CN209910639U - Fiber grating sensor for measuring bow motion of ship body - Google Patents
Fiber grating sensor for measuring bow motion of ship body Download PDFInfo
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- CN209910639U CN209910639U CN201920906160.0U CN201920906160U CN209910639U CN 209910639 U CN209910639 U CN 209910639U CN 201920906160 U CN201920906160 U CN 201920906160U CN 209910639 U CN209910639 U CN 209910639U
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Abstract
The utility model relates to a fiber grating sensor for ship body bow motion measurement mainly includes: the device comprises a sensor sealing device, a sensor transmission device and a sensor sensitive element. The fiber bragg grating in the internal structure of the sensor is a core sensitive element, and the attitude angle of the ship body, which is generated by the bow, can be dynamically measured under the condition of eliminating temperature interference by matching with a sensor transmission device and a sensor sensitive element. The periphery of the sealing cover of the sensor is provided with a sealing groove and a sealing strip, and the top of the sealing cover is provided with an optical fiber waterproof aerial connector. The sensor has the characteristics of interference resistance, humidity resistance, corrosion resistance and the like, and can be used in particularly severe use environments.
Description
Technical Field
The utility model belongs to the technical field of the fiber grating sensor, especially, relate to a fiber grating attitude angle sensor of dynamic measurement hull bow motion.
Background
Ships are usually in a severe environment with humidity, frequent vibration and continuous corrosion of seawater, and the sea is often influenced by strong wind and billows, so that periodic yawing and yawing motions can occur. The ship can also stall at the same power, seriously damage the structure of the ship body and seasickness of seafarers due to the motions. If the motions of the ship body can be monitored in time, the disaster resistance of the ship is certainly enhanced, and the overall safety performance is improved.
The fiber grating is used as an important component of the fiber sensor, and has good electromagnetic interference resistance and electrical insulation. The wavelength value of the optical fiber is not influenced by the fluctuation of the power of the light source, and a plurality of gratings with different wavelengths can also be connected on the same optical fiber in series. The optical fiber is resistant to chemical corrosion, stable in physical performance and tiny and plastic in volume, so that the optical fiber sensor is suitable for being used in severe environments such as marine ships.
Disclosure of Invention
An object of the utility model is to overcome prior art's weak point, provide a sensor suitable for ocean boats and ships bow motion measurement to realize the dynamic monitoring of hull attitude angle change under adverse circumstances.
The utility model provides an above-mentioned technical problem, realize through taking following technical scheme:
a fiber grating sensor for measuring the bow motion of a ship body is characterized by mainly comprising: the device comprises a sensor sealing device, a sensor transmission device and a sensor sensitive element;
the sensor sealing device comprises an optical fiber waterproof aerial insert 3, a sealing cover 4, a fixing screw 5, a sensor shell 8 and a base 11; the sealing cover is provided with a threaded fixing hole, the sealing cover is sealed with the sensor shell 8 through a fixing screw 5, a sealing groove is formed in the sealing cover 4, a sealing strip is embedded in the sealing groove, the top of the sealing cover is used for fixing the optical fiber waterproof aerial plug 3 through a screw, the sensor shell and the internal structure of the sensor are fixed through the screw on the base, and the bearing sleeve 9 and the sensor shell 8 are fixed through the base 11;
the sensor transmission device comprises a cam 6, a main shaft 7, a bearing sleeve 9, a bearing 10, a support sleeve 12 and a base flange 13; two bearings 10 are nested in the bearing sleeve 9, a main shaft 7 is arranged in each bearing, the upper part and the lower part of each main shaft are respectively connected with a cam 6 and a base flange 13, the minimum radius part of each cam is tightly attached to a sensitive element cantilever beam 1 of the sensor, and a support sleeve 12 is clamped between each bearing 10 and the base flange 13;
the sensor sensitive element comprises a cantilever beam 1 and a fiber grating 2; the fiber bragg grating 2 is adhered to the cantilever beam 1 through epoxy resin glue, and the internal fiber bragg grating 2 is connected with the external fiber waterproof aerial plug 3 through optical fibers.
The fiber bragg grating in the internal structure of the sensor is a core sensitive element, and is matched with the sensor transmission device and the sensor sensitive element, so that the attitude angle of the ship body, which is generated by the bow, can be dynamically measured under the condition of eliminating temperature interference;
the side surface of the sensor uses the optical fiber waterproof aerial plug, so that the corrosion resistance of the sensor is improved, and the service life of the sensor is prolonged; the periphery of the sealing cover is provided with a sealing groove, and a sealing strip is embedded in the sealing groove to ensure the sealing performance of the sensor.
The utility model further discloses a use method that is used for hull bow to shake motion measurement's fiber grating sensor, its characterized in that:
(1) firstly, connecting a tail connector of the waterproof aerial optical fiber plug with a demodulator, and then connecting a network cable between the demodulator and a computer, wherein a compensation algorithm carried by demodulation software can dynamically monitor the central wavelength of an optical fiber grating in a sensor;
(2) when the ship body moves under the heading, the base flange 13 connected with the ship body can generate the same attitude angle with the ship body, and further the cam 6 is driven to rotate through the main shaft 7, so that the effective radius of the cam is changed, the acting force of the cam is changed on the cantilever beam 1, the fiber bragg grating 2 fixed on the cantilever beam further generates a deformation action, and finally the central wavelength of the fiber bragg grating is changed;
(3) the change of the central wavelength of the fiber bragg grating displayed by the demodulator in real time represents the change of the attitude angle of the ship body, when the attitude angle of the ship body where the ship is rocked is changed continuously, the change of the attitude angle of the ship body and the central wavelength of the fiber bragg grating basically presents a linear relation, and the relation between the central wavelength of the fiber and the change of the attitude angle generated by the ship yawing motion is finally obtained through a compensation algorithm at the demodulator end.
The optical fiber in the sensor has good electromagnetic interference resistance and electrical insulation, and the sensor does not contain any electronic element, so that the sensor has the characteristic of interference resistance. The periphery of the sealing cover of the sensor is provided with a sealing groove, a sealing strip is embedded in the sealing groove, the side surface of the sensor is provided with an optical fiber waterproof aerial plug, and the inside of the sensor is made of corrosion-resistant materials, so that the sensor also has the characteristics of moisture resistance, heat resistance and corrosion resistance.
The utility model discloses mainly solved how dynamic monitoring hull because of the produced attitude angle of yawing motion, the key sensor of having investigated has how to have good sealing performance in abominable service environment very much, and main difficult point lies in using mechanical compensation method elimination temperature to the influence of hull yawing motion measurement.
The utility model discloses a positive effect that is used for hull bow motion measurement's fiber grating sensor to compare with prior art has lies in:
(1) the sensor can dynamically monitor the attitude angle of the ship body generated by the yawing motion and monitor the navigation state of the ship body under the influence of factors such as wind, waves, currents and the like in real time.
(2) Once the sensor is packaged, the variation of the center wavelength of the fiber bragg grating is not influenced by temperature, and the condition that the measurement of the heading motion attitude angle of the ship body is interfered by temperature factors is avoided.
(3) The sensor has the characteristics of interference resistance, humidity resistance, corrosion resistance and the like, and can be used in the severe using environment of the ship body with humidity, frequent vibration and continuous seawater corrosion.
Drawings
Fig. 1 is a schematic diagram of the internal structure of the sensor of the present invention;
fig. 2 is a schematic view of a sensor cam according to the present invention;
the reference numbers in the figures:
1 cantilever beam, 2 fiber grating, 3 fiber waterproof aerial plug,
4 sealing covers, 5 fixing screws, 6 cams,
7 a main shaft, 8 a sensor shell, 9 a bearing sleeve,
a bearing 10, a base 11, a support sleeve 12,
13 a base flange.
Detailed Description
The invention is described below by means of specific embodiments. Unless otherwise specified, the technical means used in the present invention are well known to those skilled in the art. Additionally, the embodiments should be considered illustrative, and not restrictive, of the scope of the invention, which is defined solely by the claims. It will be apparent to those skilled in the art that various changes or modifications can be made in the components and amounts of the materials used in the embodiments without departing from the spirit and scope of the invention. The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
Example 1
A fiber grating sensor for measuring the bow motion of a ship body mainly comprises: the device comprises a sensor sealing device, a sensor transmission device and a sensor sensitive element;
the sensor sealing device comprises an optical fiber waterproof aerial insert 3, a sealing cover 4, a fixing screw 5, a sensor shell 8 and a base 11; the sealing cover is provided with a threaded fixing hole, the sealing cover is sealed with the sensor shell 8 through a fixing screw 5, a sealing groove is formed in the sealing cover 4, a sealing strip is embedded in the sealing groove, the top of the sealing cover is used for fixing the optical fiber waterproof aerial plug 3 through a screw, the sensor shell and the internal structure of the sensor are fixed through the screw on the base, and the bearing sleeve 9 and the sensor shell 8 are fixed through the base 11;
the sensor transmission device comprises a cam 6, a main shaft 7, a bearing sleeve 9, a bearing 10, a support sleeve 12 and a base flange 13; two bearings 10 are nested in the bearing sleeve 9, a main shaft 7 is arranged in each bearing, the upper part and the lower part of each main shaft are respectively connected with a cam 6 and a base flange 13, the minimum radius part of each cam is tightly attached to a sensitive element cantilever beam 1 of the sensor, and a support sleeve 12 is clamped between each bearing 10 and the base flange 13;
the sensor sensitive element comprises a cantilever beam 1 and a fiber grating 2; the fiber bragg grating 2 is adhered to the cantilever beam 1 through epoxy resin glue, and the internal fiber bragg grating 2 is connected with the external fiber waterproof aerial plug 3 through optical fibers.
The measurement process of the sensor is further explained as follows:
(1) firstly, connecting a tail connector of the waterproof aerial optical fiber plug with a demodulator, and then connecting a network cable between the demodulator and a computer, wherein a compensation algorithm carried by demodulation software can dynamically monitor the central wavelength of an optical fiber grating in a sensor;
(2) when the ship body moves under the heading, the base flange 13 connected with the ship body can generate the same attitude angle with the ship body, and further the cam 6 is driven to rotate through the main shaft 7, so that the effective radius of the cam is changed, the acting force of the cam 6 is changed, the fiber bragg grating 2 fixed on the cantilever beam further generates a deformation action, and finally the central wavelength of the fiber bragg grating is changed;
(3) the change of the central wavelength of the fiber bragg grating displayed by the demodulator in real time represents the change of the attitude angle of the ship body, when the attitude angle of the ship body where the ship is rocked is changed continuously, the change of the attitude angle of the ship body and the central wavelength of the fiber bragg grating basically presents a linear relation, and the relation between the central wavelength of the fiber and the change of the attitude angle generated by the ship yawing motion is finally obtained through a compensation algorithm at the demodulator end, so that the problem of dynamic measurement of the yawing attitude angle can be solved.
Example 2
Fig. 1 is the internal structure schematic diagram of the sensor of the present invention, including cantilever beam 1, fiber grating 2, waterproof aerial insertion 3 of optic fibre, sealing cover 4, set screw 5, cam 6, main shaft 7, sensor housing 8, bearing 10, base 11, supporting sleeve 12, base flange 13.
The cantilever beam 1 is an equal-strength cantilever beam processed by linear cutting, and can dynamically measure the attitude angle of the ship body, which is generated by bow shaking, under the condition of eliminating temperature interference by matching with a sensor transmission device and a sensor sensitive element. The fiber grating 2 is a double grating fiber, the fiber grating is a core sensitive element, and the fiber grating is adhered to the cantilever beam 1 through a fully transparent epoxy resin AB glue (commercially available). The optical fiber waterproof navigation plug 3 is a common stainless steel optical fiber watertight flange on the market, so that the corrosion resistance of the sensor can be improved, and the service life of the sensor can be prolonged. The sealing cover 4 is made of common aluminum materials and is sealed with the sensor shell 8 through a fixing screw 5. The fixing screw 5 is a stainless steel screw and plays a role in fixing in the sensor. The cam 6 is a circular cam with the changing effective radius, wherein the minimum radius of the cam is tightly attached to the sensing element cantilever beam 1 of the sensor. The main shaft 7 is machined from a common optical axis in the market, the upper part and the lower part of the main shaft are respectively connected with the cam 6 and the base flange 13, and the sensor shell 8 is machined from a common seamless steel pipe in the market without any splicing and welding process. Two bearings 10 are nested in the bearing sleeve 9, and a buckle in the bearing sleeve can be perfectly attached to the bearings. The bearing 10 is a national standard gear, and the inside of the bearing is a main shaft 7. The base 11 is used to fix the bearing sleeve 9 and the sensor housing 8. The support sleeve 12 is sandwiched between the bearing 10 and the base flange 13 to prevent the bearing from shifting in position during long-term use. The base flange 13 is connected with an external ship body to transfer an attitude angle generated by the ship body due to yawing motion.
Example 3
In the mechanics of materials, a special beam is provided, the section of the beam is rectangular, the surface of the beam is isosceles triangle, and the beam is uniform and equal in thickness. Constant strength cantilever beams are typical elastic elements that are commonly used as transducing elements in sensors.
lThe length of the cantilever beam with equal strength;xthe distance between a certain point on the beam and the fixed end;bis the cross-sectional width of the beam;his equal toThe thickness of the strength cantilever beam;fis the deflection value of the free end.
From the concept of equal strength
Is a constant. Constant strength cantilever beam free end forceFUnder the action, the strain at a certain position of the central axis of the surface of the constant-strength cantilever beam is as follows:
in the formula (I), the compound is shown in the specification,
is the strain value of the fixed end;lis the length of the beam;xthe distance from a certain position on the central axis of the beam to the fixed end;Ethe modulus of elasticity of the material being the beam;Ais the area of the beam cross section;his the thickness of the beam.
The constant strength cantilever beam is characterized in that the sectional areas at different distances from the fixed end are different, namely:
in the formula (I), the compound is shown in the specification,the width of the fixed end of the cantilever beam with equal strength;lis the length of the beam. Substitution of formula (1) can yield:
as can be seen from the equation (3), when the free end of the cantilever beam with equal strength is stressed, the strain at each position of the cantilever beam is equal. And because of the deflection of the free end of the cantilever beam with equal strengthfComprises the following steps:
substitution of formula (3) can yield:
as can be seen from the equation (5), the strain at the central axis of the surface of the constant strength cantilever beam is equal to the length of the beamlAnd thickness of the beamhAnd deflection of free end of cantilever beam with equal strengthfIt is related.
FIG. 2 is a schematic view of a cam, where R is the difference between the maximum radius and the minimum radius of the cam, i.e., the radius difference of the cam;
when the cam rotates, the constant-strength cantilever beam is subjected to strain change due to the change of the central radius. When the deflection of the free end of the cantilever beam with equal strength is small, the deflection can be approximate to the variation of the central radius of the cam, and at the moment, the deflection is smallfCan be expressed as:
in the formula (I), the compound is shown in the specification,
the angle of rotation of the cam. Substitution of formula (5) can yield:
two identical fiber gratings are respectively stuck on two sides of the equal-strength cantilever beam, and the two fibers are respectively subjected to tensile strain and compressive strain. Let the center wavelengths of the fiber gratings be
The central wavelengths of the two fiber gratings respectively change as follows:
（9）
in the formula:
for the sensitivity coefficient of the fiber grating with respect to strain,is the sensitivity coefficient of the fiber grating with respect to temperature.
When the free end of the cantilever beam with equal strength is acted by a cam, the fiber gratings are inevitably subjected to strain change, wherein one fiber grating is subjected to tensile strain, the other fiber grating is subjected to compressive strain, the absolute values of the strain of the two are equal in magnitude and opposite in direction, namelyAnd both are in the same environment, thereforeThus, it is possible to obtain:
substituting equation (7) can result in:
by analyzing and inverting the change of the central wavelength of the fiber bragg grating, a relational expression between the heading attitude angle and the central wavelength of the fiber bragg grating can be obtained. The length of the constant-strength cantilever beam, the thickness of the constant-strength cantilever beam and the radius difference of the cam can be changed by the formula (11) ((l、hAnd R) further adjusting the detection sensitivity of the sensor. Proves the bow attitude angle and the fiber grating center waveThe long variable quantities are in one-to-one correspondence, which is beneficial to improving the detection sensitivity of the sensor.
Claims (3)
1. A fiber grating sensor for measuring the bow motion of a ship body is characterized by mainly comprising: the device comprises a sensor sealing device, a sensor transmission device and a sensor sensitive element;
the sensor sealing device comprises an optical fiber waterproof aerial insert (3), a sealing cover (4), a fixing screw (5), a sensor shell (8) and a base (11); the sealing cover is provided with a threaded fixing hole, the sealing cover is sealed with the sensor shell (8) through a fixing screw (5), a sealing groove is formed in the sealing cover (4), a sealing strip is embedded in the sealing groove, the top of the sealing cover fixes the optical fiber waterproof aerial plug (3) through the screw, the sensor shell and the internal structure of the sensor are fixed through the screw on the base, and the bearing sleeve (9) and the sensor shell (8) are fixed through the base (11);
the sensor transmission device comprises a cam (6), a main shaft (7), a bearing sleeve (9), a bearing (10), a support sleeve (12) and a base flange (13); two bearings (10) are nested in a bearing sleeve (9), a main shaft (7) is arranged in each bearing, the upper part and the lower part of each main shaft are respectively connected with a cam (6) and a base flange (13), the minimum radius part of each cam is tightly attached to a sensitive element cantilever beam (1) of the sensor, and a support sleeve (12) is clamped between each bearing (10) and the corresponding base flange (13);
the sensor sensitive element comprises a cantilever beam (1) and a fiber grating (2); the fiber grating is adhered to the cantilever beam through epoxy resin glue, and the internal fiber grating (2) is connected with the external fiber waterproof aerial plug (3) through optical fibers.
2. The fiber grating sensor for measuring bow motion of a ship hull according to claim 1, wherein: the fiber grating (2) in the internal structure of the sensor is a core sensitive element.
3. The fiber grating sensor for measuring bow motion of a ship hull according to claim 1, wherein: and sealing grooves are formed in the periphery of the sealing cover, and sealing strips are embedded in the sealing grooves.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920906160.0U CN209910639U (en) | 2019-06-17 | 2019-06-17 | Fiber grating sensor for measuring bow motion of ship body |
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| CN201920906160.0U CN209910639U (en) | 2019-06-17 | 2019-06-17 | Fiber grating sensor for measuring bow motion of ship body |
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