A rocket propellant tank volume intelligent measurement system and method

Abstract

This application provides an intelligent measurement system and method for rocket propellant tank volume. The system includes: a nitrogen tank, a manual ball valve, a delivery pump, a check valve, a gas-locked ball valve, a pressure sensor, a pressure gauge, a pneumatic ball valve, a recovery pump, an electric regulating valve, a propellant tank, a safety valve, a standard container, a first temperature sensor, and a second temperature sensor. The nitrogen tank, delivery pump, recovery pump, standard container, and the propellant tank under test constitute the gas path execution unit. The intelligent control center includes an adaptive predictive control module and a multi-parameter dynamic inversion processing module. The intelligent measurement system and method for rocket propellant tank volume provided by this invention eliminates the need for manual intervention during the entire measurement process, resulting in high measurement efficiency and ensuring intelligent measurement of rocket propellant tank volume through automatic output of reliable results.

Description

Technical Field

[0001] This invention relates to the field of spacecraft assembly and testing, and in particular to an intelligent measurement system and method for rocket propellant tank volume. Background Technology

[0002] As a critical structural component of a launch vehicle, the accurate measurement of the rocket's internal effective volume directly affects fuel loading calculations, center of gravity determination, and flight trajectory accuracy. Errors in volume measurement can lead to insufficient or excessive fuel loading, thereby impacting payload capacity and even causing safety issues. Therefore, achieving high-precision measurement of the propellant tank volume is crucial during the rocket's assembly and testing phases.

[0003] Currently, the commonly used volume measurement methods in the industry are mainly as follows, but all of them have significant limitations:

[0004] The geometric measurement method involves acquiring point cloud data of the tank's internal cavity using 3D laser scanning or photogrammetry, reconstructing a 3D model, and calculating the theoretical volume. Its drawbacks include: inability to reflect actual manufacturing deviations (such as uneven wall thickness, weld excess height, and internal component volume); complex and time-consuming data processing; and expensive equipment with stringent environmental requirements.

[0005] Description of the gravimetric / liquid displacement method: The volume is calculated by adding a liquid of known density and weighing it. Disadvantages: cumbersome operation, low efficiency, safety and environmental risks; high structural strength requirements for the storage tank; drying residue can easily affect subsequent processes; large systematic errors (such as pipeline residue, liquid evaporation).

[0006] The gas displacement method (constant volume pressure measurement method) is described as follows: Based on Boyle's law, the volume is calculated by balancing the gas pressure between a reference tank and the storage tank. Advantages: Clear principle, high precision potential; non-contact, pollution-free, and non-destructive testing; high efficiency and easy automation; high safety and environmentally friendly; suitable for complex internal spaces; the reference tank is easy to calibrate and trace. Core challenges: Accuracy is limited by the ideal gas assumption and thermal equilibrium conditions; the time-consuming equilibrium process becomes an efficiency bottleneck; reliability depends on absolute sealing and zero sensor drift, lacking self-diagnostic capabilities.

[0007] Therefore, there is an urgent need in this field for a solution that can achieve intelligent and accurate measurement. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a rocket tank volume self-optimization measurement system and method based on intelligent dynamic identification. Its core idea is to shift from passive measurement to active parameter identification and state prediction.

[0009] This invention provides an intelligent measurement system for rocket propellant tank volume, comprising: a nitrogen tank, a manual ball valve, a delivery pump, a check valve, a gas-locked ball valve, a pressure sensor, a pressure gauge, a pneumatic ball valve, a recovery pump, an electric regulating valve, a propellant tank, a safety valve, a standard container, a first temperature sensor, and a second temperature sensor.

[0010] The nitrogen tank, delivery pump, recovery pump, standard container, and the storage tank to be tested are connected by pipelines to form a gas path execution unit.

[0011] The connecting pipe between the nitrogen tank and the standard container is equipped with a manual ball valve, a delivery pump, a check valve, a gas-locking ball valve, a pressure sensor, a pressure gauge, and a manual ball valve; the connecting pipe between the standard container and the storage tank is equipped with a pneumatic ball valve, a gas-locking ball valve, a pressure sensor, and a pressure gauge; the return gas pipeline between the storage tank and the nitrogen tank is also equipped with a manual ball valve, a recovery pump, and an electric regulating valve; the exhaust pipe located at the top of the standard container is equipped with a manual ball valve, a safety valve, a standard container, and a first temperature sensor; and the bottom of the nitrogen tank is equipped with an exhaust port.

[0012] The pressure sensor is used to detect the inlet pressure of the standard container; the pressure gauge is used to read the inlet pressure of the standard container to verify the accuracy of the pressure sensor; the pressure sensor is used to control the nitrogen pressure inside the storage tank; the pressure gauge is used to read the inlet pressure of the storage tank to verify the accuracy of the pressure sensor.

[0013] The standard container is used to hold nitrogen gas at different pressures; the first temperature sensor is used to monitor temperature changes inside the standard container; the second temperature sensor is used to monitor temperature changes inside the storage tank.

[0014] The intelligent control center includes an adaptive predictive control module and a multi-parameter dynamic inversion processing module.

[0015] The adaptive predictive control module is used to pressurize the standard container with a pulse mode during a single balancing process, and monitor the pressure change rate and temperature change rate of the standard container in real time during the pulse interval. Based on the prediction model, it dynamically predicts the time required to reach balancing, and determines balancing in advance when the predicted remaining time is stable and less than the minimum time standard threshold.

[0016] The multi-parameter dynamic inversion processing module is used to conduct multiple independent gas expansion equilibrium experiments under different initial pressures by controlling the valve group. Each time, it records the initial pressure, initial temperature, equilibrium pressure, and equilibrium temperature of the standard container. It constructs an extended state equation that includes the volume to be measured, the effective leakage rate of the system, and the temperature influence coefficient. Using the data set, it synchronously inverts the optimal estimates of the multi-parameters through fitting or filtering algorithms to compensate for non-ideal factors and output the volume value.

[0017] Preferably, as one possible implementation: the nitrogen tank is used to store dry nitrogen; the manual ball valve is used to manually control the nitrogen tank to deliver nitrogen to the standard container; the delivery pump is used to provide power for delivering nitrogen from the nitrogen tank to the standard container; the one-way valve is used to control that nitrogen from the nitrogen tank can only be delivered to the standard container to prevent backflow; the gas-locked ball valve is used to control the electric switch for delivering nitrogen from the nitrogen tank to the standard container; the manual ball valve is used for testing and maintenance instruments; the pneumatic ball valve is used to control the manual switch for delivering nitrogen from the standard container to the storage tank; the gas-locked ball valve is used to control the electric switch for delivering nitrogen from the standard container to the storage tank; the manual ball valve is used to control the manual switch for delivering nitrogen from the storage tank to the nitrogen tank; the recovery pump is used to provide power for delivering nitrogen from the storage tank to the nitrogen tank; the electric regulating valve is used to control the electric switch for delivering nitrogen from the storage tank to the nitrogen tank; the manual ball valve is used to control the nitrogen pressure relief valve in the standard container.

[0018] Preferably, as one possible implementation, the safety valve is used to acquire the measured value of the nitrogen pressure in the current standard container in real time, and to control the activation of the safety valve to release the nitrogen pressure in the standard container when the measured value exceeds the preset pressure value.

[0019] This invention provides an intelligent method for measuring the volume of rocket propellant tanks, comprising the following steps:

[0020] The adaptive predictive control module uses a pulse mode to inflate the standard container during a single balancing process, and monitors the pressure change rate and temperature change rate of the standard container in real time during the pulse interval. Based on the prediction model, it dynamically predicts the time required to reach balancing. When the predicted remaining time is stable and less than the minimum time standard threshold, balancing is determined in advance.

[0021] The multi-parameter dynamic inversion processing module (i.e., used to process data and calculate volume) conducts multiple independent gas expansion equilibrium experiments under different initial pressures by controlling the valve group. Each time, it records the initial pressure, initial temperature, equilibrium pressure, and equilibrium temperature data set. It constructs an extended state equation that includes the volume to be measured, the effective leakage rate of the system, and the temperature influence coefficient. Using the data set, it synchronously inverts the optimal estimates of the multi-parameters through fitting or filtering algorithms to compensate for non-ideal factors and output the volume value.

[0022] Preferably, as one possible implementation method, the step of conducting multiple independent gas expansion equilibrium experiments under different initial pressures by controlling the valve group includes:

[0023] The control valve assembly is adjusted for each initial pressure setpoint to inject gas into the container to achieve the initial pressure.

[0024] The gas expansion process is performed until equilibrium is reached. Each experiment is conducted independently, and the initial pressure and initial temperature are collected as part of the initial data set.

[0025] After equilibrium is achieved, the equilibrium pressure and the equilibrium temperature are recorded to complete the data set.

[0026] If the number of data sets reaches the preset minimum value, the experiment is stopped; otherwise, the initial pressure is adjusted and the next experiment is conducted.

[0027] The consistency of the experiment is verified by collecting multiple sets of data. If the consistency is lower than the threshold, the data is collected again.

[0028] Preferably, as one possible implementation, the construction of the extended equation of state including the volume to be measured, the effective leakage rate of the system, and the temperature influence coefficient includes: extending the gas equation of state to the extended equation of state, wherein the extended equation of state integrates the volume to be measured as the main variable and incorporates the effective leakage rate of the system to characterize dynamic loss; introducing the temperature influence coefficient into the extended equation of state to quantify the effect of temperature unevenness on pressure; generating a set of equations using the data set input to the extended equation of state; solving the set of equations using the fitting or filtering algorithm to obtain the optimal estimate of the multi-parameters; adjusting the parameters of the extended equation of state according to the optimal estimate of the multi-parameters to optimize the subsequent inversion accuracy; outputting the volume value if the optimal estimate of the multi-parameters converges, otherwise iterating the fitting or filtering algorithm.

[0029] Preferably, as one possible implementation, the step of using a pulse mode to inflate the standard container during a single balancing process includes:

[0030] Set the high-frequency short-time pulse mode parameters to inject gas into the container in segments; pause the injection after each pulse and start real-time monitoring of pressure change rate and temperature change rate;

[0031] A continuous data sequence is collected to calculate the pressure change rate as dP / dt and the temperature change rate as dT / dt;

[0032] Input the dP / dt and the dT / dt into the prediction model, wherein the prediction model is an exponential decay model used to fit the change curve;

[0033] The time required to reach equilibrium is extrapolated from the prediction model. If the predicted remaining time is lower than a preset threshold, the early determination of equilibrium is performed.

[0034] Preferably, as one possible implementation, solving the system of equations using the fitting or filtering algorithm to obtain the optimal estimates of the multi-parameters includes:

[0035] The parameter vector for initializing the fitting or filtering algorithm includes the initial estimate of the volume to be measured; the residuals are calculated by applying least squares fitting for each set of data;

[0036] If Kalman filtering is used, the state covariance matrix is ​​updated to reflect the parameter correlation; the solution is iteratively solved until the residual is minimized to obtain the optimal estimate of the multi-parameters; the compensation effect is verified based on the optimal estimate of the multi-parameters, and if the error after compensation is lower than the threshold, the volume value is confirmed.

[0037] Preferably, as one possible implementation; the step of extrapolating the time required to reach equilibrium based on the prediction model, and performing the advance equilibrium determination if the predicted remaining time is lower than a preset threshold, includes:

[0038] Fit the dP / dt and dT / dt to the exponential decay model to extract decay parameters; calculate the prediction curve based on the decay parameters and determine the equilibrium point time.

[0039] If the predicted remaining time is lower than a preset threshold, then the advance determination balance is performed; the advance determination balance is performed and monitoring is terminated to shorten the overall process.

[0040] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0041] This invention discloses an intelligent measurement system and method for rocket propellant tank volume. The intelligent measurement system for rocket propellant tank volume provided by this invention mainly consists of a nitrogen tank, a manual ball valve, a delivery pump, a check valve, a gas-locked ball valve, a pressure sensor, a pressure gauge, a pneumatic ball valve, a recovery pump, an electric regulating valve, a propellant tank, a safety valve, a standard container, a first temperature sensor, and a second temperature sensor.

[0042] The nitrogen tank, delivery pump, recovery pump, standard container, and storage tank under test constitute the gas path execution unit. The connecting pipe between the nitrogen tank and the standard container is equipped with a manual ball valve, delivery pump, check valve, air-lock ball valve, pressure sensor, pressure gauge, and manual ball valve. The connecting pipe between the standard container and the storage tank is equipped with a pneumatic ball valve, air-lock ball valve, pressure sensor, and pressure gauge. The return gas path pipe between the storage tank and the nitrogen tank is also equipped with a manual ball valve, recovery pump, and electric regulating valve. The exhaust pipe located at the top of the standard container is equipped with a manual ball valve, safety valve, standard container, and first temperature sensor. An exhaust port is located at the bottom of the nitrogen tank.

[0043] The intelligent rocket propellant tank volume measurement system provided by this invention features an intelligent control center with intelligent execution functions, including an adaptive predictive control module and a multi-parameter dynamic inversion processing module. The multi-parameter dynamic inversion processing module can still output high-precision propellant tank volume values ​​even under non-ideal conditions such as minor leaks and temperature inhomogeneities, demonstrating strong error compensation capabilities. Furthermore, the intelligent rocket propellant tank volume measurement system provided by this invention, through its adaptive predictive control module, shortens the waiting time for the gas balancing process, thereby improving measurement efficiency. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the main principle of an intelligent measurement system for rocket propellant tank volume according to the present invention;

[0045] Figure 2 This is a diagram showing the main system hardware architecture of a rocket propellant tank volume intelligent measurement system according to the present invention.

[0046] Figure 3 This is a flowchart of an intelligent measurement method for rocket propellant tank volume according to the present invention;

[0047] Labels: Pneumatic actuator 100; Sensing and control unit 200; Intelligent control center 300; Human-machine interface 400; Nitrogen tank 1; Manual ball valve 2; Transfer pump 3; Check valve 4; Air-lock ball valve 5; Pressure sensor 6; Pressure gauge 7; Manual ball valve 8; Pneumatic ball valve 9; Air-lock ball valve 10; Pressure sensor 11; Pressure gauge 12; Manual ball valve 13; Recovery pump 14; Electric regulating valve 15; Storage tank 16; Manual ball valve 17; Safety valve 18; Standard container 19; First temperature sensor 20; Second temperature sensor 21. Detailed Implementation

[0048] 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 only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0050] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] Example 1

[0052] See Figure 1 The rocket tank volume intelligent measurement system provided in Embodiment 1 of the present invention mainly consists of four parts: a gas path execution unit 100, a sensing and control unit 200, an intelligent control center 300, and a human-machine interface 400.

[0053] See Figure 2 Specifically, the aforementioned intelligent measurement system for rocket propellant tank volume includes: nitrogen tank 1, manual ball valve 2, delivery pump 3, check valve 4, air-locked ball valve 5, pressure sensor 6, pressure gauge 7, manual ball valve 8, pneumatic ball valve 9, air-locked ball valve 10, pressure sensor 11, pressure gauge 12, manual ball valve 13, recovery pump 14, electric regulating valve 15, propellant tank 16, manual ball valve 17, safety valve 18, standard container 19, first temperature sensor 20, and second temperature sensor 21;

[0054] The connecting pipe between the nitrogen tank 1 and the standard container 19 is equipped with a manual ball valve 2, a delivery pump 3, a check valve 4, a gas-lock ball valve 5, a pressure sensor 6, a pressure gauge 7, and a manual ball valve 8; the connecting pipe between the standard container 19 and the storage tank 16 is equipped with a pneumatic ball valve 9, a gas-lock ball valve 10, a pressure sensor 11, and a pressure gauge 12; and the return gas pipeline between the storage tank 16 and the nitrogen tank 1 is also equipped with a manual ball valve 13, a recovery pump 14, and an electric regulating valve 15; the exhaust pipe located at the top of the standard container 19 is equipped with a manual ball valve 17, a safety valve 18, the standard container 19, and a first temperature sensor 20; and the bottom of the nitrogen tank 1 is equipped with an exhaust port.

[0055] The nitrogen tank 1, the delivery pump 3, the recovery pump 14, the standard container 19, and the storage tank to be tested 16 constitute the gas path execution unit 100; that is, the gas path execution unit 100 includes a gas source, delivery and recovery pumps, a standard container, the storage tank to be tested, and a valve group, which constitute the "body" of the system.

[0056] The high-precision pressure sensor, multi-point temperature sensor, flow meter and other components constitute the sensing and control unit 200. The sensing and control unit 200 is used to collect system status data in real time as the system's "sensors".

[0057] The intelligent control center 300, acting as the system's "brain," integrates the following modules: an adaptive predictive controller that executes pulse inflation and balance prediction strategies; a multi-parameter dynamic inversion algorithm module, which is the core algorithm that processes data and calculates volume and other parameters; and a system health management module with a built-in digital twin model that enables real-time fault diagnosis and sensor calibration.

[0058] The human-computer interaction interface 400 displays the measurement process, results, and system health status.

[0059] The pressure sensor 6 is used to detect the inlet pressure of the standard container and record the pressure value P1; the pressure gauge 7 is used to read the inlet pressure of the standard container to verify the accuracy of the pressure sensor; the pressure sensor 11 is used to control the nitrogen pressure in the storage tank and record the pressure value P2; the pressure gauge 12 is used to read the inlet pressure of the storage tank to verify the accuracy of the pressure sensor.

[0060] The volume to be measured in the storage tank 16 is recorded as V2; the standard container 19 is used to hold nitrogen gas at different pressures, and its known volume is V1.

[0061] The first temperature sensor 20 is used to monitor the temperature change inside the standard container and record the temperature T1; the second temperature sensor 21 is used to monitor the temperature change inside the storage tank and record the temperature T2.

[0062] It should be noted that the functions and structures of the main devices of the aforementioned intelligent measurement system for rocket propellant tank volume are as follows: Nitrogen tank 1 is used to store dry nitrogen; Manual ball valve 2 manually controls the nitrogen tank to deliver nitrogen to the standard container; Delivery pump 3 provides the power to deliver nitrogen from the nitrogen tank to the standard container; One-way valve 4: Nitrogen from the nitrogen tank can only be delivered to the standard container to prevent backflow; Gas-locked ball valve 5: An electric switch that controls the delivery of nitrogen from the nitrogen tank to the standard container; Pressure sensor 6: Used to detect the inlet pressure of the standard container and record the pressure value P1; Pressure gauge 7: Reads the inlet pressure of the standard container to verify the accuracy of the pressure sensor;

[0063] Manual ball valve 8: used for testing and repairing instruments; Pneumatic ball valve 9: manual switch for controlling the flow of nitrogen from the standard container to the storage tank; Pneumatic shut-off ball valve 10: electric switch for controlling the flow of nitrogen from the standard container to the storage tank.

[0064] Pressure sensor 11: controls the nitrogen pressure in the storage tank and records the pressure value P2; Pressure gauge 12: reads the inlet pressure of the storage tank to verify the accuracy of the pressure sensor; Manual ball valve 13: controls the manual switch for supplying nitrogen from the storage tank to the nitrogen tank; Recovery pump 14: provides the power for supplying nitrogen from the storage tank to the nitrogen tank; Electric regulating valve 15: controls the electric switch for supplying nitrogen from the storage tank to the nitrogen tank.

[0065] Tank 16: The rocket tank is the rocket's "fuel depot". Its main function is to safely and reliably store and deliver propellant (including fuel and oxidizer) to the engine. The volume to be measured is V2.

[0066] Manual ball valve 17: controls the nitrogen pressure relief valve in the standard container; safety valve 18: controls the nitrogen pressure in the standard container, and starts to release pressure when it exceeds a certain pressure value; standard container 19: used to hold nitrogen at different pressures, with a known volume V1; first temperature sensor 20: monitors the temperature change in the standard container and records the temperature T1; second temperature sensor 21: monitors the temperature change in the storage tank and records the temperature T2; control cabinet 22: a comprehensive system integrating power supply, control, gas circuit, protection and human-machine interaction functions;

[0067] In summary, the present invention discloses an intelligent measurement system for rocket propellant tank volume. Its main system architecture consists of a nitrogen tank 1, a manual ball valve 2, a delivery pump 3, a check valve 4, a gas-locked ball valve 5, a pressure sensor 6, a pressure gauge 7, a manual ball valve 8, a pneumatic ball valve 9, a gas-locked ball valve 10, a pressure sensor 11, a pressure gauge 12, a manual ball valve 13, a recovery pump 14, an electric regulating valve 15, a propellant tank 16, a manual ball valve 17, a safety valve 18, a standard container 19, a first temperature sensor 20, and a second temperature sensor 21.

[0068] The nitrogen tank 1, delivery pump 3, recovery pump 14, standard container 19, and the storage tank 16 to be tested constitute the gas path execution unit 100. A manual ball valve 2, delivery pump 3, check valve 4, air-lock ball valve 5, pressure sensor 6, pressure gauge 7, and manual ball valve 8 are installed on the connecting pipe between the nitrogen tank 1 and the standard container 19. A pneumatic ball valve 9, air-lock ball valve 10, pressure sensor 11, and pressure gauge 12 are installed on the connecting pipe between the standard container 19 and the storage tank 16. A manual ball valve 13, recovery pump 14, and electric regulating valve 15 are also installed on the return gas path pipe between the storage tank 16 and the nitrogen tank 1. A manual ball valve 17, safety valve 18, standard container 19, and first temperature sensor 20 are installed on the exhaust pipe at the top of the standard container 19. An exhaust port is provided at the bottom of the nitrogen tank 1.

[0069] The intelligent rocket propellant tank volume measurement system provided by this invention features an intelligent control center 300 with intelligent execution functions, including an adaptive predictive control module and a multi-parameter dynamic inversion processing module. The multi-parameter dynamic inversion processing module can still output high-precision propellant tank volume values ​​under non-ideal conditions such as minor leaks and temperature inhomogeneities, demonstrating strong error compensation capabilities. Furthermore, the intelligent rocket propellant tank volume measurement system provided by this invention, through its adaptive predictive control module, shortens the waiting time for the gas balancing process and improves measurement efficiency.

[0070] The intelligent measurement system for rocket tank volume provided by this invention includes an adaptive predictive control module (pulse inflation and balance prediction strategy). This module uses pulse mode inflation during a single balance process and monitors the pressure change rate (ΔP / Δt) and temperature change rate (ΔT / Δt) in real time during the pulse interval.

[0071] Based on a predictive model, the system dynamically predicts the time required to reach equilibrium. When the predicted remaining time is stable and less than the minimum time threshold, equilibrium is determined in advance. This improves efficiency, as traditional gas equilibrium processes require waiting for complete pressure stabilization, which is time-consuming. Pulse inflation allows the system to determine equilibrium earlier when the pressure change rate slows down, reducing unnecessary waiting time. For example, when the predictive model shows the remaining time decreasing from 10 seconds to 1 second and stabilizing, the system can terminate inflation early, thus shortening the single measurement cycle. It also improves accuracy: by monitoring the rate of change in real time, pressure fluctuations caused by over- or under-inflation are avoided, ensuring more accurate equilibrium determination. This indirectly improves the reliability of subsequent volume calculations. This module optimizes the inflation process, enabling the system to significantly improve measurement speed while maintaining accuracy.

[0072] The rocket propellant tank volume intelligent measurement system provided by this invention includes a multi-parameter dynamic inversion processing module (data processing and volume calculation); this module controls the valve group at different initial pressures (P... 1i Multiple independent gas expansion equilibrium experiments were conducted (n≥2) under different conditions, and data sets (P) were recorded each time. 1i , T 1i , P 2i , T 2i Then, an extended state equation is constructed, incorporating the volume V to be measured. x The system's effective leakage rate L and temperature influence coefficient C are simultaneously inverted using least squares fitting or Kalman filtering algorithms to obtain optimal estimates of multiple parameters. Inference effects: Compensation for non-ideal factors: In real-world environments, systems may experience minor leaks (L) and temperature inhomogeneities (C), which can affect the accuracy of gas law equations (such as the ideal gas law). By simultaneously inverting multiple parameters, the system actively identifies these error sources and compensates for them when calculating the volume. For example, if the leakage rate L is estimated to be positive, the algorithm adjusts the pressure value in the equation, thereby correcting the volume calculation result. This module improves accuracy and robustness by using multiple experimental data (n≥2) and mathematical optimization algorithms, reducing the impact of random errors. Kalman filtering can handle noise, and least squares fitting can find the optimal solution, making V... x The estimated value is closer to the true value. The solution explicitly states that it can still output a high-precision volume value even in the presence of minor leaks and temperature inconsistencies, demonstrating strong robustness. Conclusion: This module effectively eliminates systematic errors through multi-parameter inversion, ensuring a high level of accuracy in volume measurement.

[0073] The intelligent rocket propellant tank volume measurement system provided by this invention features a gas path execution unit design: the system uses nitrogen as the medium, achieving controllable gas flow through a delivery pump, a recovery pump, and a valve assembly. A standard container (with a known volume V1) serves as a reference, providing a measurement benchmark. Redundant design of pressure and temperature sensors (e.g., pressure sensor calibration with pressure gauges) ensures accurate data acquisition. Three modules work collaboratively—adaptive predictive control ensures rapid balancing, multi-parameter dynamic inversion processing ensures accurate calculation, and online fault diagnosis ensures system health. This integration enables the system to achieve stable measurements in complex engineering environments (such as the harsh conditions of rocket propellant tanks). Practical application reasoning: In rocket propellant tank volume measurement, accuracy and reliability are paramount. This system, through intelligent compensation and prediction, reduces the reliance on perfect sealing and constant temperature environments found in traditional methods, making it suitable for field testing and reducing costs and time.

[0074] Example 2

[0075] like Figure 3 As shown in the figure, this embodiment 2 provides a method for intelligent measurement of rocket propellant tank volume, which specifically includes the following operation steps:

[0076] S1. The adaptive predictive control module uses a pulse mode to inflate the standard container during a single balancing process, and monitors the pressure change rate and temperature change rate of the standard container in real time during the pulse interval. Based on the prediction model, it dynamically predicts the time required to reach balancing. When the predicted remaining time is stable and less than the minimum time standard threshold, balancing is determined in advance.

[0077] S2. Multi-parameter dynamic inversion processing module (i.e., used to process data and calculate volume): By controlling the valve group to conduct multiple independent gas expansion equilibrium experiments under different initial pressures, the initial pressure, initial temperature, equilibrium pressure, and equilibrium temperature are recorded each time; an extended state equation containing the volume to be measured, the effective leakage rate of the system, and the temperature influence coefficient is constructed; the optimal estimate of the multi-parameters is synchronously inverted using the data set through fitting or filtering algorithms to compensate for non-ideal factors and output the volume value;

[0078] That is, by controlling the valve assembly, at different initial pressures P 1i Perform n independent gas expansion equilibrium experiments (n≥2) with i=1,2,3…n, and record the data set (P) for each experiment. 1i , T 1i , P 2i , T 2i Algorithm: Construct a system containing the volume V to be measured. xThe extended state equations for the system's effective leakage rate L and temperature influence coefficient C are derived simultaneously using n sets of measurement data through least squares fitting or Kalman filtering algorithms to obtain optimal estimates of multiple parameters. Results: It actively identifies and compensates for non-ideal factors, outputting high-precision volume values ​​even in the presence of minor leaks and temperature inconsistencies. x .

[0079] Ideally, researchers only need to know the pressure and temperature to calculate the volume using a single formula (the ideal gas law). However, in reality, systems experience two main disturbances: micro-leakage (L): gas slowly leaks out. Temperature unevenness (C): the temperature varies at different points within the container, affecting the pressure reading. If we ignore these disturbances and directly calculate the volume, the result will certainly be inaccurate. To address this, this embodiment employs a "simultaneous inversion" approach: it acknowledges the existence of these disturbances and treats them as "unknowns" that need to be solved. Therefore, the technical problem of this embodiment lies in: solving for an unknown (volume V). x The problem has evolved into solving for three unknowns simultaneously: the volume to be measured (V) x ), System effective leakage rate (L), Temperature influence coefficient (C);

[0080] "Inverse estimation of the optimal estimate" refers to obtaining multiple sets of data through repeated experiments (n≥2) under different pressures, and then using mathematical optimization algorithms such as "least squares" or "Kalman filtering" to find the set (V) that best matches all the experimental data from these potentially erroneous data. x The values ​​are L, C, and C. This set of values ​​is the "optimal" estimate of the actual situation.

[0081] In this embodiment, the actual volume (V) of the storage tank is ultimately measured by recording the pressure (P1, P2) and temperature (T1, T2) through multiple experiments. x ), as well as the effective leakage rate L and the temperature influence coefficient C.

[0082] In the above technical solution, a structure is constructed containing the volume to be measured, V. x The extended state equations for the system's effective leakage rate L and temperature influence coefficient C are used. Utilizing n sets of measurement data, the optimal estimates of multiple parameters are simultaneously derived through least-squares fitting or Kalman filtering algorithms. Results: It actively identifies and compensates for non-ideal factors, outputting high-precision volume values ​​even in the presence of minor leaks and temperature inconsistencies.

[0083] To put it simply, this can be explained as follows: This embodiment aims to determine the internal volume (V) of the (rocket propellant tank). x But this internal volume (V) xThe gas is easily affected by the effective leakage rate (L) and the temperature influence coefficient (C), which interfere with our measurements. A traditional, cumbersome method involves assuming there is no leak and the temperature is constant, then directly measuring with a ruler (analogous to directly using the ideal gas formula). This method yields large errors because it ignores real-world interference.

[0084] However, the logic of the solution adopted in this embodiment of the invention is as follows: First, expand the scope of data analysis (construct an extended state equation); this embodiment of the invention cannot only check the volume, but must also analyze the effective leakage rate L and the temperature influence coefficient C. Thus, the unknown target of the case changes from 1 (volume) to 3 (volume, leakage, and temperature interference). Second, collect clues through multiple experiments (using n sets of measurement data); detect the pumping of air into a reference container (standard container) of known size at different times and with different forces, and record in detail each time: the initial pressure and temperature, and the pressure and temperature after equilibrium. This is like observing the crime scene from different angles and under different conditions, collecting multiple sets of clues. Third, conduct comprehensive analysis (through least squares fitting or Kalman filtering). The detection method obtained several sets of clues (data), but each set of clues might have a slight error. He used an advanced "logical reasoning method" (algorithm) to cross-validate all the clues together. The least squares method is similar to finding a "most suitable trend line" that best matches all data points, thereby solving the three unknowns. Kalman filtering is similar to a "dynamic optimizer" that can intelligently filter out random "noise" during data processing, making the results smoother and more reliable. This process is "synchronous" because it determines the values ​​of the three parameters simultaneously in the same set of analyses. Step 4: (Synchronously reverse the optimal estimates of multiple parameters); Through analysis, the above detection method not only knows the true volume of the rocket's propellant tank (V x Furthermore, it accurately grasped the influence of the effective leakage rate L and the temperature influence coefficient C.

[0085] In the specific technical solution of this embodiment, further, the step of conducting multiple independent gas expansion equilibrium experiments under different initial pressures by controlling the valve group includes:

[0086] The control valve assembly is adjusted for each initial pressure setpoint to inject gas into the container to achieve the initial pressure.

[0087] The gas expansion process is performed until equilibrium is reached. Each experiment is conducted independently, and the initial pressure and initial temperature are collected as part of the initial data set.

[0088] After equilibrium is achieved, the equilibrium pressure and the equilibrium temperature are recorded to complete the data set.

[0089] If the number of data sets reaches the preset minimum value, the experiment is stopped; otherwise, the initial pressure is adjusted and the next experiment is conducted.

[0090] The consistency of the experiment is verified by collecting multiple sets of data. If the consistency is lower than the threshold, the data is collected again.

[0091] In the specific technical solution of this embodiment, the construction of the extended equation of state including the volume to be measured, the effective leakage rate of the system, and the temperature influence coefficient includes: extending the gas equation of state to the extended equation of state, wherein the extended equation of state integrates the volume to be measured as the main variable and incorporates the effective leakage rate of the system to characterize dynamic loss; introducing the temperature influence coefficient into the extended equation of state to quantify the effect of temperature unevenness on pressure; using the data set input to the extended equation of state to generate a set of equations; solving the set of equations through the fitting or filtering algorithm to obtain the optimal estimate of the multi-parameters; adjusting the parameters of the extended equation of state according to the optimal estimate of the multi-parameters to optimize the subsequent inversion accuracy; if the optimal estimate of the multi-parameters converges, outputting the volume value; otherwise, iterating the fitting or filtering algorithm.

[0092] In the specific technical solution of this embodiment, the step of using a pulse mode to inflate the standard container during a single balancing process includes:

[0093] Set the high-frequency short-time pulse mode parameters to inject gas into the container in segments; pause the injection after each pulse and start real-time monitoring of pressure change rate and temperature change rate;

[0094] A continuous data sequence is collected to calculate the pressure change rate as dP / dt and the temperature change rate as dT / dt;

[0095] Input the dP / dt and the dT / dt into the prediction model, wherein the prediction model is an exponential decay model used to fit the change curve;

[0096] The time required to reach equilibrium is extrapolated from the prediction model. If the predicted remaining time is lower than a preset threshold, the early determination of equilibrium is performed.

[0097] In the specific technical solution of this embodiment, the step of solving the system of equations using the fitting or filtering algorithm to obtain the optimal estimate of the multi-parameters includes:

[0098] The parameter vector for initializing the fitting or filtering algorithm includes the initial estimate of the volume to be measured; the residuals are calculated by applying least squares fitting for each set of data;

[0099] If Kalman filtering is used, the state covariance matrix is ​​updated to reflect the parameter correlation; the solution is iteratively solved until the residual is minimized to obtain the optimal estimate of the multi-parameters; the compensation effect is verified based on the optimal estimate of the multi-parameters, and if the error after compensation is lower than the threshold, the volume value is confirmed.

[0100] In the specific technical solution of this embodiment, the step of extrapolating the time required to reach equilibrium based on the prediction model, and performing the advance determination of equilibrium if the predicted remaining time is lower than a preset threshold, includes:

[0101] Fit the dP / dt and dT / dt to the exponential decay model to extract decay parameters; calculate the prediction curve based on the decay parameters and determine the equilibrium point time.

[0102] If the predicted remaining time is lower than a preset threshold, then the advance determination balance is performed; the advance determination balance is performed and monitoring is terminated to shorten the overall process.

[0103] In summary, the intelligent rocket propellant tank volume measurement system and method provided in this invention fundamentally compensates for system errors (leakage, temperature effects) that traditional methods cannot overcome through multi-parameter dynamic inversion, achieving high-precision measurement under non-ideal operating conditions. Simultaneously, the adoption of an adaptive pulse inflation and balance prediction strategy overcomes the efficiency bottleneck of gas balance, making rapid measurement of large-volume propellants possible and enhancing measurement efficiency.

[0104] The intelligent rocket propellant tank volume measurement system and method provided in this invention requires no manual intervention for the entire measurement process, has high measurement efficiency, and ensures intelligent measurement of rocket propellant tank volume by automatically outputting reliable results.

[0105] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A rocket propellant tank volume intelligent measurement system, characterized in that, include: Nitrogen tank, manual ball valve, transfer pump, check valve, air-lock ball valve, pressure sensor, pressure gauge, pneumatic ball valve, recovery pump, electric regulating valve, storage tank, safety valve, standard container, first temperature sensor, second temperature sensor, intelligent control center; The nitrogen tank, delivery pump, recovery pump, standard container, and the storage tank to be tested are connected by pipelines to form a gas path execution unit. The connecting pipe between the nitrogen tank and the standard container is equipped with a manual ball valve, a delivery pump, a check valve, a gas-locking ball valve, a pressure sensor, a pressure gauge, and a manual ball valve; the connecting pipe between the standard container and the storage tank is equipped with a pneumatic ball valve, a gas-locking ball valve, a pressure sensor, and a pressure gauge; the return gas pipeline between the storage tank and the nitrogen tank is also equipped with a manual ball valve, a recovery pump, and an electric regulating valve; the exhaust pipe located at the top of the standard container is equipped with a manual ball valve, a safety valve, a standard container, and a first temperature sensor; and the bottom of the nitrogen tank is equipped with an exhaust port. The pressure sensor is used to detect the inlet pressure of the standard container; the pressure gauge is used to read the inlet pressure of the standard container to verify the accuracy of the pressure sensor; the pressure sensor is used to control the nitrogen pressure inside the storage tank; the pressure gauge is used to read the inlet pressure of the storage tank to verify the accuracy of the pressure sensor. The standard container is used to hold nitrogen gas at different pressures; the first temperature sensor is used to monitor temperature changes inside the standard container; the second temperature sensor is used to monitor temperature changes inside the storage tank. The intelligent control center includes an adaptive predictive control module and a multi-parameter dynamic inversion processing module; The adaptive predictive control module is used to pressurize the standard container with a pulse mode during a single balancing process, and to monitor the pressure change rate and temperature change rate of the standard container in real time during the pulse interval. Based on the prediction model, it dynamically predicts the time required to reach balancing, and determines balancing in advance when the predicted remaining time is stable and less than the minimum time standard threshold. The multi-parameter dynamic inversion processing module is used to conduct multiple independent gas expansion equilibrium experiments under different initial pressures by controlling the valve group. Each experiment records a data set of the initial pressure, initial temperature, equilibrium pressure, and equilibrium temperature of a standard container. It constructs an extended state equation including the volume to be measured, the system's effective leakage rate, and a temperature influence coefficient. This includes: extending the gas state equation to the extended state equation, where the extended state equation integrates the volume to be measured as the main variable and incorporates the system's effective leakage rate to characterize dynamic loss; introducing the temperature influence coefficient into the extended state equation to quantify the effect of temperature unevenness on pressure; generating an equation set using the data set as input to the extended state equation; solving the equation set using a fitting or filtering algorithm to obtain optimal estimates of the multi-parameters; adjusting the parameters of the extended state equation based on the optimal estimates of the multi-parameters to optimize subsequent inversion accuracy; outputting the volume value if the optimal estimates of the multi-parameters converge, otherwise iterating the fitting or filtering algorithm; and synchronously inverting the optimal estimates of the multi-parameters using the data set through a fitting or filtering algorithm to compensate for non-ideal factors and output the volume value.

2. The system as described in claim 1, characterized in that, It also includes a sensing and control unit and a human-machine interface; the sensing and control unit includes a high-precision pressure sensor, a multi-point temperature sensor, and a flow meter installed on the pipeline; the human-machine interface is used to display the measurement process of measuring multiple nodes and the measurement result information of the nodes.

3. The system as described in claim 2, characterized in that, The nitrogen tank is used to store dry nitrogen; the manual ball valve is used to manually control the nitrogen tank to deliver nitrogen to the standard container; the delivery pump provides the power to deliver nitrogen from the nitrogen tank to the standard container; the one-way valve controls the nitrogen tank to deliver nitrogen only to the standard container to prevent backflow; the gas-lock ball valve is used to control the electric switch for delivering nitrogen from the nitrogen tank to the standard container; the manual ball valve is used for testing and maintenance instruments; the pneumatic ball valve is used to control the manual switch for delivering nitrogen from the standard container to the storage tank; the gas-lock ball valve is used to control the electric switch for delivering nitrogen from the standard container to the storage tank; the manual ball valve is used to control the manual switch for delivering nitrogen from the storage tank to the nitrogen tank; the recovery pump provides the power for delivering nitrogen from the storage tank to the nitrogen tank; the electric regulating valve is used to control the electric switch for delivering nitrogen from the storage tank to the nitrogen tank; the manual ball valve is used to control the nitrogen pressure relief valve in the standard container.

4. The system as described in claim 3, characterized in that, The safety valve is used to obtain the measured value of the nitrogen pressure in the current standard container in real time, and to control the activation of the safety valve to release the nitrogen pressure in the standard container when the measured value exceeds the preset pressure value.

5. A method for intelligent measurement of rocket propellant tank volume, characterized in that, It utilizes the intelligent rocket propellant tank volume measurement system as described in claim 1 for measurement processing, including the following operation steps: The adaptive predictive control module uses a pulse mode to inflate the standard container during a single balancing process, and monitors the pressure change rate and temperature change rate of the standard container in real time during the pulse interval. Based on the prediction model, it dynamically predicts the time required to reach balancing. When the predicted remaining time is stable and less than the minimum time standard threshold, balancing is determined in advance. Multiple independent gas expansion equilibrium experiments were conducted by controlling the valve group under different initial pressures. Each experiment recorded a set of data including initial pressure, initial temperature, equilibrium pressure, and equilibrium temperature. An extended state equation was constructed, which included the volume to be measured, the effective leakage rate of the system, and the temperature influence coefficient. The optimal estimates of multiple parameters were synchronously inverted using the data set through fitting or filtering algorithms to compensate for non-ideal factors and output the volume value. The construction of the extended equation of state, which includes the volume to be measured, the effective leakage rate of the system, and the temperature influence coefficient, comprises: extending the gas equation of state to the extended equation of state, wherein the extended equation of state integrates the volume to be measured as the main variable and incorporates the effective leakage rate of the system to characterize dynamic loss; introducing the temperature influence coefficient into the extended equation of state to quantify the effect of temperature unevenness on pressure; generating a set of equations using the data set as input to the extended equation of state; solving the set of equations using a fitting or filtering algorithm to obtain the optimal estimate of the multi-parameters; adjusting the parameters of the extended equation of state based on the optimal estimate of the multi-parameters to optimize the subsequent inversion accuracy; and outputting the volume value if the optimal estimate of the multi-parameters converges, otherwise iterating the fitting or filtering algorithm.

6. The method as described in claim 5, characterized in that, The method of conducting multiple independent gas expansion equilibrium experiments under different initial pressures by controlling the valve group includes: The control valve assembly is adjusted for each initial pressure setpoint to inject gas into the container to achieve the initial pressure. The gas expansion process is performed until equilibrium is reached. Each experiment is conducted independently, and the initial pressure and initial temperature are collected as part of the initial data set. After equilibrium is achieved, the equilibrium pressure and the equilibrium temperature are recorded to complete the data set. If the number of data sets reaches the preset minimum value, the experiment is stopped; otherwise, the initial pressure is adjusted and the next experiment is conducted. The consistency of the experiment is verified by collecting multiple sets of data. If the consistency is lower than the threshold, the data is collected again.

7. The method as described in claim 6, characterized in that, The step of inflating the standard container using a pulse mode during a single balancing process includes: Set the high-frequency short-time pulse mode parameters to inject gas into the container in segments; pause the injection after each pulse and start real-time monitoring of pressure change rate and temperature change rate; A continuous data sequence is collected to calculate the pressure change rate as dP / dt and the temperature change rate as dT / dt; Input the dP / dt and the dT / dt into the prediction model, wherein the prediction model is an exponential decay model used to fit the change curve; The time required to reach equilibrium is extrapolated from the prediction model. If the predicted remaining time is lower than a preset threshold, the early determination of equilibrium is performed.

8. The method as described in claim 7, characterized in that, The step of solving the system of equations using the fitting or filtering algorithm to obtain the optimal estimates of the multi-parameters includes: The parameter vector for initializing the fitting or filtering algorithm includes the initial estimate of the volume to be measured; For each of the data sets, a least-squares fit is applied to calculate the residuals; If Kalman filtering is used, the state covariance matrix is ​​updated to reflect the parameter correlation; the solution is iteratively solved until the residual is minimized to obtain the optimal estimate of the multi-parameters; the compensation effect is verified based on the optimal estimate of the multi-parameters, and if the error after compensation is lower than the threshold, the volume value is confirmed.

9. The method as described in claim 8, characterized in that, The step of extrapolating the time required to reach equilibrium based on the prediction model, and performing the advance equilibrium determination if the predicted remaining time is lower than a preset threshold, includes: Fit the dP / dt and dT / dt to the exponential decay model to extract decay parameters; calculate the prediction curve based on the decay parameters and determine the equilibrium point time. If the predicted remaining time is lower than a preset threshold, then the advance determination balance is performed; the advance determination balance is performed and monitoring is terminated to shorten the overall process.

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