An adaptive variable-diameter controllable-curve flexible interventional device and a control method thereof

Abstract

The application provides a self-adaptive variable-diameter controllable bending flexible interventional device and a control method thereof, and relates to the field of surgical instruments. The device comprises an internal support rod; in the direction of the internal support rod axis, a first variable-diameter mechanism, a controllable bending continuum mechanism, a second variable-diameter mechanism and a multi-lumen tube are sequentially sleeved on the internal support rod; a blocking film is arranged outside the first variable-diameter mechanism and the second variable-diameter mechanism; the controllable bending continuum mechanism is used to drive the device to bend, and the variable-diameter mechanism is used to control the radial size of the device; the application proposes a controllable bending continuum mechanism, a modular flexible continuum joint skeleton and a variable-diameter structure are designed; through differential traction and expansion drive cooperative control, the four-way bending and linear diameter adjustment functions of the stent are finally realized.

Description

Technical Field

[0001] This invention relates to the field of surgical instrument technology, and more particularly to an adaptive variable diameter controllable bending flexible interventional device and its control method. Background Technology

[0002] Intravascular hemorrhage is a critical emergency in cardiovascular disease, characterized by sudden onset, rapid progression, and high mortality. Clinically, interventional procedures are commonly used to stop bleeding in non-compressible intravascular bleeding. Interventional hemostasis techniques deliver instruments to the bleeding site through the vascular cavity, achieving hemostasis through mechanical compression or occlusion. Common interventional hemostasis devices include balloon catheters, covered stents, coils, and various embolization materials. These devices need to adapt to changes in the curvature and diameter of the blood vessel, maintain stable adhesion to the vessel wall during hemostasis, and preserve blood flow channels as much as possible to reduce the risk of tissue ischemia.

[0003] Currently, the most widely used endovascular hemostasis techniques in clinical practice both domestically and internationally include balloon occlusion, covered stent placement, and coil or embolic material occlusion. Balloon occlusion achieves temporary hemostasis by inflating a balloon to compress the vessel wall, while covered stents permanently isolate the bleeding point. Coils and embolic materials are primarily used to fill bleeding cavities. Foreign countries started earlier in the development of interventional hemostasis devices and image-guided control, and have formed relatively mature product systems. Domestic research has also made some progress in recent years, mainly focusing on the optimization of hemostatic materials, improvement of interventional device structure, and enhancement of catheter maneuverability. Most existing methods rely on occlusion or isolation as the primary mechanism, achieving hemostasis through balloon inflation or stent deployment.

[0004] However, existing technologies have significant shortcomings. Traditional balloon occlusion techniques easily cause venous return obstruction, increasing cardiac workload and potentially exacerbating the risk of secondary bleeding. While permanent vascular stent implantation can achieve mechanical hemostasis, it relies on high-precision image-guided systems and precise interventional procedures, and the irreversible fixation of the stent makes subsequent removal difficult. Existing devices have poor adaptability to complex and tortuous vascular environments, making it difficult to achieve close contact between the device and the vessel wall in multi-branched, variable-diameter, and high-curvature vessel scenarios. Local blood flow obstruction after occlusion is common, making it impossible to simultaneously achieve hemostasis and unobstructed blood flow. Furthermore, traditional devices have low precision in controlling the contact force with the vessel wall, are highly dependent on operator experience, and lack active bending guidance and radial conformal capabilities, making it difficult to achieve safe, retrievable, and dynamically conforming precise hemostasis. Summary of the Invention

[0005] To address the aforementioned technical problem of poor adaptability of existing interventional hemostatic devices to complex and tortuous vascular environments, this invention provides an adaptive variable diameter controllable bending flexible interventional device and its control method. This invention primarily utilizes a rigid-flexible composite structure integrating a controllable bending continuum mechanism and the biomimetic opening and closing principle of flower petals to achieve four-way controllable bending and linear diameter adjustment, thereby adapting to complex vascular environments with multiple sizes and branches.

[0006] The technical means employed in this invention are as follows:

[0007] An adaptive variable diameter controllable bending flexible interventional device includes an internal support rod; along the axial direction of the internal support rod, a first variable diameter mechanism, a controllable bending continuum mechanism, a second variable diameter mechanism, and a multi-cavity tube are sequentially sleeved on the internal support rod; a sealing membrane is provided outside between the first variable diameter mechanism and the second variable diameter mechanism; the controllable bending continuum mechanism is used to drive the device to bend, and the variable diameter mechanism is used to control the radial size of the device;

[0008] The direction of the controllable bending continuum mechanism closer to the multi-cavity tube is defined as left, and the direction of the controllable bending continuum mechanism further away from the multi-cavity tube is defined as right.

[0009] The first and second diameter changing mechanisms have the same structure, including a first diameter changing disc, a bending connecting rod, and a second diameter changing disc arranged sequentially from left to right. The first and second diameter changing discs have the same structure. The internal support rod passes through the central hole of the first and second diameter changing discs. The first diameter changing disc is fixed to the internal support rod, and the second diameter changing disc can slide along the axial direction of the internal support rod. The first and second diameter changing discs are connected by several identical bending connecting rods. The outer side of the bending joint of the bending connecting rod is connected to the inner side of one end of the sealing membrane. The first and second diameter changing discs are provided with diameter changing drive wire holes, and a diameter changing drive wire passes through the diameter changing drive wire holes. The diameter changing drive wire is fixedly connected to the second diameter changing disc.

[0010] Furthermore, the controllable bending continuum mechanism includes several identical snake bones, a bending control drive wire, and a bendable wire; the snake bones are cylindrical structures, with a central hole at the center of the snake bone, and bending control drive wire holes evenly distributed around the central hole. A bending control drive wire passes through the bending control drive wire holes, with the right end of the bending control drive wire connected to the rightmost snake bone, and the left end of the bending control drive wire passing through a multi-cavity tube. The snake bones are connected to adjacent snake bones through bendable wires.

[0011] Furthermore, the controllable bending continuum mechanism includes several identical snake bones, bending control drive wires, and spherical joints; the snake bones are cylindrical structures, with a central hole at the center of the snake bone, and bending control drive wire holes evenly distributed around the central hole, with bending control drive wires passing through the bending control drive wire holes, the right end of the bending control drive wires being connected to the rightmost snake bone, a spherical joint being provided on the left side surface of the snake bone, and a spherical groove being provided on the right side surface of the snake bone, the spherical joints being adapted to and rotatably connected to the spherical grooves.

[0012] Furthermore, a spring is sleeved on the internal support rod between the first and second variable diameter discs, and the two ends of the spring abut against the first and second variable diameter discs respectively.

[0013] Furthermore, the adaptive variable diameter controllable bending flexible intervention device is externally fitted with an outer sleeve.

[0014] Furthermore, when the second variable diameter disc retracts to the left, the bending connecting rod retracts, causing the sealing membrane to expand; when the second variable diameter disc returns to the right, the bending connecting rod unfolds, causing the sealing membrane to shrink.

[0015] This invention also provides a control method for an adaptive variable diameter controllable bending flexible interventional device, implemented based on any of the aforementioned adaptive variable diameter controllable bending flexible interventional devices, comprising the following steps:

[0016] S1. Based on the surgical stage and clinical risks, dynamically allocate the control weights of the three core tasks: vascular safety support, continuum motion accuracy, and delivery speed adjustment, and set safety thresholds and emergency withdrawal conditions.

[0017] S2. By integrating the physical model with the Long Short-Term Memory (LSTM) network, blood flow impact, tissue deformation and mechanism posture are modeled, and the nonlinear error between the proximal force sensor and the contact force of the blood vessel wall is compensated to obtain a high-precision contact force estimate.

[0018] S3. The control weights obtained in S1, the expected contact force, the actual contact force estimated in S2, the target pose and the end pose are input into the force-position hybrid controller. After being processed by the safety constraint unit, the opening and closing angle control quantity and the flexible continuum pose control quantity of the variable diameter mechanism are decoupled and output through the Jacobian matrix solver.

[0019] The opening and closing angle control controls the variable diameter drive wire to move back and forth, thereby driving the second variable diameter disk to slide, driving the bending connecting rod to move, and realizing the radial expansion of the sealing membrane.

[0020] The bending drive wire is controlled by the pose control of the flexible continuum, thereby driving the controllable bending continuum mechanism to achieve four-way bending.

[0021] Furthermore, S1 specifically includes the following steps:

[0022] Define the current state feature vector of the device as:

[0023]

[0024] in, z ( t () refers to the depth or location of the instrument intervention; F ( t ) represents the contact force; The rate of change of force; For end-effector attitude / position error;

[0025] The three core tasks are defined as follows:

[0026] The vascular safety support task T1 involves the strain gauge mechanism and the allocation of weights. w 1. The continuous motion accuracy task T2 corresponds to the flexible body module and weights are assigned. w 2. Task T3 for adjusting conveyor speed corresponds to the conveyor and rotation modules and assigns weights. w 3, and satisfy:

[0027]

[0028] The surgical stage factors are set as follows:

[0029]

[0030] in, z c The depth threshold for entering the critical operating area. k z This is the depth deviation weighting coefficient. k f This is the contact force deviation weighting coefficient. z To the depth required to enter the critical operational area, F c The contact force stage threshold, F For the current contact force, σ ( () is the Sigmoid function;

[0031] when s ( t When )≈0, it is determined to be the initial stage of intervention. w 3 = 0.8 w 2= w 1 = 0.1;

[0032] when s ( t When )≈1, it is determined to be a deep operating zone, and the value is taken. w3 = 0.1 w 2= w 1 = 0.45;

[0033] The risk factors are set as follows:

[0034]

[0035] in, The rate of change of contact force, F r The dangerous contact force threshold, The threshold for force mutation; k 1 represents the weighting coefficient of the current contact force risk item. k 2 represents the weighting coefficient for the risk term of the rate of change of force. k 3 represents the weighting coefficient for the vascular abnormality detection item; The result represents the abnormal vascular test result; 0 indicates normal and 1 indicates abnormal.

[0036] when r ( t When the value is approximately 1, a risk warning is triggered and an emergency drawdown mechanism is activated. At this point, the settings are... w 1. w 2. w 3 is close to 0, and a drawdown weight is set separately. w 0=1, the control device retracts to the minimum diameter, the flexible body returns to its straight state, and then retracts to the safe area and switches to manual operation.

[0037] Furthermore, S2 specifically includes the following steps:

[0038] A static model of a variable diameter continuum is established based on Cosserat beam theory. The physical rough estimate of the end contact force is obtained by using the tension of the near-end driving wire, the continuum configuration parameters and the unfolded diameter D.

[0039] The frictional hysteresis model is used to compensate for the tension loss along the drive wire.

[0040] Construct the lever arm matrix based on the orifice radius and orifice angle of the driving wire, obtain the distributed driving internal force and internal moment distribution, substitute the driving term, blood flow disturbance term, gravity term and tissue contact term into the Cosserat equilibrium equation, numerically integrate from the proximal end to the distal end, and combine the terminal boundary conditions to obtain the physical coarse estimate.

[0041] The physical coarse estimate, driving wire tension and its rate of change, curvature, bending angle, unfolding diameter D and its rate of change, blood flow velocity, pulsating pressure, and tissue compression are used as temporal input features and fed into a long short-term memory network (LSTM) to output the contact force residual compensation.

[0042] By superimposing the coarse physical estimate with the residual compensation, a high-precision contact force estimate is obtained.

[0043] Furthermore, in S3, the constraints of the safety constraint unit are as follows:

[0044] The contact force between the blood vessel wall and the vessel wall does not exceed the threshold [0, F] max ];

[0045] The curvature of the continuum does not exceed the structural limit [-k] max ,k max ];

[0046] The opening and closing angle of the variable diameter mechanism does not exceed the limit. min theta max ];

[0047] The dilation diameter shall not exceed the permissible range of the blood vessel [D] min D max ].

[0048] Compared with the prior art, the present invention has the following advantages:

[0049] The adaptive variable diameter controllable bending flexible interventional device provided by the present invention integrates the petal-inspired variable diameter structure with the flexible continuous joint skeleton of the controllable bending continuous mechanism to construct a hemostatic device that has both active bending capability and radially controllable unfolding function, thereby achieving dynamic conformal and close fit to vascular environments with multiple sizes, multiple branches, and complex curvatures.

[0050] The variable diameter controllable bending structure provided by this invention enables the stent to have four-way controllable bending and linear diameter adjustment capabilities through the coordinated control of differential traction of the drive wire and expansion drive wire, while retaining the hollow cavity to maintain unobstructed blood flow, thus breaking through the technical limitations of traditional hemostatic devices that stop bleeding while blocking flow.

[0051] This invention proposes a control framework for a flexible device that combines force estimation, force-position control, and risk factors to achieve safe and efficient execution of various surgical tasks.

[0052] This invention adaptively allocates task operation coefficients at different stages of the surgical procedure, ensuring surgical efficiency while also taking into account precision and safety control.

[0053] This invention achieves accurate force estimation by combining mechanical modeling and time-varying factors such as blood flow in situations where force sensing is lacking at the distal end within a confined space, thus facilitating safe control. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This is a structural diagram of the device of the present invention.

[0056] Figure 2 This is a structural diagram of the device in its contracted state according to the present invention.

[0057] Figure 3 This is a structural diagram of a controllable bending continuum mechanism according to the present invention.

[0058] Figure 4 This is a structural diagram of another controllable bending continuum mechanism according to the present invention.

[0059] Figure 5 for Figure 4 The diagram shows the structure in a bent state.

[0060] Figure 6 This is a structural diagram of the variable diameter mechanism of the present invention.

[0061] Figure 7 This is a schematic diagram of the internal support rod of the present invention.

[0062] Figure 8 This is a structural diagram of the multi-cavity tube of the present invention.

[0063] Figure 9 This is a diagram of the adaptive compensation method of the present invention.

[0064] Figure 10 This is a diagram of the force-position hybrid control and cooperative driving method of the present invention.

[0065] Figure 11 This is a diagram illustrating the task priority-driven control strategy of this invention.

[0066] In the diagram: 1. Internal support rod; 2. First diameter changing mechanism; 3. Controllable bending continuum mechanism; 4. Second diameter changing mechanism; 5. Multi-cavity tube; 6. Sealing membrane; 7. First diameter changing disc; 8. Bending connecting rod; 9. Second diameter changing disc; 10. Diameter changing drive wire; 11. Snake bone; 12. Controlled bending drive wire; 13. Bending wire; 14. Spherical joint; 15. Spring. Detailed Implementation

[0067] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0070] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0071] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0072] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0073] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0074] This invention provides an adaptive variable diameter controllable bending flexible intervention device, the overall structure of which is as follows: Figure 1 As shown, the device includes an internal support rod 1. Along the axial direction of the internal support rod 1, a first diameter-changing mechanism 2, a controllable bending continuous mechanism 3, a second diameter-changing mechanism 4, and a multi-cavity tube 5 are sequentially mounted on the internal support rod 1. A sealing membrane 6 is provided externally between the first diameter-changing mechanism 2 and the second diameter-changing mechanism 4. The controllable bending continuous mechanism 3 is used to drive the device to bend, and the diameter-changing mechanism is used to control the radial size of the device. The entire device system can retract into an external sleeve in its initial state, such as... Figure 2 As shown.

[0075] For ease of description, the direction of the controllable bending continuous mechanism 3 closer to the multi-cavity tube 5 is defined as left, and the direction of the controllable bending continuous mechanism 3 away from the multi-cavity tube 5 is defined as right. The following sections will provide a detailed description of each component and its connection relationships.

[0076] The first diameter changing mechanism 2 and the second diameter changing mechanism 4 have the same structure. Taking the first diameter changing mechanism 2 as an example, as follows... Figure 6As shown, the device includes a first variable diameter disc 7, a bending connecting rod 8, and a second variable diameter disc 9 arranged sequentially from left to right. The first variable diameter disc 7 and the second variable diameter disc 9 have identical structures, each with a central hole. An internal support rod 1 passes through the central holes of the first variable diameter disc 7 and the second variable diameter disc 9. The first variable diameter disc 7 is fixed to the internal support rod 1, and the second variable diameter disc 9 can slide axially along the internal support rod 1. The first variable diameter disc 7 and the second variable diameter disc 9 are connected by several identical bending connecting rods 8, with the outer side of the bending joint of the bending connecting rod 8 connected to the inner side of one end of the sealing membrane 6. The first variable diameter disc 7 and the second variable diameter disc 9 are provided with variable diameter drive wire holes, and a variable diameter drive wire 10 passes through these holes, fixedly connected to the second variable diameter disc 9. By axially pulling the variable diameter drive wire 10, the second variable diameter disc 9 can be driven to move axially along the internal support rod 1, thereby driving the bending connecting rod 8 to move, achieving radial expansion or contraction of the sealing membrane 6.

[0077] A spring 15 is fitted onto the internal support rod 1 between the first variable diameter disc 7 and the second variable diameter disc 9, with both ends of the spring 15 abutting against the first variable diameter disc 7 and the second variable diameter disc 9, respectively. When the second variable diameter disc 9 moves to the left, the spring 15 is compressed, increasing its elastic potential energy; when the variable diameter drive wire 10 retracts, the second variable diameter disc 9 returns to its initial position to the right under the elastic force of the spring 15. Specifically, when the second variable diameter disc 9 contracts to the left, the bending connecting rod 8 contracts, causing the occlusion membrane 6 to expand; when the second variable diameter disc 9 returns to the right, the bending connecting rod 8 expands, causing the occlusion membrane 6 to shrink. Through the above structure, the device can achieve linear adjustment of the radial dimension according to the inner diameter of the blood vessel, closely fitting the blood vessel walls of different diameters.

[0078] The controllable bending continuum mechanism 3 can be implemented in two ways. The first way is as follows: Figure 3 As shown, the controllable bending continuum mechanism 3 includes several identical snake bones 11, bending control drive wires 12, and bendable wires 13. Each snake bone 11 is a cylindrical structure with a central hole at its center, and bending control drive wire holes are evenly distributed around the central hole. A bending control drive wire 12 passes through each of these holes, with its right end fixed to the rightmost snake bone 11 and its left end inserted into the multi-lumen tube 5. The snake bones 11 are connected to adjacent snake bones 11 via the bendable wires 13. When the bending control drive wires 12 are pulled, each bending control drive wire 12 experiences differential axial displacement. Under the constraint of the bendable wires 13, controllable offset movements are formed between each snake bone 11 unit, thereby achieving bending in four directions to adapt to vascular sections with large curvatures.

[0079] The second form is as follows Figure 4 and Figure 5As shown, the controllable bending continuum mechanism 3 includes several identical snake bones 11, bending control drive wires 12, and spherical joints 14. Each snake bone 11 is a cylindrical structure with a central hole at its center, and bending control drive wire holes are evenly distributed around the central hole. Bending control drive wires 12 are inserted into the bending control drive wire holes, and the right end of the bending control drive wire 12 is connected to the rightmost snake bone 11. A spherical joint 14 is provided on the left side surface of each snake bone 11, and a spherical groove is provided on the right side surface of each snake bone 11. The spherical joint 14 is adapted to and rotatably connected to the spherical groove. By pulling the bending control drive wires 12, each snake bone 11 unit forms a controllable offset movement through the spherical joints 14, achieving multi-directional bending to adapt to different blood vessel curvatures.

[0080] The structure of the multi-lumen tube 5 is as follows Figure 8 As shown, the multi-cavity tube 5 forms seven channels. The channel located at the center of the multi-cavity tube 5 serves as the intermediate support rod cavity, through which the internal support rod 1 passes. Two smaller radius cavities are symmetrically distributed on one side of the central cavity, serving as variable diameter drive wire cavities, through which the variable diameter drive wire 10 passes. Four circumferentially evenly distributed cavities serve as bending control drive wire cavities, through which the bending control drive wire 12 passes. The arrangement of the multi-cavity tube 5 ensures independent working space for each drive element, avoiding mutual interference.

[0081] The internal support rod 1 is located at the center of the device system and runs through all the discs in the system. The internal support rod 1 is fixedly connected to the controllable bending continuum mechanism 3 and the first diameter-changing disc 7 in the first diameter-changing mechanism 2 and the first diameter-changing disc 7 in the second diameter-changing mechanism 4, while each of the second diameter-changing discs 9 can move axially along the internal support rod 1. The internal support rod 1 serves to support the entire system, and its relatively soft material allows for a certain degree of bending, enabling it to cooperate with the bending of the controllable bending continuum mechanism 3 and adapt to changes in the curvature of the blood vessel, such as... Figure 7 As shown.

[0082] The entire adaptive variable diameter controllable bending flexible interventional device is encased in an outer sleeve. In its initial state, the entire system is retracted within the outer sleeve. When the device needs to undergo a diameter change or bending operation, the entire device extends out from inside the outer sleeve.

[0083] Preferably, the sealing membrane 6 is made of silicone, the internal support rod 1 is made of Pebax, the bending drive wire 12 is made of steel wire rope, and the bendable wire 13 is made of nickel-titanium wire.

[0084] This invention also provides a control method for an adaptive variable diameter controllable bending flexible interventional device, implemented based on any of the aforementioned adaptive variable diameter controllable bending flexible interventional devices, comprising the following steps:

[0085] S1. Based on the surgical stage and clinical risks, dynamically allocate the control weights of the three core tasks: vascular safety support, continuum motion accuracy, and delivery speed adjustment, and set safety thresholds and emergency withdrawal conditions.

[0086] In this step, the control weights of three core tasks (1) vascular safety support, (2) continuum motion accuracy, and (3) delivery speed adjustment are dynamically allocated according to the clinical importance of the task. Priority is given to ensuring contact safety during hemostasis, while also taking into account posture accuracy and operational efficiency. In response to sudden risk situations, rapid response and parameter adaptive adjustment can be performed when vascular abnormalities or force changes are detected, thereby achieving efficient and precise control of hemostasis while ensuring safety. The details are as follows:

[0087] State variable definition:

[0088] Let the current state characteristics of the device be:

[0089]

[0090] in, z ( t () refers to the depth or location of the instrument intervention; F ( t ) represents the contact force; The rate of change of force; For end-effector attitude / position error;

[0091] The three core tasks are defined as follows:

[0092] T1: Vascular safety support, corresponding to the variable diameter mechanism of flexible interventional devices, weight. w 1. Input to the force-position hybrid controller of S3;

[0093] T2: Continuum motion accuracy, corresponding to the flexible body module of a flexible intervention device, weight. w 2. Input to the force-position hybrid controller of S3;

[0094] T3: Conveying speed adjustment, corresponding to the conveying and rotating modules of the flexible intervention device, weight. w 3. Input to the device system for direct speed adjustment;

[0095] satisfy

[0096] Surgical stage factors s ( t ):

[0097] Using instrument depth and contact force to reflect whether a high-risk operating area has been entered, a normalized stage factor is defined:

[0098]

[0099] in: z c The depth threshold for entering the critical operating area. k z This is the depth deviation weighting coefficient. k f This is the contact force deviation weighting coefficient. z To the depth required to enter the critical operational area, F c The contact force stage threshold, F For the current contact force, σ ( () is the Sigmoid function;

[0100] therefore:

[0101] s(t)≈0 represents the initial stage of intervention, where safety requirements are weak and efficiency is prioritized. w 3 = 0.8 w 2= w 1 = 0.1;

[0102] s(t)≈1 represents the deep operation zone, which carries higher risks. Safety and accuracy are paramount in this zone. w 3 = 0.1 w 2= w 1 = 0.45;

[0103] It also includes safety monitoring and emergency withdrawal steps. If excessive contact force or abnormal blood vessel morphology is detected during the execution of S3, the current control command is interrupted and the emergency withdrawal mechanism is triggered.

[0104] Abnormal vascular morphology includes abnormal conditions such as tortuous blood vessels, blood vessel obstruction, or abnormal vascular malformations.

[0105] Risk factors r ( t );

[0106] For conditions such as vascular abnormalities and sudden changes in force, the risk factors are defined as follows:

[0107]

[0108] in: The rate of change of contact force, F r The dangerous contact force threshold, The threshold for force mutation; k 1 represents the weighting coefficient of the current contact force risk item. k 2 represents the weighting coefficient for the risk term of the rate of change of force. k 3 represents the weighting coefficient for the vascular abnormality detection item; The result represents the abnormal vascular test result; 0 indicates normal and 1 indicates abnormal.

[0109] therefore:

[0110] r(t≈0): The system is stable;

[0111] r(t≈1): Risk increases rapidly. Risk warning and activation of the withdrawal mechanism: After the above mechanism is triggered, w0=1 will be set and all others will be close to 0. The control device will shrink to the minimum diameter, the flexible body will be in a straight state, i.e. the device will be at zero position, and then the control device will withdraw to the safe area and switch to manual operation.

[0112] S2. By integrating the physical model with the Long Short-Term Memory (LSTM) network, blood flow impact, tissue deformation and mechanism posture are modeled, and the nonlinear error between the proximal force sensor and the contact force of the blood vessel wall is compensated to obtain a high-precision contact force estimate.

[0113] This step integrates physical modeling and a long short-term memory network (LSTM) to collect dynamic data such as blood flow impact, tissue deformation, and mechanism posture, constructing a multi-source fusion dataset, and further establishing an adaptive nonlinear compensation algorithm based on this dataset. The physical model outputs a basic force estimate, and the LSTM network outputs a nonlinear compensation value. The two are fused to obtain the proximal force compensation result, thereby improving the accuracy of blood vessel wall contact force control and achieving controllable bending hemostasis and safe interaction under different blood vessel morphologies.

[0114] Specifically, firstly, a static model of a variable-diameter continuum is established based on Cosserat beam theory. The internal forces and moments distributions within the continuum are solved using proximal drive wire tension, mechanism configuration, and unfolded diameter. A coarse physical estimate of the end-contact force is obtained from the end-contact boundary conditions. Subsequently, the coarse physical estimate, drive wire tension, blood flow impact, tissue deformation, and mechanism attitude are input into an LSTM network to learn the nonlinear residuals caused by fluid-structure interaction, tissue viscoelasticity, and drive friction, thus dynamically compensating for contact force estimation errors. Finally, a high-precision end-contact force estimate is obtained by superimposing the physical model output with the network residual compensation.

[0115] Consider a disk-to-disc continuum of length L, whose centerline is described by a Cosserat rod. Each cross-sectional state is represented by a position vector r(s)∈R³ and a rotation matrix R(s)∈SO(3), with the arc length parameter s∈[0,L]. The flexible membrane contacts the vessel wall, and nickel-titanium wires provide distributed bending / axial stiffness, driving the wire tension T_i to apply a generalized load through offset holes on each disk.

[0116] To facilitate the solution, the following assumptions are made:

[0117] The nickel-titanium wire is equivalent to an axial-bending composite stiffness distributed along the centerline, and the equivalent stiffness matrix is ​​denoted as K. se and K bt .

[0118] Since the disc mass and inertia are relatively small, quasi-static equilibrium is adopted first; if rapid pulsating blood flow needs to be considered, fluid disturbance can be regarded as a time-varying external load.

[0119] The geometric relations of the Cosserat beam are written as:

[0120] r′(s) = R(s) v(s),R′(s) = R(s) û(s) (1)

[0121] Where, v(s) = [v1, v2, v3] Let u(s) be the shear / elongation strain vector, where u(s) = [u1, u2, u3]. Let be the bending / torsional strain vector, and û(·) denote the mapping from the vector to the antisymmetric matrix.

[0122] For the quasi-static case without external dynamic terms, the internal forces n(s) and internal moments m(s) of the cross section satisfy the equilibrium equations:

[0123] n′(s) + f ext (s) = 0(2)

[0124] m′(s) + r′(s) × n(s) + l ext (s) = 0(3)

[0125] Among them, f ext (s) and l ext (s) represent the external force and torque per unit length, including blood flow impact, gravity, tissue contact distributed load, and the equivalent distributed term of the drive wire transmitted to the rod via the disc.

[0126] The constitutive relation can be written as:

[0127] n(s) = R(s) K se (v(s) - v) ),m(s) = R(s) K bt ( u(s) - u (4)

[0128] v with u This is the reference strain under unloaded, natural conditions. For the centerline without pre-bending or pre-torsion, v is typically taken. =[0,0,1] u =[0,0,0] .

[0129] Let the local position of the i-th driving wire at arc length s relative to the center line be . Its direction is approximately tangential to the centerline. Therefore, the equivalent force and torque exerted by the driving wire on the cross section can be written as:

[0130] (5)

[0131] (6)

[0132] Where, γ i (s) represents the equivalent distributed weight of the driving wire near this cross section. t i (s) is the unit vector of the drive wire direction. If the disk spacing is small and the trace is smooth, it can be approximated as s. The main contribution of a single driving wire to the bending moment is:

[0133] (7)

[0134] By superimposing all the driving wires, the generalized cross-sectional load caused by the driving can be obtained:

[0135] (8)

[0136] If we write the lever arm in matrix form, we can obtain an expression that is easier to calculate:

[0137] (9)

[0138] Where T(s) = [T1(s), ..., T_n(s)] B(s,q) is the lever arm matrix determined by the hole radius and the bending posture q. For a symmetrically arranged four-rope drive, the hole angle can be denoted as... α i ,but:

[0139]

[0140] (10)

[0141] Where, r t (D) is the effective radius of the drive hole relative to the center line.

[0142] If there is a concentrated external force F at the end s=L tip and external torque M tip The boundary conditions for the Cosserat beam are written as follows:

[0143] (11)

[0144] Therefore, by obtaining the internal force n(L) and internal moment m(L) of the end section from the known driving wire tension, configuration, and distributed external load, the equivalent interactive load between the end and the tissue can be deduced. For the current problem, the end external load can usually be broken down as follows:

[0145]

[0146] (12)

[0147] Among them, F contact It is the target contact force, F flow It is the fluid disturbance force caused by blood flow impact, F grav It is the attitude-dependent gravitational component, F other This represents unmodeled terms such as friction and uneven film tension. F can be obtained through fluid modeling or experimental calibration. flow M flow A rough estimate of the contact force can be written as:

[0148]

[0149] (13)

[0150] The actual system measures the proximal drive wire tension T. i p Instead of the tension T at any point along the entire length. i (s). Therefore, path friction and bending losses need to be compensated first. The physical model is as follows:

[0151] (14)

[0152] Where, μ i κ is the equivalent friction coefficient, ΔT is the curvature, and ΔT is the effective friction coefficient. i hys This represents the additional loss term caused by hysteresis and perforation friction. Let T... i Substituting (s) into the aforementioned lever arm matrix B(s,q), the driving moment distribution of each section can be obtained. Then, by combining the Cosserat static equations and numerically integrating from s=0 to s=L, the end internal forces and internal moments can be obtained.

[0153] Therefore, the solution chain for the physical model can be explicitly written as:

[0154] Step 1: Obtain from the proximal tension sensor q is obtained by the encoder / shape sensor. D.

[0155] Step 2: Calculate the friction tension Ti(s) along the friction using the friction-hysteresis model, corresponding to formula (14).

[0156] Step 3: Determine the hole radius r t (D) and aperture angle α i Construct the lever arm matrix B(s,q), corresponding to formulas (9) and (10);

[0157] Step 4: Obtain the distributed driving internal force / internal moment term n ten (s), m ten (s), corresponding to formula (8);

[0158] Step 5: Substitute the driving term, blood flow disturbance term, gravity term, and tissue distribution contact term into the Cosserat equilibrium equation and solve it using the shooting method, corresponding to formula (1-4).

[0159] Step 6: Obtain n(L) and m(L) from the terminal boundary conditions, and then obtain... The corresponding formula is (11-13).

[0160] Since physical models cannot fully cover blood flow pulsation, tissue viscoelasticity, membrane deformation coupling, and frictional hysteresis, the output of the physical model is used as a coarse estimate, and then the residuals are learned by LSTM.

[0161]

[0162]

[0163]

[0164] This physics + residual learning structure is superior to direct black-box regression because the coarse estimation has already ensured that the load direction and order of magnitude are basically correct, and LSTM only needs to learn the timing deviations caused by complex perturbations.

[0165] The network input features, output parameters, and training methods used are as follows:

[0166] The input features are divided into four categories: driving features, configuration features, environmental features, and physical coarse estimation features, as shown in Table 1;

[0167] Table 1 Input Feature Categories and Their Definitions

[0168]

[0169] The output is defined as the contact force residual ê(t), rather than the direct output of the contact force itself.

[0170] The training method is as follows:

[0171] The true value of the contact force F is obtained using an external vascular platform or calibration table. contact true .

[0172] Synchronize tension, posture, expansion, blood flow parameters, and true force using a unified clock.

[0173] Denoising, normalization, and sliding time window slicing are performed on all input channels. The time window length L can be tested from 10 to 30 sampling points.

[0174] by The LSTM is trained using the Adam optimizer as a supervisory label.

[0175] The loss function preferably uses a combination of MSE and MAE to balance the overall error and peak error.

[0176] The training set, validation set, and test set should cover different blood flow velocities, different diameters, different bending postures, and different tissue stiffnesses.

[0177] S3. The control weights obtained from S1, the expected contact force, the actual contact force estimated by S2, the target pose and the end pose are input into the force-position hybrid controller. After being processed by the safety constraint unit, the controller is decoupled through the Jacobian matrix solver and outputs the opening and closing angle control quantity of the variable diameter mechanism and the pose control quantity of the flexible continuum, so as to realize the coordinated driving of radial expansion and axial bending.

[0178] In this step, the force-position hybrid controller receives the fusion signals of the expected contact force and the actual contact force, as well as the target pose and the end pose. The output is connected to the safety constraint unit. The result processed by the constraint unit is input to the Jacobian matrix solver. The output of the Jacobian matrix solver is connected to the opening and closing angle controller of the variable diameter mechanism and the flexible continuum pose decoupler, respectively, and outputs the opening and closing angle of the variable diameter mechanism and the control quantity of the continuum, thereby realizing the force-position hybrid control and the hybrid drive of radial expansion and axial bending.

[0179] The specific steps for decoupling and outputting the opening / closing angle control value of the variable diameter mechanism and the pose control value of the flexible continuum are as follows:

[0180] Define a hybrid task space variable:

[0181]

[0182] Where: x is the end-effector pose or its key component, F c For contact force;

[0183] Redefine the mechanism control variables:

[0184]

[0185] Where: q c q represents the pose control quantity of the flexible continuum, i.e., the length of the drive wire; oThis refers to the opening / closing angle control quantity, i.e., the opening / closing angle;

[0186] The unified Jacobian relation can then be written as:

[0187]

[0188] Expanded to:

[0189]

[0190] Among them, J xc The effect of the continuum on pose can be directly obtained by solving the force estimation part; J xo The effect of the variable diameter mechanism on the pose is calculated using trigonometric functions based on the linkage relationships; J fc The effect of the continuum on the contact force can be directly obtained by solving the force estimation part; J fo The effect of the variable diameter mechanism on the contact force needs to be obtained through actual calibration.

[0191] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An adaptive variable diameter controllable bending flexible intervention device, characterized in that: It includes an internal support rod; along the axial direction of the internal support rod, a first diameter-changing mechanism, a controllable bending continuum mechanism, a second diameter-changing mechanism, and a multi-cavity tube are sequentially sleeved on the internal support rod, and a sealing membrane is provided outside between the first diameter-changing mechanism and the second diameter-changing mechanism; the controllable bending continuum mechanism is used to drive the adaptive variable diameter controllable bending flexible intervention device to bend, and the diameter-changing mechanism is used to control the radial size of the adaptive variable diameter controllable bending flexible intervention device; The direction of the controllable bending continuum mechanism closer to the multi-cavity tube is defined as left, and the direction of the controllable bending continuum mechanism further away from the multi-cavity tube is defined as right. The first and second diameter changing mechanisms have the same structure, including a first diameter changing disc, a bending connecting rod, and a second diameter changing disc arranged sequentially from left to right. The first and second diameter changing discs have the same structure. The internal support rod passes through the central hole of the first and second diameter changing discs. The first diameter changing disc is fixed to the internal support rod, and the second diameter changing disc can slide along the axial direction of the internal support rod. The first and second diameter changing discs are connected by several identical bending connecting rods. The outer side of the bending joint of the bending connecting rod is connected to the inner side of one end of the sealing membrane. The first and second diameter changing discs are provided with diameter changing drive wire holes, and a diameter changing drive wire passes through the diameter changing drive wire holes. The diameter changing drive wire is fixedly connected to the second diameter changing disc.

2. The adaptive variable diameter controllable bending flexible intervention device according to claim 1, characterized in that, The controllable bending continuum mechanism includes several identical snake bones, a bending control drive wire, and a bendable wire. The snake bones are cylindrical structures with a central hole at the center. Bending control drive wire holes are evenly distributed around the central hole. A bending control drive wire passes through the bending control drive wire holes. The right end of the bending control drive wire is connected to the rightmost snake bone, and the left end of the bending control drive wire passes into a multi-cavity tube. The snake bones are connected to adjacent snake bones through bendable wires.

3. The adaptive variable diameter controllable bending flexible intervention device according to claim 1, characterized in that, The controllable bending continuum mechanism includes several identical snake bones, bending control drive wires, and spherical joints. The snake bones are cylindrical structures with a central hole at the center. Bending control drive wire holes are evenly distributed around the central hole, and bending control drive wires are inserted into the holes. The right end of each bending control drive wire is connected to the rightmost snake bone. A spherical joint is provided on the left side surface of the snake bone, and a spherical groove is provided on the right side surface of the snake bone. The spherical joint is adapted to and rotatably connected to the spherical groove.

4. The adaptive variable diameter controllable bending flexible intervention device according to claim 1, characterized in that, A spring is fitted on the internal support rod between the first and second variable diameter discs, with the two ends of the spring abutting against the first and second variable diameter discs respectively.

5. The adaptive variable diameter controllable bending flexible intervention device according to claim 1, characterized in that, The adaptive variable diameter controllable bending flexible intervention device is covered with an outer sleeve.

6. The adaptive variable diameter controllable bending flexible intervention device according to claim 1, characterized in that, When the second variable diameter disc retracts to the left, the bending connecting rod retracts, causing the sealing membrane to expand; when the second variable diameter disc returns to the right, the bending connecting rod unfolds, causing the sealing membrane to shrink.

7. The adaptive variable diameter controllable bending flexible intervention device according to claim 1, characterized in that, The control method of the adaptive variable diameter controllable bending flexible intervention device includes the following steps: S1. Based on the surgical stage and clinical risks, dynamically allocate the control weights of the three core tasks: vascular safety support, continuum motion accuracy, and delivery speed adjustment, and set safety thresholds and emergency withdrawal conditions. S2. By integrating the physical model with the Long Short-Term Memory (LSTM) network, blood flow impact, tissue deformation and mechanism posture are modeled, and the nonlinear error between the proximal force sensor and the contact force of the blood vessel wall is compensated to obtain a high-precision contact force estimate. S3. The control weights obtained in S1, the expected contact force, the actual contact force estimated in S2, the target pose and the end pose are input into the force-position hybrid controller. After being processed by the safety constraint unit, the opening and closing angle control quantity and the flexible continuum pose control quantity of the variable diameter mechanism are decoupled and output through the Jacobian matrix solver. The opening and closing angle control controls the variable diameter drive wire to move back and forth, thereby driving the second variable diameter disk to slide, driving the bending connecting rod to move, and realizing the radial expansion of the sealing membrane. The bending drive wire is controlled by the pose control of the flexible continuum, thereby driving the controllable bending continuum mechanism to achieve four-way bending.

8. The adaptive variable diameter controllable bending flexible intervention device according to claim 7, characterized in that, S1 specifically includes the following steps: Define the current state feature vector of the device as: in, z ( t () refers to the depth or location of the instrument intervention; F ( t ) represents the contact force; The rate of change of force; For end-effector attitude / position error; The three core tasks are defined as follows: The vascular safety support task T1 involves the strain gauge mechanism and the allocation of weights. w 1. The continuous motion accuracy task T2 corresponds to the flexible body module and weights are assigned. w 2. Task T3 for adjusting conveyor speed corresponds to the conveyor and rotation modules and assigns weights. w 3, and satisfy: The surgical stage factors are set as follows: in, z c The depth threshold for entering the critical operating area. k z This is the depth deviation weighting coefficient. k f This is the contact force deviation weighting coefficient. z To the depth required to enter the critical operational area, F c The contact force threshold, F For the current contact force, σ ( () is the Sigmoid function; when s ( t When )≈0, it is determined to be the initial stage of intervention. w 3 = 0.8 w 2= w 1 = 0.1; when s ( t When )≈1, it is determined to be a deep operating zone, and the value is taken. w 3 = 0.1 w 2= w 1 = 0.45; The risk factors are set as follows: in, The rate of change of contact force, F r The dangerous contact force threshold, The threshold for force mutation; k 1 represents the weighting coefficient of the current contact force risk item. k 2 represents the weighting coefficient for the risk term of the rate of change of force. k 3 represents the weighting coefficient for the vascular abnormality detection item; The result represents the abnormal vascular test result; 0 indicates normal and 1 indicates abnormal. when r ( t When the value is approximately 1, a risk warning is triggered and an emergency drawdown mechanism is activated. At this point, the settings are... w 1. w 2. w 3 is close to 0, and a drawdown weight is set separately. w 0=1, the control device retracts to the minimum diameter, the flexible body returns to its straight state, and then retracts to the safe area and switches to manual operation.

9. The adaptive variable diameter controllable bending flexible intervention device according to claim 7, characterized in that, S2 specifically includes the following steps: A static model of a variable diameter continuum is established based on Cosserat beam theory. The physical rough estimate of the end contact force is obtained by using the tension of the near-end driving wire, the continuum configuration parameters and the unfolded diameter D. The frictional hysteresis model is used to compensate for the tension loss along the drive wire. Construct the lever arm matrix based on the orifice radius and orifice angle of the driving wire, obtain the distributed driving internal force and internal moment distribution, substitute the driving term, blood flow disturbance term, gravity term and tissue contact term into the Cosserat equilibrium equation, numerically integrate from the proximal end to the distal end, and combine the terminal boundary conditions to obtain the physical coarse estimate. The physical coarse estimate, driving wire tension and its rate of change, curvature, bending angle, unfolding diameter D and its rate of change, blood flow velocity, pulsating pressure, and tissue compression are used as temporal input features and fed into a long short-term memory network (LSTM) to output the contact force residual compensation. By superimposing the coarse physical estimate with the residual compensation, a high-precision contact force estimate is obtained.

10. The adaptive variable diameter controllable bending flexible intervention device according to claim 7, characterized in that, In S3, the constraints of the safety constraint unit are as follows: The contact force between the blood vessel wall and the vessel wall does not exceed the threshold [0, F] max ]; The curvature of the continuum does not exceed the structural limit [-k] max ,k max ]; The opening and closing angle of the variable diameter mechanism does not exceed the limit. min theta max ]; The dilation diameter shall not exceed the permissible range of the blood vessel [D] min D max ].

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