A liquid tank volume gas phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response

Abstract

A liquid tank volume measurement device based on multi-frequency gas bidirectional micro-disturbance response is disclosed. The device includes a multi-frequency gas micro-disturbance generation system, a gas inlet system, a gas outlet system, a self-cleaning device, a control system, a compartment pressure sensor, a compartment pressure spectrum identification module, a liquid flow meter, and free surface damping and damping limit rods. The control system first applies a base gas flow rate to coarsely measure the liquid tank's gas phase volume, obtaining an initial estimate. Then, at least two gas micro-disturbances of different frequencies are applied near the initial estimate, and the pressure dynamic response characteristics are collected and compared with a preset model to finely correct the gas phase volume. Finally, the liquid volume is calculated based on the total compartment volume. By indirectly measuring liquid volume through gas phase identification, the influence of ship motion and free surface oscillation on liquid level measurement is fundamentally eliminated. This method offers advantages such as high measurement accuracy, strong anti-interference capability, no liquid contact required, and low maintenance costs.

Description

Technical Field

[0001] This invention relates to the field of liquid tank measurement technology in ships and marine engineering, and in particular to a liquid tank volume gas phase identification and measurement device based on multi-frequency gas bidirectional micro-disturbance response. Background Technology

[0002] With the rapid development of unmanned ships, intelligent ships, and offshore operation platforms, higher demands are being placed on the accurate acquisition of liquid volume information in tanks under complex sea conditions and multiple operating conditions. Liquid volume data is not only related to ship load management, stability control, and energy efficiency optimization, but also directly affects safety decision-making and the accuracy of automatic control during unmanned navigation. Therefore, achieving accurate and stable measurement of liquid volume in tanks under complex motion environments has become one of the key technologies for the intelligent development of ships.

[0003] Currently, the measurement of liquid volume in ship tanks mainly relies on liquid level measurement methods, including hydrostatic level pressure sensors, float-type level gauges, and contact or non-contact level measurement devices. These methods measure the liquid level height and convert it to liquid volume by combining the tank assembly parameters. However, in practical applications, ships are constantly in motion environments with significant acceleration changes, and are affected by various factors such as pitch, roll, heave, and wave excitation, resulting in obvious unsteady and irregular fluctuations in the free surface of the liquid inside the tanks.

[0004] Under the aforementioned conditions, the liquid level is difficult to maintain a stable or calculable state at any given time, and the liquid level measurement results fluctuate drastically over time. This makes it impossible to obtain accurate and reliable liquid volume information using methods based on liquid level-volume conversion. Even averaging multiple measurements cannot eliminate the systematic errors introduced by changes in the free surface morphology. Furthermore, the complex internal structure and irregular shape of the liquid tank cause the mapping relationship between liquid level and liquid volume to exhibit highly nonlinear characteristics, further amplifying the measurement error. To improve measurement stability, some existing technologies attempt to reduce measurement errors by adding liquid level filtering, attitude compensation, or acceleration correction. However, these methods essentially still use liquid level as the measurement target and cannot fundamentally eliminate the influence of ship motion and the free surface on liquid level measurement. On the other hand, direct contact liquid measurement also suffers from the problem of sensor susceptibility to contamination, corrosion, and mechanical damage. Over long-term use, measurement accuracy decays significantly, maintenance costs are high, and this is detrimental to the long-term stable operation of unmanned systems.

[0005] Therefore, in complex motion environments, there is an urgent need for a liquid volume measurement method and device that can overcome the instability of liquid level, do not rely on direct liquid measurement, and are applicable to conditions of drastic changes in free liquid surface, so as to achieve accurate, stable and safe measurement of liquid volume in liquid tanks, thereby meeting the operational needs of unmanned intelligent ships in all mission profiles. Summary of the Invention

[0006] To address the shortcomings of existing production technologies, this applicant provides a liquid tank volume vapor phase identification and measurement device based on multi-frequency gas bidirectional micro-disturbance response. This device employs a measurement method combining graded measurement and dynamic correction. By accurately identifying the vapor phase volume within the liquid tank, it indirectly calculates the liquid volume, achieving stable measurement of liquid volume under complex motion environments. The core idea is to use the vapor phase volume measurement results to invert liquid volume measurement information, given the total volume of the tank, thus avoiding errors introduced by direct measurement.

[0007] The technical solution adopted in this invention is as follows: A liquid tank volume gas phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response, comprising: A multi-frequency gas micro-perturbation generation system is used to generate gas micro-perturbation signals in at least three different frequency bands: low frequency, medium frequency, and high frequency. The gas inlet system is connected to the multi-frequency gas micro-disturbance generation system and is used to input the gas micro-disturbance signal into the gas phase space of the liquid tank. A gas discharge system is connected to the gas phase space of the liquid tank and is used to apply reverse disturbance to the gas inside the tank or to discharge the gas outside the tank. A self-cleaning device is installed on the working slide rail of the liquid level floating slide valve of the gas inlet system to automatically remove the deposits on the slide rail. The control system is electrically connected to the multi-frequency gas micro-disturbance generation system, the gas inlet system, the gas outlet system, and the self-cleaning device, respectively. The chamber pressure sensor is installed in the gas phase space of the liquid tank or in the gas line connected to it to collect the gas pressure signal inside the chamber in real time. The compartment pressure spectrum identification module is connected to the compartment pressure sensor signal and is used to perform frequency domain analysis on the pressure signal to extract the pressure response features corresponding to disturbances in different frequency bands. The inlet liquid flow meter and the outlet liquid flow meter are installed on the inlet and outlet pipes of the liquid tank, respectively. The free liquid surface suppression device and the duckweed limiting rod are set above the liquid surface in the liquid tank to reduce the interference of liquid sloshing on gas phase pressure measurement; The liquid tank is a non-volatile liquid tank; The control system is configured to: in the initial stage of measurement, control the multi-frequency gas micro-disturbance generation system or the gas outlet system to apply a basic gas flow rate to coarsely measure the gas phase volume of the liquid tank and obtain an initial estimate of the gas phase volume; after obtaining the initial estimate, control the multi-frequency gas micro-disturbance generation system to generate gas micro-disturbances separately or collaboratively in at least two different frequency bands, and collect the pressure dynamic response characteristics detected by the chamber pressure sensor, compare the response characteristics with a preset gas phase response model or calibration data, and finely correct the measurement results of the gas phase volume so that the measurement results gradually converge to the true value; finally, calculate the liquid volume in the liquid tank based on the known total liquid tank volume.

[0008] Its further technical solution lies in: The multi-frequency gas micro-disturbance generation system includes a gas source, a filter dryer, an inlet pressure stabilizing buffer tank, an overpressure relief valve, a low-frequency gas micro-disturbance valve, a medium-frequency gas micro-disturbance valve, a high-frequency gas micro-disturbance valve, an electromagnetic control valve, a check valve, an inlet high-precision pressure sensor, a first pressure spectrum identification module, an inlet pressure stabilizing buffer tank, and a first gas flow meter; the low-frequency gas micro-disturbance valve operates at a frequency of 0.05Hz to 0.5Hz, the medium-frequency gas micro-disturbance valve operates at a frequency of 0.5Hz to 5Hz, and the high-frequency gas micro-disturbance valve operates at a frequency of 5Hz to 30Hz; The high-frequency gas perturbation valve includes a spectrum stepping throttle valve, a damping cavity, a porous damping baffle, and a damping mechanism. The damping mechanism consists of a damping spring, a damping piston, and a damping diaphragm.

[0009] The gas inlet system includes a liquid level floating valve, a Haver-type column guide rail slide rod, an airtight steel ball, a duckbill-type anti-reflective membrane, a hollow cavity, a sliding rail, a venting blade, a sliding concave guide rail, an arrow-shaped sealing slide, a compressed gas pipeline, and a sliding column. The liquid level floating valve is sleeved on the outside of the Haver-type column guide rail slide rod and floats up and down along the sliding concave guide rail via the sliding rail. The venting blade is connected to the Haver-type column guide rail slide rod via the sliding concave guide rail and can slide along the guide rail under the action of the liquid level floating valve to push open the airtight steel ball to release gas. The duckbill-type anti-reflective membrane is set in the hollow cavity to reflect and attenuate high-frequency gas disturbances.

[0010] The gas exit system includes a check valve for overpressure relief, an exit bypass solenoid control valve, a float-type check air nozzle, an exit gas reverse low-frequency micro-disturbance valve, an exit high-precision pressure sensor, a second pressure spectrum identification module, a second gas flow meter, an exit reverse micro-disturbance pressure stabilizing buffer tank, and a guide pipe. The exit gas reverse low-frequency micro-disturbance valve is connected to the guide pipe and is used to apply a low-frequency reverse disturbance within a preset frequency range to the gas on the exit side.

[0011] The self-cleaning device includes a submersible motor, a right-angle transmission gear set, a front bearing, a front dynamic seal, a crawling transmission rod, a crawling asymptotic gear, a rear dynamic seal, a rear bearing, a low-position contact switch, a cleaning device body, a sliding rod straight asymptotic rack, a cleaning blade assembly, a rectangular controllable return rod assembly, a return electric control rod, and a high-position contact switch. The submersible motor is fixed to the cleaning device body, and its output shaft is connected to the crawling asymptotic gear through the right-angle transmission gear set. The crawling asymptotic gear meshes with the sliding rod straight asymptotic rack, which is fixedly connected to the cleaning blade assembly. The low-position contact switch and the high-position contact switch are respectively installed at the low-position end and the high-position end of the crawling transmission rod stroke on the cleaning device body, and are used to output position signals to the control system.

[0012] The control system includes an attitude sensing module, a signal acquisition unit, a data processing MCU, a communication module, and a host computer. The attitude sensing module is used to collect the heave, roll, and pitch attitude information of the liquid tank, and the data processing MCU corrects the measurement results of the gas phase volume based on the attitude information.

[0013] The coverage area of ​​the free liquid surface suppression device is not less than 0.5 times the liquid surface area of ​​the tank. The duckweed limiting rod is arranged in the tank to limit the position of the free liquid surface suppression device, and a safe distance of more than 100mm is maintained between the free liquid surface suppression device and the gas inlet system.

[0014] The control system is also configured to automatically open the overpressure relief valve or the bypass solenoid control valve in the gas outlet system when the gas pressure inside the chamber exceeds a set threshold, thereby releasing the overpressure.

[0015] The gas micro-disturbance signal generated by the multi-frequency gas micro-disturbance generation system is sequentially filtered and rectified by the inlet pressure stabilizing buffer tank, then filtered again by the inlet pressure stabilizing buffer tank, and finally pneumatically filtered by the damping mechanism and the porous damping baffle before entering the gas inlet system.

[0016] The device is used to measure the liquid volume in the tanks of unmanned ships, intelligent ships, or marine engineering equipment. When the ship is in heave, roll, or pitch motion, it indirectly measures the liquid volume through gas phase identification to eliminate the influence of free surface oscillation on the measurement results.

[0017] The beneficial effects of this invention are as follows: (1) This invention fundamentally eliminates the interference of the motion environment on liquid level measurement and significantly improves the measurement stability under complex working conditions: This invention abandons the traditional method of calculating liquid volume based on liquid level. Instead, it employs the principle of gas phase identification, accurately measuring the gas volume within the tank to invert the liquid volume, completely avoiding the errors introduced by directly measuring the liquid level. Even when a ship is in a state of multi-degree-of-freedom motion, such as heave, roll, and pitch, and the free liquid surface inside the tank oscillates violently, making it impossible to stably measure the liquid level, this invention can still stably obtain the gas volume through the pressure response characteristics of the gas phase space, thereby accurately calculating the liquid volume. This fundamentally solves the technical problems of poor accuracy and low reliability of existing liquid level measurement methods in complex motion environments.

[0018] (2) This invention uses a combination of graded measurement and multi-frequency micro-perturbation to achieve high-precision gas phase volume identification: This invention employs a hierarchical iterative measurement mode of "basic flow coarse measurement + multi-frequency micro-perturbation fine correction". First, a basic gas flow coarse measurement quickly obtains the initial estimation range of the gas phase volume, narrowing the search space. Then, gas micro-perturbations in three different frequency bands—low frequency (0.05Hz–0.5Hz), medium frequency (0.5Hz–5Hz), and high frequency (5Hz–30Hz)—are applied near the initial estimate to excite the gas phase volumetric elasticity-dominated response, gas path damping characteristics, and gas-liquid coupling dynamic response, respectively. The control system extracts the amplitude characteristics, rate of change, and time response characteristics of pressure changes, compares them with a preset gas phase response model or calibration data, and iteratively corrects the measurement results, achieving a gas phase volume measurement accuracy within ±0.5%, with fast convergence and strong anti-interference capability.

[0019] (3) The present invention adopts a bidirectional gas micro-perturbation design to enhance identification stability: This invention not only applies multi-frequency positive micro-perturbations to the gas phase space of the liquid tank through the gas inlet system, but also applies low-frequency reverse perturbations within a preset frequency range on the exhaust side through a reverse low-frequency micro-perturbation valve for the exhaust gas in the gas outlet system. The synergistic effect of these two-way perturbations causes controlled oscillations in the gas pressure and flow state within the tank under the combined action of inlet and outlet, further enriching the dynamic response characteristics and significantly improving the repeatability and stability of gas phase volume identification. Experiments show that after enabling the two-way perturbations, the measurement repeatability error can be reduced to within ±0.1%.

[0020] (4) This invention utilizes the synergistic effect of free liquid surface suppression of duckweed and multi-frequency micro-disturbances to improve the signal-to-noise ratio: This invention employs a free liquid surface suppression float and float limiting rod, covering an area no less than 0.5 times the tank area, above the liquid surface within the tank to actively suppress interference from liquid sloshing on the gas phase pressure signal. This float effectively attenuates the amplitude of free liquid surface fluctuations, improving the signal-to-noise ratio of the gas phase pressure signal by 10-15 dB compared to when the float is not present. This provides a stable signal environment for multi-frequency micro-disturbance measurements, further enhancing the accuracy and stability of gas phase volume identification. This collaborative design is not disclosed in existing tank measurement technologies.

[0021] (5) This invention requires no liquid contact, has a long sensor lifespan, and low maintenance costs: The entire measurement process of this invention does not involve contact with the liquid medium inside the tank. All sensors are installed in the gas phase space or on the gas path, avoiding problems such as contamination, corrosion, scaling, and mechanical damage that occur with traditional liquid level sensors due to long-term immersion in liquid. Simultaneously, this invention integrates a self-cleaning device that can periodically and automatically remove deposits from the working slide rail of the liquid level floating valve, ensuring the valve's operational flexibility and airtightness, further extending the system's maintenance-free cycle. This makes it particularly suitable for long-term unattended operation scenarios such as unmanned ships and intelligent vessels.

[0022] (6) This invention has multiple safety protection functions and is adaptable to harsh sea conditions: This invention incorporates an overpressure relief valve in the gas inlet system and a check valve and an outlet bypass solenoid control valve in the gas outlet system. When the gas pressure inside the chamber exceeds a set threshold, the control system automatically opens the pressure relief channel to release the overpressure, preventing excessive pressure inside the chamber due to sudden temperature rise, control failure, or other abnormal conditions, thus ensuring the safe operation of the system under harsh sea conditions.

[0023] (7) The present invention has a compact structure and strong engineering applicability: The subsystems of this invention have a high degree of integration. The multi-frequency gas micro-disturbance generation system, gas inlet system, gas outlet system, and self-cleaning device all adopt a modular design, which can be flexibly configured according to the volume, shape, and measurement accuracy requirements of different liquid tanks. This invention is particularly suitable for application scenarios with high requirements for safety, stability, and automation, such as unmanned ships, intelligent ships, and marine engineering equipment, and has broad engineering application prospects and industrial promotion value. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall system structure of the gas phase identification and volume measurement device of the present invention.

[0025] Figure 2 This is a schematic diagram of the structure of the multi-frequency gas micro-disturbance generation system of the present invention.

[0026] Figure 3 for Figure 2Partial view (I).

[0027] Figure 4 for Figure 2 Partial view (II).

[0028] Figure 5 This is a schematic diagram of the gas inlet system of the present invention.

[0029] Figure 6 for Figure 5 Full sectional view along section AA (showing the level-floating slide valve).

[0030] Figure 7 for Figure 5 Full sectional view along section AA (showing the Haver-type column guide rail slide).

[0031] Figure 8 for Figure 6 Full sectional view along section BB.

[0032] Figure 9 for Figure 5 A magnified view of part C in the middle.

[0033] Figure 10 This is a schematic diagram of the gas exit system of the present invention.

[0034] Figure 11 This is a schematic diagram of the self-cleaning device of the present invention.

[0035] Figure 12 for Figure 11 Side view.

[0036] Figure 13 This is a schematic diagram of the cleaning blade assembly of the present invention in the open state.

[0037] Figure 14 This is a schematic diagram of the cleaning blade assembly in the closed state of the present invention.

[0038] The system includes: 1. Multi-frequency gas micro-disturbance generation system; 2. Gas inlet system; 3. Gas outlet system; 4. Self-cleaning device; 5. Control system; 6. Chamber pressure sensor; 7. Chamber pressure spectrum identification module; 8. Inlet liquid flow meter; 9. Outlet liquid flow meter; 10. Free surface duckweed suppression device; 11. Duckweed limiting rod; 12. Non-volatile liquid tank; 13. Transfer suction port; 14. Suction port shut-off check valve; 15. Pump outlet shut-off check valve; 16. Transfer pump; 201. Gas source; 202. Filter dryer; 203. Inlet pressure stabilizing buffer tank; 204. Low-frequency gas perturbation valve; 205. Medium-frequency gas perturbation valve; 206. High-frequency gas perturbation valve; 207. Electromagnetic control valve; 208. Check valve; 209. Overpressure relief valve; 210. Low-frequency, medium-frequency, and high-frequency bypass control solenoid valve; 212. Low-frequency, medium-frequency, and high-frequency check valve; 213. High-precision pressure sensor for inlet chamber; 214. First pressure spectrum identification module; 215. Inlet pressure stabilizing buffer tank; 216. Damping mechanism; 217. Spectrum stepping throttle valve; 218. Damping cavity; 219. Porous damping baffle; 220. Damping spring; 221. Damping piston; 222. Damping diaphragm; 223. First gas flow meter; 301. Floating slide valve; 302. Haver-type column guide rail slide rod; 303. Airtight steel ball; 304. Duckbill-type anti-reflective film; 305. Hollow cavity; 306. Sliding rail; 307. Air release blade; 308. Sliding concave guide rail; 309. Arrow-type sealing slide; 310. Compressed air pipeline; 311. Slide rod column; 401. Check valve for overpressure relief; 402. Outbound bypass solenoid control valve; 403. Float-type check air head; 404. Outbound gas reverse low-frequency micro-disturbance valve; 405. Outbound high-precision pressure sensor; 406. Second pressure spectrum identification module; 407. Second gas flow meter; 408. Outbound reverse micro-disturbance pressure stabilizing buffer tank; 409. Flow guide pipe; 501. Submersible motor; 502. Right-angle transmission gear set; 503. Front bearing; 504. Front dynamic seal; 505. Creeping transmission rod; 506. Creeping asymptotic gear; 507. Rear dynamic seal; 508. Rear bearing; 509. Low-position contact switch; 510. Cleaning device body; 511. Sliding rod straight asymptotic rack; 512. Cleaning knife assembly; 513. Rectangular controllable return rod assembly; 514. Return electric control rod; 515. High-position contact switch; 601. Attitude sensing module; 602. Signal acquisition unit; 603. Data processing MCU; 604. Communication module; 605. Host computer; 701. Free surface suppression of duckweed; 702. Floating limit rod. Detailed Implementation The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0039] like Figures 1-14 As shown, the liquid tank volume vapor phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response in this embodiment includes: A multi-frequency gas micro-perturbation generation system 1 is used to generate gas micro-perturbation signals including at least three different frequency bands: low frequency, medium frequency, and high frequency. The gas inlet system 2 is connected to the multi-frequency gas micro-disturbance generation system 1 and is used to input gas micro-disturbance signals into the gas phase space of the liquid tank. The gas discharge system 3 is connected to the gas phase space of the liquid tank and is used to apply reverse disturbance to the gas inside the tank or to discharge the gas outside the tank. The self-cleaning device 4 is installed on the working slide rail of the liquid level floating slide valve 301 of the gas inlet system 2 to automatically remove the deposits on the slide rail. The control system 5 is electrically connected to the multi-frequency gas micro-disturbance generation system 1, the gas inlet system 2, the gas outlet system 3, and the self-cleaning device 4, respectively. The chamber pressure sensor 6 is installed in the gas phase space of the liquid tank or in the gas line connected to it, and is used to collect the gas pressure signal inside the chamber in real time. The compartment pressure spectrum identification module 7 is connected to the compartment pressure sensor 6 and is used to perform frequency domain analysis on the pressure signal to extract the pressure response characteristics corresponding to disturbances in different frequency bands. The inlet liquid flow meter 8 and the outlet liquid flow meter 9 are installed on the inlet and outlet pipes of the liquid tank, respectively. The free liquid surface suppression duckweed device 10 and the duckweed limiting rod 11 are set above the liquid surface in the liquid tank to reduce the interference of liquid sloshing on gas phase pressure measurement. The liquid tank is a non-volatile liquid tank 12; The control system 5 is configured to: apply a base gas flow rate to the multi-frequency gas micro-disturbance generation system 1 or the gas outlet system 3 during the initial measurement phase to coarsely measure the gas phase volume of the liquid tank and obtain an initial estimate of the gas phase volume; after obtaining the initial estimate, control the multi-frequency gas micro-disturbance generation system 1 to generate gas micro-disturbances separately or collaboratively in at least two different frequency bands, and collect the pressure dynamic response characteristics detected by the chamber pressure sensor 6, compare the response characteristics with the preset gas phase response model or calibration data, and finely correct the measurement results of the gas phase volume so that the measurement results gradually converge to the true value; finally, calculate the liquid volume in the liquid tank based on the known total liquid tank volume.

[0040] The multi-frequency gas micro-disturbance generation system 1 includes a gas source 201, a filter dryer 202, an inlet pressure stabilizing buffer tank 203, an overpressure relief valve 209, a low-frequency gas micro-disturbance valve 204, a medium-frequency gas micro-disturbance valve 205, a high-frequency gas micro-disturbance valve 206, an electromagnetic control valve 207, a check valve 208, an inlet high-precision pressure sensor 213, a first pressure spectrum identification module 214, an inlet pressure stabilizing buffer tank 215, and a first gas flow meter 223; the low-frequency gas micro-disturbance valve 204 operates at a frequency of 0.05Hz to 0.5Hz, the medium-frequency gas micro-disturbance valve 205 operates at a frequency of 0.5Hz to 5Hz, and the high-frequency gas micro-disturbance valve 206 operates at a frequency of 5Hz to 30Hz; The high-frequency gas perturbation valve 206 includes a spectrum stepping throttle valve 217, a damping cavity 218, a porous damping baffle 219, and a damping mechanism 216. The damping mechanism 216 is composed of a damping spring 220, a damping piston 221, and a damping diaphragm 222.

[0041] The gas inlet system 2 includes a liquid level floating valve 301, a Haver-type column guide rail slide rod 302, an airtight steel ball 303, a duckbill-type anti-reflective membrane 304, a hollow cavity 305, a sliding rail 306, a venting blade 307, a sliding concave guide rail 308, an arrow-shaped sealing slide 309, a compressed gas pipeline 310, and a slide rod column 311. The liquid level floating valve 301 is sleeved on the outside of the Haver-type column guide rail slide rod 302 and floats up and down along the sliding concave guide rail 308 via the sliding rail 306. The venting blade 307 is connected to the Haver-type column guide rail slide rod 302 via the sliding concave guide rail 308 and can slide along the guide rail under the action of the liquid level floating valve 301 to open the airtight steel ball 303 to release gas. The duckbill-type anti-reflective membrane 304 is set inside the hollow cavity 305 to reflect and attenuate high-frequency gas disturbances.

[0042] The gas exit system 3 includes a check overpressure relief valve 401, an exit bypass solenoid control valve 402, a float-type check air pipe head 403, an exit gas reverse low-frequency micro-disturbance valve 404, an exit high-precision pressure sensor 405, a second pressure spectrum identification module 406, a second gas flow meter 407, an exit reverse micro-disturbance pressure stabilizing buffer tank 408, and a guide pipe 409. The exit gas reverse low-frequency micro-disturbance valve 404 is connected to the guide pipe 409 and is used to apply a low-frequency reverse disturbance within a preset frequency range to the gas on the exit side.

[0043] The self-cleaning device 4 includes a submersible motor 501, a right-angle transmission gear set 502, a front bearing 503, a front dynamic seal 504, a crawling transmission rod 505, a crawling asymptotic gear 506, a rear dynamic seal 507, a rear bearing 508, a low-position contact switch 509, a cleaning device body 510, a sliding rod straight asymptotic rack 511, a cleaning blade assembly 512, a rectangular controllable return rod assembly 513, a return electric control rod 514, and a high-position contact switch 515. The submersible motor 501 is fixed to the cleaning device. On the cleaning device body 510, its output shaft is connected to the crawling asymptotic gear 506 through a right-angle transmission gear set 502; the crawling asymptotic gear 506 meshes with the slide rod straight asymptotic rack 511, and the slide rod straight asymptotic rack 511 is fixedly connected to the cleaning blade set 512; the low-position contact switch 509 and the high-position contact switch 515 are respectively installed at the low-position end and the high-position end of the travel of the cleaning device body 510 near the crawling transmission rod 505, and are used to output position signals to the control system 5.

[0044] The control system 5 includes an attitude sensing module 601, a signal acquisition unit 602, a data processing MCU 603, a communication module 604, and a host computer 605. The attitude sensing module 601 is used to collect the heave, roll, and pitch attitude information of the liquid tank, and the data processing MCU 603 corrects the measurement results of the gas phase volume based on the attitude information.

[0045] The coverage area of ​​the free liquid surface suppression device 10 is not less than 0.5 times the liquid surface area of ​​the liquid tank. The duckweed limiting rod 11 is arranged in the liquid tank to limit the position of the free liquid surface suppression device 10. A safe distance of more than 100mm is maintained between the free liquid surface suppression device 10 and the gas inlet system 2.

[0046] The control system 5 is also configured to automatically open the overpressure relief valve 401 or the bypass solenoid control valve 402 in the control gas outlet system 3 when the gas pressure inside the chamber exceeds the set threshold, thereby releasing the overpressure.

[0047] The gas micro-disturbance signal generated by the multi-frequency gas micro-disturbance generation system 1 is sequentially filtered and rectified by the inlet pressure stabilizing buffer tank 203, filtered and rectified by the inlet pressure stabilizing buffer tank 215, and pneumatically filtered by the damping mechanism 216 and the porous damping baffle 219 before entering the gas inlet system 2.

[0048] The device is used to measure the liquid volume in the tanks of unmanned ships, intelligent ships, or marine engineering equipment. When the ship is in heave, roll, or pitch motion, it indirectly measures the liquid volume through gas phase identification to eliminate the influence of free surface oscillation on the measurement results.

[0049] To minimize the impact of ship acceleration in all directions and the free surface of the liquid tank on tank volume measurement, this embodiment employs a measurement method combining graded measurement and dynamic correction. By accurately identifying the gas phase volume within the tank, the liquid volume is indirectly calculated, achieving stable measurement of liquid volume under complex motion conditions. The core idea is to use the gas phase volume measurement results to invert liquid volume measurement information, given the total tank volume, thereby avoiding errors introduced by direct measurement.

[0050] In the initial stage of gas phase volume measurement, the system employs a basic flow rate coarse measurement method to preliminarily identify the gas phase space within the chamber. Control system 5 first applies a known or calibrable basic gas flow rate to the gas phase space through the intake or exhaust system, and the duration and flow rate parameters are recorded by control system 5. During the application of the basic flow rate, control system 5 synchronously acquires changes in the gas pressure within the chamber. When the gas pressure reaches a preset value or reaches a stable state, control system 5 performs a preliminary estimation of the gas phase volume within the chamber based on the applied gas flow rate parameters and pressure changes, obtaining a coarse measurement result of the gas phase volume. This basic flow rate coarse measurement is used to determine the order of magnitude and initial estimation range of the gas phase volume, providing a reference standard for subsequent fine-correction measurements.

[0051] After obtaining a preliminary estimate of the gas phase volume, the gas phase volume fine-correction measurement based on the micro-perturbation response begins. The control system 5 applies smaller amplitude and controlled frequency gas micro-perturbations to the gas phase space within the estimated range. These micro-perturbations do not change the overall state of the chamber, but only cause changes in the gas state within a small signal range. Under the micro-perturbation, the control system 5 collects the dynamic response process of the gas pressure within the chamber in real time and extracts the amplitude characteristics, rate of change, and time response characteristics of the pressure change. Since different gas phase volumes have different dynamic response characteristics under the same micro-perturbation conditions, the control system 5 compares the collected response characteristics with a preset gas phase response model or calibration data to correct the gas phase volume obtained from the basic flow measurement. Through the above-mentioned iterative correction process of micro-perturbation, the measurement results of the gas phase volume gradually converge to the true value, improving the accuracy and stability of the gas phase volume measurement.

[0052] After obtaining accurate measurement results of the gas volume in the cabin, the control system 5 calculates the volume information of the liquid in the cabin based on the known total volume of the cabin, thereby realizing the measurement of the liquid volume.

[0053] A liquid tank volumetric gas phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response (see...) Figure 1 It consists of a multi-frequency gas micro-disturbance generation system 1, a gas inlet system 2, a gas outlet system 3, a self-cleaning device 4, a control system 5, a chamber pressure sensor 6, a chamber pressure spectrum identification module 7, an inlet liquid flow meter 8, an outlet liquid flow meter 9, a free liquid surface suppression duckweed device 10, a duckweed limiting rod 11, and a non-volatile liquid tank 12.

[0054] During liquid loading or operation in the liquid tank, the upper gas phase space of the liquid tank is connected to the multi-frequency gas micro-disturbance generation system 1 via the gas inlet system 2. The micro-disturbance generation system applies low-amplitude, multi-spectral gas disturbance signals to the gas phase space. Simultaneously, the multi-frequency gas micro-disturbance generation system 1 works in conjunction with the gas outlet system 3 to achieve bidirectional disturbance regulation. Pressure sensors installed in the system are used to collect the absolute pressure and its dynamic changes in the gas phase space in real time, while gas flow signals are collected by corresponding flow meters. All pressure and flow signals are filtered, feature extracted, and frequency domain analyzed by the control system 5 to identify the static and dynamic response characteristics of the gas phase under different flow rates and disturbance conditions.

[0055] Meanwhile, the system is equipped with a free liquid surface suppression device 10 and a floating duckweed limiting rod 11 to reduce the interference of liquid sloshing on the gas phase pressure and improve measurement stability. In abnormal conditions, when the gas phase pressure exceeds a set threshold, the control system 5 automatically opens the bypass valve or safety valve to release overpressure and ensure safe system operation. (Not mentioned above) Figure 1 The equipment includes 13 for the transfer suction port, 14 for the suction port stop check valve, 15 for the pump outlet stop check valve, and 16 for the transfer pump. These are not included in this equipment but are still essential equipment for liquid tank transfer.

[0056] The specific structure of the liquid tank volume gas phase identification and volume measurement device with multi-frequency gas bidirectional micro-perturbation response is as follows: The multi-frequency gas micro-disturbance generation system includes a gas source 201, a filter dryer 202, an inlet pressure stabilizing buffer tank 203, an overpressure relief valve 209, a low-frequency gas micro-disturbance valve 204 (0.05Hz~0.5 Hz), a medium-frequency gas micro-disturbance valve 205 (0.5Hz~2Hz), a high-frequency gas micro-disturbance valve 206 (5Hz~30Hz), an electromagnetic control valve 207, a check valve 208, a low-frequency, medium-frequency, and high-frequency bypass control solenoid valve 210, a low-frequency, medium-frequency, and high-frequency check valve 212, an inlet high-precision pressure sensor 213, a first pressure spectrum identification module 214, an inlet pressure stabilizing buffer tank 215, a first gas flow meter 223, and piping assemblies connecting the various components. The gas source 201 generates a constant-pressure compressed gas source, which, after passing through the filter dryer 202, becomes clean and dry before entering the inlet pressure stabilizing buffer tank 203 to complete the working spectrum purification of the gas source 201. The controller controls the intermediate-frequency gas perturbation valve 204 at a stable frequency (0.05Hz–0.5Hz) to generate stable low-frequency gas perturbations, causing a uniform and slow change in the gas flow rate entering the downstream gas path. This creates a low-frequency perturbation dominated by gas volume elasticity without significantly increasing the average gas pressure in the liquid tank. The controller controls the low-frequency gas perturbation valve 205 at a stable frequency (0.5Hz–5Hz) to generate stable intermediate-frequency pulsed gas perturbations, causing the gas flow rate to change periodically over a medium time scale. This is used to excite the gas path damping characteristics and the dynamic response of the liquid tank gas-liquid coupling, enhancing the system's identification stability. The high-frequency gas perturbation valve 206 operates at a stable frequency of 5Hz–30Hz under the controller's drive. The generated high-frequency gas pulsations first control the high-frequency gas perturbation valve 206 at a frequency of (5Hz–30Hz) to generate stable high-frequency pulsed gas perturbations. This provides a high-frequency dynamic perturbation component, causing the gas flow rate to change periodically over a short time scale. This is used to excite the gas path damping characteristics and the dynamic response of the liquid tank gas-liquid coupling, enhancing the system's identification stability. Gas disturbances in each frequency band are filtered and rectified again by the confluence chamber pressure stabilizing buffer tank 215, and then enter the liquid tank with pure spectral characteristics via the electromagnetic control valve 207 and the check valve 208. The high-precision pressure sensor 213, the first pressure spectrum identification module 214, and the first gas flow meter 223 are arranged at the end of the pipeline to measure parameters such as the micro-disturbance pressure spectrum, pressure, and flow rate. The high-frequency gas micro-disturbance valve 206 can be further refined into a spectrum stepping throttle valve 217, a damping cavity 218, a porous damping baffle 219, and a damping mechanism 216.The spectrum stepping throttle valve 217 mainly transforms the "frequency distribution" of the compressed air source generated by the air source 201 from uncontrollable to programmable, scannable, and segmented micro-disturbance airflow; the porous damping baffle 219 diverts and throttles the gas entering the damping cavity (218), changing the gas flow from a local high-speed jet to a uniformly distributed low-speed flow, thereby weakening the high-speed pulsation component of the gas flow velocity. It is mainly used to eliminate the pulsation and spatial non-uniformity of the generated micro-disturbance airflow at the velocity level (velocity damping); the damping mechanism 216 mainly consists of damping spring 220, The damping piston 221 and damping diaphragm 222 are mainly used to absorb sudden changes in gas pressure from the porous damping baffle 219 and slow down the rate of gas pressure change, thereby suppressing high-frequency pressure pulsations. This results in low-frequency, continuous, and controllable gas disturbances in the output gas, primarily eliminating pressure pulsations and pressure spikes in the micro-disturbance airflow. The porous damping baffle 219 suppresses gas velocity pulsations, and the damping mechanism 216 suppresses pressure pulsations. Together, they form a bandwidth aerodynamic filter mechanism, ensuring that gas disturbances entering the liquid tank's gas phase space are mainly concentrated within a preset frequency band. The high-precision inlet pressure sensor 213 and the high-precision outlet pressure sensor 405 collaboratively collect pressure change signals from the liquid tank's gas phase space and its adjacent gas paths. These signals characterize the quasi-static pressure changes during gas entry and exit from the liquid tank, as well as the dynamic response characteristics under multi-frequency gas disturbances, thus providing pressure parameters for the basic and corrective calculations of the liquid tank's capacity. The first gas flow meter 223 is used to measure the change in gas flow rate entering or exiting the gas phase space of the liquid tank, serving as a reference for the aerodynamic disturbance excitation intensity and basic tank volume calculation, thereby improving the accuracy and consistency of the tank volume measurement results. The first pressure spectrum identification module 214 mainly performs frequency domain processing by analyzing the pressure signals measured by the high-precision inlet pressure sensor 213 and the high-precision outlet pressure sensor 405 to provide pressure response characteristics corresponding to disturbances in different frequency bands; the first pressure spectrum identification module 214 can be a stand-alone hardware module or integrated into the pressure sensor or controller.

[0057] The multi-frequency gas micro-disturbance generation system described above is configured to generate gas micro-disturbance signals separately or collaboratively in at least three different frequency bands: low frequency, medium frequency, and high frequency. The gas disturbances in each frequency band are fed into the liquid tank gas phase space after being combined and aerodynamically filtered and shaped, and then input into the liquid tank gas phase space through the gas inlet system 2 to dynamically excite the liquid tank gas phase volume.

[0058] The gas inlet system mainly consists of a liquid level floating slide valve 301, a Haver-type column guide rail slide rod 302, an airtight steel ball 303, a duckbill-type anti-reflective film 304, a hollow cavity 305, a sliding rail 306, a venting blade 307, a sliding concave guide rail 308, an arrow-shaped sealing slide 309, a compressed air pipeline 310, and a slide rod column 311. The liquid level floating slide valve 301 is located outside the Haver-type column guide rail slide rod 302 and can float up and down along the sliding concave guide rail 308 via the sliding rail 306, achieving synchronous displacement with changes in liquid level. This allows for automatic adjustment of the venting channel. The sliding concave guide rail 308 also limits the movement trajectory of the liquid level floating slide valve 301 and ensures its movement stability.

[0059] The venting blade 307 is connected to the Haver-type column guide rail slide rod 302 via the sliding concave guide rail 308, and can reciprocate along the sliding concave guide rail 308 under the action of the liquid level floating slide valve 301, thereby realizing the opening and closing of the venting channel according to the liquid level. When the liquid level floating slide valve 301 floats to the liquid level height, the venting blade 307 pushes open the airtight steel ball 303, allowing the micro-disturbance compressed gas source 201 to enter the arrow-shaped sealed slide rail 309 from the compressed gas pipeline 310 and be released into the gas phase space of the liquid tank. In order to reduce the pulsating impact generated during the gas release process and improve the spectral characteristics, a duckbill-type anti-reflective membrane 304 is installed in the hollow cavity 305. The duckbill-type anti-reflective membrane 304 is used to reflect and attenuate high-frequency gas disturbances, so that the gas entering the chamber is mainly low-frequency, thereby effectively suppressing the interference of high-frequency pressure waves on the internal structure and measurement system.

[0060] During multi-frequency gas release, the slight up-and-down movement of the liquid level floating slide valve 301 can couple with the transient displacement of the airtight steel ball 303, resulting in controlled frequency disturbance characteristics during gas release. By adjusting the stroke of the venting blade 307, the length of the Haver-type column guide rail slide rod 302, and the flow resistance parameters of the compressed gas pipeline 310, the basic flow rate, frequency range, and spectral distribution of the gas disturbance can be adjusted to meet the gas excitation requirements under different operating conditions.

[0061] In addition, the duckbill-shaped anti-reflective membrane 304 installed in front of the airtight steel ball 303 can further prevent high-frequency gas disturbances from entering the arrow-shaped sealing slide 309, prevent multi-frequency gas from generating superposition interference during the release process, and ensure that the spectrum of the excitation micro-disturbance gas entering the chamber is purer and more stable.

[0062] In summary, the gas inlet system 2 of the present invention achieves automatic control of the gas release position and suppression of interference frequency by means of the coordinated action of the liquid level floating slide valve 301, the airtight steel ball 303 and the venting blade 307. It can ensure airtightness while effectively reducing high-frequency disturbances, and improve the controllability and stability of gas excitation. It has the advantages of simple structure, sensitive response and strong adaptability.

[0063] The gas discharge system 3 is used to stably and controllably discharge gas from inside the cabin to the external environment. This system mainly consists of a check valve 401, a bypass solenoid control valve 402, a float-type check air inlet 403, a low-frequency micro-disturbance valve for reverse gas discharge 404, a high-precision pressure sensor for discharge 405, a second pressure spectrum identification module 406, a second gas flow meter 407, a reverse micro-disturbance pressure stabilizing buffer tank for discharge 408, a guide pipe 409, and other necessary accessories.

[0064] The check valve 401 is located on the main gas outlet passage and automatically opens when the gas pressure inside the chamber exceeds a set safety threshold, passively releasing the pressure. It then automatically closes once the pressure returns to a safe range, preventing backflow of external gas or reverse pressure transmission under abnormal conditions. The bypass solenoid control valve 402 is connected in parallel with the check valve 401 and actively controls the gas outlet path under the command of the control system 5, providing programmable and adjustable dynamic response capabilities during gas emission.

[0065] A float-type check air nozzle 403 is located at the final gas discharge outlet. Its structure automatically closes the channel when external liquids or foreign objects intrude, effectively preventing liquid from entering the chamber and improving the system's safety and reliability in complex environments. The outflow gas reverse low-frequency micro-disturbance valve 404 is connected to the guide pipe 409 and applies a low-frequency reverse disturbance within a preset frequency range to the gas on the outflow side. This creates a periodic feedback effect on the chamber's gas pressure and flow state without changing the main exhaust direction. A high-precision outflow pressure sensor 405 is positioned near the liquid tank or at a key location within the chamber. It collects the chamber's gas pressure signal in real time and transmits this signal to the second pressure spectrum identification module 406 for time and frequency domain analysis. This analysis enhances the characteristic frequency, amplitude, and phase information of the chamber's gas pressure changes, providing a basis for the control strategy of the outflow gas reverse low-frequency micro-disturbance valve 404.

[0066] The second gas flow meter 407 is installed on the main gas passage of the outlet chamber to measure the gas emission flow rate in real time. It forms a closed-loop feedback relationship with the high-precision pressure sensor 405 and the second pressure spectrum identification module 406 to achieve fine monitoring and regulation of the gas emission process. The outlet chamber reverse micro-disturbance stabilizing buffer tank 408 is connected to the liquid tank through the guide pipe 409. Its internal volume and structural parameters are designed according to the target disturbance frequency range to buffer, shape, and stabilize the pressure fluctuations generated by reverse excitation, thereby avoiding the adverse effects of high-frequency pressure pulsation on the overall stability of the system.

[0067] Through the coordinated operation of the above components, this gas discharge system 3 can not only achieve the safe discharge of gas inside the cabin, but also introduce controllable low-frequency reverse disturbances during the discharge process, so that the pressure state of the gas entering the cabin will respond and change within the expected frequency range, thereby providing stable and repeatable gas excitation conditions for subsequent cabin flow field control, structural response research or system state identification.

[0068] The self-cleaning device 4 consists of a submersible motor 501, a right-angle transmission gear set 502, a front bearing 503, a front dynamic seal 504, a crawling transmission rod 505, a crawling asymptotic gear 506, a rear dynamic seal 507, a rear bearing 508, a low-position contact switch 509, a cleaning device body 510, a sliding rod straight asymptotic rack 511, a cleaning blade assembly 512, a rectangular controllable return rod assembly 513, a return electric control rod 514, and a high-position contact switch 515.

[0069] The submersible motor 501 is fixedly mounted on the cleaning device body 510. Its output shaft converts the rotational motion of the motor into linear motion along the crawling direction through a right-angle transmission gear set 502. The right-angle transmission gear set 502 is connected to the crawling asymptotic gear 506 through a pin, thereby driving the crawling transmission rod 505 to perform linear reciprocating motion along a preset guide path inside the cleaning device body 510.

[0070] The front end of the crawling transmission rod 505 is supported by the front bearing 503 and sealed by the front dynamic seal 504, while the rear end is supported by the rear bearing 508 and sealed by the rear dynamic seal 507. This ensures transmission stability while preventing liquid in the liquid tank from seeping into the cleaning device body 510 along the transmission rod, thereby improving the sealing reliability and service life of the entire machine.

[0071] The crawling asymptotic gear 506 meshes with the slide bar straight asymptotic rack 511, which is fixedly connected to the cleaning blade assembly 512. This ensures that the reciprocating motion of the crawling transmission rod 505 is stably and uniformly converted into the linear movement of the cleaning blade assembly 512 along a predetermined trajectory. The cleaning blade assembly 512 adopts a fitted structural design with blades arranged along the pipe wall or structural surface, effectively scraping away adhering substances during movement to achieve automatic cleaning.

[0072] Simultaneously, a rectangular controllable return rod assembly 513 and a return electric control rod 514 are installed in the cleaning device, which together constitute the automatic return mechanism of the cleaning device. The return electric control rod 514 receives data from the data processing MCU 603... Figure 6 After the return command is issued, the rectangular controllable return rod group 513 is driven to move, so that the cleaning knife group 512 is disengaged from the working slide rail of the liquid level floating slide valve 301 in a controlled manner, thereby realizing the rapid return and locking of the cleaning mechanism.

[0073] To achieve precise limiting and safety control of the cleaning stroke, the cleaning device body 510 is equipped with a low-position contact switch 509 and a high-position contact switch 515. The low-position contact switch 509 and the high-position contact switch 515 are fixedly installed on the cleaning device body 510 near the high and low ends of the travel of the crawling transmission rod 505, respectively. Their installation positions correspond to the highest and lowest working points of the cleaning blade assembly 512 when it completes the preset cleaning stroke. When the crawling transmission rod 505 moves in a predetermined direction under the drive of the submersible motor 501, and drives the cleaning device body 510 and the cleaning blade assembly 512, or the triggering mechanism linked to it, to reach the end of the set stroke, it makes physical contact with the contact switches, thereby triggering the low-position contact switch 509 and the high-position contact switch 515 to operate. After being triggered, the contact switches send a signal to the data processing MCU 603. Figure 6 Output a position signal, which indicates that the cleaning blade assembly 512 has reached the preset minimum working position. See data processing MCU 603. Figure 6 Upon receiving this signal, execute at least one of the following control logic: Control the submersible motor 501 to stop its current rotation to prevent the cleaning structure from continuing to move forward and overtraveling.

[0074] Control the submersible motor 501 to rotate in the reverse direction, so that the crawling transmission rod 505 enters the reverse return state.

[0075] Alternatively, it can trigger the return control lever 514 to cause the rectangular controllable return lever group 513 to perform a return or disengagement action.

[0076] After the cleaning operation is completed or a cleaning shutdown command is received, the data processing MCU603 (see...) Figure 6 The control lever 514 returns to its initial position. During the return process, the cleaning blade assembly 512 rotates 90° along the guide rail and locks into the set position, achieving reliable storage and positioning of the cleaning blade assembly 512. The cleaning device then enters standby mode, ready for the next cleaning operation.

[0077] Through the above structural design, this cleaning device can achieve automatic start-stop, reciprocating cleaning and safe return in complex environments such as liquid tanks. It not only effectively avoids problems such as jamming, overtravel, collision, structural damage and liquid leakage of the cleaning mechanism, but also significantly improves cleaning efficiency and the stability of device operation. It is suitable for application scenarios of long-term unattended or automated operation.

[0078] Control system 5 is used to coordinate and control the process of measuring the gas phase volume of the compartment, so as to realize the liquid level and volume calculation based on basic flow measurement and micro-disturbance fine correction. Control system 5 mainly consists of attitude sensing module 601, signal acquisition unit 602, data processing MCU 603, communication module 604, host computer 605 and related cables.

[0079] The attitude sensing module 601 is used to collect cabin attitude state information and send the attitude signal to the signal acquisition unit 602 to correct the influence of the cabin on gas phase response measurement under tilt or dynamic conditions. The signal acquisition unit 602 is used to collect gas pressure, gas flow rate and related status and control signals in the cabin, and transmit the collected signals to the data processing MCU 603.

[0080] The data processing MCU603, as the core control unit of control system 5, is used to analyze and process the acquired pressure and flow signals. In the initial measurement phase, the data processing MCU603 controls the intake or exhaust system to apply a basic flow rate, performing a coarse measurement of the chamber's gas volume to obtain an initial estimate. After completing the basic measurement, the data processing MCU603 further controls control system 5 to apply amplitude-limited micro-perturbations to the gas system and acquires the dynamic response characteristics of the chamber's gas pressure to perform a fine-correction measurement of the gas volume.

[0081] The communication module 604 enables bidirectional communication between the data processing MCU 603 and the host computer 605. It uploads the measured gas phase volume data, calculation results, and system status information to the host computer 605, and simultaneously receives parameter configuration or control commands from the host computer 605. The host computer 605 monitors the measurement process, stores data, displays results, and provides a human-machine interface for system operation.

[0082] Through the coordinated operation of the aforementioned control system 5, stable measurement of the gas phase volume of the compartment is achieved, and the liquid volume is calculated based on the total volume of the compartment, thereby completing the liquid volume measurement.

[0083] The free surface suppression system in the cabin consists of free surface suppression floats 701 with an area of ​​not less than 0.5 times the cabin area, arranged in the middle of the cabin. Floating limit rods 702 are arranged at appropriate positions to limit the position of the free surface suppression floats 701. At the same time, the free surface suppression floats 701 should maintain an appropriate safe distance (≥100mm) from the gas inlet system 2.

[0084] Example 2: This embodiment is basically the same as Embodiment 1, except that the device is applied to a liquid tank containing highly volatile liquids (such as a fuel tank). In this case, to prevent volatile gases from interfering with the measurement, the multi-frequency gas micro-disturbance generation system 1 uses nitrogen as the gas source, and the float-type check air nozzle 403 of the gas outlet system 3 adopts an explosion-proof structure. The measurement process is consistent with Embodiment 1, and the measurement accuracy also reaches within ±0.5%.

[0085] Example 3: This embodiment is basically the same as Embodiment 1, except that the reverse low-frequency perturbation function of the gas exit system 3 is activated simultaneously during the measurement process. When the inlet gas perturbation is applied, the control system 5 controls the outlet gas reverse low-frequency perturbation valve 404 to apply a reverse perturbation at a frequency of 0.1 Hz, causing the gas pressure inside the chamber to form controlled oscillations under the combined action of inlet and outlet gases, further enhancing the stability of gas phase volume identification. Experiments show that after activating the bidirectional perturbation, the measurement repeatability error is reduced from ±0.3% to ±0.1%.

[0086] It measures and inverts the liquid volume by measuring the gas phase volume in the liquid tank, avoiding the error introduced by directly using the liquid level as the measurement object. It fundamentally eliminates the influence of changes in ship acceleration and violent fluctuations in the free liquid surface on the measurement results, and significantly improves the stability and reliability of liquid volume measurement in complex motion environments.

[0087] It adopts a graded measurement method that combines basic gas flow coarse measurement with multi-frequency gas micro-perturbation fine correction. This method can quickly obtain the initial estimation range of gas phase volume, and can also perform high-precision correction of the measurement results through the dynamic response characteristics of micro-perturbation, so that the measurement results gradually converge to the true value, improve the measurement accuracy and enhance the anti-interference ability.

[0088] The gas micro-disturbances it applies have small amplitude and low energy, do not change the overall working conditions inside the tank, and do not cause significant changes in liquid level. They are suitable for unsteady navigation and long-term continuous operation conditions, avoiding the impact on the tank structure and liquid state.

[0089] Its measurement process does not rely on direct contact with liquid, reducing problems such as sensor contamination and corrosion. The application of bidirectional micro-disturbance mode and self-cleaning device 4 not only reduces system maintenance costs and improves long-term operational reliability, but also improves the accuracy and consistency of gas phase volume identification.

[0090] This method and device are particularly suitable for applications with high requirements for safety and stability, such as unmanned ships, intelligent ships, and marine engineering equipment, and have good prospects for engineering applications.

[0091] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A liquid tank volume vapor phase identification and measurement device based on multi-frequency gas bidirectional micro-perturbation response, characterized in that, include: A multi-frequency gas micro-perturbation generation system (1) is used to generate gas micro-perturbation signals including at least three different frequency bands: low frequency, medium frequency and high frequency; The gas inlet system (2) is connected to the multi-frequency gas micro-disturbance generation system (1) and is used to input the gas micro-disturbance signal into the gas phase space of the liquid tank; The gas discharge system (3) is connected to the gas phase space of the liquid tank and is used to apply reverse disturbance to the gas inside the tank or to discharge the gas outside the tank. The self-cleaning device (4) is installed on the working slide rail of the liquid level floating slide valve (301) of the gas inlet system (2) to automatically remove the deposits on the slide rail; The control system (5) is electrically connected to the multi-frequency gas micro-disturbance generation system (1), the gas inlet system (2), the gas outlet system (3) and the self-cleaning device (4), respectively. The chamber pressure sensor (6) is installed in the gas phase space of the liquid tank or in the gas line connected to it, and is used to collect the gas pressure signal in the chamber in real time. The cabin pressure spectrum identification module (7) is connected to the cabin pressure sensor (6) and is used to perform frequency domain analysis on the pressure signal to extract the pressure response characteristics corresponding to disturbances in different frequency bands. The inlet liquid flow meter (8) and the outlet liquid flow meter (9) are installed on the inlet and outlet pipes of the liquid tank, respectively. The free liquid surface suppression duckweed device (10) and the duckweed limiting rod (11) are set above the liquid surface in the liquid tank to reduce the interference of liquid sloshing on gas phase pressure measurement; The liquid tank is a non-volatile liquid tank (12). The control system (5) is configured to: control the multi-frequency gas micro-disturbance generation system (1) or the gas outlet system (3) to apply the basic gas flow rate in the initial stage of measurement, perform a coarse measurement of the gas phase volume of the liquid tank, and obtain an initial estimate of the gas phase volume; After obtaining the initial estimate, the multi-frequency gas micro-disturbance generation system (1) is controlled to generate gas micro-disturbances separately or in concert in at least two different frequency bands, and the pressure dynamic response characteristics detected by the chamber pressure sensor (6) are collected. The response characteristics are compared with the preset gas phase response model or calibration data, and the measurement results of the gas phase volume are finely corrected so that the measurement results gradually converge to the true value. Finally, the liquid volume in the liquid tank is calculated based on the known total volume of the liquid tank.

2. The liquid tank volume gas phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response as described in claim 1, characterized in that, The multi-frequency gas micro-disturbance generation system (1) includes a gas source (201), a filter dryer (202), an inlet pressure stabilizing buffer tank (203), an overpressure relief valve (209), a low-frequency gas micro-disturbance valve (204), a medium-frequency gas micro-disturbance valve (205), a high-frequency gas micro-disturbance valve (206), an electromagnetic control valve (207), a check valve (208), an inlet high-precision pressure sensor (213), a first pressure spectrum identification module (214), an inlet pressure stabilizing buffer tank (215), and a first gas flow meter (223); the low-frequency gas micro-disturbance valve (204) operates at a frequency of 0.05Hz to 0.5Hz, the medium-frequency gas micro-disturbance valve (205) operates at a frequency of 0.5Hz to 5Hz, and the high-frequency gas micro-disturbance valve (206) operates at a frequency of 5Hz to 30Hz; The high-frequency gas perturbation valve (206) includes a spectrum stepping throttle valve (217), a damping cavity (218), a porous damping baffle (219), and a damping mechanism (216). The damping mechanism (216) consists of a damping spring (220), a damping piston (221), and a damping diaphragm (222).

3. The liquid tank volume gas phase identification and measurement device based on multi-frequency gas bidirectional micro-perturbation response as described in claim 1, characterized in that, The gas inlet system (2) includes a liquid level floating slide valve (301), a Haver-type column guide rail slide rod (302), an airtight steel ball (303), a duckbill-type anti-reflective film (304), a hollow cavity (305), a sliding rail (306), a venting blade (307), a sliding concave guide rail (308), an arrow-shaped sealing slide (309), a compressed air pipeline (310), and a slide rod column (311). The liquid level floating slide valve (301) is sleeved on the Haver-type column guide rail slide rod. (302) External, and floats up and down along the sliding concave guide rail (308) via the sliding rail plate (306); the gas release blade (307) is connected to the Haver-type column guide rail slide rod (302) via the sliding concave guide rail (308), and can slide along the guide rail under the drive of the liquid level floating slide valve (301) to open the airtight steel ball (303) to release gas; the duckbill anti-reflective film (304) is set in the hollow cavity (305) to reflect and attenuate high-frequency gas disturbances.

4. The liquid tank volume gas phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response as described in claim 1, characterized in that, The gas exit system (3) includes a check overpressure relief valve (401), an exit bypass solenoid control valve (402), a float-type check air head (403), an exit gas reverse low-frequency micro-disturbance valve (404), an exit high-precision pressure sensor (405), a second pressure spectrum identification module (406), a second gas flow meter (407), an exit reverse micro-disturbance pressure stabilizing buffer tank (408), and a guide pipe (409). The exit gas reverse low-frequency micro-disturbance valve (404) is connected to the guide pipe (409) and is used to apply a low-frequency reverse disturbance within a preset frequency range to the gas on the exit side.

5. The liquid tank volume gas phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response as described in claim 1, characterized in that, The self-cleaning device (4) includes a submersible motor (501), a right-angle transmission gear set (502), a front bearing (503), a front dynamic seal (504), a crawling transmission rod (505), a crawling asymptotic gear (506), a rear dynamic seal (507), a rear bearing (508), a low-position contact switch (509), a cleaning device body (510), a sliding rod straight asymptotic rack (511), a cleaning blade assembly (512), a rectangular controllable return rod assembly (513), a return electric control rod (514), and a high-position contact switch (515). The submersible motor (501) 01) Fixed on the body of the cleaning device (510), its output shaft is connected to the crawling asymptotic gear (506) through the right angle transmission gear set (502); the crawling asymptotic gear (506) meshes with the slide rod straight asymptotic rack (511), and the slide rod straight asymptotic rack (511) is fixedly connected to the cleaning knife set (512); the low position contact switch (509) and the high position contact switch (515) are respectively installed on the low position end and the high position end of the stroke of the crawling transmission rod (505) of the body of the cleaning device (510), and are used to output position signals to the control system (5).

6. The liquid tank volume gas phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response as described in claim 1, characterized in that, The control system (5) includes an attitude sensing module (601), a signal acquisition unit (602), a data processing MCU (603), a communication module (604), and a host computer (605); the attitude sensing module (601) is used to collect the heave, roll and pitch attitude information of the liquid tank, and the data processing MCU (603) corrects the measurement results of the gas phase volume according to the attitude information.

7. The liquid tank volume gas phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response as described in claim 1, characterized in that, The coverage area of ​​the free liquid surface suppression duckweed device (10) is not less than 0.5 times the liquid surface area of ​​the liquid tank. The duckweed limiting rod (11) is arranged in the liquid tank to limit the position of the free liquid surface suppression duckweed device (10). A safe distance of more than 100 mm is maintained between the free liquid surface suppression duckweed device (10) and the gas inlet system (2).

8. The liquid tank volume gas phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response as described in claim 1, characterized in that, The control system (5) is also configured to automatically open the overpressure relief valve (401) or the bypass solenoid control valve (402) in the gas outlet system (3) when the gas pressure inside the chamber exceeds the set threshold, so as to realize overpressure release.

9. The liquid tank volume gas phase identification and measurement device based on multi-frequency gas bidirectional micro-perturbation response as described in claim 2, characterized in that, The gas micro-disturbance signal generated by the multi-frequency gas micro-disturbance generation system (1) is sequentially purified by the spectrum of the inlet pressure stabilizing buffer tank (203), filtered and rectified again by the inlet pressure stabilizing buffer tank (215), and pneumatically filtered by the damping mechanism (216) and the porous damping baffle (219) before entering the gas inlet system (2).

10. The liquid tank volume gas phase identification and volume measurement device based on multi-frequency gas bidirectional micro-perturbation response as described in claim 1, characterized in that, The device is used to measure the liquid volume in the tanks of unmanned ships, intelligent ships, or marine engineering equipment. When the ship is in heave, roll, or pitch motion, it indirectly measures the liquid volume through gas phase identification to eliminate the influence of free surface oscillation on the measurement results.

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