Flow fault determination method and system based on pressure drop characteristics of bang-bang electronic pressure reducer

Abstract

This invention relates to a flow fault determination method and system based on the pressure drop characteristics of a Bang-Bang electronic pressure reducer, belonging to the field of spacecraft flow fault diagnosis technology. This invention utilizes the P-ρ-T relationship of the gaseous working fluid to directly calculate the output flow rate from on-orbit pressure and temperature telemetry data, eliminating the interference of temperature fluctuations on the pressure determination curve and adapting to various on-orbit temperature environments. By employing buffer gas capacity parameter calculations, the temperature measurement is closer to the actual fluid temperature, resulting in higher theoretical accuracy in fault determination. It features superior monitoring performance and a wider range of applicable scenarios. This invention can directly obtain the actual on-orbit output flow rate of the storage and supply subsystem, enabling it to determine whether the subsystem is operating normally and to identify trends in output flow rate changes in advance. By adjusting the storage and supply operating parameters in a timely manner, it can prevent thruster malfunctions.

Description

Technical Field

[0001] This invention relates to a flow fault determination method and system based on the pressure drop characteristics of a Bang-Bang electronic pressure reducer, belonging to the field of spacecraft flow fault diagnosis technology. Background Technology

[0002] With the development of aerospace technology, electric thrusters, due to their high specific impulse, are widely used in satellites to perform on-orbit position maintenance and momentum wheel unloading tasks throughout their lifespan. The energy storage and supply subsystem is a crucial component providing a stable, mg / s-level micro-flow rate to the electric thruster. If the output flow rate of the energy storage and supply subsystem is abnormal, deviating from the normal operating range of the electric thruster, it will directly affect the thruster's performance and may even lead to mission failure.

[0003] Currently, the most widely used electric propulsion storage and supply subsystem technology both domestically and internationally achieves a micro-flow rate output of mg / s by controlling the pressure and temperature of a throttle valve. It mainly consists of a Bang-Bang electronic pressure reducer and a labyrinth-type flow controller. Its working principle is that the Bang-Bang electronic pressure reducer periodically opens a valve to fill the buffer cylinder with gas. Once the upper limit of the control pressure is reached, the valve closes, releasing gas from the buffer cylinder, causing the pressure to gradually decrease. When the pressure falls below the lower limit of the control pressure, the valve opens again, repeating this process to consistently control the pressure in the buffer cylinder within the allowable error range of the target pressure. The downstream labyrinth-type flow controller then achieves the mg / s micro-flow rate output. This technology has a certain flow regulation capability, and its hardware configuration and software control are simple and reliable, making it suitable for most electric propulsion systems.

[0004] To ensure the stable and reliable operation of the on-orbit storage and supply subsystem, multiple fault detection methods are employed for pressure control and temperature control, including detection of pressure sensor faults, detection of pressure closed-loop control faults, detection of temperature closed-loop control faults, safety pressure over-limit fault protection, and inflation timeout fault protection. However, these diagnostic methods can only determine whether the storage and supply subsystem is malfunctioning and ensure the safety of the storage and supply subsystem products, but cannot obtain the actual on-orbit output flow value.

[0005] To determine the actual on-orbit output flow rate of the storage and supply subsystem, a ground-based flow calibration system is typically used to first obtain the functional relationship between the output flow rate and the pressure of the Bang-Bang electronic pressure regulator and the temperature of the flow controller. Then, the actual on-orbit output flow rate is obtained by combining on-orbit pressure and temperature telemetry values ​​with the ground-calibrated functional relationship. This method requires a sufficient number of pressure and temperature points from ground-based flow calibration tests to ensure that the fitted functional relationship covers the on-orbit pressure and temperature range, which significantly increases the workload of ground-based flow calibration. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a flow fault determination method and system based on the pressure drop characteristics of Bang-Bang electronic pressure reducers. This aims to solve the problem that existing fault detection methods for storage and supply subsystems cannot provide specific flow values ​​or predict the trend of output flow changes. Without increasing additional hardware resources, this invention provides a simple and effective flow assessment and fault determination method using only on-orbit pressure and temperature telemetry data.

[0007] The technical method used in this invention is as follows: A flow fault determination method based on the pressure drop characteristics of Bang-Bang electronic pressure reducers includes: S1, take the first i Within each Bang-Bang inflation / deflation cycle, the initial moment when the first temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop start point. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop start point time t1 is also recorded. S2, take the first i Within each Bang-Bang inflation / deflation cycle, the initial moment when the last temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop endpoint. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop endpoint time t2 is also recorded. S3. Calculate the density of the working gas in the buffer cylinder at the time t1 corresponding to the pressure drop start point. ρ 1 and the working fluid density in the buffer cylinder corresponding to the final pressure drop time t2. ρ 2; S4. Based on times t1 and t2, the densities of the working gas ρ1 and ρ2, and the volume V of the buffer cylinder, calculate the... i The average mass flow rate output of the buffer cylinder during the pressure drop process within a Bang-Bang inflation / deflation cycle. ; S5. Repeat steps S1 to S4 to calculate the average mass flow rate for each Bang-Bang inflation / deflation cycle. Using the average mass flow rate calculated for each Bang-Bang inflation / deflation cycle as a sample, when the sample size is ≥ N, the 3σ method is used to evaluate the average mass flow rate to determine whether there are any abnormal flow rates. Where N is a positive integer.

[0008] In the above-mentioned flow fault determination method based on the pressure drop characteristics of Bang-Bang electronic pressure reducers, the pressure drop start time t1 and pressure drop end time t2 are determined by the following method: The temperature of the buffer cylinder during the Bang-Bang inflation / deflation cycle varies in a stepwise manner, including several temperature plateaus that remain constant within a certain range. Assume the... iEach Bang-Bang inflation / deflation cycle is abc, where points a and c are the trough values ​​and point b is the peak value. The starting time of the next temperature plateau corresponding to point b is taken as the pressure drop start time t1, and the starting time of the temperature plateau corresponding to point c is taken as the pressure drop start time t2.

[0009] In the above-mentioned flow fault determination method based on the pressure drop characteristics of Bang-Bang electronic pressure reducer, in step S2, the P-ρ-T model of xenon is used for ground calculation, and the real gas state equation modified by the compressibility factor is used for satellite calculation to calculate the working fluid density ρ1 in the buffer gas cylinder corresponding to the pressure drop start time t1 and the working fluid density ρ2 in the buffer gas cylinder corresponding to the pressure drop end time t2.

[0010] In the above-mentioned flow fault determination method based on the pressure drop characteristics of the Bang-Bang electronic pressure reducer, the working fluid density in the buffer cylinder corresponding to the pressure drop initiation time t1 is... ρ 1 and the working fluid density in the buffer cylinder corresponding to the final pressure drop time t2. ρ The formula for calculating 2 is as follows:

[0011] Where j takes the value of 1 or 2, P is the absolute pressure Pa, M is the molar mass of xenon, R0 is the universal gas constant, T is the absolute temperature K, and Z is the compressibility factor of the gaseous working fluid.

[0012] In the above-mentioned flow fault determination method based on the pressure drop characteristics of Bang-Bang electronic pressure reducers, in step S4, the first step is calculated based on times t1 and t2, gas working fluid densities ρ1 and ρ2, and buffer cylinder volume V. i The average mass flow rate output of the buffer cylinder during the pressure drop process within a Bang-Bang inflation / deflation cycle. ,include: .

[0013] In the above-mentioned flow fault determination method based on the pressure drop characteristics of Bang-Bang electronic pressure reducers, N is set to 100.

[0014] A flow fault determination system based on the pressure drop characteristics of Bang-Bang electronic pressure reducers includes: The module for calculating the starting time of pressure drop takes the first... i Within each Bang-Bang inflation / deflation cycle, the initial moment when the first temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop start point. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop start point time t1 is also recorded. The module for calculating the final moment of the pressure drop takes the first... iWithin each Bang-Bang inflation / deflation cycle, the initial moment when the last temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop endpoint. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop endpoint time t2 is also recorded. The density calculation module calculates the density of the working fluid in the buffer cylinder at the starting time t1 of the pressure drop. ρ 1 and the working fluid density in the buffer cylinder corresponding to the final pressure drop time t2. ρ 2; The mass flow calculation module calculates the mass flow rate based on times t1 and t2, xenon densities ρ1 and ρ2, and buffer cylinder volume V. i The average mass flow rate output of the buffer cylinder during the pressure drop process within a Bang-Bang inflation / deflation cycle. ; The evaluation and judgment module uses the average mass flow rate calculated from each Bang-Bang inflation / deflation cycle as a sample. When the number of samples is ≥ N, the 3σ method is used to evaluate the average mass flow rate and determine whether there is any abnormal flow rate. Here, N is a positive integer.

[0015] A computer device includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method described above.

[0016] A computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the method described above.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: (1) This invention provides a flow fault determination method based on the pressure drop characteristics of Bang-Bang electronic pressure reducer, which solves the problem that existing fault detection methods of storage and supply subsystem cannot give specific flow values ​​and predict the trend of output flow change. Without adding extra hardware resources, it provides a simple and effective flow assessment and fault determination method using only on-orbit pressure and temperature telemetry data.

[0018] (2) This invention provides a flow fault determination method based on the pressure drop characteristics of Bang-Bang electronic pressure reducer, which can directly obtain the actual output flow of the storage and supply subsystem on orbit. On the one hand, it can determine whether the subsystem is working normally, and on the other hand, it can identify the trend of the output flow change of the storage and supply subsystem in advance. By adjusting the storage and supply working parameters in time, it can avoid the thruster from working abnormally.

[0019] (3) This invention provides a flow fault determination method based on the pressure drop characteristics of Bang-Bang electronic pressure reducer, which has the advantages of better monitoring performance and wider applicability. By utilizing the P-ρ-T relationship of the working gas, the output flow rate can be directly calculated from the on-orbit pressure and temperature telemetry data, eliminating the interference of temperature fluctuations on the pressure determination curve and adapting to various on-orbit temperature environments. The buffer gas capacity parameter calculation is adopted, and the temperature measurement is closer to the actual fluid temperature, resulting in higher theoretical accuracy of fault determination.

[0020] (4) This invention provides a flow fault determination method based on the pressure drop characteristics of Bang-Bang electronic pressure reducer. It is lightweight and easy to implement, does not increase hardware costs, does not require new satellite hardware equipment, and can complete the calculation by simply reusing the pressure and temperature telemetry data of the existing satellite buffer cylinder. The algorithm has a small computational load and can be directly embedded into the existing electric propulsion system to complete the flow abnormality fault diagnosis.

[0021] (5) This invention provides a flow fault determination method based on the pressure drop characteristics of Bang-Bang electronic pressure reducer, which has the characteristics of improving satellite on-orbit reliability and facilitating mass promotion. It can detect the health status of the electric propulsion storage and supply subsystem in real time on-orbit, identify abnormal flow faults in a timely manner, and greatly improve the operational reliability of the satellite electric propulsion system. It can be deployed based on the existing on-board telemetry system and can be widely promoted and applied in existing and new satellites. Attached Figure Description

[0022] Figure 1 This is a flowchart of the traffic fault determination method in an embodiment of the present invention; Figure 2 This is a telemetry diagram of the on-orbit pressure and temperature of the Bang-Bang electronic pressure reducer in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the principle of determining the starting and ending points of the i-th Bang-Bang cycle pressure drop in this embodiment of the invention. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments: like Figure 1 As shown, this invention proposes a flow fault determination method based on the pressure drop characteristics of the Bang-Bang electronic pressure reducer, according to the on-orbit operating characteristics of the storage and supply subsystem. The method specifically includes the following steps: (1) Take the first i Within each Bang-Bang inflation / deflation cycle, take the first... iWithin each Bang-Bang charging / discharging cycle, the initial moment when the first temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop start point. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop start point time t1 is also recorded. In this embodiment, the working gas in the buffer cylinder is xenon.

[0024] (2) Take the first i Within each Bang-Bang inflation / deflation cycle, the initial moment when the last temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop endpoint. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop endpoint time t2 is also recorded. In this embodiment, the starting time t1 and the ending time t2 of the pressure drop are determined by the following method: like Figure 2 As shown, the temperature values ​​of the buffer cylinders during the Bang-Bang inflation / deflation cycle exhibit a stepped variation, including several temperature plateaus where the temperature remains constant within a certain range (such as...). Figure 2 (Several consecutive small platforms formed by the blue lines in the middle), assuming the first i The Bang-Bang inflation / deflation cycle is abc, where points a and c are the trough values ​​and point b is the peak value. The starting time of the next temperature plateau after the temperature plateau corresponding to point b (t') is taken as the pressure drop starting time t1. Figure 3 As shown, the temperature plateau corresponding to point b is the temperature plateau at time point t', and the starting time t1 of the next temperature plateau is taken as the starting time of the pressure drop. Similarly, the starting time t2 of the temperature plateau at time t” corresponding to point c is taken as the starting time of the pressure drop.

[0025] (3) Calculate the xenon density ρ1 at the start time and the xenon density ρ2 at the end time using the P-ρ-T model of xenon (ground calculation) or the real gas equation of state based on the compressibility factor correction (on-board calculation).

[0026] Where P is the absolute pressure in Pa, M is the molar mass of xenon (0.13129 kg / mol), R0 is the universal gas constant (8.314 J / (mol·K)), T is the absolute temperature in K, and Z is the xenon compressibility factor, which can be taken as 0.985 in the range of 0.1~0.5 MPa and 20~45ºC.

[0027] (4) Calculate the time difference t2-t1, substitute the densities of the working gas ρ1 and ρ2 and the volume of the buffer cylinder V, and calculate the first... i The average mass flow rate output of the buffer cylinder during the pressure drop process within a Bang-Bang inflation / deflation cycle. ;

[0028] (5) Repeat steps (1) to (4) to calculate the average mass flow rate of each Bang-Bang inflation / deflation cycle. The average mass flow rate calculated for each Bang-Bang inflation / deflation cycle is used as a sample (all historical data of the electric propulsion system in orbit up to the present are used). When the number of samples is ≥100, the 3σ method is used to evaluate the average mass flow rate to determine whether there is any flow abnormality.

[0029] (6) The onboard software of the electric propulsion system can use the average mass flow rate and its standard deviation obtained by the above method to design an onboard autonomous threshold protection strategy.

[0030] This invention provides a flow fault determination system based on the pressure drop characteristics of a Bang-Bang electronic pressure reducer, comprising: The module for calculating the starting time of pressure drop takes the first... i Within each Bang-Bang inflation / deflation cycle, the initial moment when the first temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop start point. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop start point time t1 is also recorded. The module for calculating the final moment of the pressure drop takes the first... i Within each Bang-Bang inflation / deflation cycle, the initial moment when the last temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop endpoint. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop endpoint time t2 is also recorded. The density calculation module calculates the density of the working fluid in the buffer cylinder at the starting time t1 of the pressure drop. ρ 1 and the working fluid density in the buffer cylinder corresponding to the final pressure drop time t2. ρ 2; The mass flow calculation module calculates the mass flow rate based on times t1 and t2, xenon densities ρ1 and ρ2, and buffer cylinder volume V. i The average mass flow rate output of the buffer cylinder during the pressure drop process within a Bang-Bang inflation / deflation cycle. ; The evaluation and judgment module uses the average mass flow rate calculated from each Bang-Bang inflation / deflation cycle as a sample. When the number of samples is ≥ N, the 3σ method is used to evaluate the average mass flow rate and determine whether there is an abnormal flow rate. Here, N is a positive integer, and the preferred value is 100.

[0031] The present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method described above.

[0032] The present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described method.

[0033] The core of this invention lies in utilizing the P-ρ-T relationship of xenon gas in the buffer cylinder of the Bang-Bang electronic pressure reducer to convert changes in pressure and temperature telemetry values ​​into changes in the mass of output xenon gas. By utilizing the physical meaning of mass change, the unmeasurable flow rate value is reflected through measurable pressure and temperature values, and based on this, a flow fault determination method for the storage and supply subsystem suitable for on-orbit applications is established.

[0034] Based on practical needs, this invention provides a flow fault determination method and system based on the pressure drop characteristics of the Bang-Bang electronic pressure reducer. It can directly obtain the actual on-orbit output flow of the storage and supply subsystem, which can determine whether the subsystem is working properly and identify the trend of output flow change in the storage and supply subsystem in advance. By adjusting the storage and supply operating parameters in a timely manner, it can avoid thruster malfunction.

[0035] The above description is only the best specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

[0036] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A flow failure determination method based on the pressure drop characteristics of a Bang-Bang electronic pressure reducer, characterized by, include: S1, take the first i In the first Bang-Bang charging and discharging cycle, the initial time when the first temperature stratification value changes after the valve action of the Bang-Bang valve is taken as the falling pressure starting point, the pressure and temperature values of the buffer gas cylinder at this time are recorded, and the falling pressure starting time t1 is recorded. S2, take the first i Within each Bang-Bang inflation / deflation cycle, the initial moment when the last temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop endpoint. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop endpoint time t2 is also recorded. S3. Calculate the density of the working gas in the buffer cylinder at the time t1 corresponding to the pressure drop start point. ρ 1 and the working fluid density in the buffer cylinder corresponding to the final pressure drop time t2. ρ 2; S4. Based on times t1 and t2, the densities of the working gas ρ1 and ρ2, and the volume V of the buffer cylinder, calculate the... i The average mass flow rate output of the buffer cylinder during the pressure drop process within a Bang-Bang inflation / deflation cycle. ; S5. Repeat steps S1 to S4 to calculate the average mass flow rate for each Bang-Bang inflation / deflation cycle. Using the average mass flow rate calculated for each Bang-Bang inflation / deflation cycle as a sample, when the sample size is ≥ N, the 3σ method is used to evaluate the average mass flow rate to determine whether there are any abnormal flow rates. Where N is a positive integer.

2. The flow fault determination method based on the pressure drop characteristics of a Bang-Bang electronic pressure reducer according to claim 1, characterized in that, The starting time t1 and the ending time t2 of the pressure drop are determined by the following method: The temperature of the buffer cylinder during the Bang-Bang inflation / deflation cycle varies in a stepwise manner, including several temperature plateaus that remain constant within a certain range. Assume the... i Each Bang-Bang inflation / deflation cycle is abc, where points a and c are the trough values ​​and point b is the peak value. The starting time of the next temperature plateau corresponding to point b is taken as the pressure drop start time t1, and the starting time of the temperature plateau corresponding to point c is taken as the pressure drop start time t2.

3. The flow fault determination method based on the pressure drop characteristics of a Bang-Bang electronic pressure reducer according to claim 1, characterized in that, In step S2, the P-ρ-T model of xenon is used for ground calculations, and the real gas state equation with compressibility factor correction is used for on-board calculations to calculate the working fluid density ρ1 in the buffer cylinder at the starting time t1 of the pressure drop and the working fluid density ρ2 in the buffer cylinder at the ending time t2 of the pressure drop.

4. The flow fault determination method based on the pressure drop characteristics of the Bang-Bang electronic pressure reducer according to claim 3, characterized in that, The working fluid density in the buffer cylinder corresponding to the pressure drop initiation time t1 ρ 1 and the working fluid density in the buffer cylinder corresponding to the final pressure drop time t2. ρ The formula for calculating 2 is as follows: Where j takes the value of 1 or 2, P is the absolute pressure Pa, M is the molar mass of xenon, R0 is the universal gas constant, T is the absolute temperature K, and Z is the compressibility factor of the gaseous working fluid.

5. The flow fault determination method based on the pressure drop characteristics of a Bang-Bang electronic pressure reducer according to claim 1, characterized in that, In step S4, based on times t1 and t2, the densities of the working gas ρ1 and ρ2, and the volume V of the buffer cylinder, the calculation is performed. i The average mass flow rate output of the buffer cylinder during the pressure drop process within a Bang-Bang inflation / deflation cycle. ,include: 。 6. The flow fault determination method based on the pressure drop characteristics of a Bang-Bang electronic pressure reducer according to claim 1, characterized in that, N takes the value 100.

7. A flow fault determination system based on the pressure drop characteristics of a Bang-Bang electronic pressure reducer, characterized in that, include: The module for calculating the starting time of pressure drop takes the first... i Within each Bang-Bang inflation / deflation cycle, the initial moment when the first temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop start point. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop start point time t1 is also recorded. The module for calculating the final moment of the pressure drop takes the first... i Within each Bang-Bang inflation / deflation cycle, the initial moment when the last temperature stratification value changes after the Bang-Bang valve is activated is taken as the pressure drop endpoint. The pressure and temperature values ​​of the buffer cylinder at this moment are recorded, and the pressure drop endpoint time t2 is also recorded. The density calculation module calculates the density of the working fluid in the buffer cylinder at the starting time t1 of the pressure drop. ρ 1 and the working fluid density in the buffer cylinder corresponding to the final pressure drop time t2. ρ 2; The mass flow calculation module calculates the mass flow rate based on times t1 and t2, xenon densities ρ1 and ρ2, and buffer cylinder volume V. i The average mass flow rate output of the buffer cylinder during the pressure drop process within a Bang-Bang inflation / deflation cycle. ; The evaluation and judgment module uses the average mass flow rate calculated from each Bang-Bang inflation / deflation cycle as a sample. When the number of samples is ≥ N, the 3σ method is used to evaluate the average mass flow rate and determine whether there is any abnormal flow rate. Here, N is a positive integer.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 7.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 7.

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