Flexible needle puncture mechanism and control method based on stator winding

Abstract

A flexible needle puncture mechanism and control method based on a stator winding, belonging to the field of medical devices. It relies on the stator winding to drive the rotation of the bevel-tip flexible needle, and relies on a servo motor to drive the rotation of a support tube provided with internal threads. A drive seat that is threadedly engaged with the support tube is provided at the tail of the flexible needle, thereby driving the feeding of the flexible needle, providing two degrees of freedom of feeding and rotation for the bevel-tip flexible needle, and at the same time ensuring the support for the flexible needle during the feeding process, preventing the warping of the flexible needle due to the reaction force between the needle and the tissue during feeding; in this invention, the flexible needle moves in the support tube, and its linear motion stroke is basically equivalent to the length of the support tube. Compared with the traditional flexible needle support method, the support and the motion slideway are directly integrated, and the stroke will not be lost due to the support. Compared with the existing magnetic drive flexible needle puncture device, the use of the stator winding can also provide the rotational degree of freedom of the needle.

Description

Technical Field

[0001] The present invention belongs to the field of intelligent medical equipment and control, and particularly relates to a flexible needle puncture mechanism based on a stator winding and a control method thereof. Background Art

[0002] Minimally invasive interventional medicine is a medical technology that uses minimally invasive means such as catheters to enter the body through natural body cavities or small incisions for diagnosis and treatment. Compared with traditional open surgery, minimally invasive interventional medicine has the advantages of less surgical trauma and faster recovery time, and is widely used in multiple fields such as cardiovascular, neurology, and urology.

[0003] Flexible needle puncture technology is a new emerging minimally invasive interventional medical technology used for puncturing or sampling in the body while minimizing harm to the patient. Compared with traditional rigid needle puncture technology, flexible needle puncture technology has higher accuracy and lower injury risk. This technology is usually used for diagnosis and treatment, such as locating deep lesions in neurosurgery or sampling diseased tissues in lung cancer diagnosis. Flexible needle puncture technology generally uses imaging technologies such as ultrasound, CT, or MRI for guidance to ensure accurate puncture of the target tissue or organ. This technology usually uses a puncture needle with a flexible outer shell and a bendable tip that can advance along a curved path after entering the body to avoid damaging the surrounding tissues to the greatest extent.

[0004] A common problem with flexible needle puncture mechanisms is that during the puncture process, due to the friction and other resistance forces of the tissue on the flexible needle, the part of the flexible needle that has not penetrated into the tissue will warp. Therefore, a support structure needs to be provided for the needle body of the flexible needle. The traditional solution is to use multiple segments of telescopic circular tubes. With this method, as the number of support tube segments increases, the diameter of the support tube will become larger, and no matter how the length of each segment of the support tube is shortened, there will be a section of the travel of the flexible needle wasted on the support tube. Summary of the Invention

[0005] Aiming at the above problems, the technical problem to be solved by the present invention is to provide a flexible needle puncture mechanism based on a stator winding. The mechanism is provided with a flexible needle support tube having an inner spiral groove and a needle support seat having an outer spiral protrusion, and the relative rotation of the support tube and the needle support seat is controlled to control the feeding or rotational movement of the flexible needle.

[0006] A flexible needle puncture mechanism based on a stator winding, in which the main moving components are a flexible needle assembly and a lead screw nut mechanism. These two parts are installed on a base through bearings. At the same time, two servo motors are also installed on the base. The output shafts of the servo motors are connected to the flexible needle assembly and the lead screw nut mechanism through couplings. A winding seat is installed on the nut in the lead screw nut mechanism, and a stator winding is installed on the winding seat. The flexible needle assembly passes through the middle of the stator winding. The flexible needle assembly includes a support tube, a needle drive seat, a flexible needle, and a puncture nozzle. A spiral groove is provided inside the support tube, and spiral protrusions and a ring of permanent magnets with the same pole facing outward are provided on the periphery of the needle drive seat and cooperate with the spiral groove. The stator winding can control the rotation or locking of the needle drive seat. When the needle drive seat is locked and rotated by the stator winding, the rotation of the support tube can control the linear movement of the needle drive seat, controlling the puncture or retraction of the flexible needle. When the stator winding controls the rotation of the needle drive seat, the rotation of the flexible needle can be controlled. The lead screw nut mechanism is used to control the axial position synchronization of the stator winding and the needle drive seat.

[0007] A row of linearly arranged Hall sensors is provided on the base, and the arrangement direction is parallel to the axis of the flexible needle assembly. This Hall sensor array can detect the axial position of the needle drive seat by sensing the magnetic field. The motors driving the flexible needle assembly and the lead screw nut mechanism are both servo motors, which can achieve closed-loop control. However, the driving mode of the stator winding driving the needle drive seat is a step-by-step type, which is an open-loop control with low precision. By detecting the axial displacement of the needle drive seat by the Hall sensor, as well as the rotation angle of the flexible needle assembly and the spiral lead inside the support tube, the theoretical step angle applied by the stator winding to the needle drive seat can be calculated, and the control of the stator winding is realized in a closed-loop manner, improving the motion control precision.

[0008] The beneficial effects of the present invention are:

[0009] The support tube in the flexible needle assembly can not only control the movement of the flexible needle but also support the soft needle body of the flexible needle to prevent the flexible needle from warping during the puncture process. At the same time, relying on the Hall sensor array to detect the axial displacement of the flexible needle drive seat and the rotation angle of the flexible needle assembly, the closed-loop control of the rotation angle of the flexible needle is realized. Description of the Drawings

[0010] Figure 1 Overall schematic diagram of a flexible needle puncture mechanism based on a stator winding

[0011] Figure 2 Schematic diagram of the winding seat mechanism

[0012] Figure 3 Schematic cross-sectional view of the flexible needle assembly

[0013] In the figure: 1 flexible needle assembly, 2 stator winding, 3 winding base, 4 motor one, 5 motor two, 6 lead screw nut mechanism, 7 base, 8 Hall sensor array, 1-1 flexible needle, 1-2 puncture tip, 1-3 support tube, 1-4 needle drive base, 3-1 through hole one, 3-2 through hole two. Embodiment

[0014] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be described below through specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0015] As Figure 1 , Figure 2 , Figure 3 shown, the specific embodiment of the present invention adopts the following technical solutions: A flexible needle puncture mechanism based on a stator winding, which comprises: a flexible needle assembly 1, a stator winding 2, a winding base 3, a motor one 4, a motor two 5, a lead screw nut mechanism 6, a base 7, and a Hall sensor array 8; the winding base 3 is an L-shaped structure, and the side plate is provided with a through hole one 3-1 and a through hole two 3-2. The stator winding 2 is installed on the side plate of the winding base 3 by screws and is concentric with the through hole two 3-2; the flexible needle assembly 1 is parallel to the lead screw nut mechanism 6. The flexible needle assembly 1 is installed on the right side of the base 7 through a bearing and passes through the through hole two 3-2 of the winding base 3; the lead screw nut mechanism 6 is installed on the left side of the base 7 through a bearing and passes through the through hole one 3-1 of the winding base 3; the winding base 3 is fixed to the nut in the lead screw nut mechanism 6 and is installed on the base 7 through a slideway; the motor one 4 and the motor two 5 are both installed at the same end of the base 7. The output shaft of the motor one 4 is fixed to the flexible needle assembly 1 through a coupling, and the output shaft of the motor two 5 is fixed to the input end of the lead screw nut mechanism 6 through a coupling; the Hall sensor array 8 is installed on the base 7, and the arrangement direction is parallel to the axis of the flexible needle assembly 1; the motor one 4 drives the flexible needle assembly to rotate, and the motor two 5 drives the lead screw nut mechanism 6 to control the linear movement of the winding base 3 and the stator winding 2.

[0016] Specific embodiment two: Combine Figures 1 to 3Describing this embodiment, the flexible needle assembly 1 described in this embodiment comprises: a flexible needle 1-1, a puncture nozzle 1-2, a support tube 1-3, and a needle drive seat 1-4; the support tube 1-3 is a thin tube with a spiral groove inside, the needle drive seat 1-4 is a hollow cylindrical structure, with a circle of magnets with the same pole facing outwards on the cylindrical surface, steps are provided near both ends of the cylindrical surface, and spiral protrusions matching the spiral groove of the support tube 1-3 are provided on the steps; the puncture nozzle 1-2 is installed at one end of the support tube 1-3, the needle drive seat 1-4 is placed inside the support tube 1-3, the spiral protrusions can slide along the spiral groove, the root of the flexible needle 1-1 is fixedly connected to the middle hole of the needle drive seat 1-4 and extends out from the puncture nozzle 1-2; the stator winding 2 is in the same axial position as the needle drive seat 1-4, and the stator winding 2 can drive the needle drive seat 1-4 to rotate or lock the rotation step by step.

[0017] Specific Embodiment Three: Combining Figures 1 to 3 Describing this embodiment, the lead of the support tube 1-3 in this embodiment is P1, the lead of the ball screw nut mechanism is P2, the motor one 4 drives the support tube 1-3 to rotate n1 turns, the needle drive seat 1-4 is locked to rotate, then the linear movement distance of the flexible needle 1-1 is n1*P1, and the motor two 5 rotates n2 = n1*P1 / P2 turns to make the stator winding 2 axially synchronous with the needle drive seat 1-4; the stator winding 2 controls the rotation angle θ1 of the needle drive seat 1-4, then a rotation angle compensation θ2 = θ1*P1 / P2 is given to the motor two 5 to make the stator winding 2 axially synchronous with the needle drive seat 1-4; both the motor one 4 and the motor two 5 are servo motors, which can realize closed-loop control of the rotation angle. The Hall sensor array 8 can detect the axial position of the needle drive seat 1-4, and the axial displacement L of the needle drive seat 1-4 can be calculated. The theoretical rotation angle θ3 of the needle drive seat 1-4 is calculated by the calculation formula θ3 = 2π(L - n1*P1) / P1. The feedback of θ3 to control the step angle θ1 given by the stator winding 2 to the needle drive seat 1-4 realizes the closed-loop control of the rotation angle of the flexible needle 1-1.

[0018] The working principle of the specific embodiment of the present invention is as follows:

[0019] The flexible needle assembly and the lead screw nut mechanism are mounted on the base through bearings and can rotate, driven by two servo motors. Servo motor 1 drives the flexible needle assembly to rotate, and servo motor 2 drives the lead screw nut mechanism to move, controlling the linear movement of the winding seat and the stator winding. The flexible needle assembly passes through the middle of the stator winding. A ring of permanent magnets with the same poles facing outwards is provided on the outer circle of the needle drive seat in the flexible needle assembly. The stator winding can drive its rotation or lock its rotation. The inner spiral groove of the support tube in the flexible needle assembly cooperates with the outer spiral protrusion of the needle drive seat and can slide relative to each other. When the needle drive seat is locked by the stator winding and the support tube rotates, the linear movement of the needle drive seat can be controlled, thereby controlling the puncture or retraction of the flexible needle. When the stator winding controls the rotation of the needle drive seat, the rotation of the flexible needle can be controlled. The lead screw nut mechanism is used to control the axial position synchronization of the stator winding and the needle drive seat.

[0020] A row of Hall sensors is provided on the base, and the arrangement direction is parallel to the axis of the flexible needle assembly. The axial position of the needle drive seat can be detected by sensing the magnetic field. The motors driving the flexible needle assembly and the lead screw nut mechanism are both servo motors, which can achieve closed-loop control. However, the driving mode of the stator winding driving the needle drive seat is step-by-step, which is an open-loop control with low precision. By detecting the axial displacement of the needle drive seat by the Hall sensor, as well as the rotation angle of the flexible needle assembly and the inner spiral lead of the support tube, the theoretical step angle applied by the stator winding to the needle drive seat can be calculated, and the control of the stator winding is realized in a closed-loop manner, improving the motion control accuracy.

[0021] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A flexible needle puncture mechanism based on a stator winding, characterized in that, Including: Flexible needle assembly (1), stator winding (2), winding base (3), motor one (4), motor two (5), lead screw nut mechanism (6), base (7) and Hall sensor array (8); The winding base (3) is of an L-shaped structure, with a first through hole (3-1) and a second through hole (3-2) provided on the side plate. The stator winding (2) is installed on the side plate of the winding base (3) by screws and is concentric with the second through hole (3-2); The flexible needle assembly (1) is parallel to the lead screw nut mechanism (6). The flexible needle assembly (1) passes through the middle of the stator winding (2). The flexible needle assembly (1) is installed on the right side of the base (7) through a bearing and passes through the second through hole (3-2) of the winding base (3); The lead screw nut mechanism (6) is installed on the left side of the base (7) through a bearing and passes through the first through hole (3-1) of the winding base (3); The winding base (3) is fixed to the nut in the lead screw nut mechanism (6) and is installed on the base (7) through a slideway; The flexible needle assembly (1) consists of: flexible needle (1-1), puncture nozzle (1-2), support tube (1-3) and needle drive seat (1-4); The support tube (1-3) is a thin tube with spiral grooves inside. The needle drive seat (1-4) is a hollow cylindrical structure. There is a circle of magnets with the same pole facing outwards on the cylindrical surface. Steps are provided near both ends of the cylindrical surface, and spiral protrusions matching the spiral grooves of the support tube (1-3) are provided on the steps; The puncture nozzle (1-2) is installed at one end of the support tube (1-3). The needle drive seat (1-4) is placed inside the support tube (1-3). The spiral protrusions can slide along the spiral grooves. The root of the flexible needle (1-1) is fixedly connected to the hole in the needle drive seat (1-4) and extends out from the puncture nozzle (1-2); The stator winding (2) is in the same axial position as the needle drive seat (1-4). The stator winding (2) can stepwise drive the needle drive seat (1-4) to rotate or lock the rotation. When the needle drive seat (1-4) is locked by the stator winding (2) to rotate, rotating the support tube (1-3) can control the linear motion of the needle drive seat (1-4) and control the puncture or retraction of the flexible needle (1-1); When the stator winding (2) controls the rotation of the needle drive seat (1-4), the rotation of the flexible needle (1-1) can be controlled; Both the motor one (4) and the motor two (5) are installed at the same end of the base (7). The output shaft of the motor one (4) is fixed to the flexible needle assembly (1) through a coupling. The output shaft of the motor two (5) is fixed to the input end of the lead screw nut mechanism (6) through a coupling; The Hall sensor array (8) is installed on the base (7), and the arrangement direction is parallel to the axis of the flexible needle assembly (1); The motor one (4) drives the flexible needle assembly (1) to rotate. The motor two (5) drives the lead screw nut mechanism (6) to control the linear motion of the winding base (1-4) and the stator winding (2). The lead screw nut mechanism (6) is used to control the axial position synchronization of the stator winding (2) and the needle drive seat (1-4).

2. The flexible needle puncture mechanism based on a stator winding according to claim 1, wherein The lead of the support tube (1-3) is P1, the lead of the ball screw nut mechanism is P2. The first motor (4) drives the support tube (1-3) to rotate n1 turns. When the needle drive seat (1-4) is locked and rotated, the linear movement distance of the flexible needle (1-1) is n1*P1. The second motor (5) rotates n2 = n1*P1 / P2 turns to make the stator winding (2) axially synchronized with the needle drive seat (1-4). When the stator winding (2) controls the rotation angle θ1 of the needle drive seat (1-4), a rotation angle compensation θ2 = θ1*P1 / P2 is given to the second motor (5) to make the stator winding (2) axially synchronized with the needle drive seat (1-4). Both the first motor (4) and the second motor (5) are servo motors, which can achieve closed-loop control of the rotation angle. The Hall sensor array (8) can detect the axial position of the needle drive seat (1-4), and the axial displacement L of the needle drive seat (1-4) can be calculated. The theoretical rotation angle θ3 of the needle drive seat (1-4) is calculated by the formula θ3 = 2π(L - n1*P1) / P1. The feedback of θ3 to control the step angle θ1 given by the stator winding (2) to the needle drive seat (1-4) realizes the closed-loop control of the rotation angle of the flexible needle (1-1).

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