A microrobot for plaque removal and its control method

Abstract

The present invention provides a microrobot for plaque removal and a control method thereof, relating to the field of medical device technology. The microrobot includes a microrobot body and an in vitro control system connected to the microrobot body through signals; the microrobot body is obtained by 3D printing using a photocurable resin doped with magnetic powder; and the in vitro control system controls the operation of the microrobot body using a magnetic control system of a three-dimensional Helmholtz coil. The microrobot for plaque removal provided by the present invention uses a photocurable resin doped with magnetic powder to obtain the microrobot body through 3D printing, achieves coupling between the microrobot's atherectomy module and a magnetic drive module, and saves space occupied by permanent magnets in traditional magnetic microrobots. This facilitates a compact design of the microrobot, thereby reducing its size and expanding its application range.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a microrobot for plaque removal and a control method thereof. Background Art

[0002] Plaque, also known as atherosclerosis, is a chronic vascular disease caused by the accumulation of cholesterol, cellular waste products, fatty substances, calcium, and fibrin. In its early stages, it does not completely block blood vessels. Instead, it forms a yellowish, stone-like, hardened mass on the vessel lining, gradually narrowing the lumen and causing symptoms such as angina and transient ischemic attacks. As the lumen narrows further, slowed blood flow promotes thrombosis. If the plaque ruptures, it can completely block the vessel, leading to acute conditions such as pulmonary embolism and stroke. Therefore, early removal of arterial plaque is crucial.

[0003] Currently, the most common treatments for plaque removal include medication, coronary artery bypass grafting, and vascular interventional procedures. However, these treatments still have certain limitations, especially for conventional guidewire interventional procedures, whose results are highly dependent on the physician's skill and experience and carry the risk of radiation exposure. Given these risks, intravascular magnetically controlled microrobots that do not require catheters or guidewires have shown promise in treating vascular diseases. Magnetically controlled robots can utilize external magnetic fields for precise manipulation, overcoming the high viscous resistance in the low Reynolds number environment within blood vessels and achieving efficient movement. Their applications in medical diagnosis and treatment primarily include early diagnosis, minimally invasive surgery, targeted drug therapy, and disease monitoring.

[0004] The structural morphology of magnetically driven microrobots varies greatly depending on the application scenario. For magnetically driven microrobots used in minimally invasive interventional atherectomy, when moving in microchannels in a living organism, which can be considered a low Reynolds number environment, the viscous force on the microrobot is much greater than the inertial force and dominates. Compared with microrobots with other appearance forms, spiral magnetically driven microrobots can provide more sufficient propulsion force and can more easily overcome the resistance in the liquid environment to move and complete the corresponding work. In recent years, many researchers have studied the various mechanisms by which spiral microrobots generate rotational motion and proposed a variety of structural designs for the treatment of vascular diseases. However, all of these microrobots require internal space to place permanent magnets, which results in the larger size of the microrobots and limits their application. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: in order to solve the problem of large size of micro robots in the prior art, the present invention provides a micro robot for plaque removal. The micro robot is obtained by 3D printing using a photocurable resin doped with magnetic powder. There is no need to design a space for placing permanent magnets, which greatly reduces the size of the micro robot and solves the problem of large size of micro robots in the prior art.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A microrobot for plaque removal, characterized by comprising a microrobot body and an in vitro control system connected to the microrobot body by signals;

[0008] The microrobot body is obtained by 3D printing using a light-curing resin doped with magnetic powder;

[0009] The in vitro control system uses a magnetic control system of a three-dimensional Helmholtz coil to control the operation of the microrobot body.

[0010] Optionally, the magnetic powder is neodymium iron boron magnetic powder.

[0011] Optionally, the microrobot body includes a head, a body and a tail connected in sequence; wherein the head and the tail are both conical structures; and the body includes a spiral structure.

[0012] Optionally, the spiral structure includes two spiral lines, and the two spiral lines are respectively connected to the head and the tail.

[0013] Optionally, a drug-loading space is formed between the head, the tail and the two spiral lines.

[0014] Optionally, the outer diameter of the body is in the range of 1 mm to 5 mm.

[0015] Optionally, the length of the microrobot body ranges from 2.5 mm to 12.5 mm.

[0016] Another object of the present invention is to provide a control method for the microrobot for plaque removal as described above, comprising the following steps:

[0017] S1: Determine the patch coverage by visual grayscale detection method;

[0018] S2: determining a preset working mode and preset dynamic information of the microrobot body according to the coverage range of the plaque;

[0019] S3: controlling the microrobot body to operate in the preset working mode through an in vitro control system;

[0020] S4: acquiring real-time dynamic information of the microrobot body in real time through an image acquisition device;

[0021] S5: Compare the real-time dynamic information with the preset dynamic information, and adjust the working mode of the micro-robot body according to the comparison result.

[0022] Optionally, the working mode includes rotational atherectomy method, rotational atherectomy intensity, movement trajectory and movement speed.

[0023] Optionally, the rotational atherectomy method includes axial tip rotational atherectomy, oblique lateral rotational atherectomy and axial lateral rotational atherectomy.

[0024] The beneficial effects of the present invention are:

[0025] The microrobot for plaque removal provided by the present invention uses a photocurable resin doped with magnetic powder to obtain the microrobot body through 3D printing, realizes the coupling of the microrobot's rotational grinding function module and the magnetic drive module, saves the space occupied by the permanent magnet in the traditional magnetic microrobot, is conducive to the compact design of the microrobot, and thus helps to reduce the size of the microrobot and expand its application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings and examples.

[0027] Figure 1 This is a simplified structural diagram of the microrobot body of the present invention;

[0028] Figure 2 is a schematic diagram of a simulation of a three-dimensional Helmholtz coil system in the present invention;

[0029] Figure 3 Schematic diagram of the structure of the three-dimensional Helmholtz coil system of the present invention;

[0030] Figure 4 It is a flow chart of the control method in the present invention;

[0031] Figure 5 is a schematic diagram of the microrobot body of the present invention in a magnetic field;

[0032] Figure 6 is a schematic diagram of the microrobot body performing tilted lateral rotational atherectomy in the present invention;

[0033] Figure 7 Schematic diagram of the microrobot body performing axial rotation tip grinding and atherectomy in the present invention;

[0034] Figure 8 Schematic diagram of the microrobot body performing axial lateral rotational atherectomy in the present invention;

[0035] Figure 9It is a schematic diagram of atherectomy of vascular plaque using the traditional open-loop control method;

[0036] Figure 10 This is a schematic diagram of using the closed-loop control strategy of the present invention to remove 5mm-sized plaque in a 7mm inner diameter pipe;

[0037] Figure 11 This is a schematic diagram of using the closed-loop control strategy of the present invention to remove 4mm plaque in a 5mm inner diameter pipe;

[0038] Figure 12 This is a comparison chart of plaque removal in 5mm inner diameter and 7mm inner diameter pipes using different control methods.

[0039] In the figure: 1-head; 2-body; 3-tail. DETAILED DESCRIPTION

[0040] The present invention will now be described in further detail. The embodiments described below are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] In order to solve the problem of large size of microrobots in the prior art, the present invention provides a microrobot for plaque removal, which includes a microrobot body and an in vitro control system connected to the microrobot body by signal; the microrobot body is obtained by 3D printing using a photocurable resin doped with magnetic powder; the in vitro control system uses a magnetic control system of a three-dimensional Helmholtz coil to control the operation of the microrobot body.

[0043] Existing spiral magnetically driven microrobots are usually composed of two parts: a spiral body and a gear-shaped tip. The spiral body and the gear-shaped tip contain a cylindrical permanent magnet and an annular permanent magnet, respectively. The rotation axes of the cylindrical permanent magnet and the annular permanent magnet are perpendicular to each other. They are driven by an external biaxial rotating magnetic field to achieve rotational motion and thrombus removal, respectively. In other words, in existing spiral magnetically driven microrobots, the rotational grinding function module and the magnetic driving module are two independent modules. On the one hand, space for placing the permanent magnet is required, which results in a larger size of the microrobot. On the other hand, during operation, the rotational grinding function module and the magnetic driving module perform their functions independently, and the control process is complicated, which limits the application of microrobots in the medical field.

[0044] Based on this, the microrobot body in the present invention is obtained by 3D printing using a photocurable material doped with magnetic powder. After subsequent magnetization, the microrobot body is made magnetic, so that the microrobot can directly control the operation of the microrobot body through an in vitro control system using the magnetic control system of the three-dimensional Helmholtz coil, thereby realizing the coupling of the microrobot atherectomy module and the magnetic drive module. On the one hand, there is no need to set up a permanent magnet separately, and there is no need to set up a space for placing the permanent magnet, which greatly reduces the size of the microrobot, reduces its weight, and improves safety; on the other hand, it greatly simplifies the control process and is conducive to improving the accuracy of the control process; the travel speed and atherectomy intensity can be adjusted simultaneously by the magnetic field strength.

[0045] Based on the characteristics of the Helmholtz coil in generating a magnetic field, which is simple in principle, accurate in precision and easy to control, the present invention adopts a magnetic control system of three groups of orthogonally placed Helmholtz coils to provide a uniformly rotating magnetic field, which is the power source of the microrobot body. Each pair of coils consists of two coaxially placed circular coils, and the parameters of the coils and the internal wires need to be the same. When the spacing between the two coils is equal to the coil radius and currents of equal magnitude are passed through them in the same direction, a uniform magnetic field can be generated in the central area of ​​the pair of coils. If two pairs of Helmholtz coils are placed orthogonally and sinusoidal alternating currents with a phase difference of 90° are passed through them respectively, a uniform rotating magnetic field of a certain frequency can be generated in the orthogonal plane. Therefore, in order to realize the free movement of the microrobot in three-dimensional space, that is, to generate a rotating magnetic field that rotates around any vector direction in three-dimensional space, the present invention preferably places it orthogonally, see Figure 2 、 Figure 3 As shown, a uniform rotating magnetic field with adjustable direction and magnitude is generated by three pairs of orthogonally placed Helmholtz coils.

[0046] Taking into account the dimensions of existing microrobots and the size of the pipelines required for motion control, the present invention preferably specifies a 60mm Φ spherical range for the operable space in the center surrounded by the three pairs of Helmholtz coils. Furthermore, the magnetic field strength in the center region of each pair of Helmholtz coils can reach 8mT. Furthermore, considering that the Helmholtz coils are affected by the resistance of their own wires and will generate a large amount of heat if operated continuously for a certain period at a high input current, the input current should not exceed 5A. Based on these requirements, the coil parameters are designed as shown in Table 1:

[0047] Table 1

[0048]

[0049] The microrobot for plaque removal provided by the present invention adopts a photocurable resin doped with magnetic powder to obtain the microrobot body through 3D printing, realizes the coupling of the microrobot's atherectomy module and the magnetic drive module, saves the space occupied by the permanent magnet in the traditional magnetic microrobot, is conducive to the compact design of the microrobot, thereby reducing the size of the microrobot and expanding its application range.

[0050] The photocurable resin doped with magnetic powder of the present invention can be made from the corresponding existing technology; specifically, the magnetic powder of the present invention is preferably neodymium iron boron magnetic powder; the photocurable resin is preferably one or more of epoxy (meth)acrylate resin, polyester (meth)acrylate resin, polyurethane (meth)acrylate resin, and (meth)acrylate monomer; and further preferably, the particle size of the magnetic powder is 1-10 μm; and the percentage of the magnetic powder in the total mass of the photocurable resin is preferably 15%.

[0051] In order to facilitate the control of the microrobot body by the in vitro control system, the present invention preferably uses a light-curing resin doped with magnetic powder to obtain a prototype through 3D printing, and then magnetizes the prototype.

[0052] Since the microrobot needs to operate in a low Reynolds number environment during plaque removal, resistance has a great impact on the operation of the microrobot. Therefore, for the application of microrobots in plaque removal, in addition to considering compact design and safety, motion resistance is also an important factor that needs to be considered. Based on this, see Figure 1 As shown, the present invention further preferably comprises a microrobot body including a head 1, a body 2 and a tail 3 connected in sequence; wherein the head 1 and the tail 3 are both conical structures, specifically, the tips of the conical structures of the head 1 and the tail 3 extend in a direction away from the body 2; the body 2 comprises a spiral structure.

[0053] The microrobot body is equipped with large-angle drill bits at both ends of the structure and a spiral structure in the middle of the structure. On the one hand, it can reduce the resistance during rotation, and on the other hand, it can realize forward movement and grinding actions at the same time, which helps to provide multiple grinding methods; at the same time, the sturdy design ensures structural strength and enhances grinding capabilities.

[0054] Furthermore, the spiral structure of the present invention preferably includes two spiral lines, and the two spiral lines are respectively connected to the head 1 and the tail 3, so that the micro-robot body can change the movement direction more quickly by adjusting the direction of the magnetic field.

[0055] Furthermore, in order to further expand the scope of use of the microrobot, the present invention preferably forms a drug-loading space between the head 1, the tail 3 and the two spiral lines; for example, the drug-loading cavity can carry litholytic drugs, so that the litholytic drugs can be transported to the vicinity of the stones by the microrobot for release.

[0056] Specifically, in the present invention, the outer diameter of the body 2 is preferably in the range of 1 mm to 5 mm; the length of the microrobot body is preferably in the range of 2.5 mm to 12.5 mm.

[0057] The microrobot provided by the present invention has a microrobot body obtained by 3D printing using a photocurable resin doped with magnetic powder. After axial magnetization, an external rotating uniform magnetic field is applied along the axis of the microrobot body to induce rotational motion, which has strong controllability. Moreover, since the microrobot body of the present invention is obtained by 3D printing using a resin doped with magnetic powder to obtain a prototype and then magnetizing the prototype, it is convenient to obtain microrobots of various shapes. The obtained microrobots are magnetic and have extremely strong controllability.

[0058] Another object of the present invention is to provide a control method for the microrobot for plaque removal as described above, the control method comprising the following steps:

[0059] S1: Determine the patch coverage by visual grayscale detection method;

[0060] S2: Determine the preset working mode and preset dynamic information of the microrobot body according to the coverage of the plaque;

[0061] S3: Controlling the microrobot body to operate in a preset working mode through an in vitro control system;

[0062] S4: acquiring real-time dynamic information of the microrobot body through the image acquisition device;

[0063] S5: Compare the real-time dynamic information with the preset dynamic information, and adjust the working mode of the micro robot body according to the comparison result.

[0064] Specifically, when the microrobot is used to clear plaques, the coverage of the micro-channel, i.e., the semi-blocked plaque in the blood vessel, is first determined by a visual grayscale detection method; then, based on the coverage of the semi-blocked plaque, the preset working mode of the microrobot body and the dynamic information of the microrobot body under the preset working mode, i.e., the preset dynamic information, are preliminarily determined; then, the microrobot body is controlled by an in vitro control system to operate in the preliminarily determined preset working mode; during the operation of the microrobot body, the real-time dynamic information of the microrobot body is obtained in real time through an image acquisition device, preferably using a CCD, and then the real-time dynamic information is compared with the preset dynamic information. If the real-time dynamic information is consistent with the preset dynamic information, the microrobot body continues to operate in the preset working mode; if the real-time dynamic information is inconsistent with the preset dynamic information, i.e., there is a deviation between the real-time dynamic information and the preset dynamic information, the working mode of the microrobot body is adjusted according to the deviation to achieve efficient and accurate plaque removal.

[0065] Specifically, when the comparison results are inconsistent, the size and direction of the rotating magnetic field can be adjusted through the in vitro control system to achieve an ideal control effect on the microrobot body.

[0066] Specifically, the working mode of the present invention includes the atherectomy method, atherectomy intensity, travel trajectory and travel speed; correspondingly, the preset working mode includes the preset atherectomy method, preset atherectomy intensity, preset travel trajectory and preset travel speed.

[0067] The dynamic information in the present invention includes the position of the microrobot body and the plaque condition; correspondingly, the real-time dynamic information includes the real-time position of the microrobot body and the real-time plaque condition.

[0068] The control method of the microrobot for plaque removal provided by the present invention adopts a closed-loop control strategy, which can adjust the grinding mode and intensity, travel direction and speed in real time according to the position information and plaque status of the microrobot body fed back by the image, thereby realizing efficient and accurate plaque removal function; in the process of driving the microrobot body, due to some unavoidable interference and errors in the actual environment, the drive control of the microrobot body is difficult to achieve satisfactory results. The present invention adopts closed-loop feedback control, compares the real-time position information collected by the CCD with the preset path, and adjusts the current of the coil system according to this error to control the size and direction of the generated rotating magnetic field, so as to achieve an ideal control effect on the microrobot body.

[0069] Since the application target is semi-blocked plaque, the traditional tip drilling method cannot remove it efficiently and deeply. Therefore, when adjusting the direction of the magnetic field, three plaque removal rotational atherectomy methods are further introduced. Specifically, the preferred rotational atherectomy methods include axial tip rotational atherectomy, oblique lateral rotational atherectomy, and axial lateral rotational atherectomy. Different rotational atherectomy methods correspond to microrobots of different sizes and magnetic field control methods. Axial tip rotational atherectomy is a traditional rotational atherectomy method, which will not be described in detail in the present invention. It should be noted that oblique lateral rotational atherectomy and axial lateral rotational atherectomy are new rotational atherectomy methods introduced by the present invention through the combination of the material, structure and control method of the microrobot. The two are described as follows:

[0070] (1) Inclined lateral atherectomy: A microrobot that is larger than the gap of a semi-occluded plaque is applied with a unidirectional oblique rotating magnetic field.

[0071] (2) Axial lateral atherectomy: A microrobot smaller than the gap of a semi-occluded plaque is coupled with an axial rotating magnetic field that switches repeatedly in both directions.

[0072] That is to say, during operation, when a microrobot is selected, the atherectomy method can be selected according to the size of the semi-blocked plaque; specifically, if the gap between the semi-blocked plaque and the tube wall is smaller than the size of the microrobot body, the oblique lateral atherectomy is selected; if the gap between the semi-blocked plaque and the tube wall is larger than the size of the microrobot body, the axial lateral atherectomy is selected.

[0073] The magnetic field strength can simultaneously adjust the travel speed and the intensity of the atherectomy; thus, according to the image feedback of the microrobot body position and plaque conditions, multiple adjustments can be made to achieve efficient and accurate plaque removal.

[0074] The control method provided by the present invention can solve the problems in the prior art that the micro robot cannot switch control strategies according to different tasks and the motion posture of the micro robot is not stable enough.

[0075] For easier understanding, see Figure 4 As shown, the present invention provides the following control process:

[0076] The coverage of semi-occluded plaques in microchannels was determined by visual grayscale detection method;

[0077] Controlling the magnetic control system, that is, the in vitro control system outputs a rotating magnetic field with adjustable direction and frequency to drive the microrobot body to advance in a drill-like manner along a predetermined trajectory;

[0078] The real-time dynamic information of the micro-robot body is obtained in real time through the image acquisition device;

[0079] The magnetic field of the microrobot body is adjusted based on the real-time dynamic information until the microrobot body completes the grinding of the semi-blocked plaque.

[0080] Among them, the coverage of solid foreign matter in micro-pipes is determined by visual grayscale detection method, including;

[0081] Identifying the pipe wall boundary of the model by an image acquisition device;

[0082] The motion trajectory of the micro robot body is determined by taking the median method.

[0083] The magnetic control system is controlled to output a rotating magnetic field with a fixed frequency to drive the micro robot body to advance along a predetermined trajectory in a drill-like manner, including:

[0084] Input the required magnetic field data through the user interface of the host computer;

[0085] Convert magnetic field data into corresponding current information and send the current information to the lower computer;

[0086] Receive the current signal through the lower computer and convert the current signal into a PWM signal;

[0087] The driver receives the PWM signal and outputs the current to the electromagnetic coil;

[0088] Different types of magnetic fields are generated by adjusting the current size, frequency and phase of the electromagnetic coil to achieve arbitrary movement of the magnetic microrobot body.

[0089] Adjusting the magnetic field of the microrobot body based on real-time dynamic information until the microrobot body completes the ablation of the semi-occluded plaque, including:

[0090] When the microrobot body is monitored to have reached the edge of the solid foreign matter in the micro-pipe, the rotation frequency of the rotating magnetic field is appropriately changed so that the microrobot body can maintain sufficient torque to continue to advance in the liquid environment where the resistance suddenly increases; and the magnetic field of the microrobot body is adjusted based on the changes in the microrobot body until the microrobot body can pass through the solid foreign matter area in the micro-pipe.

[0091] Furthermore, the magnetic field of the microrobot body is adjusted based on the real-time dynamic information of the plaque, and the rotational grinding method and intensity of the microrobot body are changed, so that it can remove semi-blocked plaques more efficiently and thoroughly;

[0092] For ease of understanding, Lleft and Lright represent the left and right edges of a solid foreign object in the microchannel, such as a semi-blocked plaque, respectively. These are considered boundary conditions for changing the forward direction. Lup and Ldown represent the upper and lower edges of the solid foreign object in the microchannel, respectively. When Lup - Ldown < δ and Lleft - Lright < γ, the drilling motion is considered complete, meaning the semi-blocked plaque has been cleared at a certain speed, and the microrobot leaves the solid foreign object area in the microchannel. Otherwise, the microrobot continues to operate in the manipulation area. Under magnetic drive, the microrobot moves along the desired trajectory, switching motion modes and changing the rotation frequency. δ is the preset height of the solid foreign object, and γ is the preset width of the solid foreign object. The values ​​of δ and γ are determined based on the clearance requirements.

[0093] The present invention preferably uses the MI-12100 magnetizer to actively control the microrobot body. The magnetization in the present invention is carried out axially, such as Figure 5-Figure 8 As shown, an external rotating uniform magnetic field is then applied along the axis of the microrobot, inducing a rotational motion.

[0094] In order to highlight the advantages of the technical solution provided by the present invention, the following control methods are used for comparison:

[0095] 1. Open-loop control:

[0096] Using the traditional open-loop control method, a uniform rotating magnetic field in the same direction as the pipeline is applied, and the traditional unidirectional axial tip drilling method, such as Figure 9As shown, microrobots with diameters of 4mm and 5mm successfully completed the removal of simulated semi-blocked plaques in pipes with inner diameters of 5mm and 7mm, respectively, using axial tip rotational abrasion, taking 527s and 482s respectively; the size of the plaque in the pipe with inner diameter of 5mm was 4mm; the size of the plaque in the pipe with inner diameter of 7mm was 5mm.

[0097] 2. Closed-loop control

[0098] like Figure 10 As shown, for the removal of a 5mm-sized plaque in a 7mm-inner-diameter pipe, according to the closed-loop control strategy provided by the present invention, because there is a gap of about 2mm in the pipe, a 3mm-diameter robot is first used to perform tilted lateral grinding at a normal rotation frequency for 43s to grind out a flat surface, which is convenient for the subsequent microrobot to pass through. Then, it is switched to tip drilling and axial lateral grinding at a higher rotation frequency until it completely passes through at 97s. At this time, the feedback image, after grayscale processing, shows that the remaining size of the plaque is 3-4mm, and it is also a boss structure. Therefore, a 4mm-sized robot is replaced to perform tilted lateral grinding for 188s, and then high-frequency tip drilling and axial lateral grinding are switched to 246s, at which point the microrobot completely passes through. At this time, the feedback shows that the remaining size of the plaque is less than 2mm, so a 5mm microrobot is finally used alone to perform repeatedly switched axial lateral grinding for 319s to complete the plaque removal, which is 163s shorter than the time used for traditional tip grinding.

[0099] like Figure 11 As shown in the figure, for the removal of a 4mm plaque in a 5mm inner diameter tube, 2mm, 3mm, and 4mm microrobots were used respectively. According to the above closed-loop control strategy, the plaque removal was completed in a total of 397s, which was 130s shorter than the time taken by traditional tip grinding.

[0100] In order to more intuitively demonstrate the advantages of the closed-loop control strategy in the present invention, it is also necessary to find its removal efficiency for semi-enclosed plaques. Figure 12 In (a) and (d), there are two plaques with heights of 4 mm and 5 mm respectively; Figure 12 As shown in (b) and (e), the remaining sizes of plaques after conventional tip rotary grinding are 1.5 mm and 2 mm; Figure 12 As shown in (c) and (f), the remaining plaque size after closed-loop control rotary grinding in the present invention is 0.5mm and 1mm. Combined with the rotary grinding time measured above, the removal efficiency of the two rotary grinding methods can be obtained, as shown in Table 2:

[0101] Table 2

[0102]

[0103] Clearly, closed-loop control for semi-occluded plaque atherectomy is more thorough, time-efficient, and efficient, demonstrating its superiority. Therefore, when removing plaque, the appropriate microrobot size, atherectomy method, and intensity can be selected based on actual conditions, ensuring efficient and safe removal using closed-loop control.

[0104] The control method provided by the present invention determines the coverage of solid foreign matter in a micro-pipeline through a visual grayscale detection method; controls a magnetic control system to output a rotating magnetic field with a fixed frequency to drive a micro-robot body to advance in a drill-like manner along a predetermined trajectory; obtains real-time dynamic information of the micro-robot body and a semi-blocked plaque through an image acquisition device; adjusts the magnetic field of the micro-robot body based on the real-time dynamic information until the micro-robot body can complete the grinding of the solid foreign matter area; realizes visual feedback of the micro-robot body through the image acquisition device, and timely selects or adjusts the motion control strategy based on the current environment and the situation faced by the micro-robot body; thus solving the problems in the prior art that the micro-robot cannot switch the control strategy according to different tasks and the motion posture of the micro-robot is not stable enough.

[0105] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A microrobot for plaque removal, characterized in that: It includes a micro-robot body and an in vitro control system connected to the micro-robot body by signals; The microrobot body is obtained by 3D printing using a light-curing resin doped with magnetic powder; The in vitro control system uses a magnetic control system of a three-dimensional Helmholtz coil to control the operation of the microrobot body; The in vitro control system includes three sets of orthogonally placed Helmholtz coils; The three groups of orthogonally placed Helmholtz coils enclose a spherical area with a diameter of 60 mm in the middle; the magnetic field intensity in the middle area of ​​each group of Helmholtz coils is not less than 8 mT; Input current is not more than 5A; Also included is an image acquisition device; The image acquisition device is signal-connected to the in vitro control system; The microrobot adjusts the atherectomy mode and intensity, direction and speed in real time based on the position information of the microrobot body and the plaque status fed back by the image; The rotational atherectomy methods include axial tip rotational atherectomy, oblique lateral rotational atherectomy and axial lateral rotational atherectomy; If the gap between the semi-blocked plaque and the tube wall is smaller than the size of the microrobot body, the oblique lateral rotational atherectomy is selected; if the gap between the semi-blocked plaque and the tube wall is larger than the size of the microrobot body, the axial lateral rotational atherectomy is selected.

2. The microrobot for plaque removal according to claim 1, characterized in that: The magnetic powder is neodymium iron boron magnetic powder.

3. The microrobot for plaque removal according to claim 1, characterized in that: The microrobot body comprises a head (1), a body (2) and a tail (3) which are connected in sequence; wherein the head (1) and the tail (3) are both conical structures; and the body (2) comprises a spiral structure.

4. The microrobot for plaque removal according to claim 3, characterized in that: The spiral structure comprises two spiral lines, and the two spiral lines are respectively connected to the head (1) and the tail (3).

5. The microrobot for plaque removal according to claim 3, characterized in that: A drug-carrying space is formed between the head (1), the tail (3) and the two spiral lines.

6. The microrobot for plaque removal according to claim 3, characterized in that: The outer diameter of the body (2) ranges from 1 mm to 5 mm.

7. The microrobot for plaque removal according to claim 3, characterized in that: The length of the microrobot body ranges from 2.5 mm to 12.5 mm.

Images