阅读说明：本技术 一种光纤矢量声磁复合传感器 (Optical fiber vector acoustic-magnetic composite sensor ) 是由 曹亮 冯丹平 赵晨 杨明明 高守勇 张帅 万俊 伍宏亮 刘健 于 2020-05-19 设计创作，主要内容包括：本发明公开了一种光纤矢量声磁复合传感器,目的是解决现有传感器不能同点复合探测矢量声场、磁场的问题。本发明由球形安装外壳、三维光纤矢量水听器和三维光纤矢量磁场传感器组成。水听器和传感器一体封装于球形安装外壳内。传感器由金属立方块、6根圆柱体支柱、6个磁致伸缩圆筒、6个圆筒固定螺丝、6个磁场迈克尔逊干涉仪组成；6个磁场迈克尔逊干涉仪的磁场传感臂光纤和参考臂光纤分别缠绕在传感器6个方向的轴上。水听器由空心质量块、6个弹性支柱和3个声场迈克尔逊干涉仪组成,3个声场迈克尔逊干涉仪的6根声场传感臂光纤分别缠绕在水听器6个方向的轴上。采用本发明可同点复合探测三维矢量声场和磁场,且有无源、非接触式特点。(The invention discloses an optical fiber vector acoustic-magnetic composite sensor, which aims to solve the problem that the traditional sensor can not detect the sound field and the magnetic field of a vector in a composite mode at the same point. The invention consists of a spherical mounting shell, a three-dimensional optical fiber vector hydrophone and a three-dimensional optical fiber vector magnetic field sensor. The hydrophone and the sensor are integrally packaged in the spherical mounting shell. The sensor consists of a metal cube, 6 cylindrical pillars, 6 magnetostrictive cylinders, 6 cylinder fixing screws and 6 magnetic field Michelson interferometers; the magnetic field sensing arm optical fiber and the reference arm optical fiber of the 6 magnetic field Michelson interferometers are respectively wound on the axes of the 6 directions of the sensor. The hydrophone comprises hollow mass block, 6 elastic support columns and 3 sound field Michelson interferometers, and 6 sound field sensing arm optical fibers of the 3 sound field Michelson interferometers are respectively wound on the axis of the hydrophone in 6 directions. The invention can detect three-dimensional vector sound field and magnetic field in a same point composite way and has the characteristics of passive and non-contact.)

1. An optical fiber vector acoustic-magnetic composite sensor is characterized by comprising a spherical mounting shell (5-1), a three-dimensional optical fiber vector hydrophone (5-2) and a three-dimensional optical fiber vector magnetic field sensor (5-3); the three-dimensional optical fiber vector hydrophone (5-2) and the three-dimensional optical fiber vector magnetic field sensor (5-3) are integrally packaged in the spherical mounting shell (5-1);

the three-dimensional optical fiber vector magnetic field sensor (5-3) consists of 1 metal cube (5-3-1), 6 cylinder support columns (5-3-2), 6 magnetostrictive cylinders (5-3-3), 6 cylinder fixing screws (5-3-4) and 6 magnetic field Michelson interferometers (5-3-5); 6 cylinder support columns (5-3-2) are fixed on 6 surfaces of the metal cube (5-3-1) through threads, and 6 magnetostrictive cylinders (5-3-3) are respectively coaxially sleeved on the outer sides of the 6 cylinder support columns (5-3-2) and are respectively fixed on the 6 cylinder support columns (5-3-2) through cylinder fixing screws (5-3-4); 6 magnetostrictive cylinders (5-3-3) are respectively sleeved on 6 cylinder pillars (5-3-2) to form a three-dimensional optical fiber vector magnetic field sensor (5-3), and 6 magnetic field Michelson interferometers (5-3-5) are respectively arranged on an x + axis, an x-axis, a y + axis, a y-axis, a z + axis and a z-axis of the three-dimensional optical fiber vector magnetic field sensor (5-3) in a Cartesian coordinate system;

the metal cubic block (5-3-1) is made of non-magnetic steel materials and is in a cubic shape, and the side length is d 1; a first inner screw hole (5-3-1-1) is dug in the center of each of 6 surfaces of the metal cube (5-3-1);

the cylinder supporting columns (5-3-2) are made of non-magnetic steel materials, 6 cylinder supporting columns (5-3-2) are fixed on 6 surfaces of a metal cubic block (5-3-1), the 6 cylinder supporting columns (5-3-2) are completely identical and are composed of 2 sections of cylinders with different diameters, namely a thick cylinder (5-3-2-1) and a thin cylinder (5-3-2-2), the total length of the cylinder supporting columns (5-3-2) is L1, one end of the thick cylinder (5-3-2-1) is fixed on one surface of the metal cubic block (5-3-1), the central axis of the cylinder supporting columns (5-3-2) is perpendicular to the surface of the metal cubic block (5-3-1), the length of the thick cylinder (5-3-2-1) is L d1, the diameter of the thick cylinder (5-3-2-1) is 34 d 3-2-1), the diameter of the thin cylinder (5-3-2-2) is 3957 d 3-1, the thin cylinder (5-3-2-2) is coaxially connected with the thick cylinder (5-3-1), and the end face of the thin cylinder (395-3-2-2) is provided with a telescopic cylinder (5-3-2) and an inner side hole (3-2) far away from the inner side of the thick cylinder (3-2);

the magnetostrictive cylinder (5-3-3) is a uncovered cylinder made of magnetostrictive material, with a length of L3, an outer diameter of d1, and an inner diameter of d 3;

the cylinder fixing screw (5-3-4) is composed of a cylinder (5-3-4-1) and a second outer screw (5-3-4-2), wherein the height of the cylinder (5-3-4-1) is L4, one end of the cylinder (5-3-4-1) is connected with the second outer screw (5-3-4-2), and the other end is provided with a third inner screw hole (5-3-4-3), after the magnetostrictive cylinder (5-3-3) is sleeved on the cylinder support (5-3-2), the second outer screw (5-3-4-2) of the cylinder fixing screw (5-3-4) is inserted into the second inner screw hole (5-3-2-3) of the cylinder support (5-3-2), so that the magnetostrictive cylinder (5-3-3) is fixed on the cylinder support (5-3-2), and the cylinder fixing screw (5-3-4) axially limits the deformation of the magnetostrictive cylinder (5-3-3; the third inner screw (5-3-4) is used for fixing the magnetic sensing unit (5-3-4) and the acoustic sensing unit (5-3-2);

the magnetic field Michelson interferometer (5-3-5) consists of a first 3dB optical fiber coupler (5-3-5-1), a magnetic field sensing arm optical fiber (5-3-5-2) and a magnetic field reference arm optical fiber (5-3-5-3), wherein the magnetic field sensing arm optical fiber (5-3-5-2) and the magnetic field reference arm optical fiber (5-3-5-3) are both anti-bending single-mode optical fibers, the initial length is L0, one ends of the magnetic field sensing arm optical fiber (5-3-5-2-1) and the magnetic field reference arm optical fiber (5-3-5-3) are respectively plated with an optical reflection film (5-3-5-2-1), the other ends of the magnetic field sensing arm optical fiber (5-3-5-1-2) and the first port (5-3-5-1-2) of the first 3dB optical fiber coupler (5-3-5-1) are respectively welded by an optical fiber welding machine with a first port (5-3-5-1-3), each magnetic field sensing arm optical fiber (5-2) is wound on the outer side surface of a magnetostrictive cylinder (5-3-3), and the outer side surface of the magnetic field sensing arm optical fiber (5-3-5-3 cylinder, the optical fiber is respectively fixed on the outer surface of a magnetic field sensing arm, and the magnetic field sensing arm, the thick axis of the thick magnetic field sensing arm, and the thick axis of the thick magnetic field sensing arm;

the three-dimensional optical fiber vector hydrophone (5-2) consists of a hollow mass block (5-2-1), 6 elastic struts (5-2-2) and 3 sound field Michelson interferometers (5-2-3); 6 elastic struts (5-2-2) are bonded on 6 surfaces of the hollow mass block (5-2-1) by glue, and the axes of the elastic struts (5-2-2) are vertical to the surface connected with the hollow mass block (5-2-1);

the hollow mass block (5-2-1) is a cube die made of a non-magnetic steel material, the side length is d6, the centers of 6 top surfaces of the hollow mass block (5-2-1) are respectively provided with 1 square through hole (5-2-1-4), the sides of the square through holes (5-2-1-4) are respectively parallel to the sides of the top surface of the hollow mass block (5-2-1), and the side length of the square through holes (5-2-1-4) is d 7; the 6 top surfaces of the hollow mass block (5-2-1) are respectively provided with a circular groove (5-2-1-3), the outer diameter of the circular groove (5-2-1-3) is d9, and the square through hole (5-2-1-4) is positioned at the center of the circular groove (5-2-1-3);

the hollow mass block (5-2-1) consists of a first mass block (5-2-1-1) and a second mass block (5-2-1-2), the first mass block (5-2-1-1) and the second mass block (5-2-1-2) are symmetrical about a xoz plane, and a metal cubic block (5-3-1) is arranged at the hollow position of the hollow mass block (5-2-1);

the cross section of the first mass block (5-2-1-1) and the AA is provided with four first square intersecting surfaces (5-2-1-1-1), namely EE1E3E2, FF2F3F1, GG1G3G2 and HH2H3H1, and the side length of each of the four first square intersecting surfaces (5-2-1-1-1) is d 8; E3F3G3H3 four points enclose a first square through hole (5-2-1-1-2), the side length of the first square through hole (5-2-1-1-2) is d7, and the depth is d 12; first rectangular grooves (5-2-1-1-3) are formed between every two of the four first square intersecting surfaces (5-2-1-1-1), the depth of each first rectangular groove (5-2-1-1-3) is d10, the length is d8, and the width is d 7;

the second mass block (5-2-1-2) and the AA section also have four second square intersecting surfaces (5-2-1-2-1), namely E 'E1' E3 'E2', F 'F2' F3 'F1', G 'G1' G3 'G2', H 'H2' H3 'H1', and the four second square intersecting surfaces (5-2-1-2-1) have the same side length as d 8; e3 'F3' G3 'H3' four points enclose a second square through hole (5-2-1-2-2), wherein the side length of the second square through hole (5-2-1-2-2) is d7, and the depth is d 12; a second rectangular groove (5-2-1-2-3) is formed between every two of the four second square intersecting surfaces (5-2-1-2-1), the depth of the second rectangular groove (5-2-1-2-3) is d10, the length of the second rectangular groove is d8, and the width of the second rectangular groove is d 7;

the cylindrical pillars (5-3-2) in the y + axis direction of the three-dimensional optical fiber vector magnetic field sensor (5-3) are placed into the first square through hole (5-2-1-1-2) from the AA direction of the first mass block (5-2-1-1) to the section, and 4 cylindrical pillars (5-3-2) in the x + axis, z + axis, x-axis and z-axis directions are placed into the first rectangular groove (5-2-1-1-3); the cylindrical pillar (5-3-2) in the y-axis direction penetrates out from the AA direction of the second mass block (5-2-1-2) to the cross section along the second square through hole (5-2-1-2-2); the four second square intersecting surfaces (5-2-1-2-1) of the second mass block (5-2-1-2) and the four square intersecting surfaces (5-2-1-1-1) of the first mass block (5-2-1-1) are bonded into a hollow mass block (5-2-1) through glue;

the elastic support (5-2-2) consists of an elastic cylinder (5-2-2-1) and a metal circular plate (5-2-2-2), wherein the elastic cylinder (5-2-2-1) is made of an elastic body material and has the length of L5, the wall of the elastic cylinder (5-2-2-1) close to one end is provided with an optical fiber through hole (5-2-2-1-1), one end of the elastic cylinder (5-2-2-1) is bonded with the metal circular plate (5-2-2-2) by glue, the thickness of the metal circular plate (5-2-2-2) is h5, and the center of the metal circular plate (5-2-2-2) is provided with a metal circular plate through hole (5-2-2-3);

a first input port optical fiber (5-3-5-1-1) and a first output port optical fiber (5-3-5-1-4) of a first 3dB optical fiber coupler (5-3-5-1) penetrate out of an optical fiber through hole (5-2-2-1-1), an elastic support column (5-2-2) is coaxially sleeved on the outer side of a cylindrical support column (5-3-2) from one end far away from a metal circular plate (5-2-2-2), and the metal circular plate through hole (5-2-2-3) is bonded on a cylinder fixing screw (5-3-4) through glue;

the acoustic field Michelson interferometer (5-2-3) consists of a second 3dB optical fiber coupler (5-2-3-1) and 2 acoustic field sensing arm optical fibers (5-2-3-2), wherein the 2 acoustic field sensing arm optical fibers (5-2-3-2) are anti-bending single-mode optical fibers, the initial lengths are L6, one ends of the optical field sensing arm optical fibers are respectively plated with an optical reflection film (5-3-5-2-1), and the other ends of the acoustic field sensing arm optical fibers are respectively welded with a third port (5-2-3-1-2) and a fourth port (5-2-3-1-3) of the second 3dB optical fiber coupler (5-2-3-1-3) by an optical fiber welding machine;

6 sound field sensing arm optical fibers (5-2-3-2) of the 3 sound field Michelson interferometers are respectively wound on the outer side surfaces of 6 elastic support columns (5-2-2) in the directions of an x + axis, an x-axis, a y + axis, a y-axis, a z + axis and a z-axis;

the spherical mounting shell (5-1) is made of nonmagnetic steel materials, the inner diameter is d11, d11 meets the requirement of containing the integrally packaged three-dimensional optical fiber vector hydrophone (5-2) and the three-dimensional optical fiber vector magnetic field sensor (5-3), the thickness of the containing shell is h6, and h6 meets the requirement of enabling the optical fiber vector acoustic-magnetic composite sensor to have zero buoyancy in a working medium; the central point of the spherical mounting shell (5-1) is the origin of a Cartesian coordinate system, and fourth inner screw holes (5-1-1) are respectively formed at 6 intersection points of three coordinate axes of the spherical mounting shell (5-1) and the Cartesian coordinate system; a shell through hole (5-1-2) is formed in the vicinity of a z + point of a spherical mounting shell (5-1), the shell through hole (5-1-2) is used for enabling a first input port optical fiber (5-3-5-1-1) and a first output port optical fiber (5-3-5-1-4) of 6 first 3dB optical fiber couplers (5-3-5-1-1) of a magnetic field Michelson interferometer and a second input port optical fiber (5-2-3-1-1) and a second output port optical fiber (5-2-3-1-4) of 3 second 3dB optical fiber couplers (5-2-3-1-1) of an acoustic field Michelson interferometer to penetrate out of the spherical mounting shell (5-1) from the shell through hole (5-1-2); the three-dimensional optical fiber vector hydrophone (5-2) and the three-dimensional optical fiber vector magnetic field sensor (5-3) are arranged in the spherical mounting shell (5-1), the fourth inner screw hole (5-1-1) and the third inner screw hole (5-3-4-3) are connected through screws, and the three-dimensional optical fiber vector magnetic field sensor (5-3) and the spherical mounting shell (5-1) are fixed.

2. A fiber vector acousto-magnetic composite sensor according to claim 1 characterized in that the side length d1 of the metal cube (5-3-1) satisfies the condition that d1 is 5mm 50 mm; the diameter d2 of the first inner screw hole (5-3-1-1) meets d2< d1, and the depth h1 of the first inner screw hole (5-3-1-1) meets h1< d 1/2.

3. The fiber vector acousto-magnetic composite sensor according to claim 1 is characterized in that the 6 cylinder struts (5-3-2) are respectively screwed into the first inner screw holes (5-3-1-1) through the first outer screws (5-3-2-4) and fixed on 6 faces of the metal cube block (5-3-1), the total length L1 of the cylinder strut (5-3-2) satisfies 2d1 ≦ L1 ≦ 200mm, one end of the thick cylinder (5-3-2-1) fixes the cylinder strut (5-3-2) on one face of the metal cube block (5-3-1) through the first outer screws (5-3-2-4) and the first inner screw holes (5-3-1-1), the length 58L 6 of the thick cylinder (5-3-2-1) satisfies 58L 9 ≦ 2< 22< 8, the length 68692 ≦ 3-632-2) satisfies the diameter 6863-462, the diameter of the thin cylinder strut (5-3-2) satisfies the diameter of 3946 < 3-1, the diameter of the thin cylinder strut (5-3-2) satisfies the diameter of < 465-3-19 < 19, the diameter of the second inner screw holes (3-1).

4. An optical fiber vector acousto-magnetic composite sensor as claimed in claim 1, characterized in that the height L4 of the cylinder (5-3-4-1) of the cylinder fixing screw (5-3-4) satisfies 2mm ≤ L4 ≤ 20mm, diameter ═ d1, diameter ═ d3 and height ═ h2 of the second outer screw (5-3-4-2), diameter d5 of the third inner screw hole (5-3-4-3), d5< d1, depth h3 and h3< L4.

5. An optical fiber vector acousto-magnetic composite sensor according to claim 1, wherein each of the magnetic field sensing arm optical fibers (5-3-5-2) is wound around the outer side of the magnetostrictive cylinder (5-3-3) in a clockwise direction from the end of the magnetostrictive cylinder (5-3-3) close to the cylinder fixing screw (5-3-4) as a starting point from the end coated with the optical reflection film (5-3-5-2-1) as a starting point, the magnetic field reference arm optical fibers (5-3-5-3) are wound around the outer side of the thick cylinder (5-3-2-1) close to the magnetostrictive cylinder (5-3-3) as a clockwise starting point from the end coated with the optical reflection film (5-3-5-2-1) as a starting point from the end of the thick cylinder (5-3-3) as a starting point, the magnetic field reference arm optical fibers (5-3-3) are wound around the outer side of the thick cylinder (5-3-2-1) in a clockwise direction from the end coated with the optical reflection film (5-3-2-1) as a starting point, the winding range of the optical field reference arm optical fiber (5-3-3) on the outer side of the thick cylinder (5-3-3) as a starting point, the initial winding range from the outer side of the thick cylinder (5-3-3) in a winding range from the cylinder (5-3-3) and the initial winding range from the initial winding distance of the initial winding range from the initial:

L0>n1*π*d1 (1)

n₀the refractive index of the core of the optical fiber (5-3-5-2) of the magnetic field sensing arm is expressed, k1 is delta V/T, the ratio of the change delta V of the volume V of the magnetostrictive cylinder (5-3-3) to the magnetic field intensity T causing the change is determined by the magnetostrictive characteristic of the material of the magnetostrictive cylinder (5-3-3), and when the magnetostrictive material is determined, k1 is a constant; λ represents the wavelength of the laser light incident into the magnetic field sensing arm fiber (5-3-5-2); m1 is the magnetic field sensing sensitivity.

6. An optical fiber vector acousto-magnetic composite sensor according to claim 1 characterized in that the side length d6 of the hollow mass (5-2-1) satisfies d1+10mm < d6<4 x d 1; the side length d7 of the square through hole (5-2-1-4) of the hollow mass block (5-2-1) meets d1+5mm < d7< d6, and the depth is d 6; the outer diameter d9 of the circular groove (5-2-1-3) on the 6 top surfaces of the hollow mass block (5-2-1) meets d9>1.42 x d7, the width is h4, the requirement that h4 is more than or equal to 0.5mm and less than or equal to 4mm is met, the depth is h7, and the requirement that h7 is more than or equal to 0.2mm and less than or equal to 2mm is met; the side length d8 of the square intersecting surface (5-2-1-1-1) of the first mass block (5-2-1-1) meets the requirement that d8 is (d6-d 7)/2; the side length of the first square through hole (5-2-1-1-2) is d7, and the depth d12 is d 6/2; the depth d10 of the rectangular groove (5-2-1-1-3) between the four square intersecting surfaces (5-2-1-1-1) is d 7/2.

7. The optical fiber vector acousto-magnetic composite sensor as claimed in claim 1, wherein the elastic cylinder (5-2-2-1) has an outer diameter d9, a wall thickness h4, a length L5 satisfying L5 > L1 + h7-d5/2, the diameter of an optical fiber through hole (5-2-2-1-1) on the elastic cylinder (5-2-2-1) satisfies 2 bending-resistant optical fibers, the diameter of the metal circular plate (5-2-2-2) satisfies d9, the thickness h5 satisfies h5< L1 + L4 + h 7-L5-d 5/2, and the diameter of a metal circular plate through hole (5-2-2-3) opened in the center of the metal circular plate (5-2-2-2) satisfies d 1.

8. The fiber vector acousto-magnetic composite sensor according to claim 1, wherein the acoustic field sensing arm fiber (5-2-3-2) is wound around the outer side of the elastic strut (5-2-2) clockwise from the end of the elastic strut (5-2-2) in the x + or y + or z + direction, which is coated with the optical reflection film (5-3-5-2-1), to the end of the hollow mass block (5-2-1), to the outer side of the elastic strut (5-2-2), the acoustic field sensing arm fiber (5-2-3-2) is wound around the outer side of the elastic strut (5-2-2) for n2 turns, the other acoustic field sensing arm fiber (5-2-3-2) is wound around the outer side of the elastic strut (5-2-2) for n2 turns in the same manner, the initial length L6 of the acoustic field sensing arm fiber (5-2-3-2) satisfies the formula (3), and n2 satisfies the formula (4):

L6>n2*π*d9 (3)

in the formula n_sThe refractive index of the core of the acoustic field sensing arm optical fiber (5-2-3-2) is shown, and lambda represents incident soundThe laser wavelength of the field sensing arm optical fiber (5-2-3-2), E and mu respectively represent the Young modulus and Poisson ratio of the elastic cylinder (5-2-2-1), and m represents the mass of the hollow mass block (5-2-1); m_aFor the purpose of the acoustic field sensing sensitivity,deltaa represents the change in the sound field acceleration,showing the phase change of light wave caused by the acceleration change of sound field.

9. A fiber vector acousto-magnetic composite sensor according to claim 1 characterised in that the spherical mounting housing (5-1) has an internal diameter d11, d11 satisfies both formula (5) and formula (6):

the shell thickness h6 is required to satisfy formula (7):

wherein m1 represents the weight of the acousto-magnetic composite sensing unit inside the spherical mounting shell (5-1) (. rho)_{Spherical shell}Represents the material density, rho, of the spherical mounting shell (5-1)_{Working medium}Represents the working medium density; the diameter of a fourth inner screw hole (5-1-1) on the spherical mounting shell (5-1) is d 5; the diameter d12 of the shell through hole (5-1-2) meets the requirements that a first input port optical fiber (5-3-5-1-1) and a first output port optical fiber (5-3-5-1-4) of 6 first 3dB optical fiber couplers (5-3-5-1-1) and a second input port optical fiber (5-2-3-1-1) and a second output port optical fiber (5-2-3-1-4) of 3 second 3dB optical fiber couplers (5-2-3-1-1) penetrate through the spherical mounting shell (5-1) from the shell through hole (5-1-2)And (6) discharging.

10. An optical fiber vector acousto-magnetic composite sensor according to claim 1, characterized in that the elastic cylinder (5-2-2-1) is made of elastomer material such as SEBS or TPE; SEBS refers to a linear triblock copolymer which takes polystyrene as a terminal segment and takes an ethylene-butylene copolymer obtained by hydrogenation of polybutadiene as a middle elastic block; TPE refers to a thermoplastic elastomer.

Technical Field

The invention relates to an optical fiber sensor, in particular to a sensor which can perform homopoint composite measurement on a vector sound field and a magnetic field based on optical fibers.

Background

With the development of the underwater target stealth technology, detection means based on the characteristics of a single target such as a sound field, a magnetic field and the like face more and more serious challenges, and the underwater target comprehensive physical field combined detection technology comes along.

The optical fiber sensor becomes a hot point of industrial attention due to the advantages of light and handy structure, low cost, easy large-scale array formation, strong environmental adaptability and the like.

Currently, the optical fiber sensing technology is mainly used for acoustic-magnetic detection, and the acoustic and magnetic measurements are mainly used. An optical fiber vector hydrophone (entitled "research progress of optical fiber vector hydrophone", national acoustics conference in 2006, mansion, 2006, pp.129-130) is reported by Humingming and the like, national defense science and technology university, and three optical fiber interferometers are adopted by the vector hydrophone to measure sound field vector information as optical fiber accelerometers. The Luwen Leili of Harbin engineering university designs a differential pressure type optical fiber vector hydrophone (Luwen Leili. differential pressure type optical fiber vector hydrophone element and testing technology [ D ]. Harbin: Harbin engineering university, 2009), and the sensor can only measure sound field vector information and can not measure magnetic field vector information at the same time. An optical fiber magnetic field sensor which takes a fiber grating Fabry-Perot cavity and a giant magnetostrictive material as a sensing element and adopts a neodymium iron boron permanent magnet to provide a bias magnetic field is designed in an optical fiber magnetic field sensor based on a giant magnetostrictive material (Mary et al, Zhengzhou university school newspaper (engineering edition), 2019, 40(6), pp.6-10) by Mary et al, China academy of sciences semiconductor institute. The sensor can measure magnetic field information but cannot measure sound field information. Chen dazzling et al designed a vector magnetic field sensor based on side-polished fiber surface plasmon resonance in the patent "a vector magnetic field sensor based on side-polished fiber surface plasmon resonance and its preparation and detection method" (patent application No. 201811600803.5). The sensor can measure magnetic field vector information, but cannot simultaneously measure sound field vector information.

At present, no sensor which is based on the optical fiber sensing technology and can simultaneously carry out same-point composite measurement on a vector sound field and a vector magnetic field exists in public reports.

Disclosure of Invention

The technical problem to be solved by the invention is as follows:

the optical fiber vector acoustic-magnetic composite sensor solves the problem that the existing optical fiber sensor can not detect the sound field and the magnetic field of the vector in a composite mode at different points.

In order to solve the technical problems, the invention adopts the technical scheme that:

the optical fiber vector acoustic-magnetic composite sensor consists of a spherical mounting shell, a three-dimensional optical fiber vector hydrophone and a three-dimensional optical fiber vector magnetic field sensor. The three-dimensional optical fiber vector hydrophone and the three-dimensional optical fiber vector magnetic field sensor are integrally packaged in the spherical mounting shell.

The three-dimensional optical fiber vector magnetic field sensor consists of 1 metal cube, 6 cylinder support columns, 6 magnetostrictive cylinders, 6 cylinder fixing screws and 6 magnetic field Michelson interferometers. The 6 cylinder pillars are fixed on 6 surfaces of the metal cube through threads, and the 6 magnetostrictive cylinders are respectively coaxially sleeved on the outer sides of the 6 cylinder pillars and are respectively fixed on the 6 cylinder pillars through cylinder fixing screws (the magnetostrictive cylinders deform under the action of a magnetic field, and the cylinder fixing screws limit the deformation of the magnetostrictive cylinders in the axial direction, so that the magnetostrictive cylinders can only deform in the radial direction). 6 magnetostrictive cylinders are respectively sleeved on the 6 cylinder pillars to form a three-dimensional optical fiber vector magnetic field sensor on an x + axis, an x-axis, a y + axis, a y-axis, a z + axis and a z-axis of a Cartesian coordinate system, and 6 magnetic field Michelson interferometers are respectively arranged on the x + axis, the x-axis, the y + axis, the y-axis, the z + axis and the z-axis of the three-dimensional optical fiber vector magnetic field sensor.

The metal cubic block is made of non-magnetic steel materials and is in a cubic shape, the side length is d1, and d1 is larger than or equal to 5mm and smaller than or equal to 50 mm. First inner screw holes are dug in the centers of 6 faces of the metal cubic blocks respectively, the diameter of each first inner screw hole is d2, d2 is less than d1, the depth is h1, and h1 is less than d 1/2.

The cylinder supporting columns are made of nonmagnetic steel materials, 6 cylinder supporting columns are fixed on 6 surfaces of a metal cubic block through first outer threads (the first outer threads are screwed into first inner threaded holes 5-3-1-1 to fix the cylinder supporting columns on the metal cubic block), 6 cylinder supporting columns are completely the same and are composed of 2 sections of cylinders with different diameters, namely, a thick cylinder and a thin cylinder, the total length of the cylinder supporting columns is L, 2d1 is not less than L1 and not more than 200mm, one end of the thick cylinder is connected with the first outer threads, the cylinder supporting columns are fixed on one surface of the metal cubic block through connection of the first outer threads and the first inner threaded holes, the central axes of the cylinder supporting columns are perpendicular to the surface of the metal cubic block, the length of the thick cylinder is L, the requirements are that L11/2 is not less than 6322 and not less than L, the diameter of the thin cylinder is d1. and is connected with the thick cylinder, the length of L, L is L-L, L is not less than L, the diameter of the d3, the diameter of the thin cylinder supporting columns is larger than 4, the diameter of the cylinder supporting columns is larger than 3, the diameter of the cylinder supporting columns, the cylinder supporting columns is larger than 3, the depth of the diameter of the cylinder supporting columns is 3, the cylinder supporting columns, the cylinder.

The magnetostrictive cylinder is a uncovered cylinder made of magnetostrictive material, the length is L3, the outer diameter is d1, and the inner diameter is d3., and the magnetostrictive cylinder is coaxially sleeved outside the thin cylinder.

The cylinder fixing screw is composed of a cylinder and a second outer screw, the height of the cylinder is L4, the height of the cylinder is not more than 2mm and not more than L4 and not more than 20mm, the diameter of the cylinder is d1., one end of the cylinder is connected with the second outer screw, the other end of the cylinder is provided with a third inner screw hole, after the magnetostrictive cylinder is sleeved on the cylinder support, the second outer screw of the cylinder fixing screw is inserted into the second inner screw hole of the cylinder support, so that the magnetostrictive cylinder is fixed on the cylinder support, and the deformation of the magnetostrictive cylinder is limited in the axial direction by the cylinder fixing screw, the diameter of the second outer screw is d3, the height of the third inner screw hole is h2., the diameter of the third inner screw hole is d5, d5 is less than d1, the depth is h3, and h3 is less than L4.

The magnetic field Michelson interferometer comprises a first 3dB optical fiber coupler, a magnetic field sensing arm optical fiber and a magnetic field reference arm optical fiber, wherein the magnetic field sensing arm optical fiber and the magnetic field reference arm optical fiber are both bending-resistant single-mode optical fibers, the initial lengths are L0 (L0 is not less than the requirement of magnetic field sensing sensitivity, see formula (1)), one ends of the magnetic field sensing arm optical fiber and the magnetic field reference arm optical fiber are both plated with optical reflection films, and the other ends of the magnetic field sensing arm optical fiber and the magnetic field reference arm optical fiber are respectively fused with a first port and a second port of the first 3dB optical fiber coupler by using an optical fiber fusion splicer.

The magnetic field sensing arm optical fiber and the reference arm optical fiber of the 6 magnetic field Michelson interferometers are respectively wound on an x + axis, an x-axis, a y + axis, a y-axis, a z + axis and a z-axis of the three-dimensional optical fiber vector magnetic field sensor. Namely: a magnetic field sensing arm optical fiber and a reference arm optical fiber of a first magnetic field Michelson interferometer are wound on an x + axis of the three-dimensional optical fiber vector magnetic field sensor; the magnetic field sensing arm optical fiber and the reference arm optical fiber of the second magnetic field Michelson interferometer are wound on the x-axis of the three-dimensional optical fiber vector magnetic field sensor, the magnetic field sensing arm optical fiber and the reference arm optical fiber of the third magnetic field Michelson interferometer are wound on the y + axis of the three-dimensional optical fiber vector magnetic field sensor, the magnetic field sensing arm optical fiber and the reference arm optical fiber of the fourth magnetic field Michelson interferometer are wound on the y-axis of the three-dimensional optical fiber vector magnetic field sensor, the magnetic field sensing arm optical fiber and the reference arm optical fiber of the fifth magnetic field Michelson interferometer are wound on the z + axis of the three-dimensional optical fiber vector magnetic field sensor, and the magnetic field sensing arm optical fiber and the reference arm optical fiber of the sixth magnetic field Michelson interferometer are wound on the.

When the three-dimensional optical fiber vector magnetic field sensor is placed in a magnetic field, the outer diameter of the magnetostrictive cylinder is changed, and the length of the optical fiber of the magnetic field sensing arm is further changed. The magnetic field sensing sensitivity M1 and the number of winding turns n1 approximately satisfy the following relation:

L0>n1*π*d1 (1)

in the formula n₀The refractive index of the optical fiber core of the magnetic field sensing arm is expressed, k1 is delta V/T, the ratio of the change of the volume V of the magnetostrictive cylinder to the magnetic field intensity T causing the change is expressed, the ratio is determined by the magnetostrictive characteristic of the magnetostrictive cylinder, and when the magnetostrictive material is determined, k1 is a constant; λ represents the wavelength of the laser light incident into the magnetic field sensing arm fiber.

The three-dimensional optical fiber vector hydrophone consists of a hollow mass block, 6 elastic struts and 3 sound field Michelson interferometers. 6 elastic struts are bonded on 6 surfaces of the hollow mass block by glue, and the axes of the elastic struts are vertical to the surface connected with the hollow mass block.

The hollow mass block is a cube die made of nonmagnetic steel materials, the side length is d6, and d1+10mm < d6<4 x d1 is met. From 6 top surfaces overlooking of the hollow mass block, the center of the top surface of the hollow mass block is provided with 1 square through hole. The sides of the square through hole are respectively parallel to the sides of the top surface of the hollow mass block, the side length of the square through hole is d7, d1+5mm < d7< d6, and the depth is d 6; the hollow mass block is characterized in that 6 top surfaces of the hollow mass block are respectively provided with a circular groove, the outer diameter of the circular groove is d9, d9 is larger than 1.42 × d7, the width of the circular groove is h4, 0.5 mm-h 4-4 mm is satisfied, the depth of the circular groove is h7, 0.2 mm-h 7-2 mm is satisfied, and the square through hole is located in the center of the circular groove when the hollow mass block is overlooked from the top surface.

In order to install the three-dimensional optical fiber vector magnetic field sensor inside the three-dimensional optical fiber vector hydrophone, the hollow mass block is cut into a first mass block and a second mass block along the direction AA. The first mass is symmetrical to the second mass about a plane xoz. The metal cubic block is arranged at the hollow position of the hollow mass block.

The cross section of the first mass block and the cross section AA are provided with four first square intersecting surfaces, namely EE1E3E2, FF2F3F1, GG1G3G2 and HH2H3H1, the side length of each of the four first square intersecting surfaces is d8, and d8 is (d6-d 7)/2. Four points E3F3G3H3 enclose a first square through hole, the first square through hole has a side length d7 and a depth d12, and d12 d6/2 (which is half of the square through hole). The four first square intersecting surfaces are provided with four first rectangular grooves (four in total), the depth of each first rectangular groove is d10, d10 is d7/2, the length is d8, and the width is d 7.

The second mass is symmetrical to the first mass about the plane xoz. The cross section of the second mass block and the cross section AA also have four second square intersecting surfaces, namely E 'E1' E3 'E2', F 'F2' F3 'F1', G 'G1' G3 'G2', H 'H2' H3 'H1', and the side length of the four second square intersecting surfaces is equal to d 8. Four points of E3 'F3' G3 'H3' enclose a second square through hole, the side length of the second square through hole is d7, and the depth is d 12. And second rectangular grooves (four in all) are formed between every two of the four second square intersecting surfaces, the depth of each second rectangular groove is d10, the length of each second rectangular groove is d8, and the width of each second rectangular groove is d 7.

1 cylindrical strut (y + axis) of the three-dimensional optical fiber vector magnetic field sensor is placed into the first square through hole from the AA direction section of the first mass block, and 4 cylindrical struts (x + axis, z + axis, x-axis and z-axis) are placed into the first rectangular groove. The 6 th cylinder pillar (y-axis) penetrates out of the AA direction cross section of the second mass block along the second square through hole. The four square intersecting surfaces of the second mass block and the four square intersecting surfaces of the first mass block are bonded through glue to form the hollow mass block. Therefore, the three-dimensional optical fiber vector magnetic field sensor is arranged in the hollow mass block.

The elastic supporting column is composed of an elastic cylinder and a metal circular plate, the elastic cylinder is made of an elastomer material (such as SEBS (styrene-ethylene-butylene copolymer) which takes polystyrene as an end section and takes ethylene-butylene copolymer obtained by hydrogenation of polybutadiene as an intermediate elastic block, TPE (thermoplastic elastomer) and the like), the outer diameter is d9, the wall thickness is h4, the length is L, L > L1 + h7-d5/2, the cylinder wall of the elastic cylinder close to one end is provided with an optical fiber through hole, the diameter meets the requirement that 2 bending-resistant optical fibers pass through the optical fiber through hole, one end of the elastic cylinder is adhered with the metal circular plate by glue, the diameter of the metal circular plate is d9, the thickness is h5, h5< L1 + L + h 7-L-d 5/2, the center of the metal circular plate is provided with a metal circular plate through hole, and the diameter of the metal circular plate is d 1.

A first input port optical fiber and a first output port optical fiber of the first 3dB optical fiber coupler penetrate out of the optical fiber through hole, the elastic support is coaxially sleeved on the outer side of a cylindrical support (comprising a magnetostrictive cylinder, a cylinder fixing screw and a magnetic field Michelson interferometer) from one end far away from a metal circular plate, and the metal circular plate through hole is bonded on the outer side face of the cylinder fixing screw through glue.

The acoustic field Michelson interferometer consists of a second 3dB optical fiber coupler and 2 acoustic field sensing arm optical fibers, wherein the 2 acoustic field sensing arm optical fibers are anti-bending single-mode optical fibers, the initial lengths of the 2 acoustic field sensing arm optical fibers are L6 (see formula (3)), one ends of the 2 acoustic field sensing arm optical fibers are respectively plated with an optical reflection film, and the other ends of the 2 acoustic field sensing arm optical fibers are respectively welded with a third port and a fourth port of the second 3dB optical fiber coupler by an optical fiber welding machine.

And the acoustic field sensing arm optical fiber is wound on the outer side surface of the elastic support in a clockwise direction (viewed from one end of the bonding metal circular plate) from one end of the elastic support in the x + (y + or z +) direction, which is close to one end of the hollow mass block, with one end plated with the optical reflection film as a starting point. The acoustic field sensing arm optical fiber is wound on the outer side surface of the elastic support by n2 circles in total (see formula (4)). The other sound field sensing arm optical fiber is wound on the outer side of the elastic support in the x- (y-or z-) direction by n2 circles in the same way.

6 sound field sensing arm optical fibers of the 3 sound field Michelson interferometers are respectively wound on an x + axis, an x-axis, a y + axis, a y-axis, a z + axis and a z-axis of the three-dimensional optical fiber vector magnetic field hydrophone. Namely: two sound field sensing arm optical fibers of a first sound field Michelson interferometer are respectively wound on an x + axis and an x-axis of a three-dimensional optical fiber vector hydrophone, two sound field sensing arm optical fibers of a second sound field Michelson interferometer are respectively wound on a y + axis and a y-axis of the three-dimensional optical fiber vector hydrophone, and two sound field sensing arm optical fibers of a third sound field Michelson interferometer are respectively wound on a z + axis and a z-axis of the three-dimensional optical fiber vector hydrophone.

Acoustic field sensing sensitivityDeltaa represents the change in the sound field acceleration,showing the phase change of light wave caused by the acceleration change of sound field.

Sound field sensing sensitivity M_aApproximately the number of windings n2, the following relation is satisfied (from literature (mussajous, fibre-optic accelerometer-based vector hydrophone study [ D)]Long sand: national defense science and technology university, 2007)):

L6>n2*π*d9 (3)

in the formula n_sThe refractive index of a fiber core of the acoustic field sensing arm optical fiber is shown, lambda represents the laser wavelength incident to the acoustic field sensing arm optical fiber, E and mu respectively represent the Young modulus and the Poisson ratio of the elastic cylinder, and m represents the mass of the hollow mass block.

Therefore, the three-dimensional optical fiber vector hydrophone and the three-dimensional optical fiber vector magnetic field sensor are connected and fixed together.

The spherical mounting shell is made of nonmagnetic steel materials, the inner diameter is d11, d11 meets the requirement of containing the integrally packaged three-dimensional optical fiber vector hydrophone and the three-dimensional optical fiber vector magnetic field sensor, namely d11 meets the requirements of formula (5) and formula (6)

And is

The thickness of the shell is h6, h6 is reasonably adjusted, so that the optical fiber vector acoustic-magnetic composite sensor has zero buoyancy in a working medium (the medium in the working environment of the optical fiber vector acoustic-magnetic composite sensor, such as working in water, the working medium refers to water), namely h6 meets the formula (7)

Where m1 represents the weight of the acousto-magnetic composite sensing cell inside the spherically mounted shell, ρ_{Spherical shell}Representing the material density, ρ, of a spherically mounted shell_{Working medium}Represents the working medium density;

the central point of the spherical mounting shell is the origin of a Cartesian coordinate system, and fourth inner screw holes are respectively formed in 6 intersection points (x +, y +, z +, x-, y-, z-) of three coordinate axes of the spherical mounting shell and the Cartesian coordinate system, and the diameter of each fourth inner screw hole is d 5. And a shell through hole is formed in the vicinity of a z + point of the spherical mounting shell, the diameter of the shell through hole is d12 (the diameter is enough for 18 bending-resistant optical fibers to pass through), and the shell through hole is used for enabling the input port optical fiber and the output port optical fiber of 6 first 3dB optical fiber couplers and the second input port optical fiber and the second output port optical fiber of 3 second 3dB optical fiber couplers to pass through the spherical mounting shell from the shell through hole. The three-dimensional optical fiber vector hydrophone and the three-dimensional optical fiber vector magnetic field sensor are arranged in the spherical mounting shell, the fourth inner screw hole and the third inner screw hole are connected through screws, and the three-dimensional optical fiber vector magnetic field sensor and the spherical mounting shell are fixed.

The acousto-magnetic measuring device comprises an RIO laser, an optical isolator, a 1 × 9 optical fiber coupler, a 9 × 1 optical fiber coupler, an optical fiber vector acousto-magnetic composite sensor, a photoelectric detector and a data acquisition and signal processing device.

The working process of the acoustic magnetic measurement device adopting the invention is as follows:

firstly, an RIO laser 1 outputs 1550nm laser;

secondly, protecting the RIO laser 1 by an optical isolator 2, dividing laser into 9 paths of light by a 1 × 9 optical fiber coupler 3, and respectively outputting the 9 paths of light to 6 magnetic field Michelson interferometers 5-3-5 and 3 sound field Michelson interferometers 5-2-3 of the optical fiber vector acousto-magnetic composite sensor 5;

thirdly, the first magnetic field Michelson interferometer modulates the 1 st path of light (counted from top to bottom) output by the 1 × 9 optical fiber coupler 3 (the modulation mechanism is that the magnetostrictive cylinder 5-3-3 deforms under the influence of an external magnetic field, so that the length of the magnetic field sensing arm optical fiber 5-3-5-2 changes, and the change information is loaded to the output light of the first magnetic field Michelson interferometer);

thirdly, the first channel of the 9 × 1 fiber coupler 4 receives light carrying x + axial magnetic field strength information from the first magnetic field michelson interferometer;

fourthly, the photodetector 6 converts the light output by the optical fiber coupler 4 of 9 × 1 into a voltage signal;

fifthly, the data acquisition and signal processing device 7 receives the voltage signal output by the photoelectric detector 6 and demodulates the x + axial magnetic field intensity;

sixthly, the second magnetic field Michelson interferometer modulates the 2 nd light (counted from top to bottom) output by the 1 × 9 optical fiber coupler 3;

seventhly, a second channel of the 9 × 1 fiber coupler 4 receives light carrying x-axial magnetic field strength information from a second magnetic field Michelson interferometer;

eighthly, the photodetector 6 converts the light output by the 9 × 1 optical fiber coupler 4 into a voltage signal;

ninthly, receiving the voltage signal output by the photoelectric detector 6 and demodulating the x-axial magnetic field intensity by the data acquisition and signal processing device 7;

tenth step, the data acquisition and signal processing device 7 calculates the difference between the x + axial magnetic field strength obtained in the fifth step and the x-axial magnetic field strength obtained in the ninth step to obtain the x axial magnetic field strength gradient;

in the tenth step, the first acoustic field michelson interferometer modulates the 3 rd path of light (counted from top to bottom) output by the 1 × 9 fiber coupler 3;

twelfth, the third channel of the 9 × 1 fiber coupler 4 receives light from the first acoustic field michelson interferometer that carries x-axis acceleration modulation;

in the thirteenth step, the photodetector 6 converts the light output by the 9 × 1 fiber coupler 4 into a voltage signal;

and step fourteen, the data acquisition and signal processing device 7 receives the voltage signal output by the photoelectric detector 6 and demodulates the acceleration of the sound field in the x-axis direction.

Fifteenth step, the third magnetic field michelson interferometer modulates the 4 th light (counted from top to bottom) output by the 1 × 9 fiber coupler 3;

sixthly, the fourth channel of the 9 × 1 fiber coupler 4 receives light carrying y + axial magnetic field strength information from the third magnetic field michelson interferometer;

seventeenth step, the photodetector 6 converts the light output by the optical fiber coupler 4 of 9 × 1 into a voltage signal;

eighteenth, the data acquisition and signal processing device 7 receives the voltage signal output by the photoelectric detector 6 and demodulates the y + axial magnetic field intensity;

nineteenth step, the fourth magnetic field michelson interferometer modulates the 5 th light (counted from top to bottom) output by the 1 × 9 fiber coupler 3;

twentieth, the fifth channel of the 9 × 1 fiber coupler 4 receives light carrying y-axial magnetic field strength information from the fourth magnetic field michelson interferometer;

in the twentieth step, the photodetector 6 converts the light output by the 9 × 1 optical fiber coupler 4 into a voltage signal;

a twenty-second step, the data acquisition and signal processing device 7 receives the voltage signal output by the photoelectric detector 6 and demodulates the y-axial magnetic field intensity;

twenty-third step, the data acquisition and signal processing device 7 calculates the difference between the y + axial magnetic field strength obtained in the eighteenth step and the y-axial magnetic field strength obtained in the twenty-second step to obtain the y-axial magnetic field strength gradient;

twenty-fourth step, the second acoustic field michelson interferometer modulates the 6 th light (counted from top to bottom) output by the 1 × 9 fiber coupler 3;

in the twenty-fifth step, the sixth channel of the 9 × 1 fiber coupler 4 receives light carrying modulated acceleration in the y-axis direction from the second acoustic field michelson interferometer;

in the twenty-sixth step, the photodetector 6 converts the light output by the optical fiber coupler 4 of 9 × 1 into a voltage signal;

and twenty-seventh step, the data acquisition and signal processing device 7 receives the voltage signal output by the photoelectric detector 6 and demodulates the acceleration of the sound field in the y-axis direction.

Twenty-eighth step, the fifth magnetic field michelson interferometer modulates the 7 th light (counted from top to bottom) output by the 1 × 9 fiber coupler 3;

in a twenty-ninth step, the seventh channel of the 9 × 1 fiber coupler 4 receives light carrying z + axial magnetic field strength information from the fifth magnetic field michelson interferometer;

thirty-step, the photodetector 6 converts the light output by the 9 × 1 fiber coupler 4 into a voltage signal;

thirty-first step, the data acquisition and signal processing device 7 receives the voltage signal output by the photoelectric detector 6 and demodulates the z + axial magnetic field intensity;

thirty-second, the sixth magnetic field michelson interferometer modulates the 8 th light (from top to bottom) output by the 1 × 9 fiber coupler 3;

in a thirty-third step, the eighth channel of the 9 × 1 fiber coupler 4 receives light carrying z-axial magnetic field strength information from the sixth magnetic field michelson interferometer;

the thirty-fourth step, the photodetector 6 converts the light output by the 9 × 1 fiber coupler 4 into a voltage signal;

thirty-fifth step, the data acquisition and signal processing device 7 receives the voltage signal output by the photoelectric detector 6 and demodulates the z-axial magnetic field intensity;

a thirty-sixth step, the data acquisition and signal processing device 7 calculates the difference between the z + axial magnetic field strength obtained in the thirty-first step and the z-axial magnetic field strength obtained in the thirty-fifth step to obtain a z-axial magnetic field strength gradient;

thirty-seventh step, the third acoustic field michelson interferometer modulates the 9 th light (counted from top to bottom) output by the 1 × 9 fiber coupler 3;

in a thirty-eighth step, the ninth channel of the 9 × 1 fiber coupler 4 receives light from the third acoustic field michelson interferometer carrying z-axis acceleration modulation;

thirty-ninth step, the photodetector 6 converts the light output by the 9 × 1 fiber coupler 4 into a voltage signal;

and step forty, the data acquisition and signal processing device 7 receives the voltage signal output by the photoelectric detector 6 and demodulates the z-axis sound field acceleration.

In the fortieth step, the sound pressure information and the vibration velocity information can be obtained from the relational expression between the particle acceleration and the sound pressure gradient (Liu Bo Sheng, etc., the hydroacoustics principle (third edition), pp.368).

Where v denotes a sound field vibration velocity, a denotes a sound field acceleration, ω denotes a vibration frequency, p denotes a sound pressure, and ρ denotes a medium density.

Forty-second step, according to the measured magnetic field gradients in the three directions of the x, y and z axes, carrying out geometric vector synthesis to obtain the magnetic field direction; and then the magnetic field intensity measurement results of 6 times of the x +, x-, y +, y-, z + and z-axes are arithmetically averaged, and the magnetic field intensity at the central point of the sensor is obtained.

So far, the three-dimensional vector sound field (sound pressure and vibration velocity) and the magnetic field information are all acquired.

The invention can achieve the following technical effects:

the optical fiber vector acousto-magnetic composite sensor based on the optical fiber Michelson interferometer structure made of the magnetostrictive material and the acoustic elastic material can detect a three-dimensional vector sound field and a three-dimensional vector magnetic field in a point-by-point composite mode, has the advantages of adjustable sensitivity of the sound field and the magnetic field, compact structure, small size and the like, is a passive device and non-contact type sensing at the sensor end, has the unique advantages of high stability and environmental adaptability, easiness in large-scale networking and arraying and the like, and solves the problems that the sensitivity of a plurality of sensors such as a hydrophone is low, a front amplification module is required, the power needs to be supplied to the sensor end, and the remote transmission loss.

Drawings

Fig. 1 is a schematic diagram of the overall structure of the fiber vector acoustic-magnetic composite sensor of the present invention.

Fig. 2 is a sectional view taken along line a-a of fig. 1.

Fig. 3 is a cross-sectional view taken along the line a-a of fig. 1 after the metal cube 5-3-1, the cylinder support post 5-3-2, the magnetostrictive sleeve 5-3-3, and the cylinder set screw 5-3-4 are assembled together.

Fig. 4 is a schematic structural view of the magnetostrictive sleeve 5-3-3 in the z + axis direction of fig. 1, fig. 4(a) is a front view of the magnetostrictive sleeve, and fig. 4(b) is a top view of the magnetostrictive sleeve.

FIG. 5 is a cross-sectional view of the barrel set screw 5-3-4 in the z + axis direction of FIG. 3.

FIG. 6 is a schematic diagram of a magnetic field Michelson interferometer of the present invention.

FIG. 7 is a top view of the z + axis of the hollow mass 5-2-1 in the three-dimensional fiber vector hydrophone 5-2 of the present invention.

Fig. 8 is a structural schematic view of the first mass block 5-2-1-1 of the present invention, fig. 8(a) is a sectional front view of the first mass block 5-2-1-1AA, and fig. 8(b) is a left side view of the first mass block 5-2-1-1.

Fig. 9 is a structural schematic view of the second mass block 5-2-1-2 of the present invention, fig. 9(a) is a sectional front view of the second mass block 5-2-1-2AA, and fig. 9(b) is a left side view of the second mass block 5-2-1-2.

Fig. 10 is a schematic structural view of the elastic strut of the present invention, fig. 10(a) is a front view of the elastic strut, and fig. 10(b) is a side view of the elastic strut.

FIG. 11 is a schematic diagram of an acoustic field Michelson interferometer of the present invention.

Fig. 12 is a cross-sectional view of the ball mount housing AA of the present invention.

FIG. 13 is a diagram showing the optical logic structure of the acousto-magnetic measuring device of the present invention.

The specific implementation mode is as follows:

the technical solutions of the present invention will be described in further detail with reference to the accompanying drawings and the detailed description.

As shown in figure 1, the optical fiber vector acoustic-magnetic composite sensor comprises a spherical mounting shell 5-1, a three-dimensional optical fiber vector hydrophone 5-2 and a three-dimensional optical fiber vector magnetic field sensor 5-3. The three-dimensional optical fiber vector hydrophone 5-2 and the three-dimensional optical fiber vector magnetic field sensor 5-3 are integrally packaged in the spherical mounting shell 5-1.

Fig. 2 is a sectional view taken along line a-a of fig. 1. As shown in FIG. 2, the three-dimensional fiber vector magnetic field sensor 5-3 comprises 1 metal cube 5-3-1, 6 cylinder supports 5-3-2, 6 magnetostrictive cylinders 5-3-3, 6 cylinder fixing screws 5-3-4 and 6 magnetic field Michelson interferometers 5-3-5. 6 cylinder support columns 5-3-2 are fixed on 6 surfaces of a metal cube 5-3-1 through threads, 6 magnetostrictive cylinders 5-3-3 are respectively and coaxially sleeved on the outer sides of the 6 cylinder support columns 5-3-2 and are respectively fixed on the 6 cylinder support columns 5-3-2 through cylinder fixing screws 5-3-4 (the magnetostrictive cylinders 5-3-3 deform under the action of a magnetic field, and the cylinder fixing screws 5-3-4 limit the deformation of the magnetostrictive cylinders 5-3-3 in the axial direction, so that the magnetostrictive cylinders 5-3-3 can only deform in the radial direction). 6 magnetostrictive cylinders 5-3-3 are respectively sleeved on 6 cylinder pillars 5-3-2 to form a three-dimensional optical fiber vector magnetic field sensor 5-3 on an x + axis, an x-axis, a y + axis, a y-axis, a z + axis and a z-axis of a Cartesian coordinate system, and 6 magnetic field Michelson interferometers 5-3-5 are respectively arranged on the x + axis, the x-axis, the y + axis, the y-axis, the z + axis and the z-axis of the three-dimensional optical fiber vector magnetic field sensor 5-3.

Fig. 3 is a cross-sectional view taken along the line a-a of fig. 1 after the metal cube 5-3-1, the cylinder support post 5-3-2, the magnetostrictive sleeve 5-3-3, and the cylinder set screw 5-3-4 are assembled together. As shown in FIG. 3, the metal cube 5-3-1 is made of non-magnetic steel material and is in a cube shape, the side length is d1, and d1 is not less than 5mm and not more than 50 mm. A first inner threaded hole 5-3-1-1 is dug in the center of each of 6 faces of the metal cubic block 5-3-1, the diameter of the inner threaded hole 5-3-1-1 is d2, d2 is less than d1, the depth is h1, and h1 is less than d 1/2.

The cylinder supporting column 5-3-2 is made of nonmagnetic steel materials, 6 cylinder supporting columns 5-3-2 are fixed on 6 surfaces of a metal cubic block 5-3-1 through first outer threads 5-3-2-4 (the first outer threads 5-3-2-4 are screwed into first inner threaded holes 5-3-1-1, the cylinder supporting columns 5-3-2 are fixed on the metal cubic block 5-3-1), 6 cylinder supporting columns 5-3-2 are completely the same and are composed of 2 sections of cylinders with different diameters, namely, a thick cylinder 5-3-2-1 and a thin cylinder 5-3-2-2, the total length of the cylinder supporting columns 5-3-2 is L-1, 2d1 is not more than L mm and not more than 200mm, one end of the thick cylinder 5-3-2-1 is connected with first outer threads 5-3-2-4, one end of the thick cylinder 5-3-2-1 is connected with a first inner threaded hole 5-3-1-4 through first outer threads 5-3-2-4, the cylinder supporting column 5-3-2-3 is connected with a first inner threaded hole 5-3-1-3, the cylinder supporting column 5-3-2-3 coaxial with a cylinder supporting column 5-3 through a cylinder supporting column 5-3, the cylinder supporting column 5-3-3 coaxial cylinder 5-3, the cylinder 5-3 cylinder supporting column 3 cylinder 5-2-2 cylinder 3 cylinder 2 cylinder supporting column is connected with a cylinder 2, the cylinder 2, the cylinder 2 cylinder 3 cylinder 2.

Fig. 4 is a schematic structural view of the magnetostrictive sleeve 5-3-3 in the z + axis direction of fig. 1, fig. 4(a) is a front view of the magnetostrictive sleeve, fig. 4(b) is a top view of the magnetostrictive sleeve, as shown in fig. 4, the magnetostrictive cylinder 5-3-3 is a uncovered cylinder made of magnetostrictive material, the length is L3, the outer diameter is d1, the inner diameter is d3., as shown in fig. 2, and the magnetostrictive cylinder 5-3-3 is coaxially sleeved outside the thin cylinder 5-3-2-2.

Fig. 5 is a cross-sectional view of a cylinder fixing screw 5-3-4 in a z + axis direction of fig. 3, as shown in fig. 5, the cylinder fixing screw 5-3-4 is composed of a cylinder 5-3-4-1 and a second outer screw 5-3-4-2, the cylinder 5-3-4-1 has a height L, 2mm L4 mm or less and 20mm or less, and a diameter d1. the cylinder 5-3-4-1 has one end connected to the second outer screw 5-3-4-2 and the other end provided with a third inner screw hole 5-3-4-3, after the magnetostrictive cylinder 5-3-3 is fitted to the cylinder support 5-3-2, the second outer screw 5-3-4-2 of the cylinder fixing screw 5-3-4 is inserted into the second inner screw hole 5-3-2-3 of the cylinder support 5-3-2, so that the magnetostrictive cylinder 5-3-3 is fixed to the cylinder support 5-3-2, and the cylinder fixing screw 5-3-4 is axially restricted by the third outer screw 3-2, the cylinder has a diameter 738, a diameter 367, a diameter < 3-4934 < 3-3 d < 3< d < 3 <.

FIG. 6 is a schematic diagram of the structure of the magnetic field Michelson interferometer of the present invention, as shown in FIG. 6, the magnetic field Michelson interferometer 5-3-5 is composed of a first 3dB fiber coupler 5-3-5-1, a magnetic field sensing arm fiber 5-3-5-2, and a magnetic field reference arm fiber 5-3-5-3, the magnetic field sensing arm fiber 5-3-5-2 and the magnetic field reference arm fiber 5-3-5-3 are both bending-resistant single mode fibers, the initial length is L (L0 is not less than the magnetic field sensing sensitivity requirement, see formula (1)), one end of each of the two is coated with an optical reflective film 5-3-5-2-1, the other end is coated with a first port 5-3-5-1-2 and a second port 5-3-5-1-2 of a first 3dB fiber coupler 5-3-5-1 respectively by a fiber fusion splicer, the fiber is fixed on the outer side of the cylinder 3-5-3-5-2, the cylinder 3-5-3-5 is fixed with a thick magnetic field reflection film winding screw (3-5-2) from the outer side of the cylinder 3-5) to the cylinder 3-5-3-5, the cylinder 3-5-3-5 cylinder, the cylinder is fixed with a thick magnetic field winding cylinder, the cylinder is fixed with the cylinder, the cylinder is fixed with the cylinder, the cylinder is fixed with the cylinder, the cylinder is fixed with the cylinder, the.

As shown in FIG. 2, the magnetic field sensing arm fiber 5-3-5-2 and the reference arm fiber 5-3-5-3 of 6 magnetic field Michelson interferometers 5-3-5 are respectively wound around the x + axis, the x-axis, the y + axis, the y-axis, the z + axis and the z-axis of the three-dimensional fiber vector magnetic field sensor 5-3. Namely: a magnetic field sensing arm optical fiber 5-3-5-2 and a reference arm optical fiber 5-3-5-3 of a first magnetic field Michelson interferometer 5-3-5 are wound on an x + axis of a three-dimensional optical fiber vector magnetic field sensor 5-3; the magnetic field sensing arm optical fiber 5-3-5-2 and the reference arm optical fiber 5-3-5-3 of the second magnetic field michelson interferometer 5-3-5 are wound around the x-axis of the three-dimensional optical fiber vector magnetic field sensor 5-3, the magnetic field sensing arm optical fiber 5-3-5-2 and the reference arm optical fiber 5-3-5-3 of the third magnetic field michelson interferometer 5-3-5-3 are wound around the y + axis of the three-dimensional optical fiber vector magnetic field sensor 5-3, the magnetic field sensing arm optical fiber 5-3-5-2 and the reference arm optical fiber 5-3-5-3 of the fourth magnetic field michelson interferometer 5-3 are wound around the y-axis of the three-dimensional optical fiber vector magnetic field sensor 5-3, the magnetic field sensing arm optical fiber 5-3-5-2 and the reference arm optical fiber 5-3-5-3 of the fifth magnetic field michelson interferometer 5-3-5 are wound around the z + axis of the three-dimensional optical fiber vector magnetic field sensor 5-3, and the magnetic field sensing arm optical fiber 5-3-5-2 and the reference arm optical fiber 5-3-5-3 of the sixth magnetic field michelson interferometer 5-3-5 are wound around the z-axis of the three-dimensional optical fiber vector magnetic field sensor 5-3.

As shown in FIG. 1, the three-dimensional fiber vector hydrophone 5-2 consists of a hollow mass block 5-2-1, 6 elastic struts 5-2-2 and 3 acoustic field Michelson interferometers 5-2-3. 6 elastic struts 5-2-2 are bonded on 6 surfaces of the hollow mass block 5-2-1 by glue, and the axes of the elastic struts 5-2-2 are vertical to the surface of the hollow mass block 5-2-1.

FIG. 7 is a top view of the z + axis of the hollow mass 5-2-1 in the three-dimensional fiber vector hydrophone 5-2 of the present invention. As shown in fig. 7, the hollow mass block 5-2-1 is a cube mold made of nonmagnetic steel material, with a side length of d6, and satisfies d1+10mm < d6<4 × d 1. From the top view of 6 top surfaces of the hollow mass block 5-2-1, the center of the top surface is provided with 1 square through hole 5-2-1-4. The sides of the square through hole 5-2-1-4 are respectively parallel to the sides of the top surface of the hollow mass block 5-2-1, the side length of the square through hole 5-2-1-4 is d7, d1+5mm < d7< d6, and the depth is d 6; 6 top surfaces of the hollow mass block 5-2-1 are respectively provided with a circular groove 5-2-1-3, the outer diameter of the circular groove 5-2-1-3 is d9, d9 is larger than 1.42 x d7, the width is h4, 0.5 mm-h 4-4 mm is satisfied, the depth is h7, 0.2 mm-h 7-2 mm is satisfied, and the square through hole 5-2-1-4 is positioned in the center of the circular groove 5-2-1-3 when the top surface of the hollow mass block 5-2-1 is overlooked.

In order to install the three-dimensional optical fiber vector magnetic field sensor 5-3 inside the three-dimensional optical fiber vector hydrophone 5-2, the hollow mass block 5-2-1 is cut into a first mass block 5-2-1-1 and a second mass block 5-2-1-2 along the AA direction. The first mass 5-2-1-1 and the second mass 5-2-1-2 are symmetrical with respect to the plane xoz (AA-wise cross section). The metal cubic block 5-3-1 is arranged at the hollow position of the hollow mass block 5-2-1.

Fig. 8 is a structural schematic view of the first mass block 5-2-1-1 of the present invention, fig. 8(a) is a sectional front view of the first mass block 5-2-1-1AA, and fig. 8(b) is a left side view of the first mass block 5-2-1-1. As shown in fig. 8 (a): the cross section of the first mass block 5-2-1-1 and the AA is provided with four first square intersecting surfaces 5-2-1-1, namely EE1E3E2, FF2F3F1, GG1G3G2 and HH2H3H1, the side length of each of the four first square intersecting surfaces 5-2-1-1-1 is d8, and d8 is (d6-d 7)/2. Four points of E3F3G3H3 enclose a first square through hole 5-2-1-1-2, the side length of the first square through hole 5-2-1-1-2 is d7, the depth is d12, and d12 is d6/2 (which is half of the square through hole 5-2-1-4). First rectangular grooves 5-2-1-1-3 (four in total) are formed between every two of the four first square intersecting surfaces 5-2-1-1-1, the depth of each first rectangular groove 5-2-1-1-3 is d10, d10 is d7/2, the length is d8, and the width is d 7.

Fig. 9 is a structural schematic view of the second mass block 5-2-1-2 of the present invention, fig. 9(a) is a sectional front view of the second mass block 5-2-1-2AA, and fig. 9(b) is a side view of the second mass block 5-2-1-2. As shown in fig. 9 (a): the second mass 5-2-1-2 is symmetrical to the first mass 5-2-1-1 about the xoz plane (AA cross section). The second mass block 5-2-1-2 has, similarly to the AA section, four second square intersecting surfaces 5-2-1-2-1, which are respectively E 'E1' E3 'E2', F 'F2' F3 'F1', G 'G1' G3 'G2', H 'H2' H3 'H1', and four second square intersecting surfaces 5-2-1-2-1 are equal to d8 in side length.

Four points of E3 'F3' G3 'H3' enclose a second square through hole 5-2-1-2-2, the side length of the second square through hole 5-2-1-2-2 is d7, and the depth is d 12. Two second rectangular grooves 5-2-1-2-3 (four in total) are arranged between every two of the four second square intersecting surfaces 5-2-1-2-1, the depth of each second rectangular groove 5-2-1-2-3 is d10, the length is d8, and the width is d 7.

1 cylinder pillar 5-3-2(y + axis) of the three-dimensional optical fiber vector magnetic field sensor 5-3 is placed into the first square through hole 5-2-1-1-2 from the AA direction cross section (figure 8(a)) of the first mass block 5-2-1-1, and 4 cylinder pillars 5-3-2(x + axis, z + axis, x-axis and z-axis) are placed into the first rectangular groove 5-2-1-1-3. The 6 th cylindrical pillar 5-3-2 (y-axis) penetrates out from the AA direction cross section of the second mass block 5-2-1-2 along the second square through hole 5-2-1-2-2. The four square intersecting surfaces 5-2-1-2-1 of the second mass block 5-2-1-2 and the four square intersecting surfaces 5-2-1-1-1 of the first mass block 5-2-1-1 are bonded into a hollow mass block 5-2-1 through glue. Therefore, the three-dimensional optical fiber vector magnetic field sensor 5-3 is arranged in the hollow mass block 5-2-1.

Fig. 10 is a schematic structural view of an elastic support column 5-2-2 of the present invention, fig. 10(a) is a front view of the elastic support column 5-2-2, fig. 10(b) is a side view of the elastic support column 5-2-2, fig. 10(a) shows that the elastic support column 5-2-2 is composed of an elastic cylinder 5-2-2-1 and a metal circular plate 5-2-2, the elastic cylinder 5-2-2-1 is made of an elastomer material (such as SEBS, TPE, etc.), the outer diameter is d9, the wall thickness is h4, the length is L, L is L + h7-d5/2, the wall of the elastic cylinder 5-2-2-1 near one end is provided with an optical fiber through hole 5-2-2-1-1, the diameter is 2, the diameter is satisfied 2, the metal circular plate 5-2-2-2-1 is adhered to one end of the elastic cylinder 5-2-1 with glue, the metal circular plate 5-2-2-2-1 is adhered to the metal circular plate 5-2-2-2, the metal circular plate 5-2-2-2-1 is adhered to the end of the elastic cylinder 5-2-2-2, the metal circular plate 5-2-2-2, the circular plate is adhered to the metal circular plate 5-2, the circular plate, the metal circular plate 5-2-2-2.

As shown in fig. 2, the first input port fiber 5-3-5-1-1 and the first output port fiber 5-3-5-1-4 of the first 3dB fiber coupler 5-3-5-1 penetrate out of the fiber through hole 5-2-2-1-1, the elastic support 5-2-2 is coaxially sleeved outside the cylindrical support 5-3-2 (including the magnetostrictive cylinder 5-3-3 fixedly connected with the cylindrical support 5-3-2, the cylinder fixing screw 5-3-4 and the magnetic field michelson interferometer 5-3-5) from one end far away from the metal circular plate 5-2-2, and the metal circular plate through hole 5-2-2-3 is bonded on the outer side surface of the cylinder fixing screw 5-3-4 through glue.

FIG. 11 is a schematic diagram of an acoustic field Michelson interferometer of the present invention.

As shown in fig. 11, the acoustic field michelson interferometer 5-2-3 is composed of a second 3dB optical fiber coupler 5-2-3-1 and 2 acoustic field sensing arm optical fibers 5-2-3-2, the 2 acoustic field sensing arm optical fibers 5-2-3-2 are all bending-resistant single-mode optical fibers, the initial length is L6 (see formula (3)), one end of each optical reflection film is coated with 5-3-5-2-1, and the other end of each optical reflection film is fused with a third port 5-2-3-1-2 and a fourth port 5-2-3-1-3 of the second 3dB optical fiber coupler 5-2-3-1 by an optical fiber fusion splicer.

As shown in FIG. 2, an optical fiber 5-2-3-2 of the acoustic field sensing arm is wound around the outer side surface of the elastic support 5-2-2 from the end of the elastic support 5-2-2 in the x + (y + or z +) direction, which is close to the end of the hollow mass 5-2-1, as a starting point, clockwise (when viewed from the end of the bonded metal circular plate 5-2-2), with the end of the optical reflection film 5-3-5-2-1 plated as a starting point. The acoustic field sensing arm optical fiber 5-2-3-2 is wound on the outer side surface of the elastic strut 5-2-2 for n2 circles (see formula (4)). The other sound field sensing arm optical fiber 5-2-3-2 is wound with n2 circles on the outer side of the elastic strut 5-2-2 in the x- (y-or z-) direction in the same way.

As shown in FIG. 2, 6 sound field sensing arm fibers 5-2-3-2 of 3 sound field Michelson interferometers 5-2-3 are respectively wound around an x + axis, an x-axis, a y + axis, a y-axis, a z + axis and a z-axis of a three-dimensional fiber vector magnetic field hydrophone 5-2. Namely: namely: two sound field sensing arm optical fibers 5-2-3-2 of a first sound field michelson interferometer 5-2-3 are respectively wound on an x + axis and an x-axis of a three-dimensional optical fiber vector hydrophone 5-2, two sound field sensing arm optical fibers 5-2-3-2 of a second sound field michelson interferometer 5-2-3 are respectively wound on a y + axis and a y-axis of the three-dimensional optical fiber vector hydrophone 5-2, and two sound field sensing arm optical fibers 5-2-3-2 of a third sound field michelson interferometer 5-2-3 are respectively wound on a z + axis and a z-axis of the three-dimensional optical fiber vector hydrophone 5-2.

Fig. 12 is a cross-sectional view of the ball mount housing AA of the present invention. As shown in fig. 12: the spherical mounting shell 5-1 is made of non-magnetic steel materials, the inner diameter is d11, d11 meets the requirements of accommodating the integrally packaged three-dimensional optical fiber vector hydrophone 5-2 and the three-dimensional optical fiber vector magnetic field sensor 5-3, namely d11 meets the requirements of a formula (5) and a formula (6), the thickness of the shell is h6, and h6 meets a formula (7).

The central point of the spherical mounting shell 5-1 is the origin of a Cartesian coordinate system, and the four inner screw holes 5-1-1 are respectively arranged at 6 intersection points (x +, y +, z +, x-, y-, z-) of three coordinate axes of the spherical mounting shell 5-1 and the Cartesian coordinate system, and the diameter of the fourth inner screw hole 5-1-1 is d 5. A shell through hole 5-1-2 is formed in the vicinity of a z + point of a spherical mounting shell 5-1, the diameter of the shell through hole 5-1-2 is d12 (the diameter can meet the requirement that 18 bending-resistant optical fibers pass), and a first input port optical fiber 5-3-5-1-1 and a first output port optical fiber 5-3-5-1-4 for 6 first 3dB optical fiber couplers 5-3-5-1-1 and a second input port optical fiber 5-2-3-1-1 and a second output port optical fiber 5-2-3-1-4 for 3 second 3dB optical fiber couplers 5-2-3-1 penetrate out of the spherical mounting shell 5-1 from the shell through hole 5-1-2. The three-dimensional optical fiber vector hydrophone 5-2 and the three-dimensional optical fiber vector magnetic field sensor 5-3 are arranged in the spherical mounting shell 5-1, the fourth inner screw hole 5-1 and the third inner screw hole 5-3-4-3 are connected through screws, and the three-dimensional optical fiber vector magnetic field sensor 5-3 and the spherical mounting shell 5-1 are fixed.

Fig. 13 is an optical logic structure diagram of the acousto-magnetic measurement device of the invention, and as shown in fig. 13, the acousto-magnetic measurement device comprises an RIO laser 1, an optical isolator 2, a 1 × 9 optical fiber coupler 3, a 9 × 1 optical fiber coupler 4, an optical fiber vector acousto-magnetic composite sensor 5, a photoelectric detector 6 and a data acquisition and signal processing device 7.