A liquid level trajectory-based liquid level measurement system and method

Abstract

The application discloses a liquid level trajectory capturing-based liquid level measuring system and method, which comprises a collimating light source, an excitation optical fiber, a floating plate, a receiving optical fiber support, a receiving optical fiber bundle, a receiving optical fiber concentrator and a liquid level image trajectory capturing device; a plurality of equidistant support holes are arranged on the receiving optical fiber support in a vertical direction; the end face of the excitation 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 concentrator is used for collecting the end faces of the output ends of all the receiving optical fibers in the receiving optical fiber bundle on the same plane; the liquid level image trajectory capturing device is used for acquiring the image of the end face of the output end of the receiving optical fiber bundle, identifying the bright spots in the acquired image and the positions of the bright spots in the image, and obtaining the current liquid level height according to the positions of the bright spots and the mapping relationship between the bright spot positions and the liquid level height. The application solves the problems of low measuring precision, poor anti-interference and poor reliability of the continuous liquid level height of the liquid in the liquid medium storage device of an aerospace vehicle.

Description

Technical Field

[0001] This invention belongs to the field of measurement technology, specifically relating to a liquid level height measurement system and method based on liquid level trajectory capture. Background Technology

[0002] Currently, most aircraft in China use capacitive fuel level sensors and float-resistive fuel level sensors for fuel quantity measurement. The capacitive fuel level sensor works by utilizing the difference in dielectric constants between air and the measured liquid, converting changes in liquid level into changes in capacitance to measure the liquid level height. However, capacitive fuel level sensors suffer from problems such as susceptibility to interference, the need for separate temperature compensation, and the risk of false alarms due to water deposits in the fuel causing short circuits. The float-resistive fuel level sensor uses a sufficiently large float connected to a lever mechanism on a constant torque or pendulum. The float's movement with the liquid level drives a gear mechanism, which in turn drives a brush to slide, outputting different resistance values ​​to measure the liquid level. However, the float-resistive fuel level sensor suffers from problems such as large size, heavy weight, low measurement accuracy, and poor reliability. Summary of the Invention

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

[0004] This invention is achieved through the following technical solution:

[0005] A liquid level height measurement system based on liquid level trajectory capture includes: a collimating light source, an excitation fiber, a float, a receiving fiber support, a receiving fiber bundle, a receiving fiber collector, and a liquid level image trajectory capture device.

[0006] The collimating light source provides an optical signal to the receiving fiber bundle through an excitation fiber, one end of which is fixed to a floating plate.

[0007] The receiving optical fiber support has multiple equally spaced support holes arranged along the vertical direction.

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

[0009] The receiving fiber optic converging unit is connected to the other end of the receiving fiber in the receiving fiber bundle. The receiving fiber optic converging unit is used to converge the output end faces of all the receiving fibers in the receiving fiber bundle onto the same plane.

[0010] The liquid level image trajectory capture device is used to acquire an image of the output end face of the receiving optical fiber bundle, identify the bright spots in the acquired image and their positions in the image, and obtain the current liquid level height based on the positions of the bright spots and the mapping relationship between the bright spot positions and the liquid level height.

[0011] In some embodiments, a guide rail is also included, which is disposed opposite to the receiving optical fiber support column. The floating plate has a floating plate hole in the middle that matches the guide rail. The floating plate can slide up and down along the guide rail, so that the excitation optical fiber end face on the floating plate is disposed opposite to the receiving optical fiber end face in the support column hole.

[0012] In some embodiments, the float plate hole is an oblong hole, and the guide rail is an oblong guide rail.

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

[0014] In some embodiments, the float is made of polyether foam.

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

[0016] This invention also relates to a liquid level height measurement method based on liquid level trajectory capture. Using the aforementioned liquid level height measurement system, a float is positioned on the liquid surface so that it can move up and down with the liquid level. During this movement, the optical signal output by the excitation optical fiber can be received by the receiving optical fiber of the receiving optical fiber bundle; including:

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

[0018] Identify the bright spots in the acquired image and their locations within the image. Calculate the current liquid level based on the location of the bright spots and the mapping relationship between their locations 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 of the two height data is taken 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. This invention uses a collimated light source to provide an optical signal to the receiving fiber bundle through an excitation fiber. The liquid level image trajectory capture device acquires an image of the output end face of the receiving fiber bundle and identifies the bright spots in the acquired image and their positions in the image. Based on the positions of the bright spots and the mapping relationship between the bright spot positions and the liquid level height, the current liquid level height is obtained, which improves the measurement accuracy, anti-interference and reliability of continuous liquid level height, and is suitable for complex environments such as flammable and explosive environments.

[0022] 2. The oval hole of the float plate is used to slide in conjunction with the oval guide rail, so that the float plate does not change its orientation as the liquid level rises or falls. This ensures that the end face of the excitation fiber on the float plate is always aligned with the end face of the receiving fiber in the support hole, so that the receiving fiber can receive the light signal emitted by the excitation fiber well, thereby improving the transmission accuracy of the light signal and thus improving the measurement accuracy of the system. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the liquid level height 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 received optical fiber bundle in an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the guide rail structure in an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the structure of the floating plate in an embodiment of the present invention.

[0028] Among them: 1-Liquid level image trajectory capture device, 2-Collimating light source, 3-Receiving fiber optic collector, 4-Receiving fiber optic bundle, 5-Excitation fiber, 6-Guide rail, 7-Floating plate, 8-Receiving fiber optic support, 9-Collimator, 10-Floating point, 11-Bright spot. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0030] Example 1

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

[0032] Collimating light source 2, excitation fiber 5, float 7, receiving fiber support 8, receiving fiber bundle 4, receiving fiber collector 3, and liquid level image trajectory capture device 1;

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

[0034] The receiving fiber optic support has multiple equally spaced support holes along the vertical direction.

[0035] One end of the receiving fiber in the receiving fiber bundle 4 is inserted into and fixed in the support hole of the receiving fiber support 8, and the end face of the excitation fiber on the float 7 is set opposite to the end face of the receiving fiber in the support hole.

[0036] The receiving fiber optic concentrator 3 is connected to the other end of the receiving fiber in the receiving fiber bundle 4. The receiving fiber optic concentrator 3 is used to gather the output end faces of all the receiving fibers in the receiving fiber bundle 4 onto the same plane.

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

[0038] This invention employs a collimated light source 2 to provide an optical signal to a receiving fiber bundle 4 via an excitation fiber 5. The liquid level image trajectory capture device 1 acquires an image of the output end face of the receiving fiber bundle and identifies the bright spot 11 in the acquired image and its position in the image. Based on the position of the bright spot 11 and the mapping relationship between the bright spot position and the liquid level height, the current liquid level height is obtained, which improves the measurement accuracy, anti-interference and reliability of continuous liquid level height, and is suitable for complex environments such as flammable and explosive environments.

[0039] The collimated light source 2 uses LED white light and serves as the excitation light source for the liquid level measurement system. Using light for signal transmission helps it withstand the complex electromagnetic environment of aviation and aerospace equipment.

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

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

[0042] The receiving fiber optic support 8 is 3mm long, 5mm wide, and 500mm high, and is made of reinforced nylon material. There are 1000 support holes with a diameter of 0.3mm arranged at 0.5mm intervals along the vertical direction on the receiving fiber optic support. The spacing between the support holes affects the accuracy of liquid level measurement. The shorter the spacing between the support holes, the higher the accuracy of liquid level measurement.

[0043] The receiving optical fiber is made of PMMA material with a diameter of 0.25mm. Epoxy resin adhesive is used to fix one end of the receiving optical fiber inserted into the support hole on the receiving optical fiber support 8.

[0044] The receiving fiber optic concentrator 3 is made of polyoxymethylene material with a diameter of 50mm and a thickness of 2mm. The receiving fiber optic concentrator 3 has 1000 holes with a diameter of 0.3mm. The other end of the receiving fiber is arbitrarily inserted into the hole of the receiving fiber optic concentrator and fixed with epoxy resin adhesive. The output end of the receiving fiber optic concentrator is polished flat using a grinding machine. When the receiving fiber optic concentrator 3 receives the optical signal transmitted by the receiving fiber, a bright spot indicating the height of the reaction liquid level will be displayed at the output end of the receiving fiber optic concentrator.

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

[0046] In some embodiments, a guide rail 6 is also included. The guide rail 6 is disposed opposite to the receiving optical fiber support 8. A floating plate hole matching the guide rail 6 is provided in the middle of the floating plate. The guide rail 6 passes through the floating plate hole. The floating plate 7 can slide up and down along the guide rail 6 without jamming or sticking. This allows the excitation optical fiber end face on the floating plate 7 to be disposed opposite to the receiving optical fiber end face in the support hole.

[0047] In some embodiments, refer to Figure 3 , Figure 4 The float plate hole is an oblong hole, and the guide rail 6 is an oblong guide rail.

[0048] The diameter of the waist-shaped guide rail is 3mm.

[0049] The float plate 7 is slidably connected to the waist-shaped guide rail with the waist-shaped hole, so that the float plate 7 does not change its orientation as the liquid level rises or falls. This ensures that the end face of the excitation fiber on the float plate 7 is always aligned with the end face of the receiving fiber in the support hole, so that the receiving fiber can receive the light signal emitted by the excitation fiber well, thereby improving the transmission accuracy of the light signal and thus improving the measurement accuracy of the system.

[0050] By using the floating arrangement of float plate 7 within the medium storage device of the aircraft, float plate 7 can adapt to different liquid level conditions within the medium storage device, making it well-suited for accurate vertical measurement of the medium liquid level under different flight conditions of the aircraft.

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

[0052] In some embodiments, the float 7 is made of polyether foam.

[0053] In some embodiments, the end face of the support hole facing the excitation fiber is configured as a countersunk hole. Using a countersunk hole to process the end face of the support hole makes the end face of the support hole flat, which is beneficial for the receiving fiber to receive the optical signal transmitted by the excitation fiber 5, and improves the accuracy of the receiving fiber in receiving the optical signal.

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

[0055] This invention also relates to a liquid level height measurement method based on liquid level trajectory capture. Using the aforementioned liquid level height measurement system, a float 7 is placed on the liquid surface so that the float 7 can move up and down with the liquid surface, and during the movement, the optical signal output by the excitation fiber 5 can be received by the receiving fiber of the receiving fiber bundle 4; including:

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

[0057] Identify the bright spot 11 in the acquired image and its position in the image. Based on the position of the bright spot 11 and the mapping relationship between the bright spot position and the liquid level, obtain the current 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 of the height data is taken as the current liquid level height data.

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

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

[0061] When the receiving optical fiber is inserted into 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 output end face of the receiving optical fiber bundle is recorded. The position of the bright spot is associated with the corresponding receiving optical fiber number, and then the receiving optical fiber number is associated with the corresponding liquid level height. The mapping relationship between the position of the bright spot and the liquid level height is established and stored in the liquid level image trajectory capture device 1.

[0062] The image at the output end of the receiving fiber optic bundle is acquired using a macro camera of the liquid level image trajectory capture device 1.

[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 location of the bright spot 11 in the image. Then, based on the location of the bright spot 11, the MPU processor of the liquid level image trajectory capture device 1 finds the mapping relationship between the bright spot location and the corresponding liquid level height to obtain the current liquid level height.

[0064] The location H0 of the bright spot indicating the height of the reaction liquid level is obtained by identifying bright spot 11 in the image of the received fiber optic bundle output end.

[0065]

[0066] If two bright spots appear simultaneously in the image at the output of the receiving fiber optic bundle, the bright spot at position H1 (i.e., below height H0) should be removed.

[0067]

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A liquid level height measurement system based on liquid level trajectory capture, characterized in that, include: Collimating light source, excitation fiber, float plate, receiving fiber support, receiving fiber bundle, receiving fiber collector and liquid level image trajectory capture device; The collimating light source provides an optical signal to the receiving fiber bundle through an excitation fiber, one end of which is fixed to a floating plate. The receiving optical fiber support has multiple equally spaced support holes arranged along the vertical direction. One end of the receiving fiber in the receiving fiber bundle is inserted into and fixed in the support hole of the receiving fiber support column, and the end face of the excitation fiber on the floating plate is arranged opposite to the end face of the receiving fiber in the support hole. The receiving fiber optic converging unit is connected to the other end of the receiving fiber in the receiving fiber bundle. The receiving fiber optic converging unit is used to converge the output end faces of all the receiving fibers in the receiving fiber bundle onto the same plane. The liquid level image trajectory capture device is used to acquire an image of the output end face of the receiving optical fiber bundle, identify the bright spots in the acquired image and the position of the bright spots in the image, and obtain the current liquid level height based on the position of the bright spots and the mapping relationship between the position of the bright spots and the liquid level height. It also includes a guide rail, which is arranged opposite to the receiving fiber support column. The floating plate has a floating plate hole in the middle that matches the guide rail. The floating plate can slide up and down along the guide rail so that the end face of the excitation fiber on the floating plate is arranged opposite to the end face of the receiving fiber in the support column hole. The end face of the support column hole facing the end of the excitation fiber is set as a countersunk hole.

2. The liquid level height measurement system based on liquid level trajectory capture according to claim 1, characterized in that, The floating plate has a waist-shaped hole, and the guide rail is a waist-shaped guide rail.

3. A liquid level height measurement system based on liquid level trajectory capture according to claim 1 or 2, characterized in that, The guide rail is made of reinforced nylon material.

4. A liquid level height measurement system based on liquid level trajectory capture according to claim 1 or 2, characterized in that, The float is made of polyether foam.

5. A method for measuring liquid level height based on liquid level trajectory capture, characterized in that, The liquid level measurement system according to any one of claims 1-4 includes a float positioned on the liquid surface, allowing the float to move up and down with the liquid level, and during this movement, the optical signal output by the excitation optical fiber can be received by the receiving optical fiber of the receiving optical fiber bundle; comprising: Acquire an image of the output end face of the receiving fiber optic bundle; Identify the bright spots in the acquired image and their locations within the image. Calculate the current liquid level based on the location of the bright spots and the mapping relationship between their locations and the liquid level.

6. The method for measuring liquid level height based on liquid level trajectory capture according to claim 5, 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 acquired respectively, and the larger of the two height data is taken as the current liquid level height data.

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