Minimally invasive surgical clamp and three-dimensional force measurement method based thereon

Abstract

The present invention discloses a minimally invasive surgical clamp and a three-dimensional force measurement method based thereon. The minimally invasive surgical clamp is cylindrical in shape and includes: a contact head, a clamp fixing portion, an upper clamping surface, a rack core, and a transmission rod. The clamp fixing portion has a front end formed into a semi-cylindrical lower clamping surface, a middle portion formed into a straight circular flexible hinge, and a rear end formed into a tubular clamp housing. An elliptical flexible hinge is axially arranged inside the clamp fixing portion, passing through the top end and fixed to the contact head. The transmission rod is fixed to the rack core, and the rear end of the upper clamping surface cooperates with the rack core via a gear. Under the action of an external force, the transmission rod drives the rack core to move back and forth, causing the upper clamping surface to rotate around the gear to open and close relative to the lower clamping surface. An optical fiber is arranged in the elliptical flexible hinge for measuring the axial force applied to the contact head. Two optical fibers are symmetrically arranged in the straight circular flexible hinge for measuring the pressure and lateral force applied to the lower clamping surface. The present invention can achieve smooth transmission of the surgical clamp and accurate force measurement.

Description

Technical Field

[0001] The present invention belongs to the field of medical equipment, and in particular relates to a minimally invasive surgical clamp and a three-dimensional force measurement method based thereon. Background Art

[0002] In traditional minimally invasive surgery, the surgeon inserts a clamping instrument through a small incision deep into the patient's body. The complex internal environment and other tissues near the target organ exert a certain amount of force on the surgical instrument. Furthermore, traditional minimally invasive surgical clamping instruments use wire ropes for transmission, resulting in significant force variations during the clamping process. This can lead to a significant deviation between the force felt by the surgeon's hand and the interaction force between the instrument and tissue. This can cause tissue damage, tissue slippage, and reduced surgical efficiency. Force feedback and smooth transmission of the surgical clamps are crucial for surgeons to perform high-precision operations during minimally invasive surgery. Summary of the Invention

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

[0004] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0005] A minimally invasive surgical clamp, which is cylindrical in shape, comprises: a contact head, a clamp fixing portion, an upper clamping surface, a rack core and a transmission rod;

[0006] The front end of the clamp fixing portion is semi-cylindrical, and the axial section forms a lower clamping surface; the rear end of the lower clamping surface is formed into a straight circular flexible hinge; the rear end of the clamp fixing portion 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 provided in the interior of the clamp fixing portion along the axial direction, and the elliptical flexible hinge passes through the top end of the clamp fixing portion and is fixedly connected to the contact head;

[0007] The transmission rod is fixedly connected to the rack core, and the rear end of the upper clamping surface is matched with the rack core by a gear. The transmission rod is driven by an external force to move forward and backward, driving the rack core to move forward and backward, causing the upper clamping surface to rotate around the gear to open and close relative to the lower clamping surface.

[0008] A third optical fiber is arranged axially inside the elliptical flexible hinge to measure the axial force of the contact head according to the wavelength drift;

[0009] A first optical fiber and a second optical fiber are arranged parallel and symmetrically along the axial direction inside the lower clamping surface, and are used to measure the force condition of the lower clamping surface in the axial vertical plane according to the wavelength drift.

[0010] Furthermore, a through hole is axially arranged 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 in 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 of the elliptical flexible hinge.

[0011] Furthermore, the elliptical flexible hinge is formed by cutting a portion of an ellipse on a cylinder, and the straight circular flexible hinge is formed by cutting a portion of a semicircle on a cylinder.

[0012] Furthermore, the upper clamping surface is provided with serrations at the contact portions with the lower clamping surface.

[0013] Furthermore, a first pin shaft inner hole is set in the center of the gear at the rear end of the upper clamping surface, and a first pin shaft is also set to pass through the first pin shaft inner hole, and both ends are connected to the first pin shaft outer holes on the clamp housing.

[0014] Furthermore, a second pin shaft inner hole is provided in the middle of the rack core, and a second pin shaft is also provided to pass through the second pin shaft inner hole, and both ends are provided in the straight slots on the clamp housing; straight teeth are arranged on a plane of the rack core for engaging with the gear at the rear end of the upper clamping surface.

[0015] A method for measuring the three-dimensional force of the above-mentioned minimally invasive surgical clamp, taking the intersection O of the central axis of the clamp fixing portion and the front end surface of the right circular flexible hinge as the origin, the direction along the central axis to the rear end as the positive z-axis, and the direction perpendicular to the lower clamping surface to the top surface as the positive y-axis, and using the right-hand rule to establish a spatial rectangular coordinate system O-xyz; comprising:

[0016] When the minimally invasive surgical clamp is subjected to a force F along the clamp axis at the contact head z When the wavelength of the third optical fiber in the elliptical flexible hinge shifts ;

[0017] When the lower clamping surface of the minimally invasive surgical clamp is subjected to a force F perpendicular to the axial plane xoy When the wavelength shifts of the first optical fiber and the second optical fiber are 、 ;

[0018] Based on the wavelength drift of the first, second, and third optical fibers, the force applied to the minimally invasive surgical clamp is calculated:

[0019] ;

[0020] Where, is the initial center wavelength of the first optical fiber, the second optical fiber, and the third optical fiber, is the effective elastic-optical coefficient, They are the thermo-optical coefficient and expansion coefficient of the optical fiber material, is the hanging length 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; The contact head is subjected to axial force, that is, the force acting along the axial direction of the clamp; is the temperature change value; Respectively represent the straight circular and elliptical flexible hinges in Structural geometry coefficient in direction; Represents the Young's modulus of elasticity of the material.

[0021] Furthermore, straight circular and elliptical flexible hinges are Structural geometry coefficient in the direction , the calculation expression is:

[0022] ;

[0023] ;

[0024] ;

[0025] Wherein, on the longitudinal section of the clamp fixing portion along the axial direction and perpendicular to the lower clamping surface, with the center O1 of the annular circle of the right circular flexible hinge as the origin, along the y-axis and z-axis of the spatial rectangular coordinate system O-xyz in the same direction, a plane rectangular coordinate system O1-y1z1 is established; on the longitudinal section of the clamp fixing portion along the axial direction and perpendicular to the lower clamping surface, with the center O3 of the annular ellipse of the elliptical flexible hinge as the origin, along the y-axis and z-axis of the spatial rectangular coordinate system O-xyz in the same direction, a plane rectangular coordinate system O3-y3z3 is established; the cross section of the right circular flexible hinge is composed of a large semicircle cut out of a rectangle and a small semicircle, h represents the height of the rectangle, and 2b represents the length of the rectangle;

[0026] and There are two ways to express the height of a straight circle micro segment:

[0027] ;

[0028] Where m is the distance from the top surface of the straight circular flexible hinge to the center axis of the lower clamping surface, is the distance from the bottom end of the lower clamping surface to the center axis of the lower clamping surface; z represents the independent variable along the z1 axis and is the integral variable in the formula; is the radius of the annular circle of the straight circular flexible hinge, represents the angle between the line connecting the straight circular micro-line segment to the circle center O1 and the y1 axis of the plane rectangular coordinate system O1-y1z1, wherein the straight circular micro-line segment means that any segment of the straight circular flexible hinge annular circle is divided into countless equal parts;

[0029] and are two different expressions of the diameter of the elliptical micro-segment, and there are

[0030] ;

[0031] in, represents the shortest diameter of the elliptical flexible hinge, are the lengths of the major axis and minor axis of the elliptical flexible hinge ring cutting the ellipse, is an intermediate variable, and ; It 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 elliptical flexible hinge ring into countless equal parts, any segment of which is an elliptical micro-segment.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The minimally invasive surgical clamp of the present invention can control the rack core to move back and forth in the clamp housing by driving the transmission rod forward and backward with external force, thereby pushing the upper clamp surface to open and close synchronously. The movement and force provided by the rack and pinion transmission in the minimally invasive surgical clamp are very smooth and do not change with the change of the opening and closing stroke, and can provide a stable clamping force. The present invention is based on a designed elastomer, including a straight circular flexible hinge and an elliptical flexible hinge and the optical fiber inside thereof, which can measure the contact force of the front end of the clamp, the pressure on the clamp surface, and the lateral force on the clamp surface during the operation, thereby improving the accuracy of the operation and reducing the risk of the operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 1 is a schematic diagram of the assembly of the minimally invasive surgical clamp according to an embodiment of the present invention.

[0035] Figure 2 2 is a schematic diagram of an exploded view of the minimally invasive surgical clamp according to an embodiment of the present invention.

[0036] Figure 3 It is a schematic diagram of the internal structure of the lower clamping surface according to an embodiment of the present invention.

[0037] Figure 4 Schematic diagrams of an elliptical flexible hinge (a) and a straight circular flexible hinge (b) according to an embodiment of the present invention.

[0038] Figure 5 Schematic diagram of the optical fiber arrangement of the minimally invasive surgical clamp according to an embodiment of the present invention; (a) is the front-end viewing angle of the clamp fixing portion, and (b) is the rear-end viewing angle of the clamp fixing portion.

[0039] Figure 6 Schematic diagram of the rack and pinion transmission mechanism according to an embodiment of the present invention.

[0040] Figure 7 Detailed structural schematic diagram of the deformation analysis of the straight circular flexible hinge of the lower clamping surface described in an embodiment of the present invention when subjected to lateral force and pressure; (a) is a schematic diagram of the longitudinal section of the straight circular flexible hinge along the axial direction and perpendicular to the lower clamping surface, (b) is a schematic diagram of the cross-section of the straight circular flexible hinge, and (c) is a dimensional diagram of the straight circular flexible hinge in the O1-y1z1 coordinate system.

[0041] Figure 8 Schematic diagram of the deformation of the straight circular flexible hinge with a lower clamping surface according to an embodiment of the present invention when subjected to a lateral force.

[0042] Figure 9 Schematic diagram of the deformation of the lower clamping surface straight circular flexible hinge when subjected to pressure according to an embodiment of the present invention.

[0043] Figure 10 This is a detailed structural diagram of the deformation analysis of the elliptical flexible hinge of the lower clamping surface described in an embodiment of the present invention when subjected to contact force.

[0044] Reference numerals: 100 - Minimally invasive surgical clamp, 10 - Contact head, 20 - Clamp fixing portion, 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 - First pin shaft outer hole, 29 - Straight notch, 30 - Upper clamping surface, 31 - Clamping surface, 32 - Gear, 33 - First pin shaft inner hole, 40 - Rack core, 41 - Second pin shaft inner hole, 50 - Tool channel, 60 - First pin shaft, 70 - Second pin shaft, 80 - Transmission rod. 1 - First optical fiber fixing front hole, 2 - Second optical fiber fixing front hole, 3 - Third optical fiber fixing front hole, 4 - First optical fiber fixing rear hole, 5 - Second optical fiber fixing rear hole, 6 - Third optical fiber fixing rear hole. DETAILED DESCRIPTION

[0045] The following is a detailed description of an embodiment of the present invention. This embodiment is based on the technical solution of the present invention, provides a detailed implementation method and a specific operation process, and further explains the technical solution of the present invention.

[0046] Example 1

[0047] This embodiment provides a minimally invasive surgical clamp 100, which is cylindrical in shape. Figure 1-2 As shown, it includes: a contact head 10, a clamp fixing part 20, an upper clamping surface 30, a rack core 40, a tool cavity 50, a first pin shaft 60, a second pin shaft 70 and a transmission rod 80.

[0048] The contact head 10 is in the shape of a quarter sphere, with a cylinder designed on the rear end section for nesting with the elliptical flexible hinge 27 . A hole is dug in the center of the cylinder to serve as a front fixing hole for the third optical fiber 22 .

[0049] The front end of the clamp fixing portion 20 is semi-cylindrical, and the cross section along the axial direction forms a lower clamping surface 24 with serrations.

[0050] The rear end of the lower clamping surface 24 is formed into a straight circular flexible hinge 25 by cutting a semicircular portion. Figure 3 and Figure 4 (b)

[0051] The rear end of the clamp fixing portion 20 is a tubular clamp housing 26 .

[0052] The upper jaw 30 has serrations on its front end, on a clamping surface 31 opposite the lower jaw, and a gear 32 at its rear end. A first pin inner hole 33 is provided at the center of the gear 32. A first pin 60 passes through the first pin inner hole 33 and is connected at both ends to a first pin outer hole 28 provided on the clamp housing 26, thereby securing the upper jaw 30 to the clamp housing 26 and allowing rotation. Furthermore, a notch is provided in the clamp housing 26 at the location where the upper jaw 30 is mounted, allowing the upper jaw 30 to extend out of the clamp housing 26 and open and close with the lower jaw 24 of the clamp fixing portion 20.

[0053] like Figure 1 、 2 As shown in Figures 6 and 7, the rack core 40 is mounted within the clamp housing 26. It is rectangular in shape, with straight teeth on only one side for meshing with the gear 32 on the upper clamping surface 30. A second pin hole 41 is provided in the center of the rack core 40, which is connected to the straight slot 29 in the clamp housing 26 via a second pin 70. A hole is provided at the lower end of the rack core 40 for securely connecting the rack core 40 to the transmission rod 80.

[0054] The transmission rod 80 is driven by an external force to move forward and backward. The first optical fiber 23 and the second optical fiber 21 are arranged parallel and symmetrically along the axial direction in the lower clamping surface 24 and are side by side close to the lower clamping surface 24, so as to measure the force condition of the lower clamping surface 24 in the axial vertical plane according to the wavelength drift.

[0055] like Figure 3 and Figure 4As shown in Figure 2 (a), an elliptical flexible hinge 27 is axially disposed within the clamping portion 20. This elliptical flexible hinge 27, formed by cutting a portion of an ellipse from a cylinder, passes through the top of the clamping portion 20 and is fixedly connected to the contact head 10. A third optical fiber 22 is axially disposed within the elliptical flexible hinge 27 to measure the axial force on the contact head 10 based on wavelength shift.

[0056] Specifically, a through-hole is axially disposed within the clamping portion 20, with a diameter greater than that of the elliptical flexible hinge 27. The elliptical flexible hinge 27 is coaxially disposed within 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 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 secured to the contact head 10, and the other end is secured to the rear end of the through-hole within the clamping portion 20. This through-hole arrangement prevents inaccurate measurements caused by the influence of the peripheral clamping portion 20 when the third optical fiber 22 is used to measure axial force.

[0057] The tool cavity 50 is shaped like the tubular clamp housing 26 and is sleeved on the end of the clamp housing 26. The tool cavity 50 is partitioned to separate the transmission rod 80 and the optical fiber channel to prevent the optical fiber from breaking due to the movement of the transmission rod 80.

[0058] like Figure 3 and Figure 5 As shown, the three optical fibers of the present invention are each provided with a corresponding grating, specifically a fiber Bragg grating. A first fiber fixing front hole 1 and a second fiber fixing front hole 2 are provided at the front end of the clamp fixing portion 20, from left to right. A third fiber fixing front hole 3 is located at the front end of an elliptical flexible hinge 27. A first fiber fixing rear hole 4 is located at the rear end of the clamp fixing portion 20, with a second fiber fixing rear hole 5 symmetrically located opposite it. A third fiber fixing rear hole 6 is located at the end of the elliptical flexible hinge 27. Both ends of the three optical fibers are secured to the corresponding fiber fixing holes using UV glue, ensuring that all three fibers are in a taut, suspended state and arranged in parallel and symmetrical fashion.

[0059] 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 using a 3D printer.

[0060] Example 2

[0061] This embodiment provides a three-dimensional force measurement method for the minimally invasive surgical clamp described in Example 1. The method uses the intersection O of the central axis of the clamp fixing portion 20 and the front end surface of the right circular flexible hinge 25 as the origin, the direction along the central axis toward the rear end as the positive z-axis, and the direction perpendicular to the top surface of the lower clamping surface as the positive y-axis. The right-hand rule is used to establish a spatial rectangular coordinate system O-xyz. The method includes:

[0062] When the minimally invasive surgical clamp is subjected to a force F along the clamp axis at the contact head 10 z When the wavelength of the third optical fiber 22 in the elliptical flexible hinge 27 shifts ;

[0063] 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 When the wavelength shifts of the first optical fiber 23 and the second optical fiber 21 in the straight circular flexible hinge 25 are 、 ;

[0064] Based on the wavelength drift of the first, second, and third optical fibers, the force applied to the minimally invasive surgical clamp is calculated:

[0065] ;

[0066] Where, is the initial center wavelength of the first, second and third optical fibers, is the effective elastic-optical coefficient, They are the thermo-optical coefficient and expansion coefficient of the optical fiber material, is the hanging length of the first, second and third optical fibers; is the lateral force on the lower clamping surface 24, i.e., the force in the x-axis direction; is the pressure on the lower clamping surface 24, that is, the force acting in the y-axis direction; The contact head 10 is subjected to an axial force, that is, a force acting along the axial direction of the clamp; is the temperature change value; It represents the Young's modulus of elasticity of the material; They represent the straight circular flexible hinge 25 at The structural geometric coefficient in the direction, that is, The equivalent expression of the integral formula in the derivation of the formula for directional force is as follows:

[0067] ;

[0068] ;

[0069] ;

[0070] Principle analysis:

[0071] During the use of the minimally invasive surgical clamp of the present invention, the contact force F exerted on the contact head 10 can be calculated by converting the grating center wavelength drift of the three optical fibers. z , the pressure F perpendicular to the lower clamping surface 24 yand the lateral force F parallel to the lower clamping surface 24 x .

[0072] When the front contact head 10 of the surgical clamp is subjected to the contact force F z When the contact force is applied, the elliptical flexible hinge 27 connected to the contact head 10 undergoes approximately linear deformation. By analyzing the mechanical model of the elliptical flexible hinge 27, the relationship between the grating center wavelength shift of the third optical fiber 22 and the contact force is obtained. Because there is sufficient clearance between the elliptical flexible hinge 27 and the lower clamping surface 24, the center wavelengths of the first optical fiber 23 and the second optical fiber 21 do not shift.

[0073] When the lower jaw surface 24 of the surgical clamp is subjected to pressure F y and lateral force F x When the pressure F y When acting on the lower clamping surface 24, the two optical fibers will produce deformations of equal size and direction, and the grating center wavelengths of the first optical fiber 23 and the second optical fiber 21 will drift accordingly. The pressure F is measured by measuring the drift of the grating center wavelengths of the first optical fiber 23 and the second optical fiber 21. y When the lateral force F x When acting on the lower clamping surface 24, the two optical fibers undergo deformation of equal magnitude and opposite direction, and the grating center wavelengths of the first optical fiber 23 and the second optical fiber 21 drift accordingly. By differentially processing the drift amounts of the grating center wavelengths of the first optical fiber 23 and the second optical fiber 21, the lateral force F is measured. x .

[0074] The minimally invasive surgical clamp measures the lateral force F x , pressure F y and contact force F z The specific working principle is as follows:

[0075] refer to Figure 7 As shown, Figure 7 In (a), area I represents the lower clamping surface 24 with serrations, area II is the location of the straight circular flexible hinge 25, and area III represents the remaining part of the lower clamping surface 24 and is connected to the rear end clamp housing 26. Figure 7 (b) is a schematic cross-sectional view of a straight circular flexible hinge 25. The cross-section consists of a large semicircle with a rectangle cut out and a small semicircle cut out. h represents the height of the rectangle, and 2b represents the length of the rectangle. 、 and Represent the centroid axes of the large semicircle, small semicircle and rectangle respectively, 、 and Respectively represent the centroid axis of the small semicircle, rectangle and large semicircle to Axis distance. Figure 7 (c) shows the dimension diagram of the straight circular flexible hinge 25 in the O1-y1z1 coordinate system. x and pressure F y When , the straight circular flexible hinge 25 will be deformed, and the diameter of the straight circular micro-segment in the straight circular flexible hinge 25 along the axial direction can be expressed as:

[0076] ;

[0077] Where m is the distance from the top surface of the straight circular flexible hinge 25 to the center axis of the lower clamping surface, is the distance from the bottom end of the lower clamping surface 24 to the center axis of the lower clamping surface; z represents the independent variable along the z1 axis and is used as the integral variable in the formula; is the radius of the annular circle of the straight circular flexible hinge 25, It represents the angle between the line connecting the straight circle micro-line segment to the circle center O1 and the y1 axis of the plane rectangular coordinate system O1-y1z1, and the range is The straight circle micro segment refers to: dividing the straight circle flexible hinge ring into countless equal parts, any of which is a straight circle micro segment, that is, Figure 7 (c) dz1, where ρ1 is the distance from the straight circular micro-segment dz1 to the y1 axis.

[0078] According to the second law of Cartesian, the deformation 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 is It can be expressed as:

[0079] ;

[0080] in is the strain energy of the flexure, Represents the three-dimensional force applied to the surgical clamp.

[0081] For the lateral force applied to the lower jaw surface 24 of the clamp , which produces a displacement It can be expressed as:

[0082] ;

[0083] Among them, Substitute, It can be further expressed as:

[0084] ;

[0085] refer to Figure 8 , when the lateral force When acting on the lower clamping surface 24, the first optical fiber 23 and the second optical fiber 21 are compressed and stretched respectively. and Respectively and The midpoint of , where CD represents the distance between the first optical fiber 23 and the second optical fiber 21 when no deformation occurs, Indicates function The distance between the first optical fiber 23 and the second optical fiber 21. In the case of small deformation, the center line Rotation angle Approximate The deformation of these two optical fibers is called and , which can be expressed as:

[0086] ;

[0087] For the pressure applied on the lower jaw surface 24 , which produces a displacement It can be expressed as:

[0088] ;

[0089] Among them, Substitute, It can be further expressed as:

[0090] ;

[0091] refer to Figure 9 As shown, Indicates the length of the optical fiber when the lower clamping surface 24 is not deformed. Indicates the length of the optical fiber after the lower clamping surface 24 is deformed. Indicates from Towards a straight line Make the intersection of the perpendicular lines, Indicates from Towards a straight line Make the intersection of the perpendicular lines, Indicates the center 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 stretched at the same time and due to their symmetry, their deformation is the same. Under the action of pressure, the deformation of the two optical fibers is called and , which can be expressed as:

[0092] ;

[0093] refer to Figure 10As shown, when the front end contact 10 is subjected to the axial contact force When the force is applied, 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:

[0094] ;

[0095] in, represents the angle between the line connecting the elliptical micro-segment to the circle center O3 and the y3-axis of the plane rectangular coordinate system O3-y3z3; is an intermediate variable, and , are the lengths of the major and minor axes of the ellipse, is the diameter of the hollow hole in the elliptical hinge, represents the shortest diameter of the elliptical flexible hinge 27, and These are two different expressions of the diameter of an elliptical micro-segment. Figure 10 dz2 in the figure is the elliptical micro segment in this embodiment, where ρ2 is the distance from the elliptical micro segment dz2 to the y3 axis.

[0096] Axial deformation It can be expressed as:

[0097] ;

[0098] in, represents Young's elastic modulus, represents the moment of inertia about the z-axis.

[0099] It can be further expressed as:

[0100] ;

[0101] 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 similar to the deformation of the elliptical flexible hinge 27 .

[0102] According to the principle of fiber optic sensing, the axial deformation of the fiber Bragg grating is linearly related to the temperature and central wavelength of the fiber. Therefore, the space vector force and temperature can be simplified into a linear system, which can be expressed as:

[0103] ;

[0104] The output matrix Each element of is composed of the corresponding wavelength shift of each fiber, called . The sensitivity matrix representing force and temperature, the relationship between the fiber center wavelength shift and the applied force and temperature can be expressed as:

[0105] ;

[0106] in, is the hanging length of the three optical fibers, which is 15 mm. Indicates the initial center wavelength values ​​of the first, second, and third optical fibers used. represents the temperature increment, is the effective elastic-optical coefficient, which is only related to the material of the optical fiber. They are the thermo-optical coefficient and expansion coefficient of the optical fiber material.

[0107] By subtracting the first and second equations in the above formula, and combining the measurement principle of fiber Bragg grating, the lateral force F can be calculated. x , through the known F x And the additional reference grating can get the pressure F y Similarly, the axial force F can be obtained from the third formula and the reference grating z The initial center wavelength values ​​of the three optical fibers can be simplified to , in summary, the measurement matrix of force and temperature can be determined as follows:

[0108] ;

[0109] The above embodiments are preferred embodiments of the present application. Ordinary technicians in this field can also make various changes or improvements on this basis. Without departing from the overall concept of the present application, these changes or improvements should fall within the scope of protection required by the present application.

Claims

1. A minimally invasive surgical clamp, characterized in that: The whole is cylindrical and comprises: a contact head (10), a clamp fixing portion (20), an upper clamping surface (30), a rack core (40) and a transmission rod (80); The front end of the clamp fixing portion (20) is semi-cylindrical, and the cross section along the axial direction 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 portion (20) is a tubular clamp housing (26), and the upper clamping surface (30) and the rack core (40) are both installed in the clamp housing (26); an elliptical flexible hinge (27) is provided in the interior of the clamp fixing portion (20) along the axial direction, and the elliptical flexible hinge (27) passes through the top end of the clamp fixing portion (20) and is fixedly connected to the contact head (10); The elliptical flexible hinge (27) is formed by cutting a portion of an ellipse on a cylinder, and the straight circular flexible hinge (25) is formed by cutting a portion of a semicircle on a cylinder; The transmission rod (80) is fixedly connected to the rack core (40), and the rear end of the upper clamping surface (30) is matched with the rack core (40) by providing a gear (32); the transmission rod (80) is driven by an external force to move forward and backward, driving the rack core (40) to move forward and backward, 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 arranged axially inside the elliptical flexible hinge (27) and is used to measure the force applied to the contact head (10) along the axial direction based on wavelength drift; A first optical fiber (23) and a second optical fiber (21) are arranged parallel and symmetrically along the axial direction inside the lower clamping surface (24), and are used to measure the force applied to the lower clamping surface (24) in an axial vertical plane based on wavelength drift.

2. The minimally invasive surgical clamp according to claim 1, characterized in that: A through hole is axially arranged inside the clamp fixing portion (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 in 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).

3. The minimally invasive surgical clamp according to claim 1, characterized in that: The upper clamping surface (30) is provided with serrations at the portion in contact with the lower clamping surface (24).

4. The minimally invasive surgical clamp according to claim 1, characterized in that: A first pin shaft 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 shaft (60) is provided passing through the first pin shaft inner hole (33), and both ends are connected to the first pin shaft outer hole (28) on the clamp housing (26).

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

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