also safer and more reliable.

[0103] In the guide wire 10 operation and force feedback system, an angular displacement operating handle 13 is also provided. The doctor uses the angular displacement operating handle 13 to perform the angular displacement control operation of the guide wire 10 and directly perform the delivery operation on the guide wire 10. The angular displacement sensor 15 detects the angular displacement of the guide wire 10 by detecting the angular displacement operating handle 13, and then the linear displacement sensor 14 detects the delivery distance of the guide wire 10. When the guide wire 10 operation and force feedback system is used, a guide wire 10 of the same model as that in clinical use passes through the middle of the system. Then the system will measure the linear displacement and angular displacement of the guide wire 10 and transmit this information to the guide wire 10 action execution system in clinical use. The guide wire 10 action execution system will deliver the actually used guide wire 10 into the human body. At this time, the medical image processing system will calculate the position of the guide wire 10 in the human body and give the information to the guide wire 10 collision force detection algorithm in combination with the 3D model reconstructed by the human body CT. The algorithm calculates the collision force of the guide wire 10 in the human body, and then the calculated collision force is given to the force feedback simulation mechanism to simulate the feel of the guide wire 10.

[0104] As Figures 2 - 6 shown, the damping force device includes:

[0105] Single-slider linear guide 2; the fixed end of the single-slider linear guide 2 is set at a fixed position,

[0106] Slider groove frame 3; the first end of the slider groove frame 3 is installed on the sliding end of the single-slider linear guide 2, and the layout direction of the single-slider linear guide 2 is the same as the length direction of the guide wire 10;

[0107] Voice coil motor 11; the fixed end of the voice coil motor 11 is set at a fixed position, and the acting end of the voice coil motor 11 is connected to the middle of the slider groove frame 3. The acting direction of the voice coil motor 11 is the same as the layout direction of the single-slider linear guide 2;

[0108] Double-slider linear guide 4; the fixed end of the double-slider linear guide 4 is set at a fixed position; the layout direction of the double-slider linear guide 4 is perpendicular to the layout direction of the single-slider linear guide 2;

[0109] Slider convex column left 5; a sliding cavity 17 is horizontally arranged inside the second end of the slider groove frame 3, and the lower end of the slider convex column left 5 is connected to the first slider of the double-slider linear guide 4;

[0110] Slider convex column right 7; the lower end of the slider convex column right 7 is connected to the second slider of the double-slider linear guide 4; the upper ends of the slider convex column left 5 and the slider convex column right 7 are both placed in the sliding cavity 17. The slider convex column left 5 and the slider convex column right 7 both form an L shape. A first convex column 18 is vertically arranged above the lower end of the slider convex column left 5, and a second convex column 20 is vertically arranged above the lower end of the slider convex column right 7. Correspondingly, a first sliding groove 19 and a second sliding groove 21 are respectively arranged on both sides of the sliding cavity 17 on the slider groove frame 3. The first sliding groove 19 and the second sliding groove 21 are both inclined with respect to the length direction of the wire guide 10, and the first sliding groove 19 and the second sliding groove 21 are symmetrically distributed based on the wire guide 10 (as Figure 2 shown, the first sliding groove 19 and the second sliding groove 21 are formed to be closer to the wire guide 10 at the first end close to the slider groove frame 3 and farther from the wire guide 10 at the second end close to the slider groove frame 3). The first convex column 18 is in guiding sliding fit with the first sliding groove 19, and the second convex column 20 is in guiding sliding fit with the second sliding groove 21;

[0111] The relationship between the voice coil motor 11 and the friction plate is: where F1 is the pressure of the friction plate, is the thrust provided by the voice coil motor 11.

[0112] Pressure sensor 8; the pressure sensor 8 is installed inside the upper end of the slider convex column right 7;

[0113] First friction plate; the first friction plate is installed inside the upper end of the slider convex column left 5;

[0114] Second friction plate; the second friction plate is installed on the acting end of the pressure sensor 8; the first friction plate and the second friction plate are respectively placed on both sides of the wire guide 10.

[0115] As Figure 2 and 5 shown, the damping force device further includes a base 1, and the fixed ends of the single-slider linear guide 2 and the double-slider linear guide 4 are both fixedly installed on the base 1.

[0116] As Figure 2 and 3 shown, the damping force device further includes a motor fixing seat 12, the motor fixing seat 12 is fixedly installed on the base 1, and the fixed end of the voice coil motor 11 is fixedly installed on the motor fixing seat 12.

[0117] As Figure 2 and 4As shown, the damping force device further includes a guide wire catheter seat 6, a mounting plate 16, and a guide wire catheter 9. The mounting plate 16 is mounted above the first end of the slider groove frame 3, the guide wire catheter 9 is mounted on the mounting plate 16, the guide wire catheter seat 6 is mounted above the second end of the slider groove frame 3, and the guide wire 10 is arranged through the guide wire catheter 9 and the guide wire catheter seat 6. The guide wire catheter seat 6 and the guide wire catheter 9 realize the supporting effect on the guide wire 10.

[0118] When the damping force device is working, the voice coil motor 11 receives a control signal, and the voice coil motor 11 works to push the slider groove frame 3 to move forward or backward along the single-slider linear guide 2. Correspondingly, the first convex column 18 and the second convex column 20 are respectively mounted on the left slider convex column 5 and the right slider convex column 7, and the left slider convex column 5 and the right slider convex column 7 are slidably placed on the double-slider linear guide 4. Also, because the first convex column 18 is in guiding sliding fit with the first sliding groove 19, and the second convex column 20 is in guiding sliding fit with the second sliding groove 21, so under the pushing action of the slider groove frame 3, the first convex column 18 and the second convex column 20 move relatively inward or move outward in the opposite direction. The first convex column 18 drives the first friction plate to act on the first side of the guide wire 10, the second convex column 20 drives the pressure sensor 8, and the pressure sensor 8 drives the second friction plate to act on the second side of the guide wire 10. The first side and the second side of the guide wire 10 are two relatively arranged sides, thereby realizing the pressure control of the guide wire 10. The pressure sensor 8 is used to detect this pressure in real time. The first friction plate and the second friction plate act on the guide wire 10 to provide the resistance when operating the guide wire 10, thereby real-time simulating the force situation of the actual guide wire 10 in remote surgery.

[0119] The method for obtaining the feedback force after the tip of the guide wire 10 collides with the blood vessel in the medical image processing system is as follows:

[0120] S1. Obtain the information of the guide wire 10;

[0121] S2. Geometric modeling of the guide wire 10;

[0122] S3. Physical modeling and calculation of the guide wire 10;

[0123] S4. Motion prediction of the guide wire 10;

[0124] S5. Coarse detection: Establish a mask image using three-dimensional space voxels to obtain whether the front end of the guide wire 10 collides with the blood vessel wall; perform motion prediction using the method of S4 according to the collision information.

[0125] S6. Fine detection: Perform collision detection based on the blood vessel wall model, the blood vessel centerline, and the kd-tree.

[0126] S7. According to the relationship between the tip of the guide wire 10 and the blood vessel centerline, judge whether the tip of the guide wire 10 will penetrate the blood vessel wall. If so, enter the next step; if not, enter step S9;

[0127] S8. Calculate the collision feedback force.

[0128] Specifically, step S1 specifically includes: The precise spatial pose information of the guide wire 10 is obtained through an electromagnetic sensor, and the electromagnetic sensor provides the position of the guide wire 10 ) and the rotation quaternion ( , and is transformed into the coordinates in the world coordinate system through a transformation matrix: ( ), and then the guide wire 10 is modeled according to the obtained three-dimensional position coordinates;

[0129] Step S2 specifically includes: Describing the guide wire 10 as a three-dimensional curve in coordinates: ; where is the arc length parameterized curve describing the center line of the guide wire 10 in three-dimensional space, is an orthogonal material frame, which is assigned to each point on the center line and contains all the information required for calculating torsion and bending; the material frame satisfies represents the tangent direction of the center line and is perpendicular to each other in pairs, , represents the derivative of ; the curvature vector of the center line ;

[0130] Step S3 specifically includes: Physically modeling the tip of the guide wire 10. Based on the Kirchhoff elastic rod theory, the energy is classified into three categories: , and , and the total energy is:

[0131]

[0132] Since the guide wire 10 is inextensible, excluding the stretching energy of the guide wire 10 and applying a PBD auxiliary constraint to enforce the inextensible property of the guide wire 10, the total energy is:

[0133]

[0134] The PBD constraint uses the guass-seidel method, processes each edge separately, and converges after more than 5 iterations, and can achieve inextensibility;

[0135] Among them, the bending energy and torsion energy can be calculated through the following formulas:

[0136]

[0137] Where represents the length of the guide wire 10, represents the curvature vector of the curve, represents the first part of the curvature vector, represents the second part of the curvature vector, represents the inherent curvature of the tip of the guide wire, represents the bending Young's modulus, represents the radius of the guide wire 10, represents the shear modulus of elasticity, represents the twist of the guide wire 10, and D is the differential operator symbol;

[0138] Perform numerical calculations. Discretize the guide wire 10 into mass points for calculation. For the bending force, first calculate the curvature of each mass point after discretization , The calculation of depends on two adjacent sides. In the continuous case, the magnitude is , where represents the angle between the two sides. The discrete numerical calculation uses the following formula:

[0139]

[0140] Among them, represents the number corresponding to each mass point after discretization, ; The discretized expression of the bending energy is:

[0141]

[0142] Among them ;

[0143] For the calculation of the discrete torsional force, calculate the twist angle of each point , According to the principle of minimum energy, only the twist angle of the tip needs to be known. Use the Newton iteration method to solve the following formula:

[0144]

[0145] Among them is matrix, is the gradient; The calculation method of is as follows:

[0146]

[0147] Among them is the rotation rotation matrix, is a symmetric positive definite 2D matrix, matrix The calculation method is as follows:

[0148]

[0149] Wherein represents the torsional modulus, The calculation method of

[0150]

[0151] Finally, all are updated, Obtained through the twist angle:

[0152]

[0153] Where the scalar , represents the discrete twist;

[0154] Step S4 specifically includes: using the Lagrangian equation of motion to calculate the bending force and torsional force of each particle of the guide wire 10:

[0155]

[0156] Since the time step of the system is very short and numerical instability will not occur, directly use the semi-implicit integration method to calculate the position change and velocity change at the next moment:

[0157]

[0158] Wherein represents the mass, represents the current velocity, represents the current position, represents the magnitude of the current force;

[0159] Step S5 specifically includes: in the rough detection stage, directly obtain whether the front end of the guide wire 10 collides with the blood vessel wall through voxels. If the position value , it means a collision has occurred. According to the established physical model, predict the movement of the guide wire 10 and update the velocity, displacement, and force states of the next position of the guide wire 10; if no collision occurs, then the next step will continue to move forward in the current state;

[0160] Step S6 specifically includes: In the fine detection stage, since the next position is already known, it is necessary to combine the blood vessel centerline and the kd-tree to detect whether the blood vessel wall is penetrated. In the construction process of the kd-tree, the dimension with the largest variance is selected each time as the splitting axis:

[0161]

[0162] where represents the mean value of the data in the i-th dimension. There are a total of k dimensions and n points. By maximizing the variance, the randomness of the data distribution is ensured; then, according to the median greed, the corresponding median of the selected dimension is selected for partitioning:

[0163]

[0164] represents taking the median. The median greed ensures the balance of the data volume in the left and right subtrees, making the tree height as low as possible and achieving a query distance of log level to the nearest centerline position;

[0165] Steps S7 and S8 specifically include:

[0166] Through the above integral formula and the guidewire 10 model, the displacement information of the next step of the guidewire 10 has been obtained. According to the relationship between the tip of the guidewire 10 and the blood vessel centerline, it can be judged whether the tip of the guidewire 10 will penetrate the blood vessel wall. If penetration occurs, the distance between the tip and the blood vessel wall can be found ; since different tissues have different elastic coefficients and damping coefficients , the simple spring-damping model is:

[0167]

[0168] By combining the spring-damping system with the structure of the blood vessel wall, the calculation model of the feedback force after collision can be obtained as:

[0169]

[0170] where represents the Young's modulus of the blood vessel wall, represents the contact area between the blood vessel wall and the guidewire 10 in the image, is the thickness of the blood vessel wall.

[0171] Furthermore, the force applied to the guidewire 10 by the first friction plate and the second friction plate in the guidewire 10 operation and force feedback system is:

[0172]

[0173] Among them, is the feedback force after the tip of the guide wire 10 in the human body collides with the blood vessel, is the friction coefficient of the contact surface between the material of the guide wire 10 and the first friction plate and the second friction plate.

[0174] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A guide wire terminal force feedback simulation system, characterized in that Comprising: A guide wire operation and force feedback system located at the doctor's operation end; the guide wire operation and force feedback system includes a damping force device for simulating the resistance when the guide wire advances at the simulated execution end, a linear displacement sensor for collecting the delivery distance signal of the guide wire, and an angular displacement sensor for collecting the rotation angle signal of the guide wire. The guide wire sequentially passes through the angular displacement sensor, the linear displacement sensor, and the damping force device. A guide wire action execution system located at the patient's execution end; the signal output ends of the linear displacement sensor and the angular displacement sensor are both connected to the signal input end of the guide wire action execution system. The guide wire action execution system is used to deliver the actually used guide wire into the patient's body according to the received signal. A medical image processing system; the medical image processing system is used to provide the current position of the guide wire in the patient's body and the 3D reconstruction model of the CT in the patient's body, and deliver the feedback force after the detected tip of the guide wire collides with the blood vessel to the damping force device to simulate the touch of the guide wire actually entering the patient's body.

2. The guide wire terminal force feedback simulation system according to claim 1, wherein The damping force device includes: A single-slider linear guide; the fixed end of the single-slider linear guide is set at a fixed position. A slider groove frame; the first end of the slider groove frame is installed on the sliding end of the single-slider linear guide, and the layout direction of the single-slider linear guide is the same as the length direction of the guide wire. A voice coil motor; the fixed end of the voice coil motor is set at a fixed position, the acting end of the voice coil motor is connected to the middle of the slider groove frame, and the acting direction of the voice coil motor is the same as the layout direction of the single-slider linear guide. A double-slider linear guide; the fixed end of the double-slider linear guide is set at a fixed position; the layout direction of the double-slider linear guide is perpendicular to the layout direction of the single-slider linear guide. A left slider convex column; a sliding cavity is horizontally arranged inside the second end of the slider groove frame, and the lower end of the left slider convex column is connected to the first slider of the double-slider linear guide. A right slider convex column; the lower end of the right slider convex column is connected to the second slider of the double-slider linear guide; the upper ends of the left slider convex column and the right slider convex column are both placed in the sliding cavity. The left slider convex column and the right slider convex column both form an L shape. A first convex column is vertically arranged above the lower end of the left slider convex column, and a second convex column is vertically arranged above the lower end of the right slider convex column. Correspondingly, a first sliding groove and a second sliding groove are respectively arranged on both sides of the sliding cavity on the slider groove frame. The first sliding groove and the second sliding groove are both inclined relative to the length direction of the guide wire, and the first sliding groove and the second sliding groove are symmetrically distributed based on the guide wire. The first convex column is in guiding sliding fit with the first sliding groove, and the second convex column is in guiding sliding fit with the second sliding groove. A pressure sensor; the pressure sensor is installed inside the upper end of the right slider convex column. A first friction plate; the first friction plate is installed inside the upper end of the left slider convex column. A second friction plate; the second friction plate is installed on the acting end of the pressure sensor; the first friction plate and the second friction plate are respectively placed on both sides of the guide wire.

3. The wire terminal force feedback simulation system according to claim 1, wherein The damping force device further includes a base, and the fixed ends of the single-slider linear guide and the double-slider linear guide are both fixedly installed on the base.

4. The wire terminal force feedback simulation system according to claim 3, wherein, The damping force device further includes a motor fixing seat, the motor fixing seat is fixedly installed on the base, and the fixed end of the voice coil motor is fixedly installed on the motor fixing seat.

5. The wire terminal force feedback simulation system according to claim 1, characterized in that, The damping force device further includes a guide wire catheter seat, a mounting plate, and a guide wire catheter. The mounting plate is installed above the first end of the slider slot frame, the guide wire catheter is installed on the mounting plate, the guide wire catheter seat is installed above the second end of the slider slot frame, and the guide wire is arranged through the guide wire catheter and the guide wire catheter seat.

6. The wire guide terminal force feedback simulation system according to claim 2, wherein The method for obtaining the feedback force after the guide wire tip collides with the blood vessel in the medical image processing system is as follows: S1. Obtain the guide wire information; S2. Conduct geometric modeling of the guide wire; S3. Conduct physical modeling and calculation of the guide wire; S4. Predict the movement of the guide wire; S5. Coarse detection: Use a three-dimensional voxel to establish a mask image to obtain whether the front end of the guide wire collides with the blood vessel wall; Use the method of S4 for movement prediction according to the collision information; S6. Fine detection: Conduct collision detection based on the blood vessel wall model, the blood vessel centerline, and the kd-tree; S7. According to the relationship between the guide wire tip and the blood vessel centerline, judge whether the guide wire tip will penetrate the blood vessel wall. If so, proceed to the next step; if not, proceed to step S9; S8. Calculate the collision feedback force.

7. The wire terminal force feedback simulation system according to claim 6, characterized in that, Step S1 specifically includes: The precise spatial pose information of the guide wire is obtained by an electromagnetic sensor, and the electromagnetic sensor provides the position of the guide wire ) and the rotation quaternion ( , which is transformed into the coordinates in the world coordinate system through a transformation matrix: ( ), and then the guide wire is modeled according to the obtained three-dimensional position coordinates; Step S2 specifically includes: describing the guide wire as a three-dimensional curve with coordinates: ; where is an arc length parameterized curve that describes the center line of the guide wire in three-dimensional space, is an orthogonal material frame that is assigned to each point on the center line and contains all the information required to calculate torsion and bending; the material frame satisfies represents the tangent direction of the center line and is perpendicular to each other in pairs, , represents the derivative of ; the curvature vector of the center line ; Step S3 specifically includes: performing physical modeling on the tip of the guide wire. Based on the Kirchhoff elastic rod theory, the energy is classified into three categories: , and , and the total energy is: ； Since the guide wire is inextensible, after excluding the stretching energy of the guide wire and applying a PBD auxiliary constraint to enforce the inextensible property of the guide wire, the total energy is: ； The PBD constraint uses the guass-seidel method, processes each edge separately, and converges after more than 5 iterations, and can achieve inextensibility; Among them, the bending energy and the torsional energy can be calculated by the following formula: ； Among them represents the length of the guide wire, represents the curvature vector of the curve, represents the first part of the curvature vector, represents the second part of the curvature vector, represents the inherent curvature of the front end of the guide wire, represents the bending Young's modulus, represents the radius of the guide wire, represents the shear modulus of elasticity, represents the twist of the guide wire, and D is the differential operator symbol; Perform numerical calculations, discretize the guide wire into mass points for calculation. For the bending force, first calculate the curvature of each mass point after discretization. , The calculation depends on two adjacent sides. In the continuous case, the size is , where represents the angle between the two sides. The discrete numerical calculation uses the following formula: ； Among them, represents the number corresponding to each particle after discretization, ; The discretized expression of the bending energy is: ； Among them ; For the calculation of discrete torsional forces, the torsional angle at each point is calculated , According to the principle of minimum energy, only the torsional angle at the tip needs to be known , which is obtained by solving the following formula using the Newton iteration method: ； Among them is a matrix is the gradient; The calculation method of ； Among them is the rotation rotation matrix, is a symmetric positive definite 2D matrix, matrix is calculated as follows: ； wherein represents the torsional modulus, is calculated as follows: ； Finally updated all of the , obtained by the twist angle: ； where the scalar represents a discrete twist; Step S4 specifically includes: calculating the bending force of each mass point of the guide wire by using the Lagrangian equation of motion and the torsional force : ； Since the time step of the system is very short, numerical instability will not occur. We can directly use the semi-implicit integration method to calculate the position change and velocity change at the next moment. and the velocity change : ； wherein represents the mass, represents the current speed, represents the current position, represents the current force magnitude; Step S5 specifically includes: in the rough detection stage, directly obtain whether the front end of the guide wire collides with the blood vessel wall through voxels. If the position value indicates a collision, predict the movement of the guide wire according to the established physical model, and update the velocity, displacement, and force states of the next position of the guide wire; if there is no collision, then continue to move forward in the current state in the next step; Step S6 specifically includes: In the fine detection stage, since the next position is already known, it is necessary to combine the blood vessel centerline and the kd-tree to detect whether the blood vessel wall is penetrated. In the construction process of the kd-tree, the dimension with the largest variance is selected each time as the splitting axis: ； where represents the mean of the data in the i-th dimension. There are k dimensions and n points in total. By maximizing the variance, the randomness of the data distribution is ensured. Then, according to the median greedy algorithm, the corresponding median of the selected dimension is selected for partitioning: ； Represents taking the median. Median greed ensures the balance of the data volume of the left and right subtrees, making the tree height as low as possible and achieving a query distance of log level to the nearest center line position; Steps S7 and S8 specifically include: Through the above integral formula and the guidewire model, the displacement information of the next step of the guidewire has been obtained. According to the relationship between the tip of the guidewire and the centerline of the blood vessel, it can be judged whether the tip of the guidewire will penetrate the blood vessel wall. If penetration occurs, the distance between the tip and the blood vessel wall can be found. Since different tissues have different elastic coefficients and damping coefficients , a simple spring-damping model is as follows: ； Combining the spring damping system and the structure of the blood vessel wall, the calculation model of the feedback force after collision can be obtained as: ； wherein represents the Young's modulus of the blood vessel wall, represents the contact area between the blood vessel wall and the guide wire in the image, is the thickness of the blood vessel wall.

8. A guide wire terminal force feedback simulation system according to claim 7, characterized in that The force applied to the guide wire by the first friction plate and the second friction plate in the guide wire operation and force feedback system is: ； Among them, is the feedback force after the tip of the guide wire in the human body collides with the blood vessel, is the friction coefficient of the contact surface between the guide wire material and the first friction plate and the second friction plate.

Images