A liquid rocket engine testability analysis and state assessment method and device

Abstract

A method and device for liquid rocket engine testability analysis and state assessment, the method constructs a liquid rocket engine testability model according to a multi-signal flow graph modeling strategy; performs static fault analysis on the liquid rocket engine testability model to obtain untestable faults, fault fuzzy groups and redundant test information data; calculates the fault detection rate, fault isolation rate and fault coverage testability indicators through the untestable faults, fault fuzzy groups and redundant test information data; evaluates the engine fault detection and diagnosis capabilities according to the testability indicators; optimizes the distribution of measurement points according to the testability indicator analysis, updates the liquid rocket engine testability model, and recalculates the testability indicators through the updated liquid rocket engine testability model. The present invention can intuitively and clearly express the mapping relationship between faults and measurement points, and effectively improve the reliability of engine fault detection and diagnosis.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid rocket engine fault detection and diagnosis, and in particular to a liquid rocket engine testability analysis and state assessment method and device. Background Art

[0002] In recent years, in order to meet the needs of future space launch missions such as manned lunar landing and space station construction plans, my country is stepping up the development of a new generation of high-thrust liquid rocket engines. Compared with my country's current launch vehicle power systems, the new generation of high-thrust liquid rocket engines has the characteristics of large flow, high thrust, higher turbopump speed, higher combustion chamber pressure, adjustable mixing ratio, variable working conditions, and multiple reuse. Therefore, conducting test analysis and research on the new generation of high-thrust liquid rocket engines, as well as subsequent health monitoring, has become an important task to improve the reliability and safety of my country's future space launch missions.

[0003] At present, due to the harsh working environment of liquid rocket engines, it is difficult to fully obtain engine status information, especially fault information, which makes it difficult for existing fault diagnosis algorithms to cover all fault modes, greatly affecting the reliability of engine fault detection and diagnosis. Testability analysis technology can effectively solve the problems of engine parameter information selection and testability capability evaluation by expressing the logical relationship between measurement points and system faults through correlation models, multi-signal flow graph models, etc. It is suitable for large-scale real-time online fault diagnosis and is widely used in fault detection and diagnosis of complex equipment.

[0004] Therefore, how to design a liquid rocket engine testability analysis and state assessment method for liquid rocket engine fault detection and diagnosis and improve the reliability of engine fault detection and diagnosis has become an urgent problem to be solved. Summary of the invention

[0005] To this end, the present invention provides a liquid rocket engine testability analysis and state assessment method and device. The method is based on the multi-signal flow graph modeling concept to construct a liquid rocket engine testability model; conduct engine testability qualitative analysis, evaluate testability indicators and optimize measurement point distribution. The method can intuitively and clearly express the mapping relationship between faults and measurement points, effectively improving the reliability of engine fault detection and diagnosis.

[0006] In order to achieve the above object, the present invention provides the following technical solution: a liquid rocket engine testability analysis and state assessment method, comprising:

[0007] According to the multi-signal flow graph modeling strategy, a liquid rocket engine testability model is constructed;

[0008] Performing static fault analysis on the liquid rocket engine testability model to obtain untestable faults, fuzzy fault groups, and redundant test information data;

[0009] Calculate the testability indicators of fault detection rate, fault isolation rate and fault coverage rate through the untestable faults, fault fuzzy groups and redundant test information data; evaluate the engine fault detection and diagnosis capabilities according to the testability indicators;

[0010] The distribution of measuring points is optimized according to the testability index analysis, the liquid rocket engine testability model is updated, and the testability index is recalculated using the updated liquid rocket engine testability model.

[0011] As a preferred solution of a liquid rocket engine testability analysis and state assessment method, the modeling steps of the multi-signal flow graph modeling strategy are:

[0012] According to the set software tool, multi-signal models are constructed by generating VHDL structural models or EDIF connection tables or directly inputting structural models, schematic models or conceptual block diagrams through the graphical user interface;

[0013] Loading signals to modules and test points in the multi-signal model;

[0014] According to the setting conditions, the multi-signal model is modified;

[0015] The multi-signal model is verified based on test data and the physical model.

[0016] As a preferred solution of a liquid rocket engine testability analysis and state assessment method, in the process of static fault analysis of the liquid rocket engine testability model, the test set FS (f i ) to describe the fault f i Fault characteristics, FS(f i ) is recorded as:

[0017]

[0018] Where, t j is the test; f is the fault feature set; t ij t j For fault f i Testing;

[0019] The undetectable fault satisfies the following conditions:

[0020]

[0021] In the formula, represents the empty set;

[0022] The conditions for satisfying the fault fuzzy group are:

[0023] FS(f x )=FS(f y ),(x≠y)

[0024] In the formula, f x and f y For failure;

[0025] The set of fault fuzzy groups is denoted as AG(F):

[0026]

[0027] In the formula, A k is the fuzziness, that is, the number of faults in the fuzzy group; F is the total number of faults in the system; FS(f x ) is the fault f x Fault characteristics of FS(f y ) is the fault f y Fault characteristics;

[0028] The redundancy test satisfies the following conditions:

[0029] TS(t i )=TS(t j )

[0030] Test i and t j Mutually redundant, if you choose to test t i , then t j t i Redundancy test.

[0031] As a preferred solution for a liquid rocket engine testability analysis and condition assessment method, the mathematical model expression of the fault detection rate is:

[0032]

[0033] Where FDR is the fault detection rate; D is the total failure rate of the detected failure modes; λ is the total failure rate of all failure modes; i is the failure rate of the ith failure mode; Di is the failure rate of the i-th detected failure mode;

[0034] The calculation formula of the fault coverage is:

[0035]

[0036] The mathematical model expression of the fault isolation rate is:

[0037]

[0038] Where FIR is the fault isolation rate; D is the total failure rate of all detected failure modes; L is the sum of the failure rates of the failure modes that can be isolated to less than or equal to L replaceable units; Li is the failure rate of the i-th failure mode among the failures that can be isolated to less than or equal to L replaceable units; L is the number of replaceable units in the isolation group.

[0039] As a preferred scheme for a liquid rocket engine testability analysis and state assessment method, in the process of optimizing the distribution of measuring points according to the testability index analysis, if the fault coverage does not meet the testability requirements or there are several fuzzy fault groups, sensor measuring points are added to the untestable faults and the fuzzy fault groups; if the redundant test exists, the redundant measuring points are removed.

[0040] The present invention also provides a liquid rocket engine testability analysis and state evaluation device, based on the above liquid rocket engine testability analysis and state evaluation method, comprising:

[0041] Liquid rocket engine testability model building module, used to build a liquid rocket engine testability model based on a multi-signal flow graph modeling strategy;

[0042] A model static fault analysis module, used to perform static fault analysis on the liquid rocket engine testability model to obtain untestable faults, fault fuzzy groups and redundant test information data;

[0043] A testability index calculation module is used to calculate the testability indexes of fault detection rate, fault isolation rate and fault coverage rate through the untestable faults, fault fuzzy groups and redundant test information data; and evaluate the engine fault detection and diagnosis capability according to the testability indexes;

[0044] An indicator analysis and optimization module is used to optimize the distribution of measuring points according to the testability indicator analysis, update the liquid rocket engine testability model, and recalculate the testability indicator through the updated liquid rocket engine testability model.

[0045] As a preferred solution of a liquid rocket engine testability analysis and state assessment device, in the liquid rocket engine testability model building module, the modeling steps of the multi-signal flow graph modeling strategy are:

[0046] According to the set software tool, multi-signal models are constructed by generating VHDL structural models or EDIF connection tables or directly inputting structural models, schematic models or conceptual block diagrams through the graphical user interface;

[0047] Loading signals to modules and test points in the multi-signal model;

[0048] According to the setting conditions, the multi-signal model is modified;

[0049] The multi-signal model is verified based on test data and the physical model.

[0050] As a preferred solution of a liquid rocket engine testability analysis and state assessment device, in the model static fault analysis module, in the process of performing static fault analysis on the liquid rocket engine testability model, the test set FS (f i ) to describe the fault f i Fault characteristics, FS(f i ) is recorded as:

[0051]

[0052] Where, t j is the test; f is the fault feature set; t ij t j For fault f i Tests;

[0053] The undetectable fault satisfies the following conditions:

[0054]

[0055] In the formula, represents the empty set;

[0056] The conditions for satisfying the fault fuzzy group are:

[0057] FS(f x )=FS(f y ),(x≠y)

[0058] In the formula, f x and f y For failure;

[0059] The set of fault fuzzy groups is denoted as AG(F):

[0060]

[0061] In the formula, A k is the fuzziness, that is, the number of faults in the fuzzy group; F is the total number of faults in the system; FS(f x ) is the fault f x Fault characteristics of FS(f y ) is the fault f y Fault characteristics;

[0062] The redundancy test satisfies the following conditions:

[0063] TS(t i )=TS(t j )

[0064] Test i and t j Mutually redundant, if you choose to test t i , then t j t i Redundancy test.

[0065] As a preferred solution of a liquid rocket engine testability analysis and state assessment device, in the testability index calculation module, the mathematical model expression of the fault detection rate is:

[0066]

[0067] Where FDR is the fault detection rate; D is the total failure rate of the detected failure modes; λ is the total failure rate of all failure modes; i is the failure rate of the ith failure mode; Di is the failure rate of the i-th detected failure mode;

[0068] The calculation formula of the fault coverage is:

[0069]

[0070] The mathematical model expression of the fault isolation rate is:

[0071]

[0072] Where FIR is the fault isolation rate; D is the total failure rate of all detected failure modes; L is the sum of the failure rates of the failure modes that can be isolated to less than or equal to L replaceable units; Li is the failure rate of the i-th failure mode among the failures that can be isolated to less than or equal to L replaceable units; L is the number of replaceable units in the isolation group.

[0073] As a preferred solution for a liquid rocket engine testability analysis and state assessment device, in the indicator analysis optimization module, in the process of optimizing the measurement point distribution according to the testability indicator analysis, if the fault coverage does not meet the testability requirements or there are several fault fuzzy groups, sensor measurement points are added to the untestable faults and the fault fuzzy groups; if the redundant test exists, the redundant measurement points are removed.

[0074] The present invention has the following advantages: constructing a liquid rocket engine testability model according to a multi-signal flow graph modeling strategy; performing static fault analysis on the liquid rocket engine testability model to obtain untestable faults, fault fuzzy groups and redundant test information data; calculating the testability indicators of fault detection rate, fault isolation rate and fault coverage rate through the untestable faults, fault fuzzy groups and redundant test information data; evaluating the engine fault detection and diagnosis capability according to the testability indicators; optimizing the distribution of measuring points according to the testability indicators, updating the liquid rocket engine testability model, and recalculating the testability indicators through the updated liquid rocket engine testability model. Considering that the existing fault diagnosis methods are difficult to effectively cover the existing fault modes of the engine, the present invention proposes a liquid rocket engine testability analysis and state evaluation method, establishes a liquid rocket engine testability model based on the multi-signal flow graph modeling idea; carries out qualitative analysis of engine testability, evaluates testability indicators and optimizes the distribution of measuring points, and realizes effective coverage of engine fault mode detection and diagnosis. The present invention can intuitively and clearly express the mapping relationship between faults and measuring points, effectively improve the reliability of engine fault detection and diagnosis, and ensure the successful completion of engine test and flight missions. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0076] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0077] Figure 1 A schematic flow chart of a liquid rocket engine testability analysis and status assessment method provided in Example 1 of the present invention;

[0078] Figure 2 A schematic diagram of the internal working fluid flow process of a liquid hydrogen and liquid oxygen engine in operation in a liquid rocket engine testability analysis and state assessment method provided in Example 1 of the present invention;

[0079] Figure 3A schematic diagram of the testability indexes of an engine in a liquid rocket engine testability analysis and state assessment method provided in Example 1 of the present invention;

[0080] Figure 4 A schematic diagram of testability indicators of an optimized engine in a liquid rocket engine testability analysis and state assessment method provided in Example 1 of the present invention;

[0081] Figure 5 This is a schematic diagram of the architecture of a liquid rocket engine testability analysis and status assessment device provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0082] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0083] Example 1

[0084] See also Figure 1 Embodiment 1 of the present invention provides a liquid rocket engine testability analysis and state assessment method, comprising the following steps:

[0085] S1. Construct a liquid rocket engine testability model based on the multi-signal flow graph modeling strategy;

[0086] S2. Performing static fault analysis on the liquid rocket engine testability model to obtain untestable faults, fuzzy fault groups and redundant test information data;

[0087] S3, calculating the testability indicators of fault detection rate, fault isolation rate and fault coverage rate through the untestable faults, fault fuzzy groups and redundant test information data; evaluating the engine fault detection and diagnosis capability according to the testability indicators;

[0088] S4. Optimize the distribution of measuring points according to the testability index analysis, update the liquid rocket engine testability model, and recalculate the testability index using the updated liquid rocket engine testability model.

[0089] In this embodiment, in step S1, a liquid rocket engine testability model is constructed according to a multi-signal flow graph modeling strategy;

[0090] Specifically, the engine system is divided into system level, subsystem level, module level, components, elements and other levels according to function and structure, and the failure mode is added at the bottom layer to obtain the first-order causal correlation relationship between system modules and test points in the form of information flow.

[0091] Take liquid hydrogen and liquid oxygen engines as an example. Figure 2 As shown, it is mainly composed of thrust chamber system (cooling jacket, thrust chamber hydrogen nozzle, combustion chamber, thrust chamber oxygen nozzle), gas generator system (generator hydrogen nozzle, gas generator, generator oxygen nozzle), turbine pump system (hydrogen turbine, hydrogen pump, oxygen turbine, oxygen pump), piping system (main line after hydrogen pump, throttle ring of hydrogen auxiliary line, cavitation tube of hydrogen auxiliary line, fuel gas line in front of hydrogen turbine, main line after oxygen pump, throttle ring of oxygen auxiliary line, cavitation tube of oxygen auxiliary line, oxygen auxiliary line, fuel gas line in front of oxygen turbine, thrust chamber hydrogen main valve, thrust chamber oxygen main valve, hydrogen auxiliary control valve, oxygen auxiliary control valve, fuel gas control valve) and other components.

[0092] The steps of multi-signal flow graph modeling are:

[0093] T1. According to the set software tool, build a multi-signal model by generating a VHDL structural model or EDIF connection table or directly inputting a structural model, schematic model or conceptual block diagram through a graphical user interface;

[0094] Specifically, with the support of Qt 5.8.7 and Visual Studio 2015 software tools, VHDL structural models, EDIF connection tables, etc. are automatically generated or directly input through a graphical user interface;

[0095] T2, loading signals to the modules and test points in the multi-signal model;

[0096] T3. Modify the multi-signal model according to the setting conditions;

[0097] T4. Verify the multi-signal model based on the test data and the physical model.

[0098] In this embodiment, in step S2, during the static fault analysis of the liquid rocket engine testability model, the test set FS (f i ) to describe the fault f i Fault characteristics, FS(f i ) is recorded as:

[0099]

[0100] Where, t j is the test; f is the fault feature set; t ij t j For fault f i Testing;

[0101] The untestable fault refers to a fault that cannot be detected by all existing tests. The untestable fault meets the following conditions:

[0102]

[0103] In the formula, represents the empty set;

[0104] The fault fuzzy group refers to a group of faults that have the same characteristics and cannot be uniquely isolated. i The prerequisite for being isolated is f i The characteristics of a fault are different from those of any other fault, namely:

[0105]

[0106] The conditions for satisfying the fault fuzzy group are:

[0107] FS(f x )=FS(f y ),(x≠y)

[0108] In the formula, f x and f y For failure;

[0109] The set of fault fuzzy groups is denoted as AG(F):

[0110]

[0111] In the formula, A k is the fuzziness, that is, the number of faults in the fuzzy group; F is the total number of faults in the system; FS(f x ) is the fault f x Fault characteristics of FS(f y ) is the fault f y Fault characteristics;

[0112] The redundancy test satisfies the following conditions:

[0113] TS(t i )=TS(t j )

[0114] Test i and t j Mutually redundant, if you choose to test t i , then t j t i Redundancy test.

[0115] Specifically, for the newly established liquid hydrogen and liquid oxygen engine test model, the relevant information and data are as follows:

[0116] (1) Display undetectable fault information:

[0117] Liquid hydrogen and liquid oxygen engine system [1] -> Liquid oxygen and liquid oxygen engine [1] -> Turbopump system [1] -> Oxygen pump front valve [6] (G)

[0118] Liquid hydrogen and liquid oxygen engine system [1] -> Liquid oxygen and liquid oxygen engine [1] -> Thrust chamber system [4] -> Combustion chamber [1] -> Throat ablation [1] (F)

[0119] Liquid hydrogen and liquid oxygen engine system [1] -> Liquid oxygen and liquid oxygen engine [1] -> Turbopump system [1] -> Oxygen pump front valve [5] (G).

[0120] (2) Display fuzzy group information:

[0121] Group 1

[0122] Liquid hydrogen and liquid oxygen engine system[1]->Liquid oxygen and liquid oxygen engine[1]->Pipeline system[2]->Oxygen auxiliary control valve[5]->Opening fault[1](G)

[0123] Liquid hydrogen and liquid oxygen engine system [1] -> Liquid oxygen and liquid oxygen engine [1] -> Pipeline system [2] -> Thrust chamber hydrogen main valve [3] -> Hydrogen main valve opening failure [1] (G)

[0124] Liquid hydrogen and liquid oxygen engine system [1] -> Liquid oxygen and liquid oxygen engine [1] -> Pipeline system [2] -> Oxygen auxiliary pipeline cavitation tube [4] (G).

[0125] Group 2

[0126] Liquid hydrogen and liquid oxygen engine system [1] -> Liquid oxygen and liquid oxygen engine [1] -> Pipeline system [2] -> Oxygen pump rear main pipe [1] (G)

[0127] Liquid hydrogen and liquid oxygen engine system [1] -> Liquid oxygen and liquid oxygen engine [1] -> Pipeline system [2] -> Oxygen auxiliary pipeline throttle [2] (G).

[0128] (3) Display redundant test information:

[0129] Liquid hydrogen and liquid oxygen engine system[1]->Liquid oxygen and liquid oxygen engine[1]->Turbo pump system[1]->Oxygen pump flow[6]->Oxygen pump flow(G)

[0130] Liquid hydrogen and liquid oxygen engine system[1]->Liquid oxygen and liquid oxygen engine[1]->Turbopump efficiency[2]->Turbopump efficiency

[0131] Liquid hydrogen and liquid oxygen engine system[1]->Liquid oxygen and liquid oxygen engine[1]->Turbo pump system[1]->Oxygen pump flow[5]->Oxygen pump flow(G).

[0132] In this embodiment, in step S3, the mathematical model expression of the fault detection rate is:

[0133]

[0134] Where FDR is the fault detection rate; D is the total failure rate of the detected failure modes; λ is the total failure rate of all failure modes; i is the failure rate of the ith failure mode; Di is the failure rate of the i-th detected failure mode;

[0135] The calculation formula of the fault coverage is:

[0136]

[0137] The mathematical model expression of the fault isolation rate is:

[0138]

[0139] Where FIR is the fault isolation rate; D is the total failure rate of all detected failure modes; L is the sum of the failure rates of the failure modes that can be isolated to less than or equal to L replaceable units; Li is the failure rate of the i-th failure mode among the failures that can be isolated to less than or equal to L replaceable units; L is the number of replaceable units in the isolation group.

[0140] Specifically, for the newly established liquid hydrogen and liquid oxygen engine testability model, the testability indicators of the liquid hydrogen and liquid oxygen engine testability model are calculated as follows: Figure 3 shown.

[0141] In this embodiment, in step S4, in the process of optimizing the distribution of measuring points according to the testability index analysis, if the fault coverage does not meet the testability requirements or there are several fuzzy fault groups, sensor measuring points are added to the untestable faults and the fuzzy fault groups; if the redundant test exists, the redundant measuring points are removed.

[0142] Specifically, according to Figure 3The testability index of the liquid hydrogen and liquid oxygen engine testability model shown in the figure shows that the fault detection rate of the engine model is 93.48%, which cannot meet the index requirements for the time being. Therefore, for the previously queried untestable fault mode list, fuzzy group, etc., the failure rate of the corresponding fault mode and the difficulty of increasing the test of the fault mode are weighed, and the fault mode with the lowest difficulty and the most obvious improvement in the detection rate index is selected. Add new test points at appropriate locations to improve the fault detection rate; in addition, it is also necessary to process the redundant test list queried previously and streamline some redundant test points to further optimize the engine test resource configuration layout. For example:

[0143] (1) Improvement based on unmeasurable fault modes: Find the unmeasurable fault mode "liquid hydrogen and liquid oxygen rocket engine system [1] -> liquid hydrogen and liquid oxygen engine [1] -> turbo pump system [1] -> oxygen pump front valve [6]" in the model. Add a new measurement point "oxygen pump front valve inlet pressure" to the "oxygen pump front valve" module.

[0144] (2) Improvement based on fuzzy groups: Find “liquid hydrogen and liquid oxygen rocket engine system [1]->liquid hydrogen and liquid oxygen engine [1]->pipeline system [2]->hydrogen auxiliary control valve [5]->hydrogen auxiliary control valve opening fault [1] (G)” in the model, add the signal “gas generator hydrogen front pressure drops rapidly”, and add “gas generator hydrogen front pressure drops rapidly” to “generator hydrogen pre-spray pressure”. Find “liquid hydrogen and liquid oxygen rocket engine system [1]->liquid hydrogen and liquid oxygen engine [1]->pipeline system [2]->thrust chamber hydrogen main valve [3]->hydrogen main valve opening fault [1]” in the model, add the signal “gas generator hydrogen front pressure drops rapidly”. Find “liquid hydrogen and liquid oxygen rocket engine system [1]->liquid hydrogen and liquid oxygen engine [1]->pipeline system [2]->hydrogen auxiliary pipeline cavitation tube [4]” in the model, add a new measurement point “hydrogen auxiliary cavitation tube inlet pressure”, add the “hydrogen auxiliary cavitation tube inlet pressure” test item, add “hydrogen auxiliary cavitation tube inlet pressure increases”, and add the signal.

[0145] (3) Improvement based on redundant testing: Consider deleting some measuring points, such as deleting redundant test points such as hydrogen pump flow, oxygen pump flow, and turbine pump efficiency.

[0146] The engine testability index calculation is performed again, and the optimized calculation results are as follows: Figure 4 As shown, it can be seen that the improved testability indicators are significantly improved, and the method based on testability analysis is effective in improving the reliability of engine fault detection and diagnosis.

[0147] In summary, the present invention constructs a liquid rocket engine testability model according to a multi-signal flow graph modeling strategy; performs static fault analysis on the liquid rocket engine testability model to obtain untestable faults, fault fuzzy groups and redundant test information data; calculates the fault detection rate, fault isolation rate and fault coverage testability indicators through the untestable faults, fault fuzzy groups and redundant test information data; evaluates the engine fault detection and diagnosis capabilities according to the testability indicators; optimizes the distribution of measuring points according to the testability indicators, updates the liquid rocket engine testability model, and recalculates the testability indicators through the updated liquid rocket engine testability model. Considering that the existing fault diagnosis methods are difficult to effectively cover the existing fault modes of the engine, the present invention proposes a liquid rocket engine testability analysis and state evaluation method, establishes a liquid rocket engine testability model based on the multi-signal flow graph modeling idea; carries out qualitative analysis of engine testability, evaluates testability indicators and optimizes the distribution of measuring points to achieve effective coverage of engine fault mode detection and diagnosis. The present invention can intuitively and clearly express the mapping relationship between faults and measuring points, effectively improve the reliability of engine fault detection and diagnosis, and ensure the successful completion of engine test and flight missions.

[0148] It should be noted that the method of the embodiment of the present disclosure can be performed by a single device, such as a computer or a server. The method of the present embodiment can also be applied in a distributed scenario and completed by multiple devices cooperating with each other. In the case of such a distributed scenario, one of the multiple devices can only perform one or more steps in the method of the embodiment of the present disclosure, and the multiple devices will interact with each other to complete the described method.

[0149] It should be noted that the above describes some embodiments of the present disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0150] Example 2

[0151] See also Figure 5 Embodiment 2 of the present invention further provides a liquid rocket engine testability analysis and state assessment device, comprising:

[0152] Liquid rocket engine testability model construction module 001, used to construct a liquid rocket engine testability model according to a multi-signal flow graph modeling strategy;

[0153] The model static fault analysis module 002 is used to perform static fault analysis on the liquid rocket engine testability model to obtain untestable faults, fault fuzzy groups and redundant test information data;

[0154] The testability index calculation module 003 is used to calculate the testability indexes of fault detection rate, fault isolation rate and fault coverage rate through the untestable faults, fault fuzzy groups and redundant test information data; and evaluate the engine fault detection and diagnosis capability according to the testability indexes;

[0155] The index analysis and optimization module 004 is used to optimize the distribution of measuring points according to the testability index analysis, update the liquid rocket engine testability model, and recalculate the testability index through the updated liquid rocket engine testability model.

[0156] In this embodiment, in the liquid rocket engine testability model building module 001, the modeling steps of the multi-signal flow graph modeling strategy are:

[0157] According to the set software tool, multi-signal models are constructed by generating VHDL structural models or EDIF connection tables or directly inputting structural models, schematic models or conceptual block diagrams through the graphical user interface;

[0158] Loading signals to modules and test points in the multi-signal model;

[0159] According to the setting conditions, the multi-signal model is modified;

[0160] The multi-signal model is verified based on test data and the physical model.

[0161] In this embodiment, in the model static fault analysis module 002, in the process of performing static fault analysis on the liquid rocket engine testability model, the test set FS (f i ) to describe the fault f i Fault characteristics, FS(f i ) is recorded as:

[0162]

[0163] Where, t j is the test; f is the fault feature set; t ij t j For fault f i Tests;

[0164] The undetectable fault satisfies the following conditions:

[0165]

[0166] In the formula, represents the empty set;

[0167] The conditions for satisfying the fault fuzzy group are:

[0168] FS(f x )=FS(f y ),(x≠y)

[0169] In the formula, f x and f y For failure;

[0170] The set of fault fuzzy groups is denoted as AG(F):

[0171]

[0172] In the formula, A k is the fuzziness, that is, the number of faults in the fuzzy group; F is the total number of faults in the system; FS(f x ) is the fault f x Fault characteristics of FS(f y ) is the fault f y Fault characteristics;

[0173] The redundancy test satisfies the following conditions:

[0174] TS(t i )=TS(t j )

[0175] Test i and t j Mutually redundant, if you choose to test t i , then t j t i Redundancy test.

[0176] In this embodiment, in the testability index calculation module 003, the mathematical model expression of the fault detection rate is:

[0177]

[0178] Where FDR is the fault detection rate; D is the total failure rate of the detected failure modes; λ is the total failure rate of all failure modes; i is the failure rate of the ith failure mode; Di is the failure rate of the i-th detected failure mode;

[0179] The calculation formula of the fault coverage is:

[0180]

[0181] The mathematical model expression of the fault isolation rate is:

[0182]

[0183] Where FIR is the fault isolation rate; D is the total failure rate of all detected failure modes; L is the sum of the failure rates of the failure modes that can be isolated to less than or equal to L replaceable units; Li is the failure rate of the i-th failure mode among the failures that can be isolated to less than or equal to L replaceable units; L is the number of replaceable units in the isolation group.

[0184] In this embodiment, in the indicator analysis and optimization module 004, in the process of optimizing the distribution of measuring points according to the testability indicator analysis, if the fault coverage does not meet the testability requirements or there are several fuzzy fault groups, sensor measuring points are added to the untestable faults and the fuzzy fault groups; if the redundant test exists, the redundant measuring points are removed.

[0185] It should be noted that the information interaction, execution process and other contents between the modules of the above-mentioned system are based on the same concept as the method embodiment in Example 1 of the present application, and the technical effects they bring are the same as those of the method embodiment of the present application. For specific contents, please refer to the description in the method embodiment shown above in the present application, and will not be repeated here.

[0186] Example 3

[0187] Embodiment 3 of the present invention provides a non-transitory computer-readable storage medium, in which a program code for a liquid rocket engine testability analysis and state assessment method is stored, and the program code includes instructions for executing a liquid rocket engine testability analysis and state assessment method of embodiment 1 or any possible implementation thereof.

[0188] The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that includes one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0189] Example 4

[0190] Embodiment 4 of the present invention provides an electronic device, including: a memory and a processor;

[0191] The processor and the memory communicate with each other via a bus; the memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute a liquid rocket engine testability analysis and status assessment method of embodiment 1 or any possible implementation thereof.

[0192] Specifically, the processor can be implemented by hardware or by software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor implemented by reading software codes stored in a memory. The memory can be integrated in the processor or can be located outside the processor and exist independently.

[0193] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable systems. The computer instructions can be stored in a computer-readable storage medium, or transmitted from a computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center.

[0194] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing system, they can be concentrated on a single computing system, or distributed on a network composed of multiple computing systems, and optionally, they can be implemented by a program code executable by a computing system, so that they can be stored in a storage system and executed by the computing system, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0195] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A liquid rocket engine testability analysis and condition assessment method, characterized in that: include: According to the multi-signal flow graph modeling strategy, a liquid rocket engine testability model is constructed; Performing static fault analysis on the liquid rocket engine testability model to obtain untestable faults, fuzzy fault groups, and redundant test information data; Calculate the testability indicators of fault detection rate, fault isolation rate and fault coverage rate through the untestable faults, fault fuzzy groups and redundant test information data; evaluate the engine fault detection and diagnosis capabilities according to the testability indicators; Optimizing the distribution of measuring points according to the testability index analysis, updating the liquid rocket engine testability model, and recalculating the testability index by using the updated liquid rocket engine testability model; The modeling steps of the multi-signal flow graph modeling strategy are: Construct multi-signal models by generating VHDL structural models or EDIF connection tables, or directly inputting structural models, schematic models or conceptual block diagrams through a graphical user interface according to the set software tools; Loading signals to modules and test points in the multi-signal model; According to the setting conditions, the multi-signal model is modified; Testing the multi-signal model based on test data and a physical model; In the process of static fault analysis of the liquid rocket engine testability model, the test set FS (f i ) to describe the fault f i Fault characteristics, FS(f i ) is recorded as: Where, t j is the test; f is the fault feature set; t ij t j For fault f i Testing; The undetectable fault satisfies the following conditions: In the formula, represents the empty set; The conditions for satisfying the fault fuzzy group are: FS(f x )=FS(f y ),(x≠y) In the formula, f x and f y For failure; The set of fault fuzzy groups is denoted as AG(F): In the formula, A k is the fuzziness, that is, the number of faults in the fuzzy group; F is the total number of faults in the system; FS(f x ) is the fault f x Fault characteristics; FS(f y ) is the fault f y Fault characteristics; The redundancy test satisfies the following conditions: TS(t i )=TS(t j ) Test i and t j Mutually redundant, if you choose to test t i , then t j t i Redundancy test.

2. A liquid rocket engine testability analysis and state assessment method according to claim 1, characterized in that: The mathematical model expression of the fault detection rate is: Where FDR is the fault detection rate; D is the total failure rate of the detected failure modes; λ is the total failure rate of all failure modes; i is the failure rate of the ith failure mode; Di is the failure rate of the i-th detected failure mode; The calculation formula of the fault coverage is: The mathematical model expression of the fault isolation rate is: Where FIR is the fault isolation rate; D is the total failure rate of all detected failure modes; L is the sum of the failure rates of the failure modes that can be isolated to less than or equal to L replaceable units; λ Li is the failure rate of the i-th failure mode among the failures that can be isolated to less than or equal to L replaceable units; L is the number of replaceable units in the isolation group.

3. A liquid rocket engine testability analysis and state assessment method according to claim 2, characterized in that: In the process of optimizing the distribution of measuring points according to the testability index analysis, if the fault coverage does not meet the testability requirements or there are several fuzzy fault groups, sensor measuring points are added to the untestable faults and the fuzzy fault groups; if the redundant test exists, the redundant measuring points are removed.

4. A liquid rocket engine testability analysis and status assessment device, using any of the liquid rocket engine testability analysis and status assessment methods of claims 1-3, characterized in that: include: Liquid rocket engine testability model building module, used to build a liquid rocket engine testability model based on a multi-signal flow graph modeling strategy; A model static fault analysis module, used to perform static fault analysis on the liquid rocket engine testability model to obtain untestable faults, fault fuzzy groups and redundant test information data; A testability index calculation module is used to calculate the testability indexes of fault detection rate, fault isolation rate and fault coverage rate through the untestable faults, fault fuzzy groups and redundant test information data; and evaluate the engine fault detection and diagnosis capability according to the testability indexes; An indicator analysis and optimization module is used to optimize the distribution of measuring points according to the testability indicator analysis, update the liquid rocket engine testability model, and recalculate the testability indicator through the updated liquid rocket engine testability model.

5. A liquid rocket engine testability analysis and status assessment device according to claim 4, characterized in that: In the liquid rocket engine testability model building module, the modeling steps of the multi-signal flow graph modeling strategy are: According to the set software tool, multi-signal models are constructed by generating VHDL structural models or EDIF connection tables or directly inputting structural models, schematic models or conceptual block diagrams through the graphical user interface; Loading signals to modules and test points in the multi-signal model; According to the setting conditions, the multi-signal model is modified; The multi-signal model is verified based on test data and the physical model.

6. A liquid rocket engine testability analysis and status assessment device according to claim 5, characterized in that: In the model static fault analysis module, in the process of static fault analysis of the liquid rocket engine test model, the test set FS (f i ) to describe the fault f i Fault characteristics, FS(f i ) is recorded as: Where, t j is the test; f is the fault feature set; t ij t j For fault f i Testing; The undetectable fault satisfies the following conditions: In the formula, represents the empty set; The conditions for satisfying the fault fuzzy group are: FS(f x )=FS(f y ),(x≠y) In the formula, f x and f y For failure; The set of fault fuzzy groups is denoted as AG(F): In the formula, A k is the fuzziness, that is, the number of faults in the fuzzy group; F is the total number of faults in the system; FS(f x ) is the fault f x Fault characteristics; FS(f y ) is the fault f y Fault characteristics; The redundancy test satisfies the following conditions: TS(t i )=TS(t j ) Test i and t j Mutually redundant, if you choose to test t i , then t j t i Redundancy test.

7. A liquid rocket engine testability analysis and status assessment device according to claim 6, characterized in that: In the testability index calculation module, the mathematical model expression of the fault detection rate is: Where FDR is the fault detection rate; D is the total failure rate of the detected failure modes; λ is the total failure rate of all failure modes; i is the failure rate of the ith failure mode; Di is the failure rate of the i-th detected failure mode; The calculation formula of the fault coverage is: The mathematical model expression of the fault isolation rate is: Where FIR is the fault isolation rate; D is the total failure rate of all detected failure modes; L is the sum of the failure rates of the failure modes that can be isolated to less than or equal to L replaceable units; λ Li is the failure rate of the i-th failure mode among the failures that can be isolated to less than or equal to L replaceable units; L is the number of replaceable units in the isolation group.

8. A liquid rocket engine testability analysis and status assessment device according to claim 7, characterized in that: In the indicator analysis and optimization module, in the process of optimizing the distribution of measuring points according to the testability indicator analysis, if the fault coverage does not meet the testability requirements or there are several fuzzy fault groups, sensor measuring points are added to the untestable faults and the fuzzy fault groups; if the redundant test exists, the redundant measuring points are removed.

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