Catheter bending steering control method, catheter system, and storage medium

Abstract

The application provides a catheter bending and steering control method, a catheter system and a readable storage medium. The method comprises the following steps: obtaining a position change amount of a catheter tail end according to a catheter steering instruction from a host controller, the position change amount comprising a direction angle and a bending angle; determining a driving wheel and a driven wheel in a plurality of driving wheels according to the position change amount, and calculating an angular position change amount of the driving wheel; if the catheter tail end meets a preset condition, controlling a driving motor corresponding to the driving wheel to drive the driving wheel to rotate according to the angular position change amount, calculating a planning force of a driving motor corresponding to the driven wheel according to a zero-stress target of a driving wire corresponding to the driven wheel, and controlling the driving motor corresponding to the driven wheel to output according to the planning force. In the above manner, the application can realize bending and steering control of the catheter, and can reduce the abnormal situation of the driving wire corresponding to the driven wheel being loose or tight by performing zero-force control on the driving wire corresponding to the driven wheel.

Description

Technical Field

[0001] This application belongs to the field of medical device technology, specifically relating to a catheter bending and turning control method, a catheter system and its control system, and a computer-readable storage medium. Background Technology

[0002] Minimally invasive medical techniques aim to reduce the amount of tissue damaged during medical procedures, thereby minimizing patient recovery time, discomfort, and harmful side effects. These techniques often involve inserting catheters to the target tissue location through natural openings in the patient's anatomy or through surgical incisions. Precise control of the catheter's direction is required to ensure its accurate placement.

[0003] In related technologies, precise control of the duct is generally achieved by establishing a kinematic model of the duct, that is, finding the mapping relationship between the angular positions of each drive wheel controlling the duct and the pose of the duct tip, and then substituting the target pose of the duct into the kinematic model to solve for the angular positions of the drive wheels. However, since the duct is a flexible continuum structure, in practical applications, the material properties of the duct, assembly process, temperature changes, external force disturbances, and working space significantly interfere with the kinematic description, resulting in a large deviation between the established kinematic model and the actual motion state, making it difficult to meet the requirements for real-time and precise duct steering control. Summary of the Invention

[0004] This application proposes a catheter bending and turning control method, a catheter system and its control system, as well as a computer-readable storage medium, which can solve the problem in related technologies that it is difficult to meet the requirements of real-time and accurate control of catheter turning.

[0005] A first aspect of this application discloses a catheter system. The catheter system includes a robotic arm, a catheter instrument detachably connected to a power unit of the robotic arm, a main controller and a processor communicatively connected to the robotic arm. The catheter instrument includes an instrument housing detachably connected to the power unit and a catheter connected to the instrument housing. The instrument housing includes a drive wheel driven by the power unit and a drive wire with one end wound around the drive wheel and the other end extending along the catheter and fixed to the end of the catheter. The power unit includes multiple drive motors, with each drive motor, drive wheel, and drive wire corresponding to one another. The processor is configured to perform the following steps: based on the guide tube turning command from the master controller, obtain the position change of the guide tube end, the position change including the direction angle and the bending angle; determine the driving wheel and the driven wheel in the drive wheel according to the position change, and calculate the angular position change of the driving wheel; if the guide tube end meets the preset conditions, control the drive motor corresponding to the driving wheel to drive the driving wheel to rotate according to the angular position change, and at the same time calculate the planned force of the drive motor corresponding to the driven wheel according to the target of zero force on the drive wire corresponding to the driven wheel, and control the drive motor corresponding to the driven wheel to output the planned force. The preset conditions include that at least one of the current bending angle and the target bending angle of the guide tube end is within a preset range, and the target bending angle is the sum of the current bending angle and the bending angle in the position change.

[0006] In the initial stage of driving the drive wheel to rotate, the planning force is set to an initial value; subsequently, during the process of driving the drive wheel to rotate, the planning force is the sum of the initial value, the damping force, and the spring force, where the damping force is calculated based on the speed of the driven wheel, and the spring force is calculated based on the position of the driven wheel.

[0007] Among them, the magnitude of the damping force is positively correlated with the velocity; the magnitude of the spring force is positively correlated with the position.

[0008] The planning force is obtained based on the feedback force of the drive wire corresponding to the driven wheel.

[0009] The processor is configured to perform the following steps: if the position of the driven wheel is in the over-limit zone, then the maximum reverse force corresponding to the over-limit zone is used as the planning force.

[0010] The processor is configured to perform the following steps: if the speed of the driven wheel exceeds the speed limit, adjust the planning force to control the speed of the driven wheel back to the speed limit.

[0011] The processor is configured to perform the following steps: if the end of the guide tube does not meet the preset conditions, the processor calculates the change in the angular position of the driven wheel based on the change in the angular position of the driving wheel and the corresponding current position ratio allocation coefficient of the driven wheel, and controls the drive motor corresponding to the driven wheel to drive the driven wheel to rotate according to the change in angular position. The current position ratio allocation coefficient is used to represent the ratio of the take-up length of the driving wheel to the release length of the corresponding driven wheel in the current state.

[0012] The boundaries of the preset range include the maximum threshold for the bending angle.

[0013] The number of drive wires is n, where n is an integer greater than 2. The n drive wires divide the front end plane of the rotating section of the catheter into n intervals in terms of angle. The drive wires corresponding to the two ends of the interval to which the direction angle belongs are active drive wires. The drive wheel connected to the active drive wire is the active wheel. Some or all of the remaining drive wheels are driven wheels.

[0014] A second aspect of this application proposes a method for controlling the bending and steering of a catheter. The method includes: obtaining the position change of the catheter end based on a catheter steering command from a master controller; the position change includes a direction angle and a bending angle; determining the driving wheel and driven wheel among multiple driving wheels based on the position change, and calculating the angular position change of the driving wheel; each driving wheel is correspondingly configured with a driving motor and a driving wire; a corresponding driving wire is wound around the driving wheel and driven by the corresponding driving motor; the other end of the driving wire extends along the catheter and is fixed to the catheter end; if the catheter end meets a preset condition, the driving motor corresponding to the driving wheel is controlled to drive the driving wheel to rotate according to the angular position change; simultaneously, the planned force of the driving motor corresponding to the driven wheel is calculated according to the target of zero force on the driving wire corresponding to the driven wheel, and the driving motor corresponding to the driven wheel is controlled to output the planned force; the preset condition includes at least one of the current bending angle and the target bending angle of the catheter end falling within a preset range, and the target bending angle is the sum of the current bending angle and the bending angle in the position change.

[0015] A third aspect of this application provides a control system for a conduit system. The control system includes: a memory for storing computer program instructions; and a processor for loading and executing the computer program instructions; wherein the computer program instructions are configured to be loaded and executed by the processor to implement the method described in the second aspect of this application.

[0016] The fourth aspect of this application provides a computer-readable storage medium having computer program instructions stored thereon, which are executed by a processor to implement the method described in the second aspect of this application.

[0017] The technical solutions provided in this application embodiment have at least the following technical effects or advantages:

[0018] In this embodiment, based on the guide tube turning command from the main controller, the position change of the guide tube end is obtained, including the direction angle and bending angle. The driving wheel and driven wheel in the drive wheel are determined based on the position change, and the angular position change of the driving wheel is calculated. If the current bending angle of the guide tube end is within a preset range, the drive motor corresponding to the driving wheel is controlled to rotate according to the angular position change. Simultaneously, the planned force of the drive motor corresponding to the driven wheel is calculated according to the target of zero force on the drive wire corresponding to the driven wheel, and the drive motor corresponding to the driven wheel outputs the planned force to the driven wheel. By using the position change under the guide tube turning command instead of the target position for control, and dividing the drive wheel into driving and driven wheels, the angular position change of the driving wheel is directly calculated based on the position change. If the guide tube end meets the preset conditions, during the process of controlling the driving wheel according to the angular position change, the driven wheel is controlled to follow the rotation according to the target of zero force on the drive wire corresponding to the driven wheel. This better adapts to the nonlinear changes exhibited by the guide tube end during rotation, achieving the bending and turning of the guide tube, while reducing the possibility of abnormal tension in the drive wire corresponding to the driven wheel.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0021] Figure 1 A schematic diagram of a catheter system provided in one embodiment of this application is shown;

[0022] Figure 2 A schematic diagram of a catheter device and power unit provided in an embodiment of this application is shown;

[0023] Figure 3 A schematic diagram of a catheter device provided in one embodiment of this application is shown;

[0024] Figure 4 A schematic flowchart of a catheter bending and turning control method according to an embodiment of this application is shown;

[0025] Figure 5 This illustration shows a schematic diagram of determining the driving wheel and driven wheel based on the direction angle in an embodiment of this application where n=3 and the driving wires are evenly distributed;

[0026] Figure 6This illustration shows a schematic diagram of determining the driving wheel and driven wheel based on the direction angle in one embodiment of this application, where n=4 and the driving wires are evenly distributed.

[0027] Figure 7 This document shows a flowchart illustrating the calculation of the angular position change of the drive wheel in a specific embodiment of this application.

[0028] Figure 8 A schematic diagram of a kinematic model established for the rotation segment in one embodiment of this application is shown;

[0029] Figure 9 This invention illustrates a flowchart for calculating the angular position change of the drive wheel in another specific embodiment of the present application.

[0030] Figure 10 This paper illustrates a flowchart for calculating the angular position change of the drive wheel in another specific embodiment of this application.

[0031] Figure 11 A schematic diagram of the joint space division of the drive wheel and the corresponding control strategy is shown in another specific embodiment of this application;

[0032] Figure 12 A schematic diagram of the control system of a catheter system provided in an embodiment of this application is shown;

[0033] Figure 13 A schematic diagram of a computer-readable storage medium provided in one embodiment of this application is shown. Detailed Implementation

[0034] Exemplary embodiments of this application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0035] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application pertains.

[0036] The following description, in conjunction with the accompanying drawings, describes the catheter bending and turning control method, catheter system and control system according to embodiments of this application, as well as a computer-readable storage medium.

[0037] Figure 1An embodiment of the catheter system 1000 provided in this application is illustrated. The catheter system 1000 includes an imaging cart 100, a trolley 200 and a main controller 300 respectively connected to the imaging cart 100, a catheter device 400 that can be coupled (i.e., detachably connected) to the trolley 200, a sensor system 500 connected to the trolley 200, and a control system 600 for controlling the catheter device 400, the main controller 300, the sensor system 500, and the imaging cart 100. The main controller 300 can be wired or wirelessly connected to the trolley 200. When an operator performs various procedures on a patient next to the trolley 200, they can trigger control commands by operating the main controller 300, which, driven by the trolley 200, controls the catheter device 400 to move forward, retract, and bend / turn.

[0038] The trolley 200 can typically be moved to the side of the operating table to engage the catheter instrument 400. Under control commands, it controls the catheter instrument 400 to move vertically, horizontally, or in non-vertical and non-horizontal directions, thus providing a better preoperative preparation angle for the operation of the catheter instrument 400. The control commands can be triggered by the operator operating the main controller 300, or by the operator directly clicking or pressing buttons on the trolley 200. In other embodiments, the control commands can also be voice control or commands triggered through a force feedback mechanism.

[0039] like Figure 1 As shown, the trolley 200 may further include a base 210, a sliding seat 220 that can move up and down along the base 210, and two robotic arms 230 fixedly connected to the sliding seat 220. Each robotic arm 230 may include multiple arm segments connected at joints, providing multiple degrees of freedom, for example, seven degrees of freedom corresponding to seven arm segments. A power unit (not shown) is installed at the end of each robotic arm 230. The power unit engages the catheter instrument 400 and, under the driving action of the power unit, controls the end of the catheter instrument 400 to bend and turn accordingly. The two robotic arms 230 may have identical or partially identical structures; one robotic arm 230 engages the internal catheter instrument 410, and the other robotic arm 230 engages the external catheter instrument 420. During installation, the external catheter device 420 can be installed first. After the external catheter device 420 is installed, the catheter of the internal catheter device 410 is inserted into the catheter of the external catheter device 420.

[0040] The sensor system 500 has one or more subsystems for receiving information about the catheter device 400. The subsystems may include: a position sensor system; a shape sensor system for determining the position, orientation, velocity, rate, pose, and / or shape of the distal end of the catheter device 400 and / or along one or more segments of the catheter that may constitute the catheter device 400; and / or a visualization system for capturing images from the distal end of the catheter device 400.

[0041] The imaging vehicle 100 may be equipped with a display system 110 and a flushing system (not shown in the figure), etc. The display system 110 is used to display images or representations of the surgical site and catheter instruments 400 generated by the subsystems of the sensor system 500. It can also display real-time images of the surgical site and catheter instruments 400 captured by a visualization system. Image data from imaging technologies such as computed tomography (CT), magnetic resonance imaging (MRI), optical coherence tomography (OCT), and ultrasound can also be used to present images of the surgical site recorded preoperatively or intraoperatively. Preoperative or intraoperative image data can be presented as two-dimensional, three-dimensional, or four-dimensional (e.g., time-based or rate-based information) images and / or as images from models created based on preoperative or intraoperative image datasets, and virtual navigation images can also be displayed. In the virtual navigation images, the actual position of the catheter instruments 400 is registered with the preoperative images to present a virtual image of the catheter instruments 400 within the surgical site to the operator from the outside.

[0042] The control system 600 includes at least one memory and at least one processor. It is understood that the control system 600 can be integrated into the trolley 200 or the imaging cart 100, or it can be set up independently. The control system 600 can support wireless communication protocols such as IEEE 802.11, IrDA, Bluetooth, HomeRF, DECT, and wireless telemetry. The control system 600 can transmit one or more signals instructing the catheter device 400 to move, which is then moved by the power unit. The catheter device 400 can extend to the surgical site within the body through an opening in the patient's natural cavity or a surgical incision.

[0043] Furthermore, the control system 600 may include a mechanical control system (not shown in the figure) and an image processing system (not shown in the figure). The mechanical control system is used to control the movement of the catheter instrument 400, and therefore can be integrated into the trolley 200. The image processing system is used for virtual navigation path planning, and therefore can be integrated into the imaging vehicle 100. Of course, the various subsystems of the control system 600 are not limited to the specific cases listed above, and can be reasonably set according to actual conditions. Among them, the image processing system can image the surgical site based on images of the surgical site recorded before or during the operation, using the above-mentioned imaging technology. Software that can be used in conjunction with manual input can also convert the recorded images into two-dimensional or three-dimensional synthetic images of parts or the entire anatomical organ or segment. During the virtual navigation procedure, the sensor system 500 can be used to calculate the position of the catheter instrument 400 relative to the patient's anatomical structure. This position can be used to generate external tracking images and internal virtual images of the patient's anatomical structure, realizing the registration of the actual position of the catheter instrument 400 with the preoperative image, thereby presenting a virtual image of the catheter instrument 400 within the surgical site to the operator from the outside.

[0044] The internal catheter device 410 and the external catheter device 420 have largely the same structure, each having a slender and flexible internal catheter 41 and an external catheter 42, respectively. The diameter of the external catheter 42 is slightly larger than that of the internal catheter 41, so that the internal catheter 41 can pass through the external catheter 42 and provide some support for the internal catheter 41. This allows the internal catheter 41 to reach the target location in the patient's body, so as to facilitate operations such as tissue or cell sampling from the target location.

[0045] Certain movements of the master controller 300 can cause corresponding movements of the catheter instrument 400. For example, when the operator moves the directional lever of the master controller 300 up or down, the movement of the directional lever can be mapped to a corresponding pitch movement of the end of the catheter instrument 400; when the operator moves the directional lever of the master controller 300 left or right, the movement of the directional lever can be mapped to a corresponding yaw movement of the end of the catheter instrument 400. In this embodiment, the master controller 300 can control the end of the catheter instrument 400 to move within a 360° spatial range.

[0046] Figure 2 and Figure 3An embodiment of the catheter device 400 provided in this application is illustrated. The catheter device 400 is detachably connected to the power unit 240 of a robotic arm 230. The catheter device 400 includes a device housing 45 detachably connected to the power unit 240 and a catheter 48 connected to the device housing 45. When the device housing 45 is installed in the power unit 240, the driving force of the power unit 240 can be transmitted to the device housing 45, enabling the catheter 48 to move normally. For example, under the driving force of the power unit 240, the end of the catheter 48 can bend or change direction.

[0047] The instrument box 45 includes multiple drive wheels 451 driven by a power unit 240 and multiple drive wires 452. The power unit 240 includes multiple drive motors 241, and the drive motors 241, drive wheels 451, and drive wires 452 are arranged in a one-to-one correspondence. Each drive wheel 451 is detachably connected to its corresponding drive motor 241. When the instrument box 45 is installed on the power unit 240, the corresponding drive motor 241 can drive the drive wheel 451 to rotate, and the corresponding drive wire 452 is wound on the drive wheel 451. The movable part of the corresponding drive wire 452, that is, the part not wound on the drive wheel 451, extends into the catheter 48, extends along the length of the catheter 48, and is finally fixed to the end of the catheter.

[0048] In this application, the end, also referred to as the distal end or head, refers to the end away from the instrument box 45; the anterior end, also referred to as the proximal end or tail, refers to the end close to the instrument box 45.

[0049] A portion of the conduit 48, including its distal end, is a rotating section 49, the distal end of which is the distal end of the conduit 48. The rotating section 49 can be a joint assembly with high stiffness in the extension direction and low stiffness in the bending direction, capable of bending under the control of the drive wire 452, thereby achieving the steering of the conduit 48. In some embodiments, this joint assembly may be referred to as a snake bone.

[0050] In the plane perpendicular to the length direction of the rotating segment 49, the positions of each drive wire 452 can be considered fixed, while the drive wires 452 can extend or shorten along the length direction of the rotating segment 49. The fact that the end of the drive wire 452 is fixed to the end of the rotating segment 49 does not necessarily mean that the fixed position of the end of the drive wire 452 is within the end plane of the rotating segment 49. In practical applications, to better protect devices that may be mounted on the catheter 48 (such as endoscopes, surgical instruments, etc.), the end of the drive wire 452 can be fixed at a position that moves a small distance proximally from the end plane of the rotating segment 49. In this case, if the ratio of this distance to the length of the rotating segment 49 is less than a threshold, the fixed position of the end of the drive wire 452 can be considered to be within the end plane of the rotating segment 49 during the turning process of the end of the driving catheter 48.

[0051] The drive wheel 451 can rotate clockwise or counterclockwise under the drive of the corresponding drive motor 241. If the drive wheel 451 rotates in one direction, more of the corresponding drive wire 452 will be wound around the drive wheel 451, meaning some of the drive wire 452 that was originally part of the moving part will become wound, resulting in a shortening of the moving part. This process can also be called pulling the drive wire 452 or pulling / reeling in the wire; for ease of description, this direction is called forward. If the drive wheel 451 rotates in one direction, less of the drive wire 452 will be wound around the drive wheel 451, meaning some of the drive wire 452 that was originally wound around the drive wheel 451 will become part of the moving part, resulting in a lengthening of the moving part. This process can also be called unwinding the wire; for ease of description, this direction is called reverse. The direction of the winding of the corresponding drive wire 452 determines which direction is forward (clockwise) or reverse (counterclockwise).

[0052] The processor of the control system 600 is configured to perform the following steps to implement the conduit bending and redirection control method provided in an embodiment of this application. For example... Figure 4 As shown, this method includes:

[0053] Step S11: Obtain the position change of the catheter tip according to the catheter turning command from the master controller.

[0054] The positional change can include the direction angle α and the bending angle θ used to control the bending and turning of the catheter. The user can input catheter turning commands by operating at least one of the input devices such as the direction lever and buttons on the main controller.

[0055] Taking a directional lever as an example, a user can move the lever in any direction within the operating plane. This action is converted into an electrical signal by sensors within the main controller, which is the guide tube steering command. Specifically, this includes a first voltage and a second voltage collected on two mutually perpendicular axes of the main controller (i.e., the axes of the operating plane). The directional angle operated by the user is calculated based on the ratio of the first voltage and the second voltage. Specifically, the arctangent function or inverse cotangent function of this ratio can be calculated to obtain the directional angle operated by the user.

[0056] The square root of the sum of the squares of the first and second voltages is calculated as the composite value of the first and second voltages. This composite value reflects the force of the user's operation. Based on this composite value, the bending speed at the end of the conduit can be calculated; for example, the product of the composite value and a preset coefficient can be used as the bending speed. The bending angle of the user's operation is obtained by integrating the bending speed with respect to the command holding time, which refers to the duration of the same user operation.

[0057] The control interval is the interval between two adjacent duct tip turning controls. In some embodiments, only one duct turning command exists within each control interval, and the sampling interval of the master controller is fixed. In this case, the integration process can be omitted, and the bending speed can be directly used as the bending angle θ operated by the user.

[0058] To reduce the impact of operator jitter and main controller noise, the first and second voltages can be smoothed and filtered before calculating the direction angle and bending angle of the user's operation.

[0059] The bending angle operated by the user can be directly used as the bending angle θ in the position change. Furthermore, if the coordinate system of the operating plane is aligned with the coordinate system of the front end plane of the rotating section of the guide tube, i.e., the rotation angle between them is 0, then the direction angle operated by the user can be directly used as the direction angle α in the position change. Otherwise, the direction angle operated by the user can be transformed according to the mapping relationship between the two coordinate systems to obtain the direction angle α.

[0060] Alternatively, in addition to the necessary angle transformations, to make the steering smoother and reduce jumps, the calculated direction angle and bending angle of the user operation can be divided into multiple parts to obtain the direction angle α and bending angle θ in the position change. For example, if the bending angle of the user operation is 30°, the current duct steering command input by the user can be completed in 10 parts, with the bending angle θ in the position change used in each part being 3°.

[0061] Step S12: Determine the driving wheel and driven wheel in the drive wheel according to the position change, and calculate the angular position change of the driving wheel.

[0062] For the sake of simplicity, the direction angle α in the subsequent position change will be simply referred to as the direction angle change α, and the bending angle θ in the position change will be simply referred to as the bending angle change θ. These may not be the same as the direction angle and bending angle input by the user.

[0063] To facilitate the description of the rotation segment's attitude, coordinate systems are established for the front and rear planes of the rotation segment. For simplified calculations, the focal point of each coordinate system is the center of the plane. The coordinates of a certain driving wire in the front / rear plane refer to the coordinates of its fixed position within the front / rear plane. The angle is the angle between the vector pointing from the origin to the coordinates of the driving wire and the positive x-axis of the front / rear plane. The coordinates and angles of the same driving wire are consistent in both coordinate systems.

[0064] When the assembled catheter is in its natural state, i.e., before the end is turned, the coordinate system of the end plane of the rotating section is generally aligned with the coordinate system of the front plane. During the process of controlling the bending / turning of the catheter end, it can be assumed that the coordinate system of the front plane of the rotating section remains unchanged, while the coordinate system of the end plane will change under the action of the drive wire.

[0065] When the assembled conduit is in its natural state, the drive wires on each drive wheel can maintain a suitable tension. If a drive wire is pulled, it will cause the end of the conduit to bend in its fixed direction. This bending will pull on some or all of the other drive wires. If the tension on the drive wire from the bending of the conduit end is large enough, it will cause the corresponding drive wheel to rotate in the opposite direction a short distance. This distance is generally affected by the tension and elastic modulus of the drive wire. During this reverse rotation, because the change in tension is discontinuous, the abrupt change in force will cause abrupt changes in the speed of the corresponding drive wheel, which may lead to loosening of the wire. After rotating this distance, the drive wire is tightened. If the corresponding motor does not drive the drive wheel to rotate accordingly, the conduit will jam. If the tension on the drive wire from the bending of the conduit end is insufficient to overcome the resistance and cause the corresponding drive wheel to rotate in the opposite direction, the conduit will also jam after the drive wire is tightened to the limit determined by the system parameters (such as mechanical structure and dimensions, material properties, etc.). A stuck guide tube means the drive pulley cannot continue taking in the line, often preventing it from rotating to the position indicated by the angular position change, and the end of the guide tube cannot bend properly to the target position. Therefore, in order for the drive pulley to take in the line normally, some or all of the drive pulleys corresponding to the pulled drive wire need to act as driven pulleys to follow the line release.

[0066] Taking a pair of opposing drive wheels as an example, opposing setting means that the line connecting the drive wires corresponding to the two drive wheels at the fixed position at the end of the guide tube passes through the center of the plane at the end of the guide tube, that is, the angle difference between the drive wires is π. When one drive wheel rotates forward as the driving wheel to pull the line, the other drive wheel needs to follow the line release as the driven wheel.

[0067] The number of drive wires is n, where n is an integer greater than 2. These n drive wires divide the front end plane of the rotating section of the catheter into n angular intervals. The drive wires corresponding to the two ends of the interval to which the angular change α belongs can be designated as active drive wires, and the drive wheels connected to these active drive wires are designated as active wheels. Some or all of the remaining drive wheels are designated as driven wheels. When determining the interval to which the angular change α belongs, the endpoints of the interval are not included. If the angular change α falls on an endpoint, i.e., has the same angle as a certain drive wire, only that drive wire can be selected as the active drive wire. In some embodiments, if the number and position of the drive wires support this, the number of active wheels can be greater than 2. When the active wheels are determined, some or all of the drive wheels other than the active wheels can be selected as driven wheels based on the number and position distribution of the drive wires.

[0068] The following examples, with reference to the accompanying diagrams, illustrate the specific methods for identifying the driving and driven wheels. For simplicity, the numbers of the corresponding drive wires, drive wheels, and motors are the same in the examples below, but they may differ in practice; the drive wires are shown as uniformly distributed, but they may not be uniformly distributed in practice.

[0069] Example 1:

[0070] In this example, n=3 and the driving wires are evenly distributed. The angles of driving wires 1, 2, and 3 in the front plane coordinate system of the rotating segment are 0, 2π / 3, and 4π / 3, respectively.

[0071] If the change in direction angle is one of 0, 2π / 3, or 4π / 3, then the drive wheel connected to the drive wire with the same angle as the change in direction angle is the driving wheel, and the remaining two drive wheels are the driven wheels.

[0072] If the change in direction angle That is, falling into Figure 5 The shaded area in section A indicates that drive wheels 1 and 2 are the driving wheels, and drive wheel 3 is the driven wheel.

[0073] If the change in direction angle That is, falling into Figure 5 The shaded area in section B indicates that drive wheels 2 and 3 are the driving wheels, and drive wheel 1 is the driven wheel.

[0074] If the change in direction angle That is, falling into Figure 5 The shaded area in section C indicates that drive wheels 3 and 1 are the driving wheels, and drive wheel 2 is the driven wheel.

[0075] Example 2:

[0076] In this example, n=4 and the driving wires are evenly distributed. The angles of driving wires 5, 6, 7, and 8 in the front plane coordinate system of the rotating segment are 0, π / 2, π, and 3π / 2, respectively.

[0077] If the change in azimuth angle is one of 0, π / 2, π, or 3π / 2, then the drive wheel connected to the drive wire with the same angle as the change in azimuth angle is the driving wheel, and the drive wheel opposite to the driving wheel is the driven wheel. For example, if the change in azimuth angle is π / 2, then drive wheel 6 is the driving wheel, drive wheel 8 is the driven wheel, and drive wheels 5 and 7 are neither driving wheels nor driven wheels, meaning they do not need to rotate.

[0078] If the change in direction angle That is, falling into Figure 6 The shaded area in section A indicates that drive wheels 5 and 6 are the driving wheels, and drive wheels 7 and 8 are the driven wheels.

[0079] If the change in direction angle That is, falling into Figure 6 The shaded area in section B indicates that drive wheels 6 and 7 are the driving wheels, and drive wheels 8 and 5 are the driven wheels.

[0080] If the change in direction angle That is, falling into Figure 6 The shaded area in section C indicates that drive wheels 7 and 8 are the driving wheels, and drive wheels 5 and 6 are the driven wheels.

[0081] If the change in direction angle That is, falling into Figure 6 The shaded area in section D indicates that drive wheels 8 and 5 are the driving wheels, and drive wheels 6 and 7 are the driven wheels.

[0082] Similarly, when n is an odd number greater than 4 and the driving wires are uniformly distributed, if the change in direction angle... If the angle is the same as that of a certain drive wire, then the drive wheel corresponding to that drive wire can be selected as the driving wheel, and the angle is opposite to the change in direction angle. The drive wheels corresponding to the two closest drive wires are taken as driven wheels; if the change in direction angle... If the angle is the same as that of a certain drive wire, then the drive wheel corresponding to that drive wire can be selected as the driven wheel, and the change in angle and direction angle... The drive wheels corresponding to the two closest drive wires are taken as the driving wheels; if the change in direction angle... and Since the angles of any driving wires are different, the changes in angle and direction angle can be selected. The drive wheels corresponding to the two closest drive wires are used as the driving wheels, and the opposite angle of the change in angle and direction angle is... The drive wheels corresponding to the two closest drive wires are designated as driven wheels. Unselected drive wheels do not need to move.

[0083] When n is an even number greater than 4 and the driving wires are uniformly distributed, if the change in direction angle... If the angle is the same as that of a certain drive wire, then the drive wheel corresponding to that drive wire can be selected as the driving wheel, and the angle is opposite to the change in direction angle. The drive wheel corresponding to the same drive wire is the driven wheel; if the change in direction angle... Since the angles of any driving wires are different, the changes in angle and direction angle can be selected. The drive wheels corresponding to the two closest drive wires are used as the driving wheels, and the opposite angle of the change in angle and direction angle is... The drive wheels corresponding to the two closest drive wires are designated as driven wheels. Unselected drive wheels do not need to move.

[0084] In addition, there is a special case where n=2, that is, two drive wires are set opposite each other. In this case, the change in the direction angle of the drive wire controlling the rotation of the catheter end can actually only be the angle of one of the two drive wires. The drive wheel corresponding to the drive wire with the same change in direction angle is the driving wheel, and the other drive wheel is the driven wheel.

[0085] Generally, under the action of the drive wire, the rotating segment / catheter tip can bend with two degrees of freedom. The state / pose of the rotating segment / catheter tip can be described by two joint variables—bending angle and orientation angle. Typically, the orientation angle describes the direction in which the rotating segment / catheter tip bends, and its value range can be 2π. The specific range can be determined according to actual needs, such as [0, 2π], [-π,π], etc. The bending angle describes the degree of bending of the rotating segment / catheter tip. Its lower limit can be 0, representing the unbent natural state, and the upper limit can be determined according to actual conditions, generally not exceeding π, such as π / 2, 2π / 3, etc.

[0086] Under the influence of position change, the guide tube tip transforms from its current state to the target state, that is, from its current pose to the target pose. In guide tube steering control, the focus is mainly on the transformation of the guide tube tip from its current position to the target position, and based on this, the change in the length of the active drive wire, that is, the take-up length of the drive wheel, is calculated, and then the change in the angular position of the drive wheel is calculated. The following example, with reference to the attached diagram, illustrates the specific calculation process of the change in the angular position of the drive wheel.

[0087] like Figure 7 As shown in a specific embodiment of this application, calculating the angular position change of the drive wheel includes the following sub-steps:

[0088] S101: Calculate the position increment offset of the catheter tip under the influence of position change.

[0089] Due to the structural design of the rotating segment, it can be approximated as a circular arc during bending and turning. A kinematic model can be established for the rotating segment based on this characteristic, and the position increment offset can be calculated based on this kinematic model.

[0090] For example, a structure like this can be established for the rotating segment. Figure 8 The kinematic model shown has a rotation segment of length L, which is abstracted as a circle with radius r perpendicular to the length direction. The coordinate system of the front end of the rotation segment is... The xoy plane is the front-end plane with its origin at the center of the circle on the front-end plane. During rotation, it can be treated as stationary, functioning similarly to a world coordinate system. The coordinate system of the end point of the rotating segment in the current state is... The xoy plane is the end plane, and the origin is the center of the circle on the end plane. The transformation of the end coordinate system of the rotating segment relative to the front coordinate system in the current state can be achieved using the current direction angle. and current bending angle To describe. More specifically, the current bending angle. The arc angle is the arc angle of a circle of length L formed by the center of the front plane and the center of the end plane in the current state, and the current direction angle. Let be the rotation angle of the xoy plane of the end coordinate system relative to the xoy plane of the front coordinate system in the current state. Based on this model, in the Cartesian coordinate system, the transformation matrix of the end coordinate system relative to the front coordinate system in the current state can be expressed as:

[0091]

[0092] in This indicates the attitude transformation of the end-effector coordinate system relative to the front-effector coordinate system in the current state; The positional transformation of the end coordinate system relative to the front coordinate system in the current state can be represented by a vector pointing from the center of the front plane to the center of the end plane in the current state.

[0093] Calculate the current direction angle Direction angle in position change The sum of these values ​​is used as the target direction angle. Calculate the current bending angle With the bending angle in the change of position The sum is used as the target bending angle In practical applications, if the calculated target direction angle exceeds the set range, it can be added to or subtracted by 2π to return it to the range; if the calculated target curvature angle is greater than the upper limit of the curvature angle range, it can be corrected to the upper limit of the curvature angle range; if the calculated target curvature angle is negative, it can be added to or subtracted by π according to the range of the direction angle to reverse it, and the target curvature angle can be modified to its absolute value.

[0094] In a Cartesian coordinate system, the transformation matrix of the end coordinate system relative to the front coordinate system in the target state can be expressed as:

[0095]

[0096] in This represents the attitude transformation of the end-effector coordinate system relative to the front-effector coordinate system under the target state; The positional transformation of the end coordinate system relative to the front coordinate system in the target state can be represented by a vector pointing from the center of the front plane to the center of the end plane in the target state.

[0097] The position increment offset can be calculated based on the position changes in the current state and the position changes in the target state. It can be represented by a vector pointing from the center of the end plane in the current state to the center of the end plane in the target state.

[0098] S102: Calculate the take-up length of each drive wheel based on the position increment offset.

[0099] The position increment offset describes the transformation of the guide tube tip from its current position to its target position. A drive wire can be added to the kinematic model described above. Each drive wire is fixed at a position on a circle perpendicular to its length. The drive wire can be treated as a straight line, arc, multi-segment broken line, or multi-segment arc along its length. When discussing kinematic model-related content, unless otherwise specified, the drive wire generally refers to the drive wire within the rotating segment. Based on the kinematic model, a mapping function between the position increment offset and the winding length of the driving wheel (i.e., the shortening of the driving wire) can be calculated. Substituting this into the position increment offset obtained in S101 allows the calculation of the winding length of each driving wheel.

[0100] The mapping function can be an analytical solution calculated from a kinematic model, or a function obtained by approximating or fitting the analytical solution to simplify the calculation.

[0101] S103: Calculate the change in angular position of the driving wheel based on the length of the line taken up by the driving wheel.

[0102] Specifically, by combining the geometric parameters of the drive wheel (such as the winding radius of the drive wire) and the winding length of the drive wheel, the value of the change in angular position can be calculated. Then, based on the winding direction of the drive wire, the rotation direction of the drive wheel (clockwise or counterclockwise) can be determined. By combining the two, the change in angular position of the drive wheel can be obtained.

[0103] like Figure 9 As shown, in another specific embodiment of this application, calculating the angular position change of the drive wheel includes the following sub-steps:

[0104] S111: Obtain the kinematic model of the rotation segment.

[0105] S112: Calculate the length difference of the active drive wire in the current state and the target state under the influence of position change based on the kinematic model, and use it as the take-up length of the active wheel.

[0106] Still with Figure 8 The kinematic model shown is used as an example. There are 4 driving wires that are evenly distributed, and each driving wire is abstracted as a straight line. Figure 8 The plane at the bottom center is the front end plane, denoted by i-1. B1, B2, B3, and B4 are the fixed points of drive wires 1, 2, 3, and 4 on the front end plane, respectively. O is the center of the front end plane. For ease of calculation, OB1 is defined as the positive x-axis of the front end coordinate system, OB2 is defined as the positive y-axis of the front end coordinate system, and the z-axis of the front end coordinate system is perpendicular to the front end plane and points to the end plane. Figure 8 The plane above the middle is the end plane, denoted by i. P1, P2, P3, and P4 are the fixed points of drive wires 1, 2, 3, and 4 on the end plane, respectively. C is the center of the end plane. For ease of calculation, CP1 is defined as the positive x-axis of the end coordinate system, CP2 is defined as the positive y-axis of the end coordinate system, and the z-axis of the end coordinate system is perpendicular to the end plane and points away from the front plane.

[0107] Based on this model, the current state can be obtained. The length of the j-th driving wire:

[0108]

[0109]

[0110] Where j = 1, 2, 3, 4.

[0111] target state Substituting into the above formula, we can obtain the target state. The length of the j-th driving wire:

[0112]

[0113]

[0114] Based on the previously determined numbering of the driving wheels, the change in length of the driving wire between the current state and the target state is calculated as the take-up length of the driving wheel. If the driving wheel numbered j is the driving wheel, the take-up length is directly calculated based on the kinematic model. for:

[0115]

[0116] The above formulas can be processed using approximation, fitting, or other methods to simplify calculations.

[0117] S113: Calculate the change in angular position of the driving wheel based on the length of the line taken up by the driving wheel.

[0118] Specifically, by combining the geometric parameters of the drive wheel (such as the winding radius of the drive wire) and the winding length of the drive wheel, the value of the change in angular position can be calculated. Then, based on the winding direction of the drive wire, the rotation direction of the drive wheel (clockwise or counterclockwise) can be determined. By combining the two, the change in angular position of the drive wheel can be obtained.

[0119] like Figure 10 As shown, in another specific embodiment of this application, calculating the angular position change of the drive wheel includes the following sub-steps:

[0120] S121: Calculate the single-wheel take-up length based at least on the bending angle.

[0121] In this embodiment, the calculation of the take-up length is further decomposed. If the change in direction angle is consistent with the angle of a certain drive wire, only the drive wheel corresponding to that drive wire will be selected as the driving wheel. In this case, the take-up length of the driving wheel is the single-wheel take-up length. The single-wheel take-up length is not affected by the actual change in direction angle and can be determined by the current bending angle and the change in bending angle at the end of the rotating section.

[0122] Still with Figure 8 The motion model shown is used as an example for illustration; a detailed description of this motion model can be found in the relevant content of the foregoing embodiments. The single-wheel take-up length is directly calculated based on the model. for:

[0123]

[0124] The above formulas can be processed using approximation, fitting, or other methods to simplify calculations.

[0125] S122: Calculate the take-up length of each drive wheel based on the single wheel take-up length and direction angle.

[0126] In actual control, the change in direction angle is often different from the angle of the drive wire, requiring two drive wheels to work together to pull the wire and control the end of the guide tube to turn according to the change in direction angle. The take-up length of a single wheel can be mapped to the take-up length of each drive wheel according to the angle between the change in direction angle and each active drive wire.

[0127] S123: Calculate the change in angular position of the driving wheel based on the length of the line taken up by the driving wheel.

[0128] Specifically, by combining the geometric parameters of the drive wheel (such as the winding radius of the drive wire) and the winding length of the drive wheel, the value of the change in angular position can be calculated. Then, based on the winding direction of the drive wire, the rotation direction of the drive wheel (clockwise or counterclockwise) can be determined. By combining the two, the change in angular position of the drive wheel can be obtained.

[0129] In the kinematic model example given above, the drive wire is treated as a straight line. However, this model contains errors compared to reality, and these errors increase non-linearly with the increase of the bending angle at the end of the rotating segment / conduit. To improve the accuracy of steering control, a more complex but accurate kinematic model can be selected, such as treating the drive wire as a multi-segment broken line / multi-segment arc, or treating the rotating segment as a multi-segment circular arc. Furthermore, other calculation methods besides the kinematic model can be introduced as needed to modify the formula for calculating the take-up length and / or correct the model's calculation results.

[0130] The calculation methods given above can be used individually or in combination. For example, one of the calculation methods can be selected based on the segmentation of the bending angle. Experiments can be conducted to determine how to segment the bending angle and / or the calculation method corresponding to each segment in order to meet the requirements for the accuracy and / or real-time performance of steering control.

[0131] Step S13: If the end of the guide tube meets the preset conditions, control the drive motor corresponding to the drive wheel to drive the drive wheel to rotate according to the angular position change. At the same time, calculate the planned force of the drive motor corresponding to the driven wheel according to the target of zero force on the drive wire corresponding to the driven wheel, and control the drive motor corresponding to the driven wheel to output the planned force.

[0132] The angular position change of the corresponding drive motor can be calculated based on the engagement method between the drive wheel and the corresponding drive motor, according to the angular position change of the drive wheel obtained in S12.

[0133] Drive motors can have three basic control modes: position control, speed control, and current control (also known as torque control). Position control can be selected, in which case the control quantity for the drive motor is angular position. The target angular position can be calculated by summing the current angular position and the change in angular position, and then sent to the drive motor controller; alternatively, the change in angular position can be directly sent to the drive motor controller, which then calculates the target angular position. Alternatively, speed control can be selected, in which case the control quantity for the drive motor is angular velocity. The angular velocity is obtained by dividing the change in angular position by the control interval, and then sent to the drive motor controller.

[0134] Furthermore, drive motors typically employ a three-loop control system, consisting of a current loop, a speed loop, and a position loop from the inside out. The output of the outer loop is the input of its adjacent inner loop. The drive motor controller can perform the three-loop control independently, or it can delegate some or all of the three loops to a host computer (in this application, the processor of the control system 600). For example, if angular position is originally used as the control variable, the position loop of the motor control can be handled by the host computer, in which case the processor sends the angular velocity processed by the position loop to the drive motor controller.

[0135] For the driven wheel, the same position control as for the driving wheel can be used. This involves calculating the angular position change of the driven wheel and controlling the corresponding drive motor to rotate the driven wheel according to the angular position change. For this purpose, a parameter is introduced: a position ratio distribution coefficient, which represents the ratio of the take-up length of the driving wheel to the release length of the corresponding driven wheel. Using the position ratio distribution coefficient of a given driven wheel and the take-up length of the corresponding driving wheel calculated in S12, the release length of that driven wheel can be calculated.

[0136] For a duct with n driving wheels, theoretically each driving wheel can have n-1 position proportionality coefficients, which represent the position proportionality coefficients of itself as a driven wheel when all other driving wheels are driving wheels (excluding itself). For the i-th driving wheel, its position proportionality coefficients can be represented as a set [k ij Let i, j = 1, ..., n and i ≠ j. In practical applications, depending on the number of drive wheels and the corresponding distribution of drive wires, some positional allocation coefficients can be fixed as 0. In this case, these positional allocation coefficients can be omitted from the set. For example, when n = 4 and the drive wires are evenly distributed, the positional allocation coefficient between the drive wheels corresponding to two adjacent drive wires can be fixed as 0, and only the positional allocation coefficient between the two pairs of oppositely positioned drive wheels is retained.

[0137] If the rotating segment can be treated as a rigid body, then the position proportionality coefficient is a constant. However, the deformation of the rotating segment during motion is often non-negligible, and the actual position proportionality coefficient changes non-linearly. To more accurately describe the position proportionality coefficient, a current position proportionality coefficient is defined to represent the ratio of the take-up length of the driving wheel to the corresponding let-out length of the driven wheel in the current state.

[0138] If the current position proportional allocation coefficient is the ratio of the line length released by the driven wheel to the line length taken up by the driving wheel, the change in the angular position of the driven wheel can be the sum of the product of the change in the angular position of the driving wheel corresponding to the driven wheel and the current position proportional allocation coefficient.

[0139] The calculation function for the angular position change of the driven wheel can be independent or combined with the calculation function for the angular position change of the driving wheel. For example, if position increment offset is used for calculation, a combined function—an angle increment allocation function—can be set for all driving wheels. The input of this function can include the current position proportional allocation coefficient and the direction angle in the position change. In addition to the position increment offset, based on the input, this function can determine the driving wheel and the driven wheel, calculate the angular position change of the driving wheel and the angular position change of the driven wheel, and finally output the angular position change of each driving wheel.

[0140] Before this step, the current position proportional allocation coefficient can be obtained. The current bending angle of the guide tube end is input into a pre-stored mapping relationship to obtain the current position proportional allocation coefficient of the driven wheel. The output of the mapping relationship includes the current position proportional allocation coefficient, and the input must include at least the current bending angle.

[0141] Multiple test samples can be pre-collected, and the samples can be processed using methods such as piecewise function, curve (e.g., polynomial) fitting, and neural network training to obtain the mapping relationship. During the sample collection process, the driven wheel can be manually adjusted to a suitable position, i.e., a position that meets the line feeding conditions. Then, the angular position of the driven wheel is recorded to calculate the line feeding length / angular position change. The line feeding conditions can include the driving wheel moving to the target position and the driven drive wire wound on the driven wheel maintaining a suitable tension.

[0142] Based on the structural design of the rotating section, the nonlinear change of the position ratio allocation coefficient is sensitive to at least the bending angle. Each sample set must include at least one of the following: the current bending angle, the change in bending angle during the current motion, and the target bending angle; at least one of the following: the line length of the driving wheel, the change in angular position, and the angular position; and at least one of the following: the line length of the driven wheel, the change in angular position, and the angular position. Of course, a direction angle can be introduced into the independent variable of the mapping relationship. In this case, the sample can further include at least one of the following: the current direction angle, the change in direction angle during the current motion, and the target direction angle.

[0143] For example, when n=4 and the drive wires are uniformly distributed, one drive wire can be selected and stretched individually from its natural state until the set maximum bending angle is reached. During this process, multiple sets of samples are collected. Each set includes the angular position of the driving wheel, the angular position of the driven wheel, and the current bending angle. For the m-th sample, the difference between its angular position and that of the driving and driven wheels in the (m-1)-th sample can be calculated. Then, the ratio of the difference in the driven wheel's angular position to the difference in the driving wheel's angular position is calculated and used as the current position proportional allocation coefficient for the m-th sample. The mapping relationship can be in the form of a high-order polynomial. The input is the current bending angle, and the output is the current position proportional allocation coefficient. Multiple sets of samples are used to fit and determine the coefficients of each term in the polynomial, resulting in the final mapping relationship for subsequent control.

[0144] It can be seen that in the above-mentioned position control scheme of the driven wheel, the control effect is directly related to the accuracy of the position proportional distribution coefficient. The nonlinear change of the position proportional distribution coefficient comes from the structural design of the rotating section. The larger the bending angle of the end of the guide tube, that is, the further away from the unbent state, the more obvious the nonlinear change of the position proportional distribution coefficient is.

[0145] To improve control performance, the aforementioned position control scheme pre-collects and processes multiple sets of samples to obtain mapping relationships for calculating the current position proportional allocation coefficient. However, due to inconsistencies in catheter material properties and assembly processes, different catheters yield different samples, and may even require different models to construct the mapping relationship. This necessitates collecting samples and processing the mapping relationship for each catheter before use, which is time-consuming. Furthermore, in areas with significant curvature at the catheter tip, insufficient sample collection or an inappropriate model selection may lead to large errors in the current position proportional allocation coefficient calculated using the mapping relationship. This can cause the catheter to jam or the driven wheel to slacken during bending and turning, affecting the control performance.

[0146] To at least partially solve the above problems, at least under the condition that the catheter tip meets the preset conditions, the drive motor corresponding to the driven wheel is controlled in force mode. The control target is that the drive wire corresponding to the driven wheel is under zero force, that is, the drive wire corresponding to the driven wheel can move in accordance with the external force (here referring to the tension caused by the bending of the catheter) as if it is in an environment with zero force. This control method can also be called zero force control of the drive wire corresponding to the driven wheel.

[0147] The preset conditions include at least one of the current bending angle and the target bending angle at the catheter tip falling within a preset range. Specifically, the preset conditions can be that the current bending angle falls within a preset range, or the target bending angle falls within a preset range, or either the current bending angle or the target bending angle falls within a preset range, or both the current bending angle and the target bending angle fall within a preset range.

[0148] If the catheter tip does not meet the preset conditions, the force mode can still be used to control the drive wire corresponding to the driven wheel with zero force, or the same position control as the driving wheel can be used. If the force mode is used, the process of collecting samples and constructing a mapping relationship can be omitted. If position control is used, since the nonlinear change of the position proportional allocation coefficient outside the preset range is less obvious, a smaller number of samples and a simpler model can construct a sufficiently accurate mapping relationship, and the change of the position proportional allocation coefficient can even be treated as linear.

[0149] Because controlling the position of the driven wheel is less effective in areas with significant bending at the catheter tip, the preset range generally includes a range far from the initial bending angle (i.e., the bending angle in the unbent state). Specifically, the boundary of the preset range may include the maximum bending angle threshold, and another boundary of the preset range may be called the bending angle transition threshold. The maximum bending angle threshold at the catheter tip is T. m The bending angle transition threshold is T. g Then the preset range can be represented as [T] g , T m ].

[0150] Bending angle transition threshold T g The range of values ​​is [0, T] m The bending angle transition threshold T can be set according to requirements. g The value, for example, the change of the distribution coefficient at positions outside the preset range can be regarded as linear as the target, and the bending angle transition threshold T is estimated based on system parameters (such as mechanical structure and size, material properties, etc.). g Alternatively, samples can be collected to fit the mapping relationship between the bending angle and the positional allocation coefficient, thereby determining the bending angle transition threshold T. g .

[0151] To achieve the goal of zero force on the drive wire corresponding to the driven wheel, the force on the drive wire corresponding to the driven wheel can be acquired in real time during the control of the drive wheel's rotation. Based on this, the planned force of the drive motor corresponding to the driven wheel can be set. For example, the planned force can be the same as the force on the drive wire corresponding to the driven wheel, enabling the driven wheel to follow the drive wheel in line release. For ease of description, in this application, each force has two attributes: direction and magnitude. The direction is simplified to positive and negative. Positive force can be directed away from the end of the guide tube, and it acts to either drive the line take-up or hinder line release. Negative force can be directed towards the end of the guide tube, and it acts to either drive the line release or hinder the take-up. Conversely, positive force can be directed towards the end of the guide tube, and it acts to either drive the line take-up or hinder the take-up; negative force can be directed away from the end of the guide tube, and it acts to either drive the line take-up or hinder the take-up. The following explanation uses an example where positive force is directed away from the end of the guide tube and negative force is directed towards the end of the guide tube.

[0152] In some embodiments, force / torque sensors may be provided on the drive wheel and / or drive wire. Based on the feedback value of the force / torque sensors on the driven wheel and / or its corresponding drive wire, the force on the drive wire corresponding to the driven wheel, i.e., the feedback force, can be obtained directly or indirectly. Then, a planning force can be set based on the feedback force of the drive wire corresponding to the driven wheel; for example, the planning force can be set to be equal to the feedback force.

[0153] If neither the drive wheel nor the drive wire has a force / torque sensor, a position sensor is needed to indirectly obtain the force on the drive wire corresponding to the driven wheel. The position sensor can be located on the drive motor or on the drive wheel / drive wire, and can directly measure angular or linear position. For example, the position sensor can be the encoder of the drive motor.

[0154] During the wire laying process, the drive wire can be regarded as a spring-damped system. According to the model of the spring-damped system, the resistance experienced by the drive wire is the sum of the spring force and the damping force. The magnitude of the spring force is proportional to the position of the drive wire, and the direction is opposite to the direction of the position. The position of the drive wire can be calculated using the position feedback from the position sensor. The magnitude of the damping force is proportional to the velocity, and the direction is opposite to the velocity. The velocity of the drive wire can be obtained by calculating the differential of the position of the drive wire with respect to time.

[0155] The prerequisite for using a position sensor to accurately determine the force on the drive wire corresponding to the driven wheel is that the drive wire can rotate under the action of external forces (the force output by the drive motor and / or the tension caused by the bending of the guide tube end). In the initial stage of controlling the motor corresponding to the drive wheel to rotate, the guide tube end begins to bend and change direction under the action of the drive wheel winding, bringing tension to the drive wire corresponding to the driven wheel. The actual force on the drive wire corresponding to the driven wheel changes. If this tension is insufficient to overcome the resistance, the driven wheel will not rotate, and the position and velocity obtained from the sensor will remain unchanged. The calculated force on the drive wire will remain unchanged, which does not match the actual situation. It is impossible to accurately control the rotation of the driven wheel, and the guide tube may still get stuck.

[0156] To at least partially solve the above problems, an initial force can be applied to the drive wire during the initial stage of driving the drive wheel's rotation to help overcome resistance; that is, the planned force is set as the initial value. The magnitude of the initial value can be measured experimentally or estimated based on system parameters (such as mechanical structure and dimensions, material properties, etc.), and the direction is opposite. Under the action of the initial value, the driven wheel will start rotating directly to lay out the wire, or it may remain stationary temporarily, and then begin rotating to lay out the wire under the tension from the end of the guide tube.

[0157] The initial values ​​for different drive wheels can be the same or different. For a given drive wheel, the initial value can be a single fixed value; or the preset range can be further divided into at least two parts, each corresponding to an initial value; or a function for calculating the initial value, including the bending angle, can be obtained beforehand through experiments / modeling, and then the initial value can be calculated using this function. Generally, a suitable initial value should be sufficient to assist the driven wheel in starting to rotate before the corresponding drive wire is stretched to the limit determined by the system parameters (e.g., mechanical structure and dimensions, material properties, etc.) by the end of the guide tube.

[0158] Subsequently, during the rotation of the drive wheel, the planned force is equal to the sum of the initial value, the damping force, and the spring force. The change in tension brought by the end of the guide tube will affect the speed and position of the drive wheel, which in turn will affect the damping force and the spring force, and thus affect the calculated planned force.

[0159] Apart from the initial stage, the formula for calculating planning force can be expressed as:

[0160] F prf =F0+F v +F p

[0161] Where F prf For the planning force, F0 is the initial value, F v For damping force, F p This is the spring force.

[0162] For example, a position sensor is an encoder mounted on a drive motor, which can provide feedback on the motor's current angular position. Based on the dimensions and assembly relationship of the motor and drive wheels, the position of the drive wheels can be calculated. Alternatively, an encoder can be mounted on the drive wheels, and the position of the drive wheels can be directly obtained from the encoder's feedback signal. The speed of the drive wheels can be obtained by calculating the derivative of the drive wheel's position with respect to its velocity. For example, subtracting the previous position from the current position of the drive wheel, and then dividing the difference by the time interval between the two encoder feedback moments, gives the current speed of the drive wheel.

[0163] The damping force is calculated based on the speed of the driven wheel; specifically, the magnitude of the damping force is directly proportional to the speed. Strictly following the spring-damped system model, the magnitude of the damping force is directly proportional to the speed, and this proportionality coefficient can be called the damping coefficient. However, in practical applications, the formula for calculating the damping force can be adjusted based on actual needs. The adjusted damping force and speed may not always maintain a direct proportional relationship. But generally speaking, as the current speed increases, the magnitude of the damping force either increases or remains constant; this relationship is defined as a positive correlation between the damping force and speed.

[0164] The spring force is calculated based on the position of the driven wheel; specifically, the magnitude of the spring force is positively correlated with the position. Strictly following the spring-damped system model, the magnitude of the spring force is directly proportional to the position, and this proportionality constant can be called the spring constant. However, in practical applications, the formula for calculating the spring force can be adjusted based on actual needs. The adjusted spring force and position may not always maintain a direct proportional relationship. But generally speaking, as the current position increases, the magnitude of the spring force either increases or remains constant; this relationship is defined as a positive correlation between the spring force and the position.

[0165] Optionally, to make the control in force mode smoother, a maximum value can be set for the damping force and / or spring force. If the calculated damping force and / or spring force are greater than the maximum value, they can be corrected to the maximum value. If both the damping force and spring force are set to maximum values, their magnitudes can be the same or different.

[0166] In force mode, the calculated control quantity for the drive motor is force. If the motor becomes uncontrollable during control, such as when its position and / or speed exceed allowable limits, the planned force calculated using the above formula may not be sufficient to resolve the uncontrollability issue promptly. This could lead to the motor remaining uncontrollable for an extended period, causing motor malfunction or even damage. To address potential motor uncontrollability issues promptly, position and / or speed limits can be added to the force control mechanism.

[0167] Optionally, if the driven wheel's position falls within the over-limit zone, the maximum reverse force corresponding to the over-limit zone is used as the planning force to control the driven wheel to quickly return to its allowable position. The over-limit zone refers to the area of ​​the drive wheel outside the restricted area of ​​the joint space, while the restricted area refers to the area where the drive wheel can move freely. The over-limit zone includes two sub-regions: the forward over-limit zone and the reverse over-limit zone. The forward over-limit zone is closer to the forward boundary of the restricted area, and the reverse over-limit zone is closer to the reverse boundary of the restricted area. The direction of the maximum reverse force corresponding to the over-limit zone is from the over-limit zone to the restricted area, and its magnitude is the maximum allowable value of the system parameters (e.g., the parameters of the drive motor). For example, if the position falls within the forward over-limit zone, the planning force is the maximum reverse force that the drive motor can output; if the position falls within the reverse over-limit zone, the planning force is the maximum forward force that the drive motor can output. Here, forward and reverse can be defined based on take-up and let-out, such as forward corresponding to take-up and reverse corresponding to let-out, or forward and reverse can be defined according to the rotation direction of the drive wheel, such as forward corresponding to clockwise and reverse corresponding to counterclockwise.

[0168] Specifically, the guide tube can be pre-pulled to the boundary of the bending angle range at multiple directional angles, and the corresponding positions of each drive wheel can be recorded. These directional angles generally include the directional angles corresponding to a single drive wheel acting as the driving / driven wheel. During this process, manual adjustment or the introduction of force / torque sensors can be used to maintain each drive wire at a suitable tension. Then, all recorded positions are counted to obtain the maximum range of motion of each drive wheel. The maximum range of motion can be directly used as the limiting area, or it can be appropriately adjusted (e.g., appropriately expanded or reduced) before being used as the limiting area.

[0169] Since the drive wheel typically experiences the greatest positional change when acting alone as the driving / driven wheel, the process of determining its maximum range of motion can be simplified. Specifically, for a drive wire with an angle γ in the front / end plane, the guide tube can be controlled to bend to (γ, The position of ) This represents the maximum value within the range of bending angles. The position of the drive wheel corresponding to the drive wire at this point is recorded as its positive maximum value. Additionally, the guide tube is controlled to bend to (γ+π, The position of the drive wire is recorded, and the position of the corresponding drive wheel is taken as its maximum reverse value. This process is repeated for each drive wire to obtain the maximum range of motion of each drive wheel. Furthermore, if there are pairs of drive wheels positioned opposite each other, the position of the other drive wheel is its maximum reverse value when the position of one drive wheel reaches its maximum forward value. Bending to these two positions yields the maximum range of motion for a pair of opposite drive wheels.

[0170] Specifically, if the speed of the driven wheel exceeds the speed limit, the control force is adjusted to bring the speed of the driven wheel back to the speed limit. The control force can be adjusted so that the direction of the force output by the drive motor immediately or quickly changes to the opposite direction of the speed, thereby reducing the speed of the driven wheel and bringing it back to the speed limit.

[0171] Furthermore, the restricted area of ​​the drive wheel in the joint space can be further divided into a free zone and a transition zone, with the transition zone located between the free zone and the over-limit zone. The control strategy in the transition zone can be the same as or different from that in the free zone.

[0172] The specific control strategy is illustrated below with reference to the attached diagram. The joint space of the drive wheel is divided into... Negative over-limit zone negative transition region Free Zone Positive transition zone, and Positive over-limit zone. If the current position of the driven wheel is in... In the negative over-limit zone, the planned force is the maximum positive force. If the current position of the driven wheel is... In the negative transition zone, the planned force is calculated based on a target speed of 0, so that the drive wheel stops as close to the negative transition zone as possible and does not enter the negative over-limit zone. If the current position of the driven wheel is in In the free zone, it checks if the current speed exceeds the speed limit. If it does, it calculates the planning force to return the speed to the speed limit; otherwise, it uses the standard formula to calculate the planning force to control the driven wheel to follow the lead wheel's line release. If the current position of the driven wheel is in... In the positive transition zone, the planned force is calculated based on a target speed of 0, so that the driving wheel stops as close to the target speed as possible in the positive transition zone without entering the positive over-limit zone. If the current position of the driven wheel is in In the positive over-limit zone, the planning force is the maximum force in the opposite direction.

[0173] Under normal circumstances, the planning force is calculated using the conventional formula, i.e., F. prf =F0+F v +F p In unconventional conditions, new control objectives arise, such as achieving zero speed, returning to the speed limit, or leaving the over-limit zone. In these cases, the planning force can be set to a preset value, or a different calculation formula can be used than that used in conventional conditions. The direct expression of the calculation formula in unconventional conditions can differ from the conventional formula, for example, by introducing new variables; or the calculation formula in unconventional conditions may still be F. prf =F0+F v +F p However, the calculation formulas for damping force and / or spring force differ from those under normal conditions in order to achieve new control objectives.

[0174] In addition, to make the control of the driven wheel smoother and reduce jumps, the calculated planning force can be processed by at least one method, such as segmentation and smoothing filtering, before being sent to the drive motor corresponding to the driven wheel.

[0175] Since there is no force in the basic control mode of the drive motor, the controller of the drive motor cannot directly control the drive motor according to the force. Therefore, it is necessary to convert the planned force into a control quantity that the drive motor can handle and then send it to the controller of the drive motor.

[0176] For example, the planning force can be converted into the current controlling the drive motor according to the following formula:

[0177] fCurrent= F prf *fAxisRadius / (fDecRatio*fTrqCon)

[0178] Where fCurrent is the control current, F prf The planned force is calculated after necessary processing. fAxisRadius is the radius of the drive wheel, fTrqCon is the motor's current torque constant, and fDecRatio is the motor reduction ratio, i.e., the transmission ratio between the drive wheel and the corresponding drive motor. Since the torque of the drive motor can be considered directly proportional to the control current, the control torque can be obtained by calculating the product of the control current and the corresponding coefficient.

[0179] Since the planning force affects the acceleration of the drive wheel rotation, the integral of the acceleration is the velocity, and the integral of the velocity is the position. The target velocity / position of the driven wheel can be calculated based on the planning force and the current velocity / position of the driven wheel, and used as the control quantity for the corresponding drive motor.

[0180] In this embodiment, the position change under the action of the catheter turning command is used for control instead of the target position. The drive wheel is divided into a driving wheel and a driven wheel. The angular position change of the driving wheel is directly calculated based on the position change. If the catheter end meets the preset conditions, while controlling the driving wheel according to the angular position change, the driven wheel is controlled to rotate according to the target of zero force on the drive wire corresponding to the driven wheel. This is more adaptable to the nonlinear changes exhibited by the catheter end during the rotation process, realizing the bending and turning of the catheter, while reducing the occurrence of abnormal tension in the drive wire corresponding to the driven wheel.

[0181] This application also provides a control system for a catheter system. Please refer to... Figure 12 This illustrates a schematic diagram of the control system of a catheter system provided in an embodiment of this application. Figure 11As shown, the control system 600 includes: a processor 60, a memory 61, a bus 62, and a communication interface 63. The processor 60, the communication interface 63, and the memory 61 are connected through the bus 62. The memory 61 stores computer program instructions that can be executed by the processor 60. When the processor 60 executes the computer program instructions, it executes the duct bending and turning control method provided in any of the foregoing embodiments of this application.

[0182] The memory 61 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Communication between this device network element and at least one other network element is achieved through at least one communication interface 63 (which can be wired or wireless), such as the Internet, wide area network, local area network, metropolitan area network, etc.

[0183] Bus 62 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. The memory 61 is used to store programs. After receiving an execution instruction, the processor 60 executes the program. The conduit bending and steering control method disclosed in any of the foregoing embodiments of this application can be applied to the processor 60, or implemented by the processor 60.

[0184] Processor 60 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of processor 60 or by instructions in software form. Processor 60 can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application-Specific Integrated Circuit (ASIC), an Off-the-shelf Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory 61. Processor 60 reads the information in memory 61 and, in conjunction with its hardware, completes the steps of the above method.

[0185] The electronic device provided in this application embodiment and the duct bending and turning control method provided in this application embodiment are based on the same inventive concept and have the same beneficial effects as the methods they adopt, operate or implement.

[0186] This application also provides a computer-readable storage medium corresponding to the duct bending and redirection control method provided in the foregoing embodiments. Please refer to... Figure 13 The computer-readable storage medium 6 shown thereon stores computer program instructions that, when executed by a processor, implement the conduit bending and turning control method provided in any of the foregoing embodiments.

[0187] It should be noted that examples of the computer-readable storage medium may include, but are not limited to, optical discs, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory, or other optical and magnetic storage media, which will not be elaborated here.

[0188] The computer-readable storage medium provided in the above embodiments of this application and the duct bending and turning control method provided in the embodiments of this application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by the application stored therein.

[0189] It should be noted that:

[0190] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known structures and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0191] Similarly, it should be understood that, for the sake of brevity and to aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of this application, various features of this application are sometimes grouped together in a single embodiment, figure, or description thereof. However, this disclosure should not be construed as reflecting a schematic diagram in which the claimed application requires more features than expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0192] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0193] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A catheter system, characterized in that, The catheter system includes a robotic arm, a catheter instrument detachably connected to a power unit of the robotic arm, a main controller and a processor communicatively connected to the robotic arm, and the catheter instrument including an instrument housing detachably connected to the power unit and a catheter connected to the instrument housing. The instrument housing includes a drive wheel driven by the power unit and a drive wire with one end wound around the drive wheel and the other end extending along the catheter and fixed to the end of the catheter. The power unit includes multiple drive motors, with each drive motor, drive wheel, and drive wire corresponding to one another. The processor is configured to perform the following steps: Based on the catheter turning command from the master controller, the position change of the catheter tip is obtained, and the position change includes the direction angle and the bending angle. The driving wheel and driven wheel in the drive wheel are determined based on the position change, and the angular position change of the driving wheel is calculated. If the end of the conduit meets the preset conditions, the drive motor corresponding to the drive wheel is controlled to drive the drive wheel to rotate according to the angular position change. At the same time, the planned force of the drive motor corresponding to the driven wheel is calculated according to the target of zero force on the drive wire corresponding to the driven wheel, and the drive motor corresponding to the driven wheel is controlled to output according to the planned force. The preset conditions include that at least one of the current bending angle and the target bending angle of the end of the conduit is within a preset range. The target bending angle is the sum of the current bending angle and the bending angle in the position change.

2. The catheter system according to claim 1, characterized in that, In the initial stage of driving the drive wheel to rotate, the planning force is set to an initial value; subsequently, during the process of driving the drive wheel to rotate, the planning force is the sum of the initial value, the damping force, and the spring force, wherein the damping force is calculated based on the speed of the driven wheel, and the spring force is calculated based on the position of the driven wheel.

3. The catheter system according to claim 2, characterized in that, The magnitude of the damping force is positively correlated with the velocity; the magnitude of the spring force is positively correlated with the position.

4. The catheter system according to claim 1, characterized in that, The planning force is obtained based on the feedback force of the drive wire corresponding to the driven wheel.

5. The catheter system according to any one of claims 1-4, characterized in that, The processor is configured to perform the following steps: If the position of the driven wheel is in the over-limit zone, then the maximum reverse force corresponding to the over-limit zone is taken as the planning force.

6. The catheter system according to any one of claims 1-4, characterized in that, The processor is configured to perform the following steps: If the speed of the driven wheel exceeds the speed limit range, the planning force is adjusted to control the speed of the driven wheel back to the speed limit range.

7. The catheter system according to claim 1, characterized in that, The processor is configured to perform the following steps: If the end of the guide tube does not meet the preset conditions, the angular position change of the driven wheel is calculated based on the angular position change of the driving wheel and the current position ratio allocation coefficient of the corresponding driven wheel. The drive motor corresponding to the driven wheel is then controlled to drive the driven wheel to rotate according to the angular position change. The current position ratio allocation coefficient is used to represent the ratio of the take-up length of the driving wheel to the release length of the corresponding driven wheel in the current state.

8. The catheter system according to claim 1, characterized in that, The boundary of the preset range includes the maximum threshold value for the bending angle.

9. The catheter system according to claim 1, characterized in that, The number of drive wires is n, where n is an integer greater than 2. The n drive wires divide the front end plane of the rotating section of the catheter into n intervals in terms of angle. The drive wires corresponding to the two ends of the interval to which the direction angle belongs are active drive wires. The drive wheel connected to the active drive wire is the active wheel. Some or all of the remaining drive wheels are driven wheels.

10. A method for controlling the bending and turning of a catheter, characterized in that, include: Based on the catheter turning command from the master controller, the change in position of the catheter tip is obtained, including the direction angle and the bending angle. The driving wheel and driven wheel among the multiple driving wheels are determined according to the position change, and the angular position change of the driving wheel is calculated. The driving wheel is set in a one-to-one correspondence with the driving motor and driving wire. The driving wheel is wound with the corresponding driving wire and is driven by the corresponding driving motor. The other end of the driving wire extends along the guide and is fixed to the end of the guide. If the end of the conduit meets the preset conditions, the drive motor corresponding to the drive wheel is controlled to drive the drive wheel to rotate according to the angular position change. At the same time, the planned force of the drive motor corresponding to the driven wheel is calculated according to the target of zero force on the drive wire corresponding to the driven wheel, and the drive motor corresponding to the driven wheel is controlled to output according to the planned force. The preset conditions include that at least one of the current bending angle and the target bending angle of the end of the conduit is within a preset range. The target bending angle is the sum of the current bending angle and the bending angle in the position change.

11. A computer-readable storage medium storing computer program instructions configured to be loaded by a processor and executed to implement the steps of the method of claim 10.

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