Liquid level height measuring system and method based on liquid level trajectory capture

Abstract

The invention discloses a liquid level height measuring system and method based on liquid level track capturing. The system comprises a collimation light source, an excitation optical fiber, a floating plate, a receiving optical fiber supporting column, a receiving optical fiber bundle, a receiving optical fiber collector and a liquid level image track capturing device. A plurality of equidistant strut holes are formed in the receiving optical fiber strut along the vertical direction; the excitation fiber end face on the floating plate is opposite to the receiving fiber end face in the pillar hole; the receiving optical fiber collector is used for collecting the end faces of the output ends of all receiving optical fibers in the receiving optical fiber bundle on the same plane; the liquid level image track capturing device is used for acquiring an image of the end face of the output end of the receiving optical fiber bundle, identifying a bright spot in the acquired image and the position of the bright spot in the image, and obtaining the current liquid level height according to the position of the bright spot and the mapping relation between the position of the bright spot and the liquid level height. According to the invention, the problems of low measurement precision, poor interference resistance and poor reliability of the continuous liquid level height of liquid in a liquid medium storage device of an aerospace craft are solved.

Description

Technical Field

[0001] The present invention belongs to the field of measurement technology, and in particular relates to a liquid level height measurement system and method based on liquid level trajectory capture. Background Art

[0002] At present, domestic aircraft mostly use capacitive fuel level sensors and float resistance fuel level sensors for fuel level measurement. The measurement principle of the capacitive fuel level sensor is to use the different dielectric constants between air and the measured liquid to convert the liquid level change into capacitance change to measure the liquid level; however, the capacitive fuel level sensor has the problem that the capacitance signal is easily interfered, requires separate temperature compensation, and the water deposited in the fuel will cause the sensor to short-circuit and cause false alarms. The measurement principle of the float resistance fuel level sensor is to use a large enough float, and the lever mechanism is connected to the constant torque or pendulum. The float drives the rotation of the gear mechanism with the rise and fall of the liquid level, thereby driving the brush to slide, outputting different resistance values, and realizing the measurement of the liquid level; however, the float resistance fuel level sensor has the problems of large size, large weight, low measurement accuracy, and poor reliability. Summary of the invention

[0003] The purpose of the present invention is to provide a liquid level measurement system and method based on liquid level trajectory capture to solve the problems of low measurement accuracy, poor anti-interference and poor reliability of continuous liquid level measurement in liquid medium storage devices of aerospace vehicles.

[0004] The present invention is achieved through the following technical solutions:

[0005] A liquid level height measurement system based on liquid level trajectory capture, comprising: a collimated light source, an excitation optical fiber, a floating plate, a receiving optical fiber support, a receiving optical fiber bundle, a receiving optical fiber collector and a liquid level image trajectory capture device;

[0006] The collimated light source provides an optical signal to the receiving optical fiber bundle through an excitation optical fiber, and one end of the excitation optical fiber is fixed on the floating plate;

[0007] The receiving optical fiber support pillar is provided with a plurality of support holes at equal intervals in the vertical direction;

[0008] One end of the receiving optical fiber in the receiving optical fiber bundle is inserted into and fixed in the support hole of the receiving optical fiber support, and the end face of the exciting optical fiber on the floating plate is arranged opposite to the end face of the receiving optical fiber in the support hole;

[0009] The receiving optical fiber collector is connected to the other end of the receiving optical fiber in the receiving optical fiber bundle, and the receiving optical fiber collector is used to collect the output end faces of all the receiving optical fibers in the receiving optical fiber bundle into the same plane;

[0010] The liquid level image trajectory capture device is used to obtain an image of the end face of the output end of the receiving optical fiber bundle, and identify the bright spot in the obtained image and the position of the bright spot in the image, and obtain the current liquid level according to the position of the bright spot and the mapping relationship between the position of the bright spot and the liquid level.

[0011] In some embodiments, a guide rail is further included, which is arranged opposite to the receiving optical fiber pillar. A floating plate hole matching the guide rail is arranged in the middle of the floating plate. The floating plate can slide up and down along the guide rail so that the end face of the exciting optical fiber on the floating plate is arranged opposite to the end face of the receiving optical fiber in the pillar hole.

[0012] In some embodiments, the floating plate hole is a waist-shaped hole, and the guide rail is a waist-shaped guide rail.

[0013] In some embodiments, the guide rail is made of reinforced nylon material.

[0014] In some embodiments, the floating plate is made of polyether foam plastic.

[0015] In some embodiments, the end face of the pillar hole facing one end of the excitation optical fiber is configured as a countersunk hole.

[0016] The present invention also relates to a liquid level measurement method based on liquid level trajectory capture, which adopts the above-mentioned liquid level measurement system, arranges a floating plate on the liquid surface so that the floating plate can move up and down with the liquid surface and excites the optical signal output by the optical fiber to be received by the receiving optical fiber of the receiving optical fiber bundle during the movement; comprising:

[0017] Acquire an image of the end face of the output end of the receiving optical fiber bundle;

[0018] The bright spot in the acquired image and the position of the bright spot in the image are identified, and the current liquid level is obtained according to the position of the bright spot and the mapping relationship between the position of the bright spot and the liquid level.

[0019] In some embodiments, when there are two bright spots in the acquired image, the liquid level height data corresponding to the two bright spots are acquired respectively, and the larger height data is used as the current liquid level height data.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] 1. The present invention adopts a collimated light source to provide an optical signal to a receiving optical fiber bundle through an excitation optical fiber. The liquid level image trajectory capture device obtains an image of the end face of the output end of the receiving optical fiber bundle, and identifies the bright spot in the obtained image and the position of the bright spot in the image. The current liquid level is obtained according to the position of the bright spot and the mapping relationship between the position of the bright spot and the liquid level, thereby improving the measurement accuracy, anti-interference and reliability of the continuous liquid level, and is suitable for complex environments such as flammable and explosive environments.

[0022] 2. The waist-shaped hole of the floating plate is used to slide in cooperation with the waist-shaped guide rail, so that the floating plate does not change its position as the liquid level rises or falls, ensuring that the end face of the excitation optical fiber on the floating plate is always facing the end face of the receiving optical fiber in the support hole, so that the receiving optical fiber can well receive the optical signal emitted by the excitation optical fiber, thereby improving the transmission accuracy of the optical signal and thus improving the measurement accuracy of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 Schematic diagram of the structure of a liquid level measurement system based on liquid level trajectory capture in an embodiment of the present invention.

[0025] Figure 2 This is an image of the bright spot at the output end of the receiving optical fiber bundle in an embodiment of the present invention.

[0026] Figure 3 Schematic diagram of the structure of the guide rail in an embodiment of the present invention.

[0027] Figure 4 Schematic diagram of the structure of the floating plate in an embodiment of the present invention.

[0028] Among them: 1-liquid level image trajectory capturing device, 2-collimated light source, 3-receiving fiber collector, 4-receiving fiber bundle, 5-excitation fiber, 6-guide rail, 7-floating plate, 8-receiving fiber support, 9-collimator, 10-floating point, 11-bright spot. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0030] Example 1

[0031] A liquid level measurement system based on liquid level trajectory capture, referring to Figure 1 , Figure 2 and Figure 4 ,include:

[0032] A collimated light source 2, an excitation optical fiber 5, a floating plate 7, a receiving optical fiber support 8, a receiving optical fiber bundle 4, a receiving optical fiber collector 3 and a liquid level image trajectory capturing device 1;

[0033] The collimated light source 2 provides an optical signal to the receiving optical fiber bundle 4 through the excitation optical fiber 5, and one end of the excitation optical fiber is fixed on the floating plate 7;

[0034] A plurality of equally spaced support holes are arranged on the receiving optical fiber support in the vertical direction;

[0035] One end of the receiving optical fiber in the receiving optical fiber bundle 4 is inserted into and fixed in the support hole of the receiving optical fiber support 8, and the end face of the exciting optical fiber on the floating plate 7 is arranged opposite to the end face of the receiving optical fiber in the support hole;

[0036] The receiving optical fiber collector 3 is connected to the other end of the receiving optical fiber in the receiving optical fiber bundle 4, and the receiving optical fiber collector 3 is used to collect the output end faces of all the receiving optical fibers in the receiving optical fiber bundle 4 into the same plane;

[0037] The liquid level image trajectory capture device 1 is used to obtain an image of the end face of the output end of the receiving optical fiber bundle, and identify the bright spot 11 in the obtained image and the position of the bright spot 11 in the image, and obtain the current liquid level according to the position of the bright spot 11 and the mapping relationship between the bright spot position and the liquid level.

[0038] The present invention adopts a collimated light source 2 to provide a light signal to a receiving optical fiber bundle 4 through an excitation optical fiber 5. The liquid level image trajectory capture device 1 obtains an image of the end face of the output end of the receiving optical fiber bundle, and identifies a bright spot 11 in the obtained image and the position of the bright spot 11 in the image. The current liquid level is obtained according to the position of the bright spot 11 and the mapping relationship between the position of the bright spot and the liquid level, thereby improving the measurement accuracy, anti-interference and reliability of the continuous liquid level, and is suitable for complex environments such as flammable and explosive environments.

[0039] The collimated light source 2 uses LED white light and is used as the excitation light source of the liquid level measurement system. Using light as signal transmission can resist the complex electromagnetic environment in aviation and aerospace equipment.

[0040] The excitation optical fiber 5 is made of PMMA material with a diameter of 0.5 mm. One end of the excitation optical fiber is bonded to the floating plate 7, and the end face of the excitation optical fiber is fixed to the collimator 9, thereby ensuring the light quality of the optical signal transmitted by the excitation optical fiber 5 when it is emitted.

[0041] Adjust the distance between the collimator 9 on the floating plate 7 and the receiving fiber pillar 8 to ensure that the optical signal emitted by the excitation fiber 5 covers at least 1 to 2 receiving fiber end faces in the receiving fiber pillar 8, so that a bright spot 11 is always generated at the output end of the receiving fiber collector when the floating plate 7 rises or falls.

[0042] The receiving optical fiber pillar 8 has a length of 3 mm, a width of 5 mm, and a height of 500 mm. It is made of reinforced nylon material. Pillar holes with a diameter of 0.3 mm are arranged on the receiving optical fiber pillar at a spacing of 0.5 mm in the vertical direction. There are 1000 pillar holes. The spacing between the pillar holes affects the accuracy of the liquid level measurement. The shorter the spacing between the pillar holes, the higher the accuracy of the liquid level measurement.

[0043] The receiving optical fiber is made of PMMA material with a diameter of 0.25 mm, and one end of the receiving optical fiber inserted into the support hole on the receiving optical fiber support 8 is fixed using epoxy resin adhesive.

[0044] The receiving optical fiber concentrator 3 is made of polyformaldehyde material with a diameter of 50mm and a thickness of 2mm. The receiving optical fiber concentrator 3 is provided with small holes with a diameter of 0.3mm, and the number of small holes is 1000. The other end of the receiving optical fiber is inserted into the small hole of the receiving optical fiber concentrator arbitrarily, and the other end of the receiving optical fiber inserted into the small hole of the receiving optical fiber concentrator is fixed with epoxy resin adhesive, and the output end of the receiving optical fiber concentrator is polished and flat with a grinder; when the receiving optical fiber concentrator 3 receives the optical signal transmitted by the receiving optical fiber, a bright spot reflecting the liquid level height will be displayed at the output end of the receiving optical fiber concentrator.

[0045] The liquid level image trajectory capturing device 1 comprises a macro camera and an MPU processor, and the liquid level image trajectory capturing device 1 is placed outside the fuel tank.

[0046] In some embodiments, a guide rail 6 is also included, which is arranged opposite to the receiving optical fiber pillar 8. A floating plate hole matching the guide rail 6 is arranged in the middle of the floating plate. The guide rail 6 passes through the floating plate hole, and the floating plate 7 can slide up and down along the guide rail 6 without sticking or adhesion, so that the end face of the excitation optical fiber on the floating plate 7 is arranged opposite to the end face of the receiving optical fiber in the pillar hole.

[0047] In some embodiments, reference Figure 3 , Figure 4 , the floating plate hole is a waist-shaped hole, and the guide rail 6 is a waist-shaped guide rail.

[0048] Among them, the diameter of the waist-shaped guide rail is 3mm.

[0049] The waist-shaped hole of the floating plate is used to slide in cooperation with the waist-shaped guide rail, so that the floating plate 7 does not change its orientation as the liquid level rises or falls, ensuring that the end face of the excitation optical fiber on the floating plate 7 is always facing the end face of the receiving optical fiber in the support hole, so that the receiving optical fiber can well receive the optical signal emitted by the excitation optical fiber, thereby improving the transmission accuracy of the optical signal and thus improving the measurement accuracy of the system.

[0050] By the floating arrangement of the float plate 7 in the aircraft medium storage device, the float plate 7 can adapt to different conditions of the liquid level in the medium storage device, and can be well applied to the accurate measurement of the medium liquid level in the vertical direction under different flight conditions of the aircraft.

[0051] In some embodiments, the guide rail 6 is made of reinforced nylon material. The use of reinforced nylon material can improve the wear resistance, impact resistance and self-lubrication of the guide rail 6.

[0052] In some embodiments, the floating plate 7 is made of polyether foam plastic.

[0053] In some embodiments, the end face of the pillar hole facing one end of the excitation optical fiber is set as a countersink. The end face of the pillar hole is processed by the countersink to make the end face of the pillar hole flat, which is conducive to the receiving optical fiber receiving the optical signal transmitted by the excitation optical fiber 5 and improving the accuracy of the receiving optical fiber receiving the optical signal.

[0054] The end surface of one end of the receiving optical fiber that passes through the supporting hole is flush with the bottom of the countersunk hole.

[0055] The present invention also relates to a liquid level measurement method based on liquid level trajectory capture, which adopts the above-mentioned liquid level measurement system, arranges a floating plate 7 on the liquid surface so that the floating plate 7 can move up and down with the liquid surface and excites the optical fiber 5 to output an optical signal that can be received by a receiving optical fiber of a receiving optical fiber bundle 4 during the movement; comprising:

[0056] Acquire an image of the end face of the output end of the receiving optical fiber bundle;

[0057] The bright spot 11 in the acquired image and the position of the bright spot 11 in the image are identified, and the current liquid level is obtained according to the position of the bright spot 11 and the mapping relationship between the position of the bright spot and the liquid level.

[0058] In some embodiments, when there are two bright spots 11 in the acquired image, the liquid level height data corresponding to the two bright spots 11 are acquired respectively, and the larger height data is used as the current liquid level height data.

[0059] When the receiving optical fiber is connected to the receiving optical fiber collector 3, determining the liquid level corresponding to the bright spot 11 in the image of the end face of the output end of the receiving optical fiber bundle comprises the following steps:

[0060] The receiving optical fibers on the receiving optical fiber support 8 are numbered from bottom to top, and all the receiving optical fibers are numbered 1, 2, ..., 1000 respectively; the height of the receiving optical fiber support 8 is 500 mm, and the height of the receiving optical fiber support is equal to the highest height of the liquid level to be measured, and the spacing between two adjacent support holes on the receiving optical fiber support 8 is 0.5 mm. If the spacing between two adjacent receiving optical fibers on the receiving optical fiber support is 0.5 mm, then the liquid level height corresponding to the receiving optical fiber 1 is 0.5 mm, and the liquid level height corresponding to the receiving optical fiber 2 is 1 mm, and the liquid level height corresponding to any receiving optical fiber i (i=1, ..., 1000) is i*0.5 mm;

[0061] When the receiving optical fiber passes through the receiving optical fiber collector 3, the receiving optical fiber number corresponding to the position of each bright spot 11 in the image of the end face of the output end of the receiving optical fiber bundle is recorded, and the bright spot position is associated with the corresponding receiving optical fiber number, and then the receiving optical fiber number is associated with the corresponding liquid level height, and a mapping relationship between the bright spot position and the liquid level height is established and stored in the liquid level image trajectory capture device 1.

[0062] Use the macro camera of the liquid level image trajectory capture device 1 to obtain an image of the output end of the receiving optical fiber bundle;

[0063] The MPU processor of the liquid level image trajectory capture device 1 is used to identify the acquired image, identify the bright spot 11 in the image and calculate the position of the bright spot 11 in the image. The MPU processor of the liquid level image trajectory capture device 1 then searches for the mapping relationship between the bright spot position and the corresponding liquid level height based on the position of the bright spot 11 to obtain the current liquid level height.

[0064] The bright spot position H0 of the reaction liquid level is obtained by identifying the bright spot 11 in the image obtained at the output end of the receiving optical fiber bundle.

[0065]

[0066] If two bright spots appear simultaneously in the image at the output end of the receiving fiber bundle, the bright spot at the floating point 10 position H1, which is lower than the height H0, needs to be removed.

[0067]

[0068] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A liquid level measurement system based on liquid level trajectory capture, characterized in that: include: A collimated light source, an excitation optical fiber, a floating plate, a receiving optical fiber support, a receiving optical fiber bundle, a receiving optical fiber collector and a liquid level image trajectory capturing device; The collimated light source provides an optical signal to the receiving optical fiber bundle through an excitation optical fiber, and one end of the excitation optical fiber is fixed on the floating plate; The receiving optical fiber support pillar is provided with a plurality of support holes at equal intervals in the vertical direction; One end of the receiving optical fiber in the receiving optical fiber bundle is inserted into and fixed in the support hole of the receiving optical fiber support, and the end face of the exciting optical fiber on the floating plate is arranged opposite to the end face of the receiving optical fiber in the support hole; The receiving optical fiber collector is connected to the other end of the receiving optical fiber in the receiving optical fiber bundle, and the receiving optical fiber collector is used to collect the output end faces of all the receiving optical fibers in the receiving optical fiber bundle into the same plane; The liquid level image trajectory capture device is used to obtain an image of the end face of the output end of the receiving optical fiber bundle, and identify the bright spot in the obtained image and the position of the bright spot in the image, and obtain the current liquid level according to the position of the bright spot and the mapping relationship between the position of the bright spot and the liquid level.

2. A liquid level measurement system based on liquid level trajectory capture according to claim 1, characterized in that: It also includes a guide rail, which is arranged opposite to the receiving optical fiber pillar. A floating plate hole matching the guide rail is arranged in the middle of the floating plate. The floating plate can slide up and down along the guide rail so that the end face of the exciting optical fiber on the floating plate is arranged opposite to the end face of the receiving optical fiber in the pillar hole.

3. A liquid level measurement system based on liquid level trajectory capture according to claim 2, characterized in that: The floating plate hole is a waist-shaped hole, and the guide rail is a waist-shaped guide rail.

4. A liquid level measurement system based on liquid level trajectory capture according to claim 2 or 3, characterized in that: The guide rail is made of reinforced nylon material.

5. A liquid level measurement system based on liquid level trajectory capture according to any one of claims 1, 2 or 3, characterized in that: The floating plate is made of polyether foam plastic.

6. The liquid level measurement system based on liquid level trajectory capture according to claim 1, characterized in that: The end surface of the pillar hole facing one end of the excitation optical fiber is configured as a countersunk hole.

7. A liquid level measurement method based on liquid level trajectory capture, characterized in that: A liquid level measurement system according to any one of claims 1 to 6 is adopted, wherein a floating plate is arranged on the liquid surface so that the floating plate can move up and down with the liquid surface and during the movement, an optical signal output by the excitation optical fiber can be received by a receiving optical fiber of a receiving optical fiber bundle; comprising: Acquire an image of the end face of the output end of the receiving optical fiber bundle; The bright spot in the acquired image and the position of the bright spot in the image are identified, and the current liquid level is obtained according to the position of the bright spot and the mapping relationship between the position of the bright spot and the liquid level.

8. The method for measuring liquid level based on liquid level trajectory capture according to claim 7, characterized in that: When there are two bright spots in the acquired image, the liquid level height data corresponding to the two bright spots are respectively acquired, and the larger height data is used as the current liquid level height data.

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