Jawed flexible surgical instrument for minimally invasive surgical robots and method of controlling the same

Abstract

The utility model belongs to the field of minimally invasive surgery robot, and the pincer end flexible mechanism control mechanism includes pincer end left opening and closing control mechanism, pincer end right opening and closing control mechanism, pincer end upper deflection control mechanism, pincer end lower deflection control mechanism and pincer end 360 degree rotation control mechanism, through pincer end left opening and closing control mechanism, pincer end right opening and closing control mechanism, pincer end upper deflection control mechanism, pincer end lower deflection control mechanism and pincer end 360 degree rotation control mechanism respectively control pincer end flexible mechanism and carry out left opening and closing movement, right opening and closing movement, upper deflection movement, lower deflection movement and 360 degree rotation movement, the utility model carries out the zoning to flexible surgical instrument function and then plans motor arrangement, and the motor warehouse occupation space is greatly saved, and the gradient structure design is carried out to steering pulley, realizes transmission shaft transmission non -interference, and through the method that minimally invasive surgery robot controls flexible surgical instrument movement solves the steel wire deflection problem.

Description

Technical Field

[0001] This invention belongs to the field of minimally invasive surgical robot technology, specifically relating to a flexible surgical instrument with a forceps end for use in a minimally invasive surgical robot and its control method. Background Technology

[0002] To overcome the numerous problems associated with conventional laparoscopic surgery and expand the application of minimally invasive surgery, minimally invasive surgical robots have emerged. Research institutions and technology companies worldwide are undertaking significant costs to develop minimally invasive surgical robots, driving continuous progress and increasingly widespread application of this technology. Currently, the total cost of commercially available minimally invasive surgical robot systems for clinical use is extremely high. For example, introducing a daVinci minimally invasive surgical robot system to China would cost over 20 million RMB, with annual maintenance costs reaching up to 1.4 million RMB, hindering its widespread adoption. Furthermore, the surgical instruments used have a lifespan of only 10 uses, resulting in very high costs per surgery. Therefore, most ordinary families cannot afford such high surgical costs, limiting the widespread application of minimally invasive surgical robots to a small number of patients.

[0003] In response to the above situation, my country has actively conducted research on minimally invasive surgical robots and promoted the transformation of corresponding products. However, to date, my country's research and development of minimally invasive surgical robots has mainly focused on multi-port minimally invasive surgery, showing a rapid development trend and achieving considerable results. Research on single-port minimally invasive surgical robots, on the other hand, is still in its early stages. Single-port minimally invasive surgical robots, due to their advantages such as fewer surgical incisions, smaller incision area, lower operator fatigue, and the ability to perform more precise and complex surgical procedures, have become a very important research direction in the field of medical surgical robots. With an aging population and increasing medical needs, the medical robot market is becoming increasingly important. Developing a lightweight, flexible, highly integrated, and safe single-port minimally invasive surgical robot can not only stimulate innovation in medical robot technology and its practical application, but also help my country achieve rapid and continuous progress in the field of medical robots. Simultaneously, this will also help improve people's living standards and bring more benefits to the national economic development.

[0004] Chinese Patent Publication No. CN102028548A discloses a clamp-type surgical instrument for a minimally invasive laparoscopic surgical robot. This surgical instrument is mainly connected to an interface base. Four drive mechanisms on the interface base drive the operating tube transmission mechanism, left finger transmission mechanism, right finger transmission mechanism, and wrist joint transmission mechanism on the surgical instrument, respectively. The wrist joint, left fingers, and right fingers on the end effector are moved via forward and backward drive wires for the left and right fingers, and forward and backward drive wires for the right and right fingers. The disadvantages of this surgical instrument are: the overall space occupied by the transmission and drive mechanisms is large, and the structure of the transmission and drive mechanisms is complex. Furthermore, the surgical instrument uses a drive shaft wound with wires to achieve the opening and closing motion of the clamp tip, and uses gears to compensate for the wire's yaw motion, resulting in complex wire winding, transmission interference, and a low degree of yaw capability at the clamp tip. Summary of the Invention

[0005] The purpose of this invention is to provide a flexible surgical instrument with a clamp tip for use in minimally invasive surgical robots and its control method, to solve the problems of complex wire winding, transmission interference, and low wobble range of existing surgical instruments used in minimally invasive surgical robots. This invention significantly saves space in the motor compartment by dividing the flexible surgical instrument's functions into functional zones and planning the motor arrangement. Simultaneously, a gradient structure design for the steering pulley ensures interference-free transmission of the drive shaft, and the wire wobble problem is solved by controlling the movement of the flexible surgical instrument using a method specific to minimally invasive surgical robots.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows:

[0007] This invention provides a flexible clamp tip surgical instrument for a minimally invasive surgical robot, comprising: a flexible clamp tip mechanism and a flexible clamp tip mechanism control mechanism. The flexible clamp tip mechanism control mechanism includes: a left clamp tip opening and closing control mechanism, a right clamp tip opening and closing control mechanism, an upper clamp tip swing control mechanism, a lower clamp tip swing control mechanism, and a 360-degree clamp tip rotation control mechanism. The left clamp tip opening and closing control mechanism, the right clamp tip opening and closing control mechanism, the upper clamp tip swing control mechanism, the lower clamp tip swing control mechanism, and the 360-degree clamp tip rotation control mechanism control the flexible clamp tip mechanism to perform left opening and closing movement, right opening and closing movement, upper swing movement, lower swing movement, and 360-degree rotation movement, respectively.

[0008] Furthermore, the control mechanism for the flexible clamping end also includes: a rigid clamping end connecting outer tube and a rigid clamping end connecting inner tube, the rigid clamping end connecting inner tube being located inside the rigid clamping end connecting outer tube; the rigid clamping end connecting inner tube is connected to the flexible clamping end mechanism and the 360-degree rotation control mechanism for the clamping end, respectively.

[0009] Furthermore, the flexible clamp mechanism includes: a left-hand opening and closing clamp, a right-hand opening and closing clamp, an opening and closing clamp fixing seat, an opening and closing clamp fixing pin, an upper swing guide pulley, a lower swing guide pulley, a clamp opening and closing seat fixing pin, a flexible clamp connecting seat, a flexible clamp cross-shaped swing pin, a flexible clamp connecting seat fixing pin, a connector, a flexible inner clamp tube, and a flexible outer clamp tube. Multiple flexible clamp connecting seats are connected sequentially via clamp flexible connecting seat fixing pins to form a flexible outer clamp tube. The rear end of the flexible outer clamp tube is connected to the front end of the rigid outer clamp tube, and the front end of the flexible outer clamp tube is connected to one end of the connector. The rear end of the flexible inner clamp tube is connected to the clamp... The rigid connecting inner tube is connected; there are multiple flexible cross-shaped swing pins at the clamp ends, the number of which is the same as the number of flexible connecting seats at the clamp ends. The outer ring of the flexible cross-shaped swing pin is fixed to the inner wall of the flexible connecting seat at the clamp ends, and the inner ring of the flexible cross-shaped swing pin is fitted onto the flexible inner tube at the clamp ends; the rear end of the opening and closing clamp fixing seat is connected to the flexible inner tube at the clamp ends through clamp opening and closing seat fixing pins, and the front end of the opening and closing clamp fixing seat is connected to the left opening and closing clamp and the right opening and closing clamp at the clamp ends through opening and closing clamp fixing pins; the left opening and closing clamp and the right opening and closing clamp at the clamp ends are provided with serrated mating structures on their opposite sides; the upper swing steering pulley and the lower swing steering pulley at the clamp ends are both fixed inside the opening and closing clamp fixing seat by pins.

[0010] Furthermore, the clamp left-opening / closing control mechanism includes: a clamp left-opening / closing control motor, a lower clamp left-opening / closing control motor connecting base, an upper clamp left-opening / closing control motor connecting base, a clamp left-opening / closing transmission shaft winding shaft, a clamp left-opening / closing transmission shaft steering pulley, a first transmission shaft, and a clamp left-opening / closing transmission shaft steering pulley fixing base; the lower clamp left-opening / closing control motor connecting base is fixedly connected to the upper clamp left-opening / closing control motor connecting base, the output end of the clamp left-opening / closing control motor is fixed on the lower clamp left-opening / closing control motor connecting base, the clamp left-opening / closing transmission shaft winding shaft is fixed on the upper clamp left-opening / closing control motor connecting base, and the output shaft of the clamp left-opening / closing control motor passes through the lower clamp left-opening / closing control motor connecting base and connects to the clamp left-opening / closing control motor connecting base. The ends of the drive shaft are connected to the winding shaft. The left opening and closing drive shaft steering pulley is fixed on the clamp opening and closing drive shaft steering pulley fixing seat. The front end of the first drive shaft is wound around the left opening and closing clamp. The rear end of the first drive shaft passes through the clamp flexible inner tube and the clamp rigid connecting inner tube in sequence, and then winds around the clamp left opening and closing drive shaft steering pulley and then winds around the clamp left opening and closing drive shaft winding shaft. The clamp left opening and closing control motor drives the clamp left opening and closing drive shaft winding shaft to rotate clockwise through the clamp left opening and closing control motor connecting lower seat and clamp left opening and closing control motor connecting upper seat. This causes the first drive shaft to wind clockwise around the clamp left opening and closing drive shaft winding shaft. Pulling the first drive shaft opens the clamp left opening and closing clamp, and vice versa.

[0011] Furthermore, the right-hand opening and closing control mechanism includes: a right-hand opening and closing control motor, a lower connecting seat for the right-hand opening and closing control motor, an upper connecting seat for the right-hand opening and closing control motor, a winding shaft for the right-hand opening and closing transmission shaft, a steering pulley for the right-hand opening and closing transmission shaft, a second transmission shaft, and a fixing seat for the steering pulley for the right-hand opening and closing transmission shaft. The lower connecting seat for the right-hand opening and closing control motor is fixedly connected to the upper connecting seat for the right-hand opening and closing control motor. The output end of the right-hand opening and closing control motor is fixed on the lower connecting seat for the right-hand opening and closing control motor. The winding shaft for the right-hand opening and closing transmission shaft is fixed on the upper connecting seat for the right-hand opening and closing control motor. The output shaft of the right-hand opening and closing control motor passes through the lower connecting seat for the right-hand opening and closing control motor and connects to the right-hand opening and closing control motor. The ends of the drive shaft are connected to the winding shaft. The right-opening drive shaft steering pulley is fixed on the right-opening drive shaft steering pulley fixing seat. The front end of the second drive shaft is wound around the right-opening clamp. The rear end of the second drive shaft passes through the flexible inner tube of the clamp and the rigid connecting inner tube of the clamp in sequence, then winds around the right-opening drive shaft steering pulley and then winds around the right-opening drive shaft winding shaft. The right-opening control motor of the clamp drives the right-opening drive shaft winding shaft to rotate clockwise through the lower and upper seats of the right-opening control motor connection, thereby winding the second drive shaft clockwise around the right-opening drive shaft winding shaft. Pulling the second drive shaft opens the right-opening clamp, and pulling it closes it.

[0012] Furthermore, the clamp tip tilting control mechanism includes: a clamp tip tilting control motor, a lower clamp tip tilting control motor connecting base, an upper clamp tip tilting control motor connecting base, a clamp tip tilting drive shaft winding shaft, a clamp tip tilting drive shaft steering pulley, and a third drive shaft; the lower clamp tip tilting control motor connecting base and the upper clamp tip tilting control motor connecting base are fixedly connected, the output end of the clamp tip tilting control motor is fixed on the lower clamp tip tilting control motor connecting base, the upper clamp tip tilting drive shaft winding shaft is fixed on the upper clamp tip tilting control motor connecting base, and the output shaft of the clamp tip tilting control motor passes through the clamp tip tilting control motor. The lower connecting seat is connected to the end of the upper swing drive shaft winding shaft of the clamp end; the front end of the third drive shaft is wound around the upper swing steering pulley of the clamp end, and the rear end of the third drive shaft passes through the flexible inner tube of the clamp end and the rigid connecting inner tube of the clamp end in sequence, then winds around the upper swing drive shaft steering pulley of the clamp end and then winds around the upper swing drive shaft winding shaft of the clamp end; the upper swing control motor of the clamp end drives the upper swing drive shaft winding shaft of the clamp end to rotate clockwise through the lower connecting seat and the upper connecting seat of the upper swing control motor of the clamp end, thereby winding the third drive shaft clockwise around the upper swing drive shaft winding shaft of the clamp end, and the upper swing of the clamp end is realized by pulling the third drive shaft.

[0013] Furthermore, the clamp tip deflection control mechanism includes: a clamp tip deflection control motor, a lower clamp tip deflection control motor connecting base, an upper clamp tip deflection control motor connecting base, a clamp tip deflection drive shaft winding shaft, a clamp tip deflection drive shaft steering pulley, and a fourth drive shaft; the lower clamp tip deflection control motor connecting base and the upper clamp tip deflection control motor connecting base are fixedly connected, the output end of the clamp tip deflection control motor is fixed on the lower clamp tip deflection control motor connecting base, the clamp tip deflection drive shaft winding shaft is fixed on the upper clamp tip deflection control motor connecting base, and the output shaft of the clamp tip deflection control motor passes through the clamp tip deflection control motor. The lower connecting seat is connected to the end of the clamp lower swing drive shaft winding shaft; the front end of the fourth drive shaft is wound around the clamp lower swing steering pulley, and the rear end of the fourth drive shaft passes through the clamp flexible inner tube and the clamp rigid connecting inner tube in sequence, then winds around the clamp lower swing drive shaft steering pulley and then winds around the clamp lower swing drive shaft winding shaft; the clamp lower swing control motor drives the clamp lower swing drive shaft winding shaft to rotate clockwise through the clamp lower swing control motor connected to the lower seat and the clamp lower swing control motor connected to the upper seat, thereby winding the fourth drive shaft clockwise around the clamp lower swing drive shaft winding shaft, and the clamp lower swing is achieved by pulling the fourth drive shaft.

[0014] Furthermore, the 360-degree rotation control mechanism for the clamp ends includes: a 360-degree rotation control motor for the clamp ends, a lower connecting base for the 360-degree rotation motor for the clamp ends, an upper connecting base for the 360-degree rotation motor for the clamp ends, a drive shaft for the 360-degree rotation motor for the clamp ends, a 360-degree rotation output gear for the clamp ends, a 360-degree rotation input gear for the clamp ends, and a fixed seat for the input gear for the clamp ends. The lower connecting base for the 360-degree rotation motor for the clamp ends is fixedly connected to the upper connecting base for the 360-degree rotation motor for the clamp ends. The output end of the 360-degree rotation control motor for the clamp ends is fixed to the lower connecting base for the 360-degree rotation motor for the clamp ends. The drive shaft of the 360-degree rotation motor for the clamp ends is fixed to the upper connecting base for the 360-degree rotation motor for the clamp ends. The output shaft of the 360-degree rotation control motor for the clamp ends passes through the lower connecting base for the 360-degree rotation motor for the clamp ends and connects to the drive shaft of the 360-degree rotation motor for the clamp ends. The jaws are connected, with the 360° rotation output gear mounted on the upper end of the jaw 360° rotation motor drive shaft; the jaw 360° rotation input gear is mounted in the jaw 360° rotation input gear fixing seat, and the jaw 360° rotation input gear is mounted on the upper end of the jaw rigid connection inner tube, and the jaw 360° rotation input gear and the jaw 360° rotation output gear are meshed; when the jaw 360° rotation control motor drives the jaw 360° rotation motor drive shaft and the jaw 360° rotation output gear to rotate through the jaw 360° rotation motor connecting lower seat and jaw 360° rotation motor connecting upper seat, the meshing action between the jaw 360° rotation output gear and the jaw 360° rotation output gear drives the jaw rigid connection inner tube and the jaw flexible inner tube to rotate 360°.

[0015] Furthermore, the clamp-end flexible mechanism control mechanism also includes a left motor compartment pressing unlock post and a right motor compartment pressing unlock post. The motor compartment includes a first outer shell and a second outer shell, which are connected to the right motor compartment pressing unlock post via the left motor compartment pressing unlock post. The front end of the first outer shell has slots on its upper and lower sides. The right motor compartment pressing unlock post achieves a radial elastic range of motion through a first spring. When the first spring is at its original length, the first hook on the right motor compartment pressing unlock post is in the slot at the upper end of the first outer shell. When the right motor compartment pressing unlock post is pressed, the first hook disengages. The upper end of the outer casing has a slot; the left motor compartment pressing unlocking post achieves radial elastic movement range through the second spring. When the second spring is at its original length, the second hook on the left motor compartment pressing unlocking post is in the slot at the lower end of the outer casing; when the left motor compartment pressing unlocking post is pressed, the second hook disengages from the slot at the lower end of the outer casing; the operator holds the outer casing with one hand and the outer casing with the other hand, and simultaneously presses the left motor compartment pressing unlocking post and the right motor compartment pressing unlocking post, thereby causing the first hook and the second hook to disengage from the slot on the outer casing and causing the outer casing to move away from the outer casing, thus realizing the unlocking process.

[0016] This invention provides a control method for a flexible surgical instrument with a forceps tip used in a minimally invasive surgical robot, comprising the following steps:

[0017] (1) Method for positive kinematic control of flexible surgical instruments with forceps tip;

[0018] 1) Rigid section

[0019] The forward kinematics of the rigid segment of a flexible surgical instrument were modeled using an improved DH parameter method. The improved DH parameters for the rigid segment of the flexible surgical instrument are shown in the table below. θ2 is the displacement of the probe joint, θ3 is the rotation angle of the control lever, and θ3 is the yaw angle of the rigid rod.

[0020]

[0021]

[0022] The homogeneous transformation matrix of the coordinate system of adjacent joints in the rigid segment of a flexible surgical instrument, obtained by the improved DH parameter method, is as follows:

[0023]

[0024]

[0025] Where c and s are the simplified forms of cosθi and sinθ, respectively.

[0026] 2) Flexible segment

[0027] The flexible segment of the flexible surgical instrument consists of seven flexible units. Each flexible unit includes a cross-shaped pivot and a rigid block. The cross-shaped pivot is a flexible cross-shaped pivot pin at the clamp end, and the rigid block is a flexible connecting seat at the clamp end. The position of the end of the flexible segment is related to the movement of each rigid block. First, we analyze the pivot in a single direction: There are four small holes on the rigid block, through which steel wire ropes L1, L2, L3, and L4 pass. Steel wire ropes L1, L2, L3, and L4 correspond to the first, second, third, and fourth drive shafts, respectively, controlling the bending of the flexible segment. We select the end rigid block and rigid block i for analysis: Since the steel wire rope can transmit tension in the pre-tensioned state, the end rigid block is subjected to the tension forces -F1 and -F3 of the steel wire rope and the force -F of rigid block i. i The combined effect of -1, when force balance analysis is performed on the end rigid block, yields the following results: φ and α are both angles between the line of action of the force and the end face of the rigid block. From the above formula, we can obtain... Right now Therefore, based on the force balance of the rigid block at the end, we can obtain: F i =F1+F3; This is obtained from the force balance of rigid block i:

[0028]

[0029] Where β and Ψ are both angles between the force and the left end face of the rigid block i, according to F i =F1+F3 and formula (1) yield tanβ=tanΨ, that is, β=Ψ;

[0030] Therefore, according to F i =F1+F3, formula (1), β=Ψ yields: F i-1 =F1+F3; This is obtained based on the torque balance of the end rigid block about shaft Oi:

[0031]

[0032] Where t is the distance between wire ropes L1 and L3 and shaft Oi, h is the length of the rigid block, and l is the distance between the axes of two adjacent cross shafts. This is the distance between the shaft and the end face of the adjacent rigid block;

[0033] Based on the torque balance of rigid block i about axis Oi, the following is obtained:

[0034]

[0035] according to β=Ψ、F i-1 =F1+F3, Formula (2), Formula (3) yield:

[0036]

[0037] According to formulas (2) and (4), we get tanα = tanβ, that is, α = β;

[0038] Therefore, according to β=Ψ, α=β. It can be seen that α, β, The four angles of Ψ are equal;

[0039] Therefore, it can be seen that the angle between the end face of each rigid block in the flexible section and the wire rope is consistent, and the deflection angle of each rigid block in the flexible section is also equal. Similarly, considering the sway of the flexible section under the tension of wire ropes L2 and L4, the deflection angle of each rigid block is also equal. Therefore, no matter which direction the flexible section sways, the sway angle of each rigid block is equal. Since each wire rope in the flexible section can be controlled individually, it is only necessary to adjust the length of the four wire ropes in the flexible section to make the flexible section bend in all directions.

[0040] Establish a coordinate system for each flexible element at a distance l / 2 from the center point of each cross axis. Assume the flexible segment consists of n flexible elements. Using the geometric relationship between the coordinate systems of each flexible element in the flexible segment, the homogeneous transformation matrix of the end position of the flexible segment in its own base coordinate system can be calculated by the projection method:

[0041]

[0042] Where θ is the angle between the axes of two adjacent flexible elements, i.e., the angle between the Z axes in the coordinate systems of two adjacent flexible elements, and φ is the angle between the axes of each flexible element around the base coordinate system. R O0- R X0 R Y0 R Z0 R The deflection angle of the Z0 axis; the attitude transformation matrix between adjacent flexible elements can be calculated using the projection method based on the geometric relationship between the coordinate systems of adjacent flexible elements in the flexible segment:

[0043]

[0044] 3) End effector

[0045] The homogeneous transformation matrix of the end position of the end effector in the coordinate system of the flexible segment end:

[0046]

[0047] Where g is the length from the end of the flexible segment to the end of the end effector, the forward kinematic equation of the flexible surgical instrument is:

[0048]

[0049] (2) Inverse kinematic control method for flexible surgical instruments with forceps tip;

[0050] Numerical methods were used to solve the inverse kinematics of flexible surgical instruments. This was based on the mechanical structure and forward kinematics model of the flexible surgical instruments, and the requirements of single-port surgery for flexible surgical instruments. θ2, θ3, θ, The ranges are as follows:

[0051]

[0052] -180°≤θ2≤180°

[0053] -30°≤θ3<0°

[0054] 0° < θ ≤ 15°

[0055]

[0056] The rotation joint of the joystick and the yaw joint of the rigid rod are used as attitude adjustment joints, which are directly controlled by joints 6 and 5 of the main operator, respectively. During position control, the rotation joint of the joystick and the yaw joint of the rigid rod are fixed, so θ2 and θ3 are known parameters in the kinematic model; by transforming formula (10), we get:

[0057]

[0058] Let Tleft and Tright be the left and right sides of the equation (11) respectively, then:

[0059]

[0060] From formulas (11) and (12), we obtain:

[0061] T 左 (1,4)=T 右 (1,4) (13)

[0062] T 左 (2,4)=T 右 (2,4) (14)

[0063] T 左 (3,4)=T 右 (3,4) (15)

[0064] The terms in formulas (13), (14), and (15) obtained by MATLAB calculations are as follows:

[0065]

[0066] Simplify the terms of formula (16) to:

[0067]

[0068] In formula (17), F1(θ), F2(θ), H1(θ2,θ3), H2(θ2), and H3(θ2,θ3) are respectively:

[0069]

[0070] From formulas (13), (15), and (17), we obtain:

[0071]

[0072] Then, from formulas (14), (17), and (19), we obtain:

[0073] F1 2 (θ)=(F2(θ)tθ3+H1(θ2, θ3)-H3(θ2, θ3)tθ3)2 +H2 2 (θ2) (20)

[0074] Formula (20) contains only the unknown parameter θ. Let:

[0075] E(θ)=F1 2 (θ)-(F2(θ)tθ3+H1(θ2,θ3)-H3(θ2,θ3)tθ3) 2 -H2 2 (θ2) (21)

[0076] The solution θ satisfying 0° < θ ≤ 15° can be obtained by the bisection method; therefore, by formula (14) and formula (17):

[0077]

[0078] From formulas (15) and (17), we obtain:

[0079]

[0080] At this point θ2, θ3, θ All have been solved;

[0081] Since flexible surgical instruments are driven and controlled by steel wire ropes, it is necessary to change the length of the steel wire ropes to control the movement of the end of the flexible surgical instruments. Therefore, it is necessary to obtain the relationship between the joint variables of the flexible surgical instruments and the changes in the length of each part of the rope: Let the radius of the joystick rotation unit be r1, and the length changes of the steel wire ropes L5 and L6 controlling the joystick rotation be Δl5 and Δl6, then we have: Δl5(Δl6)=±r1×θ2;

[0082] Let L7 and L8 be the steel wire ropes controlling the sway of the rigid rod. Neglecting the weight of the flexible surgical instruments and the friction between the steel wire ropes and the mechanical structure, and assuming that the tension of the steel wire ropes remains constant throughout the control process, the radius of the through-hole is equal to the radius of the steel wire rope, and the length of the steel wire rope within the control rod and the rigid rod remains constant, then the length changes of steel wire ropes L7 and L8 are only reflected in the transition section from the through-hole of the control rod to the through-hole of the rigid rod. When the rigid rod does not sway, the lengths of steel wire ropes L7 and L8 between the through-hole of the control rod and the through-hole of the rigid rod are G1, G2, and G3, respectively. The angle between G4, G1O, and G2O is Y, where Y is a structural parameter of the flexible surgical instrument; when the rigid rod wobbles, the lengths of the steel wire ropes L7 and L8 between the rope hole of the control lever and the rope of the rigid rod are G1'G2' and G3'G4', respectively; the angle between G1'O' and G2'O is Y-θ3; the angle between G3'O' and G3'O is Y+θ3; θ3<0, where θ3 is the wobbling angle of the rigid rod. Therefore:

[0083] G1O=G2O=G3O=G4O=G1'O=G2'O=G3'O=G4'O (24)

[0084] Let each term in formula (24) equal m, where m is the structural parameter of the flexible surgical instrument, then we have:

[0085]

[0086] Let the changes in length of wire ropes L7 and L8 be Δl7 and Δl8, respectively. Then we have:

[0087]

[0088] The flexible segment of the flexible surgical instrument is driven and controlled by four steel wire ropes L1, L2, L3, and L4. One end of each steel wire rope is fixed to the end of the flexible segment, and the other end is fixed to a reel driven by the corresponding motor. Each steel wire rope is independently controlled. Since steel wire ropes L1, L2, L3, and L4 pass along the axis when passing the control lever and rigid lever, their lengths within the control lever and rigid lever remain unchanged. Simultaneously, their lengths within each flexible unit also remain unchanged. Therefore, the length changes of steel wire ropes L1, L2, L3, and L4 are only reflected in the portion between the upper and lower surfaces of adjacent flexible units. Because the deflection angle of each flexible unit is equal when the flexible segment deflects in any direction, the length changes of steel wire ropes L1, L2, L3, and L4 between the upper and lower surfaces of any adjacent flexible unit are the same. The length changes of the steel wire ropes between the upper and lower surfaces of adjacent flexible units are as follows:

[0089]

[0090] Based on the aforementioned changes in the length of the steel wire rope controlling the movement of each joint of the flexible surgical instrument and the insertion distance... By using the structural parameters and electronic gear ratios of the flexible surgical instrument, the pulse values ​​required for each motor to move the end of the flexible surgical instrument to the target position T can be calculated. This enables the control of the left opening and closing control motor, the right opening and closing control motor, the upward swing control motor, the 360-degree rotation control motor, and the downward swing control motor of the clamp end, thereby completing the motion control of the entire flexible surgical instrument at the clamp end.

[0091] The beneficial effects of this invention are:

[0092] (1) Flexible structure: The rigid rod of the present invention is connected to a flexible bending structure at the front end, which allows the posture adjustment and the opening, closing and rotation of the flexible end clamp mechanism of the present invention to be performed inside the patient's body, greatly improving the working range and flexibility of the flexible surgical instrument inside the patient's body.

[0093] (2) Modular design: The present invention has a simple structure, uses an electric motor as power, and achieves multiple functions through the cooperation of various transmission structures, so that the entire minimally invasive surgical robot can be modularized.

[0094] (3) The space occupied by the motor compartment is greatly reduced: This invention achieves miniaturization and compactness of the motor compartment of flexible surgical instruments through transmission structure design and motor arrangement.

[0095] (4) Multi-strand drive shaft transmission anti-interference: Currently, the drive shaft winding method of the flexible surgical instruments used in minimally invasive surgical robots to realize the opening and closing motion of the forceps end is complicated and the motion is subject to interference. This invention achieves non-interference of drive shaft transmission by dividing the transmission function of the flexible surgical instruments into zones and designing a gradient structure for the steering pulley.

[0096] (5) Control method of flexible surgical instruments at the forceps end: There are many methods for controlling the movement of surgical instruments in minimally invasive surgical robots. This invention achieves precise control of the movement of flexible surgical instruments by mapping the forward motion algorithm and the inverse motion algorithm. Attached Figure Description

[0097] Figure 1 This is a schematic diagram of the overall structure of a flexible surgical instrument with a forceps end for use in a minimally invasive surgical robot, provided by the present invention.

[0098] Figure 2 This is a schematic diagram of the control mechanism of the flexible clamping end mechanism.

[0099] Figure 3 This is a schematic diagram of the control mechanism of the flexible clamping end mechanism.

[0100] Figure 4 This is a schematic diagram of the control mechanism of the flexible clamping end mechanism.

[0101] Figure 5 This is a schematic diagram showing the meshing relationship between the output gear and the input gear that rotates 360 degrees from the clamp end.

[0102] Figure 6 This is a cross-sectional view of the control mechanism of the flexible clamping end mechanism.

[0103] Figure 7 This is a schematic diagram showing the installation positions of the upper and lower sway drive shaft steering pulleys on the clamp end.

[0104] Figure 8 This is an exploded view of the flexible clamping mechanism.

[0105] Figure 9 This is a schematic diagram of the flexible clamping mechanism.

[0106] Figure 10This is a schematic diagram of the flexible clamping mechanism.

[0107] Figure 11 The results of the positive kinematic modeling for the rigid segment of a flexible surgical instrument with forceps tip.

[0108] Figure 12 This is the coordinate system for each joint of the rigid segment of the flexible surgical instrument at the forceps end.

[0109] Figure 13 This is a schematic diagram of the force analysis of a flexible element.

[0110] Figure 14 Coordinate system of each flexible element in the flexible segment.

[0111] Figure 15 This is a schematic diagram illustrating the analysis of the length variation of the steel wire rope in the rigid rod section.

[0112] Figure 16 This is a diagram showing the change in the length of the wire rope between the upper and lower surfaces of adjacent flexible units.

[0113] Figure 17 This is a schematic diagram showing the positional relationship between the left and right motor compartment release pins. Detailed Implementation

[0114] The present invention will be further described in detail below with reference to the accompanying drawings.

[0115] In a first aspect, the present invention provides a flexible surgical instrument with a forceps tip for use in a minimally invasive surgical robot.

[0116] See Figures 1 to 10 As shown, the present invention provides a flexible surgical instrument with a forceps tip for use in a minimally invasive surgical robot, which mainly includes the following components:

[0117] The motor housing 1, the clamp-end flexible mechanism 2, and the clamp-end flexible mechanism control mechanism are all included. The clamp-end flexible mechanism control mechanism is installed inside the motor housing 1, and the clamp-end flexible mechanism control mechanism is connected to the clamp-end flexible mechanism 2 by a pin connection.

[0118] The control mechanism of the clamp-end flexible mechanism mainly includes the following components:

[0119] 101. Left opening / closing control motor for clamp ends; 102. Right opening / closing control motor for clamp ends; 103. Upward swing control motor for clamp ends; 104. 360-degree rotation control motor for clamp ends; 105. Downward swing control motor for clamp ends; 106. Right opening / closing control motor for clamp ends connected to lower base; 107. Downward swing control motor for clamp ends connected to lower base; 108. Left opening / closing control motor for clamp ends connected to lower base; 109. Upward swing control motor for clamp ends connected to lower base; 110. 360-degree rotation motor for clamp ends connected to lower base; 111. Right opening / closing control motor for clamp ends connected to upper base; 112. Left opening / closing control motor for clamp ends connected to upper base; 113. Upward swing control motor for clamp ends connected to upper base; 114. 360-degree rotation motor for clamp ends connected to upper base; 115. Downward swing drive shaft winding shaft for clamp ends; 116. Upward swing drive shaft winding shaft for clamp ends; 117. Right opening / closing control motor for clamp ends. The components include: a winding shaft 118 for the opening and closing drive shaft, a winding shaft 119 for the left opening and closing drive shaft of the clamp end, a pressing and unlocking post 120 for the left motor compartment, a pressing and unlocking post 121 for the right motor compartment, a steering pulley 122 for the right opening and closing drive shaft of the clamp end, a steering pulley 123 for the left opening and closing drive shaft of the clamp end, a 360-degree rotating motor drive shaft 124 for the clamp end, a 360-degree rotating output gear 125 for the clamp end, a 360-degree rotating input gear 126 for the clamp end, a steering pulley 127 for the upper sway drive shaft of the clamp end, a steering pulley 128 for the lower sway drive shaft of the clamp end, a rigid connecting outer tube 129 for the clamp end, a rigid connecting inner tube 130 for the clamp end, a first drive shaft 131, a second drive shaft 132, a third drive shaft 133, and a fourth drive shaft 134, a fixing seat 135 for the steering pulley of the opening and closing drive shaft of the clamp end, and a fixing seat 136 for the 360-degree rotating input gear of the clamp end.

[0120] The connection relationships between the clamp left opening / closing control motor 101, the clamp left opening / closing control motor connecting lower seat 108, the clamp left opening / closing control motor connecting upper seat 112, and the clamp left opening / closing drive shaft winding shaft 119 are as follows:

[0121] The lower connector 108 of the clamp left opening and closing control motor is fixed on the inner wall of the motor compartment 1. The lower connector 108 of the clamp left opening and closing control motor is fixedly connected to the upper connector 112 of the clamp left opening and closing control motor. The output end of the clamp left opening and closing control motor 101 is fixed on the lower connector 108 of the clamp left opening and closing control motor. The clamp left opening and closing drive shaft winding shaft 119 is fixed on the upper connector 112 of the clamp left opening and closing control motor. The output shaft of the clamp left opening and closing control motor 101 passes through the lower connector 108 of the clamp left opening and closing control motor and is connected to the end of the clamp left opening and closing drive shaft winding shaft 119.

[0122] The connection relationships between the clamp right opening / closing control motor 102, the clamp right opening / closing control motor connected to the lower base 106, the clamp right opening / closing control motor connected to the upper base 111, and the clamp right opening / closing drive shaft winding shaft 118 are as follows:

[0123] The lower connector 106 of the right-hand opening and closing control motor is fixed on the inner wall of the motor compartment 1. The lower connector 106 of the right-hand opening and closing control motor is fixedly connected to the upper connector 111 of the right-hand opening and closing control motor. The output end of the right-hand opening and closing control motor 102 is fixed on the lower connector 106 of the right-hand opening and closing control motor. The winding shaft 118 of the right-hand opening and closing drive shaft is fixed on the upper connector 111 of the right-hand opening and closing control motor. The output shaft of the right-hand opening and closing control motor 102 passes through the lower connector 106 of the right-hand opening and closing control motor and is connected to the end of the winding shaft 118 of the right-hand opening and closing drive shaft.

[0124] The connection relationships between the clamp end swing control motor 103, the clamp end swing control motor connecting lower base 109, the clamp end swing control motor connecting upper base 113, and the clamp end swing drive shaft winding shaft 117 are as follows:

[0125] The lower mounting base 109 of the clamping end swing control motor is fixed on the inner wall of the motor compartment 1. The lower mounting base 109 of the clamping end swing control motor is fixedly connected to the upper mounting base 113 of the clamping end swing control motor. The output end of the clamping end swing control motor 103 is fixed on the lower mounting base 109 of the clamping end swing control motor. The upper mounting drive shaft winding shaft 117 of the clamping end swing is fixed on the upper mounting base 113 of the clamping end swing control motor. The output shaft of the clamping end swing control motor 103 passes through the lower mounting base 109 of the clamping end swing control motor and is connected to the end of the upper mounting drive shaft winding shaft 117 of the clamping end swing.

[0126] The connection relationships between the 360-degree rotation control motor 104, the lower mounting base 110 connected to the 360-degree rotation motor, the upper mounting base 114 connected to the 360-degree rotation motor, the drive shaft 124 of the 360-degree rotation motor, and the output gear 125 of the 360-degree rotation motor are as follows:

[0127] The lower connector 110 of the 360-degree rotating clamp motor is fixed to the inner wall of the motor compartment 1. The lower connector 110 of the 360-degree rotating clamp motor is fixedly connected to the upper connector 114 of the 360-degree rotating clamp motor. The output end of the 360-degree rotating clamp control motor 104 is fixed on the lower connector 110 of the 360-degree rotating clamp motor. The drive shaft 124 of the 360-degree rotating clamp motor is fixed on the upper connector 114 of the 360-degree rotating clamp motor. The output shaft of the 360-degree rotating clamp control motor 104 passes through the lower connector 110 of the 360-degree rotating clamp motor and is connected to the end of the drive shaft 124 of the 360-degree rotating clamp motor. The output gear 125 of the 360-degree rotating clamp motor is installed on the upper end of the drive shaft 124 of the 360-degree rotating clamp motor.

[0128] The connection relationships between the clamp end swing control motor 105, the clamp end swing control motor connecting lower base 107, the clamp end swing control motor connecting upper base 115, and the clamp end swing drive shaft winding shaft 116 are as follows:

[0129] The lower mounting base 107 of the clamp lower swing control motor is fixed on the inner wall of the motor compartment 1. The lower mounting base 107 of the clamp lower swing control motor is fixedly connected to the upper mounting base 115 of the clamp lower swing control motor. The output end of the clamp lower swing control motor 105 is fixed on the lower mounting base 107 of the clamp lower swing control motor. The clamp lower swing drive shaft winding shaft 116 is fixed on the upper mounting base 115 of the clamp lower swing control motor. The output shaft of the clamp lower swing control motor 105 passes through the lower mounting base 107 of the clamp lower swing control motor and is connected to the end of the clamp lower swing drive shaft winding shaft 116.

[0130] The clamp-end opening and closing drive shaft steering pulley fixing seat 135 is fixed on the inner wall of the motor compartment 1. The clamp-end left opening and closing drive shaft steering pulley 123 and the clamp-end right opening and closing drive shaft steering pulley 122 are both fixed on the clamp-end opening and closing drive shaft steering pulley fixing seat 135. The clamp-end left opening and closing drive shaft steering pulley 123 is installed on the upper left side of the clamp-end opening and closing drive shaft steering pulley fixing seat 135, and the clamp-end right opening and closing drive shaft steering pulley 122 is installed on the upper right side of the clamp-end opening and closing drive shaft steering pulley fixing seat 135.

[0131] like Figure 17 As shown, the motor compartment 1 mainly consists of two parts: outer shell 101 and outer shell 2 102. Outer shell 101 and outer shell 2 102 are connected by a left motor compartment pressing unlocking post 120 and a right motor compartment pressing unlocking post 121. Outer shell 101 has slots 1011 on its upper and lower front sides. Specifically, the unlocking principle and connection relationship of the left and right motor compartment pressing unlocking posts 120 and 121 are the same, mainly distinguished by their left and right sides. The right motor compartment pressing unlocking post 121 achieves radial elastic movement through a first spring 1211. When the first spring 1211 is at its original length, the first hook 1212 on the right motor compartment pressing unlocking post 121 is in the slot 1011 at the upper end of outer shell 101; when the right motor compartment pressing unlocking post 121 is pressed, the first hook 1212 disengages from the slot 1011 at the upper end of outer shell 101. Similarly, the left motor compartment pressing unlock post 120 achieves a radial elastic range of motion through the second spring 1201. When the second spring 1201 is at its original length, the second hook 1202 on the left motor compartment pressing unlock post 120 is in the slot 1011 at the lower end of the outer casing 101; when the left motor compartment pressing unlock post 120 is pressed, the second hook 1202 disengages from the slot 1011 at the lower end of the outer casing 101. Unlocking process: The operator holds the outer casing 101 with one hand and the outer casing 2 with the other hand, and simultaneously presses the left motor compartment pressing unlock post 120 and the right motor compartment pressing unlock post 121, thereby causing the first hook 1212 and the second hook 1202 to disengage from the slot 1011 on the outer casing 101 and causing the outer casing 2 102 to move away from the outer casing 101, thus realizing the unlocking process.

[0132] The 360-degree rotating input end gear fixing seat 136 is connected to the inner wall of the motor compartment 1, and the 360-degree rotating input end gear 126 is installed in the 360-degree rotating input end gear fixing seat 136. Figure 5 As shown, the 360-degree rotating input end gear 126 of the clamp end is installed on the upper end of the rigid connecting inner tube 130 of the clamp end, and the 360-degree rotating input end gear 126 of the clamp end and the 360-degree rotating output end gear 125 of the clamp end are in a meshing relationship.

[0133] The upper yaw drive shaft steering pulley 127 and the lower yaw drive shaft steering pulley 128 are both fixed on the upper end of the 360-degree rotating input end gear fixing seat 136.

[0134] Among them, the clamp end rigid connection outer tube 129 is installed at the lower end of the clamp end opening and closing drive shaft steering pulley fixing seat 135, and the clamp end rigid connection inner tube 130 is located inside the clamp end rigid connection outer tube 129.

[0135] Among them, such as Figure 6 As shown, the first drive shaft 131, the second drive shaft 132, the third drive shaft 133, and the fourth drive shaft 134 are all installed in the rigid connecting inner tube 130 at the clamp end. The first drive shaft 131, the second drive shaft 132, the third drive shaft 133, and the fourth drive shaft 134 can be made of steel wire rope.

[0136] The front end of the first drive shaft 131 is wound around the left opening and closing clamp 201 of the clamp end, and the rear end of the first drive shaft 131 passes through the flexible inner tube 212 of the clamp end and the rigid connecting inner tube 130 of the clamp end in sequence, then winds around the left opening and closing drive shaft steering pulley 123 of the clamp end, and then winds around the left opening and closing drive shaft winding shaft 119 of the clamp end.

[0137] The front end of the second drive shaft 132 is wound around the right opening and closing clamp 202 of the clamp end, and the rear end of the second drive shaft 132 passes through the flexible inner tube 212 of the clamp end and the rigid connecting inner tube 130 of the clamp end in sequence, then winds around the right opening and closing drive shaft steering pulley 122 of the clamp end and then winds around the right opening and closing drive shaft winding shaft 118 of the clamp end.

[0138] The front end of the third drive shaft 133 is wound around the upper swing steering pulley 205 of the clamp end, and the rear end of the third drive shaft 133 passes through the flexible inner tube 212 of the clamp end and the rigid connecting inner tube 130 of the clamp end in sequence, then winds around the upper swing drive shaft steering pulley 127 of the clamp end and then winds around the upper swing drive shaft winding shaft 117 of the clamp end.

[0139] The front end of the fourth drive shaft 134 is wound around the lower swing steering pulley 206 of the clamp end, and the rear end of the fourth drive shaft 134 passes through the flexible inner tube 212 of the clamp end and the rigid connecting inner tube 130 of the clamp end in sequence, then winds around the lower swing drive shaft steering pulley 128 of the clamp end, and then winds around the lower swing drive shaft winding shaft 116 of the clamp end.

[0140] The clamp-end flexible mechanism 2 mainly includes the following components:

[0141] The clamps include: left-hand opening and closing clamp 201, right-hand opening and closing clamp 202, opening and closing clamp fixing seat 203, opening and closing clamp fixing pin 204, upper swing steering pulley 205, lower swing steering pulley 206, clamp opening and closing seat fixing pin 207, flexible connecting seat 208, flexible cross-shaped swing pin 209, flexible connecting seat fixing pin 210, connector 211, flexible inner tube 212, and flexible outer tube 213.

[0142] The clamp-end flexible connector 208 is multiplied and connected sequentially by clamp-end flexible connector fixing pins 210, thereby forming a clamp-end flexible outer tube 213. The rear end of the clamp-end flexible outer tube 213 is connected to the front end of the clamp-end rigid connecting outer tube 129, and the front end of the clamp-end flexible outer tube 213 is connected to one end of the connector 211.

[0143] Among them, the rear end of the flexible inner tube 212 of the clamp end is connected to the rigid inner tube 130 of the clamp end.

[0144] The clamp end flexible cross-shaped deflecting pins 209 are multiple in number, and the number of clamp end flexible cross-shaped deflecting pins 209 is the same as the number of clamp end flexible connecting seats 208. The outer ring of the clamp end flexible cross-shaped deflecting pins 209 is fixed to the inner wall of the clamp end flexible connecting seat 208, and the inner ring of the clamp end flexible cross-shaped deflecting pins 209 is fitted onto the clamp end flexible inner tube 212. The clamp end flexible connecting seat 208 and the clamp end flexible cross-shaped deflecting pins 209 form a flexible unit.

[0145] The opening and closing clamp fixing base 203 is provided with a first pin hole 2030 and two second pin holes 2031. The rear end of the opening and closing clamp fixing base 203 is connected to the flexible inner tube 212 of the clamp end through the first pin hole 2030 and the clamp end opening and closing base fixing pin 207. The front end of the opening and closing clamp fixing base 203 is connected to the left opening and closing clamp 201 and the right opening and closing clamp 202 of the clamp end through the two second pin holes 2031 and the opening and closing clamp fixing pin 204.

[0146] The left-hand opening and closing clamp 201 and the right-hand opening and closing clamp 202 are both provided with serrated mating structures on their opposite sides.

[0147] The upper swing guide pulley 205 and the lower swing guide pulley 206 of the clamp end are both fixed inside the clamp fixing seat 203 by pins.

[0148] The present invention provides a flexible surgical instrument with forceps tip for use in minimally invasive surgical robots, the specific working principle of which is as follows:

[0149] 1. Explanation of the left and right opening and closing method controlled by the clamp tip:

[0150] The left-hand opening and closing pliers 201 and the right-hand opening and closing pliers 202 are fixed to the front end of the opening and closing pliers fixing base 203 by the opening and closing pliers fixing pin 204. The left-hand opening and closing pliers 201 and the right-hand opening and closing pliers 202 can perform opening and closing movements with the opening and closing pliers fixing pin 204 as the center.

[0151] Left-opening clamp: The front end of the first drive shaft 131 is wound around the left-opening clamp 201. The rear end of the first drive shaft 131 passes through the flexible inner tube 212 and the rigid connecting inner tube 130 of the clamp in sequence, then winds around the left-opening drive shaft guide pulley 123 and then winds around the left-opening drive shaft winding shaft 119. The left-opening control motor 101 drives the left-opening drive shaft winding shaft 119 to rotate clockwise through the left-opening control motor connecting lower seat 108 and the left-opening control motor connecting upper seat 112, thereby winding the first drive shaft 131 clockwise around the left-opening drive shaft winding shaft 119. Pulling the first drive shaft 131 opens the left-opening clamp 201, and vice versa.

[0152] Right-hand opening and closing of the clamp: The front end of the second drive shaft 132 is wound around the right-hand opening and closing clamp 202. The rear end of the second drive shaft 132 passes through the flexible inner tube 212 and the rigid connecting inner tube 130 of the clamp in sequence, then winds around the right-hand opening and closing drive shaft guide pulley 122 and then winds around the right-hand opening and closing drive shaft winding shaft 118. The right-hand opening and closing control motor 102 drives the right-hand opening and closing drive shaft winding shaft 118 to rotate clockwise through the right-hand opening and closing control motor connecting lower seat 106 and the right-hand opening and closing control motor connecting upper seat 111. This causes the second drive shaft 132 to wind clockwise around the right-hand opening and closing drive shaft winding shaft 118. Pulling the second drive shaft 132 opens the right-hand opening and closing clamp 202, and vice versa.

[0153] 2. Explanation of the clamp tip control method for vertical tilting:

[0154] The left-hand opening and closing pliers 201 and the right-hand opening and closing pliers 202 are fixed to the front end of the opening and closing pliers fixing base 203 by the opening and closing pliers fixing pin 204. The left-hand opening and closing pliers 201 and the right-hand opening and closing pliers 202 can perform up and down swinging movements.

[0155] Upper jaw tilt: The front end of the third drive shaft 133 is wound around the upper jaw tilt steering pulley 205. The rear end of the third drive shaft 133 passes through the flexible inner tube 212 and the rigid inner tube 130 of the jaw in sequence, then winds around the upper jaw tilt drive shaft steering pulley 127 and then winds around the upper jaw tilt drive shaft winding shaft 117. The upper jaw tilt control motor 103 drives the upper jaw tilt drive shaft winding shaft 117 to rotate clockwise through the lower jaw tilt control motor connecting seat 109 and the upper jaw tilt control motor connecting seat 113, thereby winding the third drive shaft 133 clockwise around the upper jaw tilt drive shaft winding shaft 117. The upper jaw tilt is achieved by pulling the third drive shaft 133.

[0156] Lowering of the clamp end: The front end of the fourth drive shaft 134 is wound around the lowering guide pulley 206 of the clamp end. The rear end of the fourth drive shaft 134 passes through the flexible inner tube 212 and the rigid connecting inner tube 130 of the clamp end in sequence, then winds around the lowering guide pulley 128 of the clamp end and then winds around the lowering guide shaft winding shaft 116 of the clamp end. The lowering control motor 105 drives the lowering guide shaft winding shaft 116 of the clamp end to rotate clockwise through the lower clamping control motor connecting base 107 and the upper clamping control motor connecting base 115 of the clamp end, thereby winding the fourth drive shaft 134 clockwise around the lower clamping guide shaft winding shaft 116 of the clamp end, and the lowering of the clamp end is achieved by pulling the fourth drive shaft 134.

[0157] 3. Explanation of the 360-degree rotation method of the clamp tip:

[0158] The left-hand opening and closing clamp 201 and the right-hand opening and closing clamp 202 are fixed to the front end of the opening and closing clamp fixing base 203 by the opening and closing clamp fixing pin 204. The 360-degree rotation input end gear 126 is installed on the upper end of the rigid connection inner tube 130 of the clamp end, and the 360-degree rotation input end gear 126 and the 360-degree rotation output end gear 125 of the clamp end are in a meshing relationship.

[0159] When the clamp end 360-degree rotation control motor 104 drives the clamp end 360-degree rotation motor transmission shaft 124 and the clamp end 360-degree rotation output end gear 125 to rotate through the clamp end 360-degree rotation motor connecting lower seat 110 and clamp end 360-degree rotation motor connecting upper seat 114, the clamp end 360-degree rotation output end gear 125 is driven to rotate 360 ​​degrees through the meshing action between the clamp end 360-degree rotation output end gear 125 and the clamp end rigid connecting inner tube 130 and the clamp end flexible inner tube 212.

[0160] Secondly, the present invention provides a control method for a flexible surgical instrument with a forceps tip used in a minimally invasive surgical robot.

[0161] This invention provides a control method for a flexible surgical instrument at the tip of a forceps-end used in a minimally invasive surgical robot, mainly including a forward kinematics control method and an inverse kinematics control method for the flexible surgical instrument at the tip of a forceps-end. The specific implementation process is as follows:

[0162] (1) Method for controlling the positive kinematics of flexible surgical instruments with forceps tip

[0163] 1) Rigid section

[0164] The rigid section of the flexible surgical instrument has two degrees of freedom: the rotation of the control lever (corresponding to the rigid connecting tube 129 of the clamp end mentioned earlier) and the rigid rod (corresponding to the section where the front end of the rigid connecting tube 129 of the clamp end connects to the flexible outer tube 213 of the clamp end, such as...). Figure 10 The yaw rate (as shown) is such that, in actual use, an additional insertion degree of freedom is added to the flexible surgical instrument. Therefore, the forward kinematic modeling of the rigid segment of the flexible surgical instrument is as follows: Figure 11 As shown.

[0165] The forward kinematics of the rigid segment of a flexible surgical instrument is modeled using the improved DH parameter method. The positional relationships of each joint coordinate system are as follows: Figure 12 As shown in the diagram. The origins of coordinate systems GO0-GX0GY0GZ0, GO1-GX1GY1GZ1, GO2-GX2GY2GZ2, and GO3-GX3GY3GZ3 are all located at the intersection of the joystick axis and the rigid rod axis. The origin of coordinate system GO4-GX4GY4GZ4 is located at the center of the end face of the rigid section, and L1 is the distance between the intersection of the joystick axis and the rigid rod axis and the center of the end face of the rigid section.

[0166] The improved DH parameters for the rigid segment of flexible surgical instruments are shown in Table 1. In Table 1, θ2 is the displacement of the probe joint, θ3 is the rotation angle of the control lever, and θ4 is the yaw angle of the rigid rod.

[0167] Table 1. Improved DH Parameters for the Rigid Section of Flexible Surgical Instruments

[0168]

[0169] The homogeneous transformation matrix of the coordinate system of adjacent joints in the rigid segment of a flexible surgical instrument can be obtained by the improved DH parameter method as follows:

[0170]

[0171]

[0172] Where c and s are the simplified forms of cosθi and sinθ, respectively.

[0173] 2) Flexible segment

[0174] like Figure 11 As shown, the flexible segment of the flexible surgical instrument consists of seven flexible units. Each flexible unit includes a cross shaft (corresponding to the flexible cross-shaped pivot pin 209 mentioned earlier) and a rigid block (corresponding to the flexible connecting seat 208 mentioned earlier). The flexible units are connected by the cross shaft, thereby achieving bidirectional pivoting of the flexible segment. Therefore, the pose of the end of the flexible segment is related to the movement of each rigid block. Thus, it is necessary to analyze the pivoting angle of each rigid block in the flexible segment. Since the rigid block can pivot bidirectionally, the pivoting in a single direction can be analyzed first. For example... Figure 13 As shown, the rigid block has four small holes through which steel wire ropes L1, L2, L3, and L4 pass (corresponding to the first drive shaft 131, second drive shaft 132, third drive shaft 133, and fourth drive shaft 134 mentioned earlier), controlling the bending of the flexible section. The analysis focuses on the end rigid block and rigid block i, considering only the sway of the flexible section under the tension of steel wire ropes L1 and L3, neglecting the friction between the steel wire rope and the mechanical structure, as well as its own weight. Therefore, the force on the steel wire rope is equal at any position.

[0175] Since the wire rope can transmit tension under pre-tension, the end rigid block is subjected to the tension forces -F1 and -F3 of the wire rope and the force -F of the rigid block i. i The combined effect of -1, when used in force balance analysis of the rigid block at the end, yields the following: Where φ and α are both angles between the line of action of the force and the end face of the rigid block, and from the above formula, we can obtain: Right now:

[0176] Therefore, based on the force balance of the rigid block at the end, we can obtain: F i =F1+F3; According to the force balance of rigid block i, we can obtain:

[0177]

[0178] Where β and Ψ are both angles between the force and the left end face of the rigid block i, according to F i =F1+F3 and formula (1) can be used to obtain: tanβ=tanΨ, that is: β=Ψ.

[0179] Therefore, according to F i =F1+F3, formula (1), β=Ψ, we can get: F i-1 =F1+F3; Based on the torque balance of the end rigid block about shaft Oi, we can obtain:

[0180]

[0181] Where t is the distance between wire ropes L1 and L3 and shaft Oi, h is the length of the rigid block, and l is the distance between the axes of two adjacent cross shafts. This is the distance between the shaft and the end face of the adjacent rigid block.

[0182] Based on the torque balance of rigid block i about axis Oi, we can obtain:

[0183]

[0184] according to β=Ψ、F i-1 =F1+F3, formula (2), formula (3) yield:

[0185]

[0186] According to formulas (2) and (4), we can obtain: tanα=tanβ, that is: α=β.

[0187] Therefore, according to β=Ψ, α=β. It can be seen that α, β, The four angles of Ψ are equal.

[0188] From the above analysis of the forces acting on the rigid blocks, it is clear that the angle between the end face of each rigid block and the wire rope in the flexible section remains consistent. Therefore, the deflection angle of each rigid block in the flexible section is also equal. Similarly, considering the swaying of the flexible section under the tension of wire ropes L2 and L4, the deflection angle of each rigid block is also equal. This indicates that regardless of the direction in which the flexible section sways, the sway angle of each rigid block is equal. Because each wire rope in the flexible section can be controlled individually, only the lengths of the four wire ropes within the flexible section need to be adjusted to cause bending in all directions.

[0189] To establish a positive kinematic model for the flexible segment, such as Figure 14 As shown, a coordinate system for each flexible element is established at a distance of l / 2 from the center point of each cross axis. From the above force analysis of the rigid block, it can be seen that the deflection angle of each rigid block in any direction is equal.

[0190] To ensure the scalability of the established forward kinematic model of the flexible segment, we assume the flexible segment consists of n flexible elements. Then, by using the projection method based on the geometric relationships of the coordinate systems of each flexible element in the flexible segment, we can obtain the homogeneous transformation matrix of the end position of the flexible segment in its own base coordinate system:

[0191]

[0192] In the formula, θ is the angle between the axes of two adjacent flexible elements, that is, the angle between the Z axes in the coordinate systems of two adjacent flexible elements, and φ is the angle between the axes of each flexible element around the base coordinate system. RO0- R X0 R Y0 R Z0 R The deflection angle of the Z0 axis, They are respectively The simplified form.

[0193] The attitude transformation matrix between adjacent flexible elements can be calculated using the projection method based on the geometric relationship between their coordinate system positions in the flexible segment:

[0194]

[0195] Therefore, the transformation relationship between the coordinate systems of adjacent flexible units can be regarded as first translating the coordinate system of the i-th flexible unit along the Zi axis by l / 2, then rotating it around the Zi axis by an angle φ, then rotating it around the Yi axis by an angle θ, then translating it along the Zi axis by l / 2, and finally rotating it around the Zi axis by an angle -φ, to obtain the coordinate system of the (i+1)-th flexible unit.

[0196] The flexible surgical instrument in this invention has a total of 7 flexible units in its flexible segment. Therefore, the homogeneous transformation matrix of the coordinate system at the end of the flexible segment in its own base coordinate system is:

[0197]

[0198] Therefore, from formulas (5), (6), and (7), we can obtain:

[0199]

[0200] 3) End effector

[0201] Since the rotation and opening / closing of the end effector are controlled one-to-one by joints 7 and 8 of the main operator, it is not necessary to establish a kinematic model of the end effector. The length of the end effector can be simply added to the end of the flexible segment. That is, the homogeneous transformation matrix of the end position of the end effector in the coordinate system of the end of the flexible segment is:

[0202]

[0203] In the formula, g is the length from the end of the flexible segment to the end of the end effector. From the above, the forward kinematic equation of the flexible surgical instrument can be obtained as follows:

[0204]

[0205] (2) Inverse kinematics control method for flexible surgical instruments with forceps tip

[0206] In practical use, flexible surgical instruments are controlled by a master operator, and the target position of their end effector can be obtained from the forward kinematics model of the master operator. Therefore, in actual control, px, py, and pz in formula (10) are all known parameters for solving the inverse kinematics of the flexible surgical instrument. Thus, the parameters that need to be solved for the inverse kinematics of the flexible surgical instrument are: θ2, θ3, θ, Because the forward kinematics equations of flexible surgical instruments contain many trigonometric functions and are quite complex, it is difficult to obtain accurate results using analytical methods. Therefore, numerical methods are used to solve the inverse kinematics of flexible surgical instruments.

[0207] Based on the mechanical structure and forward kinematics model of flexible surgical instruments, and the requirements of single-port surgery for flexible surgical instruments... θ2, θ3, θ, The ranges are as follows:

[0208]

[0209] -180°≤θ2≤180°

[0210] -30°≤θ3<0°

[0211] 0° < θ ≤ 15°

[0212]

[0213] In actual control, considering that the rigid rod of the flexible surgical instrument is used to establish a triangular operating area in the narrow space inside the body, and that the control rod is a direct joint from outside to inside the body, the flexible segment and the insertion joint can meet the degree of freedom requirements of spatial movement, the rotation joint of the control rod and the yaw joint of the rigid rod are used as posture adjustment joints, which are directly controlled by joints 6 and 5 of the main operator, respectively. During position control, the rotation joint of the control rod and the yaw joint of the rigid rod are fixed, so θ2 and θ3 are known parameters in the kinematic model.

[0214] Since formula (8) is the most complex, formula (10) can be transformed to obtain:

[0215]

[0216] Let T be the left and right sides of the equation (11). 左 T 右 ,but:

[0217]

[0218] From formulas (11) and (12), we can obtain:

[0219] T左 (1,4)=T 右 (1,4) (13)

[0220] T 左 (2,4)=T 右 (2,4) (14)

[0221] T 左 (3,4)=T 右 (3,4) (15)

[0222] The terms in formulas (13), (14), and (15) obtained by MATLAB calculations are as follows:

[0223]

[0224] Observing formula (16), the terms in the formula can be simplified to:

[0225]

[0226] In formula (17), F1(θ), F2(θ), H1(θ2,θ3), H2(θ2), and H3(θ2,θ3) are respectively:

[0227]

[0228] From formulas (13), (15), and (17), we can obtain:

[0229]

[0230] From formulas (14), (17), and (19), we can obtain:

[0231] F1 2 (θ)=(F2(θ)tθ3+H(θ2, θ3)-H3(θ2, θ3)tθ3) 2 +H2 2 (θ2) (20)

[0232] Formula (20) contains only the unknown parameter θ. Let:

[0233] E(θ)=F1 2 (θ)-(F2(θ)θ3+H1(θ2,θ3)-H3(θ2,θ3)tθ3) 2 -H2 2 (θ2) (21)

[0234] Then, by the bisection method, we can obtain the solution θ that satisfies 0° < θ ≤ 15°. Therefore, from formulas (14) and (17), we can obtain:

[0235]

[0236] From formulas (15) and (17), we can obtain:

[0237]

[0238] In summary, θ2, θ3, θ, All have been solved.

[0239] Since flexible surgical instruments are driven and controlled by steel wire ropes, it is necessary to control the movement of the instrument's end effector by changing the length of the steel wire ropes. Therefore, it is necessary to obtain the relationship between the joint variables of the flexible surgical instrument and the changes in the rope length of each part. The rotation of the flexible surgical instrument's control lever is achieved by controlling the rotation of a rotation unit (spool) coaxial with the control lever. The rotation of the rotation unit is achieved through wire transmission. Two steel wire ropes are fixed at one end to the rotation unit and at the other end to the spool driven by the motor that controls the rotation of the control lever. The two steel wire ropes are wound on the spool in a forward and reverse manner, respectively. Let the radius of the control lever's rotation unit be r1, and the length changes of the steel wire ropes L5 and L6 controlling the rotation of the control lever be Δl5 and Δl6, respectively. Then we have: Δl5(Δl6)=±r1×θ2.

[0240] The oscillation motion of the rigid rod of the flexible surgical instrument is achieved by fixing one end of two steel wire ropes through a through-hole in the rigid rod to both sides of the end of the rigid rod, and the other end through a channel in the control lever to a spool driven by a motor that controls the oscillation of the rigid rod. The two steel wire ropes are wound on the spool in a forward and reverse manner. Let the steel wire ropes controlling the oscillation of the rigid rod be L7 and L8. Neglecting the weight of the flexible surgical instrument and the friction between the steel wire ropes and the mechanical structure, and assuming that the tension of the steel wire ropes remains constant throughout the control process, the radius of the through-hole is equal to the radius of the steel wire rope, and the length of the steel wire rope within the control lever and the rigid rod remains constant, then the length changes of steel wire ropes L7 and L8 are only reflected in the section transitioning from the through-hole in the control lever to the through-hole in the rigid rod. For example... Figure 15 As shown in (a), when the rigid rod does not wobble, the lengths of the wire ropes L7 and L8 between the rope hole of the control lever and the rope through the rigid rod are G1 G2 and G3 G4, respectively, and the angle between G1O and G2O is Y, where Y is a structural parameter of the flexible surgical instrument; Figure 15 As shown in (b), when the rigid rod sways, the lengths of wire ropes L7 and L8 between the rope hole of the control lever and the rope through-hole of the rigid rod are G1'G2' and G3'G4', respectively. The angle between G1'O' and G2'O is Y-θ3, and the angle between G3'O' and G3'O is Y+θ3, where θ3<0, and θ3 is the sway angle of the rigid rod. Therefore:

[0241] G1O=G2O=G3O=G4O=G1'O=G2'O=G3'O=G4'O (24)

[0242] Let each term in formula (24) equal m, where m is the structural parameter of the flexible surgical instrument, then we have:

[0243]

[0244] Let the changes in length of wire ropes L7 and L8 be Δl7 and Δl8, respectively. Then we have:

[0245]

[0246] The flexible segment of the flexible surgical instrument is driven and controlled by four steel wire ropes L1, L2, L3, and L4. One end of each wire rope is fixed to the end of the flexible segment, and the other end is fixed to a reel driven by a corresponding motor. Each wire rope is independently controlled. Since it is assumed that wire ropes L1, L2, L3, and L4 pass along the axis when crossing the control lever and rigid lever, their lengths within these segments remain constant. Simultaneously, the lengths of wire ropes L1, L2, L3, and L4 within each flexible unit remain constant; therefore, changes in the length of wire ropes L1, L2, L3, and L4 are only reflected in the portion between the upper and lower surfaces of adjacent flexible units. Because the deflection angle of each flexible unit is equal when the flexible segment deflects in any direction, the changes in the lengths of wire ropes L1, L2, L3, and L4 between the upper and lower surfaces of any adjacent flexible unit are the same. Figure 16 As shown, points Oi and Oi+1 are the center points of the upper surface of the i-th flexible unit and the lower surface of the (i+1)-th flexible unit, respectively. Point O is the center point of the cross axis. L1i, L2i, L3i, and L4i are the rope holes on the upper surface of the i-th flexible unit, and L1i+1, L2i+1, L3i+1, and L4i+1 are the rope holes on the lower surface of the (i+1)-th flexible unit. Perpendiculars Oi+1Hi and Oi+1Ni are drawn from point Oi+1 to lines L2i and L4i and surfaces L1i, L2i, L3i, and L4i, respectively, with feet at Hi and Ni. Connect OiNi and HiNi. Based on the principle of establishing the coordinate system for the flexible segment, the angle between line OOi and line OOi+1 is θ, and the angle between line OiHi and line OiNi is... Since line Oi+1Ni is perpendicular to surface L1iL2iL3iL4i, line Oi+1Ni is perpendicular to line L2iL4i. Therefore, line L2iL4i is perpendicular to surface Oi+1HiNi, and line L2iL4i is perpendicular to line HiNi.

[0247] therefore:

[0248]

[0249] From formula (27), we can obtain:

[0250]

[0251] Draw a perpendicular line Oi+1Mi from point Oi+1 to line L1iL3i, with Mi as the foot of the perpendicular. Connect MiNi. Following the same principle as above, we can obtain:

[0252]

[0253] Due to the bending of the flexible segment, such as Figure 16 As shown, the lengths of lines L1iL3i, L2iL4i, L1i+1L3i+1, and L2i+1L4i+1 are always equal. Let their length be D, where D is a structural parameter of the flexible unit. Therefore, after the flexible segment bends, the figures enclosed by points L2i, L4i, L4i+1, L2i+1 and points L1i, L3i, L3i+1, L1i+1 are all isosceles trapezoids. Thus, the length of the steel wire rope between the upper and lower surfaces of adjacent flexible units is:

[0254]

[0255] O i+1 O i M i After the flexible segment bends, line O i O i+1 The length is:

[0256]

[0257] Before the flexible segment bends, the length of the steel wire rope between the upper and lower surfaces of adjacent flexible units is:

[0258] L2 i L2 i+1 =L4 i L4 i+1 =L1 i L1 i+1 =L3 i L3 i+1 =lh (32)

[0259] Therefore, from formulas (28), (29), (30), (31), and (32), the change in the length of the wire rope between the upper and lower surfaces of adjacent flexible units can be obtained as follows:

[0260]

[0261] The flexible surgical instrument in this invention has a total of 7 flexible units in its flexible segment. Therefore, the length of each steel wire in the flexible segment changes by 7 × ΔLj. i Lj i+1(j = 1, 2, 3, 4).

[0262] The rotation and opening / closing of the end effector are controlled by steel wire ropes L9, L10 and L11, L12, respectively. One end of each steel wire rope is fixed to a rotating joint controlling the rotation and opening / closing of the end effector, wound in a forward and reverse manner. Let the radii of the rotating joints controlling the rotation and opening / closing of the end effector be r2 and r3, respectively. The other end passes through the rope passages in the center holes of each flexible unit, the rigid rod, and the control lever, wound in a forward and reverse manner onto the reels controlling the rotation and opening / closing of the end effector. Since the length of the steel wire ropes L9, L10, L11, and L12 passing through the flexible section is affected when the flexible section of the flexible surgical instrument bends, the change in distance between the center points of the upper and lower surfaces of adjacent flexible units needs to be taken into account, i.e., ΔO. i O i+1 Let the changes in length of the wire ropes L9, L10 and L11, L12 be Δl9, Δl, and Δl, respectively. 10 Δl 11 Δl 12 Then, when the rotation and opening / closing angles of the end effector are δ1 and δ2 respectively, we have:

[0263]

[0264] Based on the aforementioned changes in the length of the steel wire rope controlling the movement of each joint of the flexible surgical instrument and the insertion distance... By using the structural parameters and electronic gear ratio of the flexible surgical instrument, the pulse values ​​required for each motor to move the end of the flexible surgical instrument to the target position T can be calculated, thereby realizing the control of the left opening and closing control motor 101, the right opening and closing control motor 102, the upward swing control motor 103, the 360-degree rotation control motor 104, and the downward swing control motor 105 of the clamp end, and thus completing the motion control of the entire flexible surgical instrument at the clamp end.

[0265] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this invention and to simplify the description, and 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. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0266] 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 of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A forceps-end flexible surgical instrument for a minimally invasive surgical robot, characterized by, Comprise: The flexible mechanism of the end of the clamp and the control mechanism of the flexible mechanism of the end of the clamp, the control mechanism of the flexible mechanism of the end of the clamp comprises: the left opening and closing control mechanism of the end of the clamp, the right opening and closing control mechanism of the end of the clamp, the upper deflection control mechanism of the end of the clamp, the lower deflection control mechanism of the end of the clamp and the 360 degree rotation control mechanism of the end of the clamp; the left opening and closing control mechanism of the end of the clamp, the right opening and closing control mechanism of the end of the clamp, the upper deflection control mechanism of the end of the clamp, the lower deflection control mechanism of the end of the clamp and the 360 degree rotation control mechanism of the end of the clamp are connected with the flexible mechanism of the end of the clamp respectively, and the flexible mechanism of the end of the clamp is controlled to move left, right, up, down and rotate 360 degrees through the left opening and closing control mechanism of the end of the clamp, the right opening and closing control mechanism of the end of the clamp, the upper deflection control mechanism of the end of the clamp, the lower deflection control mechanism of the end of the clamp and the 360 degree rotation control mechanism of the end of the clamp respectively; The control mechanism of the flexible mechanism of the end of the clamp further comprises: a rigidly connected outer tube of the end of the clamp and a rigidly connected inner tube of the end of the clamp, and the rigidly connected inner tube of the end of the clamp is located inside the rigidly connected outer tube of the end of the clamp; the rigidly connected inner tube of the end of the clamp is connected with the flexible mechanism of the end of the clamp and the 360 degree rotation control mechanism of the end of the clamp respectively; The flexible mechanism of the end of the clamp comprises: a left opening and closing clamp of the end of the clamp, a right opening and closing clamp of the end of the clamp, an opening and closing clamp fixed seat, an opening and closing clamp fixed pin, an upper swing deflection pulley of the end of the clamp, a lower swing deflection pulley of the end of the clamp, a clamp end opening and closing seat fixed pin, a flexible connecting seat of the end of the clamp, a flexible cross deflection pin of the end of the clamp, a flexible connecting seat fixed pin of the end of the clamp, a connecting head, a flexible inner tube of the end of the clamp and a flexible outer tube of the end of the clamp; the number of the flexible connecting seat of the end of the clamp is multiple, and the multiple flexible connecting seats of the end of the clamp are connected in sequence through the flexible connecting seat fixed pin of the end of the clamp to form the flexible outer tube of the end of the clamp; the rear end of the flexible outer tube of the end of the clamp is connected with the front end of the rigidly connected outer tube of the end of the clamp, and the front end of the flexible outer tube of the end of the clamp is connected with one end of the connecting head; the rear end of the flexible inner tube of the end of the clamp is connected with the rigidly connected inner tube of the end of the clamp; the number of the flexible cross deflection pin of the end of the clamp is multiple, and the number of the flexible cross deflection pin of the end of the clamp is the same as that of the flexible connecting seat of the end of the clamp; the outer ring of the flexible cross deflection pin of the end of the clamp is fixed on the inner wall of the flexible connecting seat of the end of the clamp, and the inner ring of the flexible cross deflection pin of the end of the clamp is sleeved on the flexible inner tube of the end of the clamp; the rear end of the opening and closing clamp fixed seat is connected with the flexible inner tube of the end of the clamp through the clamp end opening and closing seat fixed pin, and the front end of the opening and closing clamp fixed seat is connected with the left opening and closing clamp of the end of the clamp and the right opening and closing clamp of the end of the clamp through the opening and closing clamp fixed pin; the opposite faces of the left opening and closing clamp of the end of the clamp and the right opening and closing clamp of the end of the clamp are both provided with sawtooth-shaped matching structures; the upper swing deflection pulley of the end of the clamp and the lower swing deflection pulley of the end of the clamp are both fixed in the opening and closing clamp fixed seat through a pin shaft; The left jaw opening and closing control mechanism comprises a left jaw opening and closing control motor, a left jaw opening and closing control motor connecting lower seat, a left jaw opening and closing control motor connecting upper seat, a left jaw opening and closing transmission shaft winding shaft, a left jaw opening and closing transmission shaft steering pulley, a first transmission shaft and a jaw opening and closing transmission shaft steering pulley fixing seat; the left jaw opening and closing control motor connecting lower seat and the left jaw opening and closing control motor connecting upper seat are fixedly connected, the output end of the left jaw opening and closing control motor is fixed on the left jaw opening and closing control motor connecting lower seat, the left jaw opening and closing transmission shaft winding shaft is fixed on the left jaw opening and closing control motor connecting upper seat, and the output shaft of the left jaw opening and closing control motor is connected with the end of the left jaw opening and closing transmission shaft winding shaft through the left jaw opening and closing control motor connecting lower seat; the left jaw opening and closing transmission shaft steering pulley is fixed on the jaw opening and closing transmission shaft steering pulley fixing seat; the front end of the first transmission shaft is wound on the left jaw opening and closing jaw, the rear end of the first transmission shaft is sequentially connected with the left jaw flexible inner tube, the left jaw rigid connecting inner tube, wound on the left jaw opening and closing transmission shaft steering pulley and then wound on the left jaw opening and closing transmission shaft winding shaft; the left jaw opening and closing control motor drives the left jaw opening and closing transmission shaft winding shaft to rotate clockwise through the left jaw opening and closing control motor connecting lower seat and the left jaw opening and closing control motor connecting upper seat, and then the first transmission shaft is wound on the left jaw opening and closing transmission shaft winding shaft clockwise, so that the left jaw opening and closing jaw is opened by pulling the first transmission shaft, and vice versa; The right jaw opening and closing control mechanism comprises a right jaw opening and closing control motor, a right jaw opening and closing control motor connecting lower seat, a right jaw opening and closing control motor connecting upper seat, a right jaw opening and closing transmission shaft winding shaft, a right jaw opening and closing transmission shaft steering pulley, a second transmission shaft and a jaw opening and closing transmission shaft steering pulley fixing seat; the right jaw opening and closing control motor connecting lower seat and the right jaw opening and closing control motor connecting upper seat are fixedly connected, the output end of the right jaw opening and closing control motor is fixed on the right jaw opening and closing control motor connecting lower seat, the right jaw opening and closing transmission shaft winding shaft is fixed on the right jaw opening and closing control motor connecting upper seat, and the output shaft of the right jaw opening and closing control motor is connected with the end of the right jaw opening and closing transmission shaft winding shaft through the right jaw opening and closing control motor connecting lower seat; the right jaw opening and closing transmission shaft steering pulley is fixed on the jaw opening and closing transmission shaft steering pulley fixing seat; the front end of the second transmission shaft is wound on the right jaw opening and closing jaw, the rear end of the second transmission shaft is sequentially connected with the right jaw flexible inner tube, the right jaw rigid connecting inner tube, wound on the right jaw opening and closing transmission shaft steering pulley and then wound on the right jaw opening and closing transmission shaft winding shaft; the right jaw opening and closing control motor drives the right jaw opening and closing transmission shaft winding shaft to rotate clockwise through the right jaw opening and closing control motor connecting lower seat and the right jaw opening and closing control motor connecting upper seat, and then the second transmission shaft is wound on the right jaw opening and closing transmission shaft winding shaft clockwise, so that the right jaw opening and closing jaw is opened by pulling the second transmission shaft, and vice versa; The upper jaw end swing control mechanism comprises an upper jaw end swing control motor, an upper jaw end swing control motor connecting lower seat, an upper jaw end swing control motor connecting upper seat, an upper jaw end swing control transmission shaft winding shaft, an upper jaw end swing control transmission shaft steering pulley and a third transmission shaft; the upper jaw end swing control motor connecting lower seat and the upper jaw end swing control motor connecting upper seat are fixedly connected, the output end of the upper jaw end swing control motor is fixed on the upper jaw end swing control motor connecting lower seat, the upper jaw end swing control transmission shaft winding shaft is fixed on the upper jaw end swing control motor connecting upper seat, and the output shaft of the upper jaw end swing control motor is connected with the end of the upper jaw end swing control transmission shaft winding shaft through the upper jaw end swing control motor connecting lower seat; the third transmission shaft is wound on the upper jaw end swing steering pulley at the front end, and the rear end of the third transmission shaft is wound on the upper jaw end swing control transmission shaft winding shaft through the upper jaw end flexible inner tube, the upper jaw end rigid connecting inner tube and the upper jaw end swing control transmission shaft steering pulley in sequence; the upper jaw end swing control motor drives the upper jaw end swing control transmission shaft winding shaft to rotate clockwise through the upper jaw end swing control motor connecting lower seat and the upper jaw end swing control motor connecting upper seat, and then the third transmission shaft is wound on the upper jaw end swing control transmission shaft winding shaft clockwise, and the upper jaw end swing control transmission shaft winding shaft is wound on the upper jaw end swing control transmission shaft winding shaft through pulling the third transmission shaft to realize the upper jaw end swing control transmission shaft winding shaft. The lower jaw end swing control mechanism comprises a lower jaw end swing control motor, a lower jaw end swing control motor connecting lower seat, a lower jaw end swing control motor connecting upper seat, a lower jaw end swing control transmission shaft winding shaft, a lower jaw end swing control transmission shaft steering pulley and a fourth transmission shaft; the lower jaw end swing control motor connecting lower seat and the lower jaw end swing control motor connecting upper seat are fixedly connected, the output end of the lower jaw end swing control motor is fixed on the lower jaw end swing control motor connecting lower seat, the lower jaw end swing control transmission shaft winding shaft is fixed on the lower jaw end swing control motor connecting upper seat, and the output shaft of the lower jaw end swing control motor is connected with the end of the lower jaw end swing control transmission shaft winding shaft through the lower jaw end swing control motor connecting lower seat; the fourth transmission shaft is wound on the lower jaw end swing steering pulley at the front end, and the rear end of the fourth transmission shaft is wound on the lower jaw end swing control transmission shaft winding shaft through the lower jaw end flexible inner tube, the lower jaw end rigid connecting inner tube and the lower jaw end swing control transmission shaft steering pulley in sequence; the lower jaw end swing control motor drives the lower jaw end swing control transmission shaft winding shaft to rotate clockwise through the lower jaw end swing control motor connecting lower seat and the lower jaw end swing control motor connecting upper seat, and then the fourth transmission shaft is wound on the lower jaw end swing control transmission shaft winding shaft clockwise, and the lower jaw end swing control transmission shaft winding shaft is wound on the lower jaw end swing control transmission shaft winding shaft through pulling the fourth transmission shaft to realize the lower jaw end swing control transmission shaft winding shaft. The control method of the flexible surgical instrument of the minimally invasive surgical robot comprises the following steps: (1) The positive kinematics control method of the flexible surgical instrument of the minimally invasive surgical robot; 1) Rigid segment The improved DH parameter method is used to model the forward kinematics of the rigid segment of the flexible surgical instrument, and the improved DH parameters of the rigid segment of the flexible surgical instrument are shown in the following table, is the displacement of the joint, is the rotation angle of the manipulator, is the deflection angle of the rigid rod, is the distance between the intersection of the manipulator axis and the rigid rod axis and the center of the end face of the rigid segment; the manipulator is rigidly connected to the outer tube at the end of the pincers, and the rigid rod is the segment rigidly connected to the front end of the outer tube at the end of the pincers and the flexible outer tube of the pincers. ； The homogeneous transformation matrix of the adjacent joint coordinate system of the rigid segment of the flexible surgical instrument obtained by the improved DH parameter method is as follows: ； ； Wherein c and s are the simplified forms of cos and sin respectively; 2) Flexible segment The flexible section of the flexible surgical instrument is composed of seven flexible units, each of which contains a cross shaft, which is a pincer end flexible cross yaw pin, and a rigid block, which is a pincer end flexible connecting seat. The pose of the end of the flexible section is related to the movement of each rigid block. First, the yaw in a single direction is analyzed. There are four small holes in the rigid block, through which steel wires L1, L2, L3 and L4 pass, respectively. The steel wires L1, L2, L3 and L4 correspond to the first transmission shaft, the second transmission shaft, the third transmission shaft and the fourth transmission shaft, respectively, to control the bending of the flexible section. The end rigid block and the rigid block i are selected for analysis. Since the steel wire can transmit tension in the pre-tightening state, the end rigid block is subjected to the combined action of the tension of the steel wire and the force of the rigid block i Force balance analysis of the end rigid block gives: , are the angles between the force lines and the end face of the end rigid block. From the above formula, it can be obtained that , that is ; therefore, according to the force balance of the end rigid block, it is obtained that ; and according to the force balance of the rigid block i, it is obtained that （1） wherein and are the angles between the force and the left end face of the rigid block i, are the angles between the force and the right end face of the rigid block i, according to , and equation (1) are obtained i.e. ; According to the above formula (1), formula (2) and formula (3), the following formula (4) is obtained: , , , ; according to the moment balance of the end rigid block on the shaft at the point A, the following formula (5) is obtained: ​ （2） where t is the distance between the steel wire rope L1, L3 and the shaft h is the length of the rigid block, is the distance between the axes of two adjacent cross shafts, is the distance between the shaft and the end face of the adjacent rigid block; According to the moment balance of the rigid block i about the axis we obtain: （3） According to , , , equation (2), equation (3) we have: （4） According to equation (2) and equation (4), we have ; Therefore, according to , , it is known that the four angles are equal; Therefore, the angle between the end face of each rigid block in the flexible section and the steel wire rope is consistent, and the deflection angle of each rigid block in the flexible section is also equal. Similarly, considering the deflection of the flexible section under the tension of the steel wire ropes L2 and L4, the deflection angle of each rigid block is also equal. Therefore, regardless of the direction of the deflection of the flexible section, the deflection angle of each rigid block is equal. Since each steel wire rope in the flexible section can be controlled independently, adjusting the length of the four steel wire ropes in the flexible section can make the flexible section bend in various directions. A coordinate system of each flexible unit is established at a distance from the center point of each cross axis The flexible segment is composed of n flexible units. The homogeneous transformation matrix of the position of the end of the flexible segment in the base coordinate system is calculated by using the projection method based on the geometric relationship of the positions of the coordinate systems of the flexible units in the flexible segment. （5） wherein is the angle between two adjacent flexible unit axes, i.e. the angle between two adjacent flexible unit Z-axes, is the deflection angle of each flexible unit around the base coordinate system axis axis. The pose transformation matrix between adjacent flexible units can be calculated by the geometric relationship of the adjacent flexible unit coordinate system positions of the flexible segment using the projection method as follows: （6） 3) End effector The homogeneous transformation matrix of the end position of the end effector in the flexible section coordinate system is: （9） wherein L is the length from the end of the flexible segment to the end of the end effector, then the forward kinematics equation for the flexible surgical instrument is: （10） (2) Control method of the inverse kinematics of the flexible surgical instrument with a jaw end The numerical solution method is used to solve the inverse kinematics of the flexible surgical instrument. According to the mechanical structure and the forward kinematics model of the flexible surgical instrument, the requirements of the single-hole surgery on the flexible surgical instrument are taken into account The ranges are respectively: ； The self-rotation joint of the manipulator and the yaw joint of the rigid rod are taken as the posture adjustment joints and are directly controlled by the joints 6 and 5 of the master manipulator respectively. The self-rotation joint of the manipulator and the yaw joint of the rigid rod are fixed in position control, so , are known parameters in the kinematic model; and the formula (10) is transformed to obtain: （11） Let the left and right sides of equation (11) be respectively , then: （12） From formula (11) and formula (12), we have: ； The terms in formula (13), formula (14), and formula (15) are calculated by MATLAB as follows: ； Simplify the terms in formula (16) as follows: （17） In equation (17) respectively. （18） From formula (13), formula (15), and formula (17), we have: （19） From formula (14), formula (17), and formula (19), we have: （20） Equation (20) contains only unknown parameters Let: （21） Then the solution satisfying is obtained by bisection method. Thus, from equation (14) and equation (17), we have​ ； From formula (15) and formula (17), we have: ； To this end are already solved; Since the flexible surgical instrument is controlled by driving the steel wire rope, the motion of the tip of the flexible surgical instrument needs to be controlled by changing the length of the steel wire rope, so the relationship between the joint variables of the flexible surgical instrument and the length changes of each part of the rope needs to be obtained: Let the radius of the joystick rotation unit be , the length change of the steel wire rope L5, L6 controlling the joystick rotation be , , then: ; The steel wires L7 and L8 for controlling the deflection of the rigid rod are provided, the gravity of the flexible surgical instrument and the friction between the steel wires and the mechanical structure are not considered, the tension of the steel wires is considered to be constant in the whole control process, the radius of the wire hole is considered to be equal to the radius of the steel wire, the length of the part of the steel wire in the control rod and the rigid rod is considered to be constant, the length change of the steel wires L7 and L8 is only reflected on the section from the wire hole of the control rod to the wire hole of the rigid rod, the length of the steel wires L7 and L8 between the wire hole of the control rod and the wire hole of the rigid rod is respectively and , and the included angle between the two is Y, Y is a structural parameter of the flexible surgical instrument, the length of the steel wires L7 and L8 between the wire hole of the control rod and the wire hole of the rigid rod is respectively and , and the included angle between the two is , and the included angle between the two is is the deflection angle of the rigid rod, and the following is obtained: ； Let the terms in formula (24) equal m, which is a structural parameter of the flexible surgical instrument, then we have: （25） Let the length variation of the steel wire ropes L7 and L8 be then there is: （26） The flexible section of the flexible surgical instrument is driven and controlled by four steel wire ropes L1, L2, L3, and L4. One end of each steel wire rope is fixed at the end of the flexible section, and the other end is fixed on the corresponding motor-driven wire wheel. Each steel wire rope is independently controlled. Since the steel wire ropes L1, L2, L3, and L4 pass through the shaft when passing through the control lever and the rigid rod, the length of the steel wire ropes L1, L2, L3, and L4 inside the control lever and the rigid rod remains unchanged. At the same time, the length of the steel wire ropes L1, L2, L3, and L4 inside each flexible unit remains unchanged. Therefore, the length change of the steel wire ropes L1, L2, L3, and L4 only occurs between the upper and lower surfaces of adjacent flexible units. Since the deflection angle of each flexible unit is equal when the flexible section deflects in any direction, the length change of the steel wire ropes L1, L2, L3, and L4 between the upper and lower surfaces of adjacent flexible units is the same. The length change of the steel wire ropes between the upper and lower surfaces of adjacent flexible units is: （33） Since the length of the line L1 i L3 i , the line L2 i L4 i , the line L1 i+1 L3 i+1 , the line L2 i+1 L4 i+1 is always equal, and let the length be D, D is a structural parameter of the flexible unit, according to the above control of the length change of the steel wire rope of each joint movement of the flexible surgical instrument, the probe distance and the structural parameters of the flexible surgical instrument and the electronic gear ratio, the pulse value required by the end of the flexible surgical instrument to move to the target pose T can be calculated, the control of the left opening and closing control motor of the end of the clamp, the right opening and closing control motor of the end of the clamp, the up swing control motor of the end of the clamp, the 360-degree rotation control motor of the end of the clamp and the down swing control motor of the end of the clamp is realized, and then the movement control of the whole end of the clamp flexible surgical instrument is completed.

2. The tined flexible surgical instrument for use with a minimally invasive surgical robot of claim 1, wherein, The tongs end 360-degree rotation control mechanism comprises a tongs end 360-degree rotation control motor, a tongs end 360-degree rotation motor connecting lower seat, a tongs end 360-degree rotation motor connecting upper seat, a tongs end 360-degree rotation motor transmission shaft, a tongs end 360-degree rotation output end gear, a tongs end 360-degree rotation input end gear and a tongs end 360-degree rotation input end gear fixing seat; the tongs end 360-degree rotation motor connecting lower seat is fixedly connected with the tongs end 360-degree rotation motor connecting upper seat, the output end of the tongs end 360-degree rotation control motor is fixed on the tongs end 360-degree rotation motor connecting lower seat, the tongs end 360-degree rotation motor transmission shaft is fixed on the tongs end 360-degree rotation motor connecting upper seat, the output shaft of the tongs end 360-degree rotation control motor is connected with the end of the tongs end 360-degree rotation motor transmission shaft through the tongs end 360-degree rotation motor connecting lower seat, and the tongs end 360-degree rotation output end gear is installed on the upper end of the tongs end 360-degree rotation motor transmission shaft; the tongs end 360-degree rotation input end gear is installed in the tongs end 360-degree rotation input end gear fixing seat and on the upper end of the tongs end rigid connecting inner tube, and the tongs end 360-degree rotation input end gear and the tongs end 360-degree rotation output end gear are in meshing relationship; when the tongs end 360-degree rotation control motor drives the tongs end 360-degree rotation motor transmission shaft and the tongs end 360-degree rotation output end gear to rotate through the tongs end 360-degree rotation motor connecting lower seat and the tongs end 360-degree rotation motor connecting upper seat, the tongs end rigid connecting inner tube and the tongs end flexible inner tube are driven to rotate 360 degrees through the meshing action between the tongs end 360-degree rotation output end gear and the tongs end 360-degree rotation output end gear.

3. The tined flexible surgical instrument for use with a minimally invasive surgical robot of claim 1, wherein, The tongs end flexible mechanism control mechanism further comprises a left motor compartment pressing unlocking column and a right motor compartment pressing unlocking column, the motor compartment comprises a shell one and a shell two, the shell one and the shell two are connected through the left motor compartment pressing unlocking column and the right motor compartment pressing unlocking column, and the upper and lower sides of the front end of the shell one are respectively provided with clamping grooves; the right motor compartment pressing unlocking column realizes radial elastic movement range through a first spring, when the first spring is at the original length, the first clamping hook on the right motor compartment pressing unlocking column is in the clamping groove on the upper end of the shell one; when the right motor compartment pressing unlocking column is pressed, the first clamping hook is separated from the clamping groove on the upper end of the shell one; the left motor compartment pressing unlocking column realizes radial elastic movement range through a second spring, when the second spring is at the original length, the second clamping hook on the left motor compartment pressing unlocking column is in the clamping groove on the lower end of the shell two; when the left motor compartment pressing unlocking column is pressed, the second clamping hook is separated from the clamping groove on the lower end of the shell two; the operator holds the shell one with one hand and holds the shell two with the other hand and simultaneously presses the left motor compartment pressing unlocking column and the right motor compartment pressing unlocking column, so that the first clamping hook and the second clamping hook are separated from the clamping grooves on the shell one and the shell two moves away from the shell one, and the unlocking process is realized.

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