Minimally invasive surgery clamp and three-dimensional force measuring method based on minimally invasive surgery clamp

Abstract

The invention discloses a minimally invasive surgery clamp and a three-dimensional force measuring method based on the minimally invasive surgery clamp, the whole minimally invasive surgery clamp is a cylinder, and the minimally invasive surgery clamp comprises a contact head, a clamp fixing part, an upper clamping surface, a rack core and a transmission rod; a semi-cylindrical lower clamping surface is formed at the front end of the clamp fixing part, a straight circular flexible hinge is formed in the middle of the clamp fixing part, and a tubular clamp shell is arranged at the rear end of the clamp fixing part; an elliptical flexible hinge is arranged in the clamp fixing part along the axial direction and penetrates through the top end to be fixed with the contact head; the transmission rod is fixed to the rack core, and the rear end of the upper clamping face is matched with the rack core through a gear. The transmission rod drives the rack core to move back and forth under the action of external force, so that the upper clamping surface rotates around the gear to perform opening and closing movement relative to the lower clamping surface; an optical fiber is arranged in the elliptical flexible hinge and is used for measuring the axial stress of the contact head; and two optical fibers are symmetrically arranged in the straight circular flexible hinge and are used for measuring the pressure and lateral stress of the lower clamping surface. According to the invention, stable transmission of the surgical clamp and accurate measurement of force can be realized.

Description

Technical Field

[0001] The present invention belongs to the field of medical devices, and particularly relates to a minimally invasive surgical clamp and a three-dimensional force measurement method based on the same. Background Art

[0002] In traditional minimally invasive surgeries, doctors insert clamping instruments through small incisions deep into the patient's body. The complex internal environment and other tissues near the target organ will exert a certain amount of force on the surgical instruments. Coupled with the fact that traditional minimally invasive surgical clamping instruments use wire rope transmission, the force changes significantly during the clamping process, resulting in a large deviation between the force felt by the doctor's hand and the force of the interaction between the instrument and the tissue. As a result, it may lead to consequences such as tissue damage, slipping of the clamped tissue, and reduced surgical efficiency. During the minimally invasive surgical process, the force feedback of the surgical clamp and the stable transmission of the clamp are extremely important for doctors to perform high-precision operations. Summary of the Invention

[0003] The present invention provides a minimally invasive surgical clamp and a three-dimensional force measurement method based on the same, which can achieve the stable transmission of the surgical clamp and the accurate measurement of force.

[0004] To achieve the above technical objectives, the present invention adopts the following technical solutions: A minimally invasive surgical clamp, which is integrally cylindrical and includes: a contact head, a clamp fixing part, an upper clamping surface, a rack core, and a transmission rod; The front end of the clamp fixing part is semi-cylindrical, and the axial section forms a lower clamping surface; the rear end of the lower clamping surface forms a straight circular flexible hinge; the rear end of the clamp fixing part is a tubular clamp housing, and the upper clamping surface and the rack core are both installed in the clamp housing; an elliptical flexible hinge is axially arranged inside the clamp fixing part, and the elliptical flexible hinge passes through the top of the clamp fixing part and is fixedly connected to the contact head; The transmission rod is fixedly connected to the rack core, and the rear end of the upper clamping surface is provided with a gear to cooperate with the rack core; the transmission rod is driven by an external force to move back and forth, driving the rack core to move back and forth, and causing the upper clamping surface to rotate around the gear to perform an opening and closing movement relative to the lower clamping surface; A third optical fiber is axially arranged inside the elliptical flexible hinge for measuring the force of the contact head along the axial direction according to the wavelength drift; The first optical fiber and the second optical fiber are axially arranged in parallel and symmetrically inside the lower clamping surface for measuring the force of the lower clamping surface in the vertical plane of the axial direction according to the wavelength drift.

[0005] Further, a through hole is axially provided inside the clamp fixing portion, and the diameter of the through hole is larger than the diameter of the elliptical flexible hinge; the elliptical flexible hinge is coaxially arranged inside the through hole, and the distance between the elliptical flexible hinge and the inner wall of the through hole is larger than the maximum radial deformation amount of the elliptical flexible hinge.

[0006] Further, the elliptical flexible hinge is formed by circumferentially cutting an ellipse on a cylinder, and the straight circular flexible hinge is formed by circumferentially cutting a semi-circle on a cylinder.

[0007] Further, the upper clamping surface is serrated at the portion in contact with the lower clamping surface.

[0008] Further, a first pin inner hole is provided at the center of the gear at the rear end of the upper clamping surface, and a first pin is additionally provided to pass through the first pin inner hole, and both ends are connected to the first pin outer holes on the clamp housing.

[0009] Further, a second pin inner hole is provided in the middle of the rack core, and a second pin is additionally provided to pass through the second pin inner hole, and both ends are arranged in the straight slot openings on the clamp housing; straight teeth are arranged on a plane of the rack core for meshing with the gear at the rear end of the upper clamping surface.

[0010] A three-dimensional force measurement method for the above-mentioned minimally invasive surgical clamp, with the intersection point O of the central axis of the clamp fixing portion and the front end face of the straight circular flexible hinge as the origin, the direction along the central axis towards the rear end as the positive direction of the z-axis, and the direction perpendicular to the lower clamping surface towards the top surface as the positive direction of the y-axis, and a right-hand rule is used to establish a space rectangular coordinate system O-xyz; including: When the minimally invasive surgical clamp is subjected to a force F along the axial direction of the clamp at the contact head z a wavelength shift occurs in the third optical fiber inside the elliptical flexible hinge ; When the lower clamping surface of the minimally invasive surgical clamp is subjected to a force F perpendicular to the plane of the axial direction xoy a wavelength shift occurs in the first optical fiber and the second optical fiber respectively as 、 ; According to the wavelength shifts generated by the first optical fiber, the second optical fiber, and the third optical fiber, calculate the force on the minimally invasive surgical clamp: ; In the formula, is the initial central wavelength of the first optical fiber, the second optical fiber, and the third optical fiber, is the effective elasto-optic coefficient, are respectively the thermo-optic coefficient and the expansion coefficient of the optical fiber material, are the suspension lengths of the first, second, and third optical fibers; is the lateral force on the lower clamping surface, that is, the force acting in the x-axis direction; is the pressure on the lower clamping surface, that is, the force acting in the y-axis direction; is the axial force on the contact head, that is, the force acting along the axis of the clamp; is the temperature change value; respectively represent the structural geometric coefficients of the straight circular and elliptical flexible hinges in the direction; represents the Young's modulus of elasticity of the material.

[0011] Furthermore, the structural geometric coefficients of the straight circular and elliptical flexible hinges in the direction , and the calculation expression is: ; ; ; In the formula, on the longitudinal section along the axis and perpendicular to the lower clamping surface of the clamp fixing part, with the center O1 of the circumferential cutting circle of the straight circular flexible hinge as the origin, along the y-axis and z-axis of the space rectangular coordinate system O-xyz in the same direction, a plane rectangular coordinate system O1-y1z1 is established; on the longitudinal section along the axis and perpendicular to the lower clamping surface of the clamp fixing part, with the center O3 of the circumferential cutting ellipse of the elliptical flexible hinge as the origin, along the y-axis and z-axis of the space rectangular coordinate system O-xyz in the same direction, a plane rectangular coordinate system O3-y3z3 is established; the cross-section of the straight circular flexible hinge is composed of a large semi-circle cut off a rectangle and a small semi-circle, h represents the height of the rectangle, and 2b represents the length of the rectangle; and are two expression forms of the height of the straight circular micro-segment, and there is ; In the formula, m is the distance from the top surface of the straight circular flexible hinge to the central axis of the lower clamping surface, is the distance from the bottom end of the lower clamping surface to the central axis of the lower clamping surface; z represents the independent variable along the z1-axis and is used as the integration variable in the formula; is the radius of the circumferential cutting circle of the straight circular flexible hinge, represents the angle between the line connecting the straight circular micro-segment to the center O1 and the y1-axis of the plane rectangular coordinate system O1-y1z1. The straight circular micro-segment refers to: dividing the circumferential cutting circle of the straight circular flexible hinge into countless equal parts, and any one of them is a straight circular micro-segment; and are two different expression forms of the diameter of the elliptical micro-segment, and there is ; Among them, represents the shortest diameter of the elliptical flexible hinge, are respectively the lengths of the major axis and the minor axis of the circumferential ellipse of the elliptical flexible hinge, is an intermediate variable, and ; represents the angle between the line connecting the elliptical micro-segment to the center O3 and the y3-axis of the plane rectangular coordinate system O3-y3z3. The elliptical micro-segment refers to: dividing the circumferential ellipse of the elliptical flexible hinge into countless equal parts, and any one of them is an elliptical micro-segment.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] For the minimally invasive surgical clamp of the present invention, by driving the transmission rod to move back and forth with an external force, the rack core can be controlled to move back and forth horizontally in the clamp housing, thereby driving the upper clamping surface to open and close synchronously. The movement and force provided by the gear-rack transmission in the minimally invasive surgical clamp are very stable and will not change with the change of the opening and closing stroke, and a stable clamping force can be provided. Based on the designed elastic body of the present invention, including the straight circular flexible hinge and the elliptical flexible hinge and the optical fiber inside them, the contact force at the front end of the clamp, the pressure on the clamping surface, and the lateral force on the clamping surface during the surgical process can be measured, improving the accuracy of the surgery and reducing the surgical risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is an assembly schematic diagram of the minimally invasive surgical clamp described in the embodiment of the present invention.

[0015] Figure 2 is an exploded schematic diagram of the minimally invasive surgical clamp described in the embodiment of the present invention.

[0016] Figure 3 is an internal structure schematic diagram of the lower clamping surface described in the embodiment of the present invention.

[0017] Figure 4 is a schematic diagram of the elliptical flexible hinge (a) and the straight circular flexible hinge (b) described in the embodiment of the present invention.

[0018] Figure 5 is a schematic diagram of the optical fiber layout of the minimally invasive surgical clamp described in the embodiment of the present invention; wherein (a) is the front-end view of the fixed part of the clamp, and (b) is the rear-end view of the fixed part of the clamp.

[0019] Figure 6 is a schematic diagram of the gear-rack transmission mechanism described in the embodiment of the present invention.

[0020] Figure 7Schematic diagram of the detailed structure of the straight circular flexible hinge on the lower clamping surface of the embodiment of the present invention under lateral force and pressure; among them, (a) is a longitudinal sectional view of the straight circular flexible hinge along the axis and perpendicular to the lower clamping surface, (b) is a cross-sectional view of the straight circular flexible hinge, and (c) is a dimensional drawing of the straight circular flexible hinge in the O1-y1z1 coordinate system.

[0021] Figure 8 Schematic diagram of the deformation of the straight circular flexible hinge on the lower clamping surface of the embodiment of the present invention when subjected to lateral force.

[0022] Figure 9 Schematic diagram of the deformation of the straight circular flexible hinge on the lower clamping surface of the embodiment of the present invention when subjected to pressure.

[0023] Figure 10 Schematic diagram of the detailed structure of the elliptical flexible hinge on the lower clamping surface of the embodiment of the present invention under contact force for deformation analysis.

[0024] Reference numerals: 100 - minimally invasive surgical clamp, 10 - contact head, 20 - clamp fixing part, 21 - second optical fiber, 22 - third optical fiber, 23 - first optical fiber, 24 - lower clamping surface, 25 - straight circular flexible hinge, 26 - clamp housing, 27 - elliptical flexible hinge, 28 - outer hole of the first pin shaft, 29 - straight slot, 30 - upper clamping surface, 31 - clamping surface, 32 - gear, 33 - inner hole of the first pin shaft, 40 - rack core, 41 - inner hole of the second pin shaft, 50 - tool channel, 60 - first pin shaft, 70 - second pin shaft, 80 - transmission rod. 1 - front hole for fixing the first optical fiber, 2 - front hole for fixing the second optical fiber, 3 - front hole for fixing the third optical fiber, 4 - rear hole for fixing the first optical fiber, 5 - rear hole for fixing the second optical fiber, 6 - rear hole for fixing the third optical fiber. Detailed implementation manners

[0025] The embodiments of the present invention will be described in detail below. Based on the technical solutions of the present invention, detailed implementation manners and specific operation processes are given, and the technical solutions of the present invention are further explained.

[0026] Embodiment 1

[0027] This embodiment provides a minimally invasive surgical clamp 100, which is integrally cylindrical, as Figure 1-2 shown, and includes: a contact head 10, a clamp fixing part 20, an upper clamping surface 30, a rack core 40, a tool channel 50, a first pin shaft 60, a second pin shaft 70, and a transmission rod 80.

[0028] The contact head 10 has the shape of a quarter sphere, and a cylinder is designed on the rear end section for nested combination with the elliptical flexible hinge 27. A hole is dug in the center of the cylinder for use as the front hole for fixing the third optical fiber 22.

[0029] The front end of the clamp fixing part 20 is semi-cylindrical, and the axial section forms a serrated lower clamping surface 24.

[0030] The rear end of the lower clamping surface 24 is formed into a straight circular flexible hinge 25 by cutting a partial semi-circle, as Figure 3 and Figure 4 shown in (b).

[0031] The rear end of the clamp fixing part 20 is a tubular clamp housing 26.

[0032] On the front end of the upper clamping surface 30, serrations are arranged on the clamping surface 31 opposite to the lower clamping surface. A gear 32 is arranged at the rear end. A first pin inner hole 33 is arranged at the center of the gear 32. Additionally, a first pin 60 is arranged to pass through the first pin inner hole 33, and both ends are connected to the first pin outer holes 28 arranged on the clamp housing 26 to fix the upper clamping surface 30 to the clamp housing 26 and enable rotation. Additionally, the clamp housing 26 is provided with a notch at the position where the upper clamping surface 30 is installed, for the upper clamping surface 30 to extend out of the clamp housing 26 and perform an opening and closing movement with the lower clamping surface 24 of the clamp fixing part 20.

[0033] As Figure 1 , 2 , 6 shown, the rack core 40 is installed in the clamp housing 26. Its shape is a cuboid, and straight teeth are arranged only on one surface, for meshing with the gear 32 of the upper clamping surface 30. A second pin inner hole 41 is arranged in the middle of the rack core 40, and is connected to the straight slot 29 on the clamp housing 26 through a second pin 70. A hole is opened at the lower end of the rack core 40, for fixedly connecting the rack core 40 to the transmission rod 80.

[0034] The transmission rod 80 is driven to move back and forth by an external force. First optical fiber 23 and second optical fiber 21 are arranged parallel and symmetrically along the axial direction inside the lower clamping surface 24, and are arranged side by side close to the lower clamping surface 24, for measuring the force condition of the lower clamping surface 24 in the axial vertical plane according to wavelength drift.

[0035] As Figure 3 and Figure 4 shown in (a), an elliptical flexible hinge 27 is arranged along the axial direction inside the clamp fixing part 20. The elliptical flexible hinge 27 is formed by cutting a partial ellipse on a cylinder, passes through the top end of the clamp fixing part 20 and is fixedly connected to the contact head 10. Inside the elliptical flexible hinge 27, a third optical fiber 22 is arranged along the axial direction, for measuring the force condition of the contact head 10 along the axial direction according to wavelength drift.

[0036] Specifically, a through-hole is axially provided inside the clamp fixing part 20, and the diameter of the through-hole is larger than the diameter of the elliptical flexible hinge 27; the elliptical flexible hinge 27 is coaxially arranged inside the through-hole, and the distance between the elliptical flexible hinge 27 and the inner wall of the through-hole is larger than the maximum radial deformation of the elliptical flexible hinge 27, providing sufficient deformation space for the elliptical flexible hinge 27. One end of the third optical fiber 22 is fixed to the contact head 10, and the other end is fixed to the rear end of the through-hole inside the clamp fixing part 20. By setting the through-hole in this way, when measuring the axial force using the third optical fiber 22, the influence of the peripheral clamp fixing part 20 can be avoided, resulting in inaccurate measurement.

[0037] The shape of the tool cavity 50 is consistent with that of the tubular clamp housing 26 and is sleeved at the end of the clamp housing 26. The inside of the tool cavity 50 is partitioned to separate the channels for the transmission rod 80 and the optical fiber, preventing the optical fiber from breaking due to the movement of the transmission rod 80.

[0038] As Figure 3 and Figure 5 shown, gratings are correspondingly arranged on the 3 optical fibers of the present invention, specifically using fiber Bragg gratings. A first optical fiber fixing front hole 1, a second optical fiber fixing front hole 2 are respectively arranged at the front end of the clamp fixing part 20 from left to right, a third optical fiber fixing front hole 3 is located at the front end of the elliptical flexible hinge 27, a first optical fiber fixing rear hole 4 is located at the rear end of the clamp fixing part 20, a second optical fiber fixing rear hole 5 is symmetrically distributed on its opposite side, and a third optical fiber fixing rear hole 6 is located at the end of the elliptical flexible hinge 27. Both ends of the 3 optical fibers are fixed to the corresponding optical fiber fixing holes using UV glue, so that the 3 optical fibers are all in a taut suspension state and are arranged in parallel symmetry.

[0039] The contact head 10, the lower clamping surface 24, the upper clamping surface 30, the rack core 40, and the tool cavity 50 of this embodiment are all made of black resin material by a 3D printer.

[0040] Embodiment 2

[0041] This embodiment provides a three-dimensional force measurement method for the minimally invasive surgical clamp described in Embodiment 1. Taking the intersection point O of the central axis of the clamp fixing part 20 and the front end face of the straight circular flexible hinge 25 as the origin, the direction along the central axis towards the rear end is the positive direction of the z-axis, and the direction perpendicular to the lower clamping surface towards the top surface is the positive direction of the y-axis. A spatial rectangular coordinate system O-xyz is established using the right-hand rule; it includes: When the minimally invasive surgical clamp is subjected to an axial force F along the clamp at the contact head 10 z the third optical fiber 22 inside the elliptical flexible hinge 27 generates a wavelength drift ; When the lower clamping surface 24 of the minimally invasive surgical clamp is subjected to a force F in the plane perpendicular to the axis xoyWhen the first optical fiber 23 and the second optical fiber 21 in the straight circular flexible hinge 25 generate wavelength drifts of and respectively; According to the wavelength drifts generated by the first optical fiber, the second optical fiber, and the third optical fiber, calculate the force on the minimally invasive surgical clamp: ; In the formula, is the initial central wavelength of the first, second, and third optical fibers, is the effective elasto-optic coefficient, are the thermo-optic coefficient and the expansion coefficient of the optical fiber material respectively, is the suspension length of the first, second, and third optical fibers; is the lateral force received by the lower clamping surface 24, that is, the force acting in the x-axis direction; is the pressure received by the lower clamping surface 24, that is, the force acting in the y-axis direction; is the axial force received by the contact head 10, that is, the force acting along the axis of the clamp; is the temperature change value; represents the Young's elastic modulus of the material; respectively represent the structural geometric coefficients of the straight circular flexible hinge 25 in the direction, that is, the equivalent representation form of the integral formula in the process of deriving the force formula in the direction. Specifically: ; ; ; Principle analysis: During the use of the minimally invasive surgical clamp of the present invention, the contact force F z received by the contact head 10, the pressure F y perpendicular to the lower clamping surface 24, and the lateral force F x parallel to the lower clamping surface 24 can be calculated by converting the grating center wavelength drift amounts of 3 optical fibers.

[0042] When the contact head 10 at the front end of the surgical clamp receives the contact force F z , the elliptical flexible hinge 27 connected to the contact head 10 undergoes an approximately linear deformation under the action of the contact force. By analyzing the mechanical model of the elliptical flexible hinge 27, the relationship between the grating center wavelength drift amount of the third optical fiber 22 and the contact force under the action of the contact force is obtained. Since there is a sufficient gap between the elliptical flexible hinge 27 and the lower clamping surface 24, the first optical fiber 23 and the second optical fiber 21 do not generate center wavelength drifts.

[0043] When the lower clamping surface 24 of the surgical clamp receives the pressure Fy and the lateral force F x When the pressure F acts on the lower clamping surface 24, the straight circular flexible hinge 25 located on the lower clamping surface 24 undergoes approximately linear deformation under the action of the clamping surface force, and corresponding wavelength drifts will occur in the first optical fiber 23 and the second optical fiber 21. When the pressure F y acts on the lower clamping surface 24, the two optical fibers will undergo deformations of equal magnitude and the same direction, and the grating center wavelengths of the first optical fiber 23 and the second optical fiber 21 will undergo corresponding drifts. The pressure F can be measured by measuring the grating center wavelength drifts of the first optical fiber 23 and the second optical fiber 21 y . When the lateral force F x acts on the lower clamping surface 24, the two optical fibers undergo deformations of equal magnitude and opposite directions, and the grating center wavelengths of the first optical fiber 23 and the second optical fiber 21 will undergo corresponding drifts. By performing differential processing on the grating center wavelength drifts of the first optical fiber 23 and the second optical fiber 21, the lateral force F x can be measured

[0044] The specific working principle of this minimally invasive surgical clamp for measuring the lateral force F x , the pressure F y and the contact force F z is as follows: Refer to Figure 7 as shown Figure 7 (a) Region Ⅰ in it represents the serrated lower clamping surface 24, region Ⅱ is the location of the straight circular flexible hinge 25, and region Ⅲ represents the remaining part of the lower clamping surface 24, which is connected to the rear clamp housing 26 Figure 7 (b) is a cross-sectional schematic diagram of the straight circular flexible hinge 25. The cross-section is composed of a large semi-circle with a rectangle and a small semi-circle cut off. h represents the height of the rectangle, and 2b represents the length of the rectangle , and respectively represent the centroid axes of the large semi-circle, the small semi-circle and the rectangle , and respectively represent the distances from the centroid axes of the small semi-circle, the rectangle and the large semi-circle to the axis Figure 7 (c) represents the dimension diagram of the straight circular flexible hinge 25 in the O1-y1z1 coordinate system. When the minimally invasive surgical clamp is subjected to the lateral force F x and the pressure F y , the straight circular flexible hinge 25 will deform, and the diameter of the straight circular micro-segment along the axial direction in the straight circular flexible hinge 25 can be expressed as: ; In the formula, m is the distance from the top surface of the straight circular flexible hinge 25 to the central axis of the lower clamping surface is the distance from the bottom end of the lower clamping surface 24 to the central axis of the lower clamping surface; z represents the independent variable along the z1 axis and is used as the integration variable in the formula; is the radius of the circumferential cutting circle of the straight circular flexible hinge 25, represents the angle between the line connecting the straight circular micro-segment to the center O1 and the y1 axis of the plane rectangular coordinate system O1-y1z1, and the range is , and the straight circular micro-segment refers to: the circumferential cutting circle of the straight circular flexible hinge is equally divided into countless parts, and any one of them is a straight circular micro-segment, that is Figure 7 dz1 in (c), where ρ1 is the distance from the straight circular micro-segment dz1 to the y1 axis.

[0045] According to Castigliano's second theorem, the deformations of the straight circular flexible hinge 25 and the elliptical flexible hinge 27 integrated in the lower clamping surface along the x, y, and z directions can be expressed as: ; where is the strain energy of the flexure member, represents the three-dimensional force applied to the surgical clamp.

[0046] For the lateral force applied to the lower clamping surface 24 of the clamp, the displacement it generates can be expressed as: ; where, substituting into it, it can be further expressed as: ; Referring to Figure 8 , when the lateral force acts on the lower clamping surface 24, the first optical fiber 23 and the second optical fiber 21 are respectively compressed and stretched. and respectively represent and the midpoints of, where CD represents the distance between the first optical fiber 23 and the second optical fiber 21 without deformation, represents the distance between the first optical fiber 23 and the second optical fiber 21 after the action of . In the case of small deformation, the rotation angle of the center line is approximately . The deformations of these two optical fibers are called and , and can be expressed as: ; For the pressure , the displacement generated can be expressed as: ; Among them, substituting into it, can be further expressed as: ; Refer to Figure 9 as shown, represents the length of the optical fiber when the lower clamping surface 24 does not deform, represents the length of the optical fiber after the lower clamping surface 24 deforms, represents from to the straight line the intersection point of the perpendicular line, represents from to the straight line the intersection point of the perpendicular line, represents the central axis of the lower clamping surface 24. When the pressure acts on the lower clamping surface 24, the first optical fiber 23 and the second optical fiber 21 are simultaneously stretched and due to symmetry of the positions, the deformations of the two are the same. Under the action of the pressure, the deformations of these two optical fibers are called and , and can be expressed as: ; Refer to Figure 10 as shown, when the front end contact head 10 is subjected to an axial contact force acts, the main deformation occurs in the elliptical flexible hinge 27 structure. The axial diameter of the elliptical micro-segment of the elliptical flexible hinge 27 can be expressed as: ; Among them, represents the angle between the line connecting the elliptical micro-segment to the center O3 and the y3 axis of the plane rectangular coordinate system O3-y3z3; is an intermediate variable, and , are respectively the lengths of the major axis and the minor axis of the ellipse, is the diameter of the hollow hole of the elliptical hinge, represents the shortest diameter of the elliptical flexible hinge 27, and are two different expression forms of the diameter of the elliptical micro-segment. Figure 10 The dz2 in , that is, the elliptical micro-segment in this embodiment, where ρ2 is the distance from the elliptical micro-segment dz2 to the y3 axis.

[0047] The axial deformation can be expressed as: ; Among them, represents Young's modulus of elasticity, represents the moment of inertia about the z-axis.

[0048] It can be further expressed as: ; Since the third optical fiber 22 is arranged in the central hollow channel of the elliptical flexible hinge 27, in the case of small deformation, the deformation of the third optical fiber 22 is approximately the same as that of the elliptical flexible hinge 27.

[0049] According to the optical fiber sensing principle, there is a linear relationship between the axial deformation of the fiber grating and the temperature and central wavelength of the optical fiber. Therefore, the spatial vector force and temperature can be simplified into a linear system, which can be expressed as: ; Among them, the output matrix is composed of the corresponding wavelength shifts of each optical fiber, and is called . Represents the sensitivity matrix of force and temperature. The relationship between the central wavelength shift of the optical fiber and the applied force and temperature can be expressed as: ; Among them, is the suspension length of 3 optical fibers, and the value is 15 mm. Represents the initial central wavelength values of the first, second, and third optical fibers used. Represents the temperature increment, is the effective elasto-optic coefficient, which is only related to the material of the optical fiber. Are respectively the thermo-optic coefficient and the expansion coefficient of the optical fiber material.

[0050] By subtracting the first and second equations in the above formula and combining with the measurement principle of the fiber grating, the lateral force F x can be calculated. Through the known F x and the additionally set reference grating, the pressure F y can be obtained. Similarly, the axial force F z can be obtained from the third equation and the reference grating. The initial central wavelength values of the 3 optical fibers can be simplified to . In summary, the measurement matrix of force and temperature can be determined as follows: ; The above embodiments are the preferred embodiments of the present application. Those of ordinary skill in the art can also make various transformations or improvements on this basis. Without departing from the general concept of the present application, these transformations or improvements should all fall within the scope of protection required by the present application.

Claims

1. A minimally invasive surgical clamp, characterized in that, It is in the shape of a cylinder as a whole and includes: a contact head (10), a clamp fixing part (20), an upper clamping surface (30), a rack core (40), and a transmission rod (80); The front end of the clamp fixing part (20) is semi-cylindrical, and the axial section forms a lower clamping surface (24); the rear end of the lower clamping surface (24) is formed into a straight circular flexible hinge (25); the rear end of the clamp fixing part (20) is a tubular clamp housing (26), and both the upper clamping surface (30) and the rack core (40) are installed inside the clamp housing (26); an elliptical flexible hinge (27) is axially arranged inside the clamp fixing part (20), and the elliptical flexible hinge (27) passes through the top of the clamp fixing part (20) and is fixedly connected to the contact head (10); The transmission rod (80) is fixedly connected to the rack core (40), and the rear end of the upper clamping surface (30) is provided with a gear (32) to cooperate with the rack core (40); the transmission rod (80) is driven to move back and forth by an external force, driving the rack core (40) to move back and forth, and causing the upper clamping surface (30) to rotate around the gear (32) to perform an opening and closing movement relative to the lower clamping surface (24); A third optical fiber (22) is axially arranged inside the elliptical flexible hinge (27) for measuring the axial force on the contact head (10) according to the wavelength drift; First optical fibers (23) and second optical fibers (21) are axially arranged in parallel and symmetrically inside the lower clamping surface (24) for measuring the force on the lower clamping surface (24) in the vertical plane of the axis according to the wavelength drift.

2. The minimally invasive surgical clamp according to claim 1, wherein A through hole is axially arranged inside the clamp fixing part (20), and the diameter of the through hole is larger than the diameter of the elliptical flexible hinge (27); the elliptical flexible hinge (27) is coaxially arranged inside the through hole, and the distance between the elliptical flexible hinge (27) and the inner wall of the through hole is greater than the maximum radial deformation amount of the elliptical flexible hinge (27).

3. The minimally invasive surgical clamp according to claim 1, characterized in that, The elliptical flexible hinge (27) is formed by circumferentially cutting an ellipse on the cylinder, and the straight circular flexible hinge (25) is formed by circumferentially cutting a semi-circle on the cylinder.

4. The minimally invasive surgical clamp according to claim 1, wherein The parts of the upper clamping surface (30) in contact with the lower clamping surface (24) are all serrated.

5. The minimally invasive surgical clamp according to claim 1, wherein, A first pin inner hole (33) is provided at the center of the gear (32) at the rear end of the upper clamping surface (30), and a first pin (60) is additionally provided to pass through the first pin inner hole (33), and both ends are connected to the first pin outer holes (28) on the clamp housing (26).

6. The minimally invasive surgical clamp according to claim 1, characterized in that, A second pin inner hole (41) is provided in the middle of the rack core (40), and a second pin (70) is additionally provided to pass through the second pin inner hole (41), and both ends are arranged in the straight slot openings (29) on the clamp housing (26); straight teeth are arranged on one plane of the rack core (40) for meshing with the gear (32) at the rear end of the upper clamping surface (30).

7. A three-dimensional force measurement method for the minimally invasive surgical clamp according to any one of claims 1-6, characterized in that, Taking the intersection point O of the central axis of the clamp fixing part (20) and the front end face of the straight circular flexible hinge (25) as the origin, the positive direction of the z-axis is along the central axis towards the rear end, and the positive direction of the y-axis is perpendicular to the lower clamping surface towards the top surface. A space rectangular coordinate system O-xyz is established using the right-hand rule; including: When the micro-invasive surgical clamp is subjected to an axial force F along the clamp axis at the contact head (10) z a wavelength shift occurs in the third optical fiber within the elliptical flexible hinge (27) ; When the lower clamping surface (24) of the minimally invasive surgical clamp is subjected to a force F in a plane perpendicular to the axial direction xoy the first optical fiber (23) and the second optical fiber (21) generate wavelength drifts of and respectively; Calculating the force on the minimally invasive surgery clamp according to the wavelength drift generated by the first optical fiber, the second optical fiber, and the third optical fiber: ； In the formula, is the initial central wavelength of the first optical fiber, the second optical fiber, and the third optical fiber, is the effective elasto-optic coefficient, are the thermo-optic coefficient and the expansion coefficient of the optical fiber material respectively, are the suspension lengths of the first, second, and third optical fibers; is the lateral force received by the lower clamping surface (24), that is, the acting force in the x-axis direction; is the pressure received by the lower clamping surface (24), that is, the acting force in the y-axis direction; is the axial force received by the contact head (10), that is, the acting force along the axial direction of the clamp; is the temperature change value; respectively represent the structural geometric coefficients of the straight circular and elliptical flexible hinges in the direction; represents the Young's elastic modulus of the material.

8. The three-dimensional force measurement method of the minimally invasive surgical clamp according to claim 7, wherein Structural geometric coefficients of straight circular and elliptical flexible hinges in the direction are , and the calculation expression is: ； ； ； In the formula, on the longitudinal section of the clamp fixing part along the axis and perpendicular to the lower clamping surface, with the center O1 of the circumferential cutting circle of the straight circular flexible hinge (25) as the origin, and the positive directions of the y-axis and z-axis of the space rectangular coordinate system O-xyz being the same, a plane rectangular coordinate system O1-y1z1 is established; on the longitudinal section of the clamp fixing part along the axis and perpendicular to the lower clamping surface, with the center O3 of the circumferential cutting ellipse of the elliptical flexible hinge (27) as the origin, and the positive directions of the y-axis and z-axis of the space rectangular coordinate system O-xyz being the same, a plane rectangular coordinate system O3-y3z3 is established; the cross-section of the straight circular flexible hinge is composed of a large semi-circle with a rectangle and a small semi-circle cut off. h represents the height of the rectangle, and 2b represents the length of the rectangle; and are two expression forms of the height of a straight circular micro-segment, and there are ； In the formula, m is the distance from the top surface of the straight circular flexible hinge (25) to the central axis of the lower clamping surface, is the distance from the bottom end of the lower clamping surface to the central axis of the lower clamping surface; z represents the independent variable along the z1 axis and serves as the integration variable in the formula; is the radius of the circumferential cutting circle of the straight circular flexible hinge (25), represents the angle between the line connecting the straight circular micro-segment to the center O1 and the y1 axis of the plane rectangular coordinate system O1-y1z1. The straight circular micro-segment refers to: the circumferential cutting circle of the straight circular flexible hinge (25) is equally divided into countless parts, and any one of them is a straight circular micro-segment; and are two different expression forms of the diameter of the elliptical micro-segment, and there is ； Among them, represents the shortest diameter of the elliptical flexure hinge (27), are respectively the lengths of the major axis and the minor axis of the circumferential cut ellipse of the elliptical flexure hinge, is an intermediate variable, and ; represents the angle between the line connecting the elliptical micro-segment to the center O3 and the y3-axis of the plane rectangular coordinate system O3-y3z3. The elliptical micro-segment refers to: dividing the circumferential cut ellipse of the elliptical flexure hinge into countless equal parts, and any one of them is an elliptical micro-segment.

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