Aero-engine function logic scheme design method

Abstract

The application belongs to the field of aero-engine architecture design, and is a kind of aero-engine function logic scheme design method. The top working state / mode of the aero-engine is divided first, and the state conversion logic between each working state / mode of the engine is defined preliminarily. A state machine model is preliminarily constructed, and the logic condition analysis is carried out on the constructed state machine model. Then the correlation between the working state / mode of the engine and the corresponding function running state of the engine is analyzed, and the function execution and switching logic under any working state / mode is determined. The state machine model is reconfigured to obtain a new state machine model. The state deviation analysis is carried out on the new state machine model through the engine whole machine test, and the state conversion logic defects are modified. After the modification is completed, the designed function logic scheme is output. The specification of the aero-engine function logic scheme design and optimization process is improved, and the occurrence probability of design defects is reduced.

Description

Technical Field

[0001] This application belongs to the field of aero-engine architecture design, and specifically relates to a design method for aero-engine functional logic scheme. Background Technology

[0002] In the architectural design of aero-engines, it is generally necessary to conduct design work on functional logic conditions, especially the switching of some critical state modes, which directly affects the engine's operational safety. The settings of some functional logic directly determine the conditions and timing of these state mode transitions, which is of great significance to the normal operation of the engine. If the design results are flawed, it will increase the probability of failure, raise the cost of troubleshooting later, and even affect the development schedule of the entire project.

[0003] In the field of aero-engine engineering, based on industry consensus, these design flaws are often introduced in the early stages of design and propagate from the entire engine to components / subsystems as the design and development process progresses. Analysis of existing technical means reveals a lack of effective means of checking functional logic conditions in the early overall design phase, relying primarily on engineers' design experience and textual analysis. Much verification work is delayed until the simulation and semi-physical testing phases of the engine control system to uncover some logical errors. However, latent defects caused by subtle deviations between the overall design intent and logical implementation are difficult to detect in the subsystem design phase, as these defects are already ingrained in the subsystem's design inputs. Especially when facing new requirements and technological challenges, the lack of corresponding experience means that potential defects are not fully identified in the overall design phase and only surface during later physical verification. Some logical conditions may only become apparent in specific operating environments and during the use of individual products. Although the probability of such failures is low, some failures seriously endanger flight safety, leading to increased troubleshooting and maintenance costs that significantly impact product usability.

[0004] In general, there is currently no standardized technical solution for checking functional logic design defects in the early design stage of aero engines. Relying on personal experience and text-based inspection methods are inefficient and the validity of the results is difficult to guarantee, which cannot meet the increasingly complex functional logic design and quality assurance requirements of engines.

[0005] The relevant drawbacks are listed below:

[0006] 1) Existing functional logic inspection techniques in the early design phase rely too much on individual engineering experience, and the process is not standardized, resulting in large fluctuations in inspection quality and a large number of design defects being passed on to downstream processes.

[0007] 2) Existing inspection methods still rely primarily on text analysis, and some descriptions and definitions are ambiguous, which may lead to missing or even incorrect semantic communication during cross-disciplinary collaborative design processes;

[0008] 3) In the development process of modern aero-engines with significantly increased functional logic complexity, traditional text-based inspection methods are no longer sufficient to deal with the problems that may be introduced due to the increased system complexity, resulting in frequent failures during the operation of complex functional logic and increased product lifecycle costs. Summary of the Invention

[0009] The purpose of this application is to provide a design method for the functional logic scheme of aero-engines, so as to solve the problem that it is difficult to efficiently check the design defects of functional logic in the prior art.

[0010] The technical solution of this application is: a design method for functional logic schemes of aero-engines, including:

[0011] Based on the upper-level input, the operating states / modes of each level of the aero-engine are defined, and then the top-level operating states / modes of the aero-engine are divided according to the design input of the aero-engine.

[0012] Based on the defined working states / modes at each level, the initial state transition logic between the engine's various working states / modes is defined;

[0013] Based on the defined working states / modes at each level and the state transition modes between the engine's working states / modes, a preliminary state machine model is constructed. Logical condition analysis is performed on the constructed state machine model to determine if there are any logical errors. If not, the next step is executed; if so, the state transition logic for the corresponding working states / modes is redefined.

[0014] Analyze the relationship between engine operating state / mode and corresponding engine function operating state, and determine the function execution and switching logic for any operating state / mode;

[0015] After determining the functional execution and switching logic of all working states / modes, engine functional architecture design and performance simulation tests are carried out to determine the parameters and threshold range of variables within any state transition logic, and then the quantitative design of all state transition logic is performed.

[0016] Based on the quantitative design results of all state transition logics, the corresponding logical conditions are refined, and the state machine model is reconfigured to obtain a new state machine model.

[0017] For the new state machine model, state deviation analysis is carried out by conducting engine whole machine tests to determine whether there are defects in the existing state transition logic. If so, the type of defect is determined again. If the parameter setting or threshold range deviates from the engine whole machine test data, the engine functional architecture design and performance simulation test are carried out again until the parameter setting or threshold range requirements are met. If there are logic defects, the corresponding state transition logic is changed and the state deviation separation is repeated until no logic defects are found.

[0018] If there are no defects, output the completed functional logic solution.

[0019] Preferably, the specific analysis method of the state deviation analysis is as follows: conduct a deviation analysis between the given logical conditions and the theoretical design intention, determine whether there are influencing factors that cause deviations in the state transition logic under different working conditions, and if so, evaluate the deviation range of the corresponding influencing factors through simulation or measurement.

[0020] Then, the threshold range of variables within the state transition logic is analyzed and checked to determine whether the deviation range of the above-mentioned influencing factors affects the normal execution of the corresponding state transition logic and to calculate the probability of false jumps in other working states / logics under the same logic conditions. If the deviation range of the influencing factors affects the normal execution of the state transition logic or the probability of false jumps in the state transition logic is greater than the expected probability, then the engine functional architecture design and performance simulation test are carried out again, and a new threshold range is redefined.

[0021] Preferably, when conducting engine functional architecture design and performance simulation tests, any state transition logic is run to determine the degree of its function execution and implementation, and then the parameters and threshold range required for its execution switching logic are obtained, thereby providing quantified logical conditions.

[0022] Preferably, when refining the logical conditions corresponding to the state transition logic, if there is a need for further decomposition, the sub-working states / modes are further refined.

[0023] Preferably, the top-level operating states / modes of the aero-engine include a stationary mode, an operating mode, and an emergency mode. The operating modes include an idle state, a throttling state, a maximum state, an afterburner state, and a transition mode required for state transitions.

[0024] Preferably, the logic error analysis includes confirming whether the state / mode transition process is consistent with the design intent, whether the specific combination of logic parameters can meet the specific logic transition requirements, and whether there are contradictions, errors, or omissions among the transition logic conditions; if not, then it is determined that a logic error has occurred.

[0025] This application discloses a functional logic scheme design method for aero-engines. First, based on the aero-engine's design inputs, the top-level operating states / modes of the aero-engine are divided, and the state transition logic between each operating state / mode is preliminarily defined. A preliminary state machine model is constructed, and logical condition analysis is performed on the constructed state machine model to determine if any logical errors exist. If no errors are found, the correlation between the engine's operating states / modes and their corresponding functional operating states is analyzed to determine the functional execution and switching logic under any operating state / mode. The state machine model is then reconfigured to obtain a new state machine model. State deviation analysis is conducted on the new state machine model through a full-engine test, and defects in the state transition logic are corrected. After modification, the completed functional logic scheme is output. This method improves the standardization of the aero-engine functional logic scheme design and optimization process and reduces the probability of design defects. Attached Figure Description

[0026] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0027] Figure 1 This is a schematic diagram of the overall process of this application;

[0028] Figure 2 This is a schematic diagram illustrating the hierarchical division of the operating states / modes of the turbofan engine in this application.

[0029] Figure 3 This is a schematic diagram of the state machine model of the aero-engine in this application;

[0030] Figure 4 This is a schematic diagram illustrating the joint analysis of the aero-engine state machine model and system simulation analysis in this application. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0032] A design method for functional logic schemes of aero-engines, such as Figure 1 As shown, it includes the following steps:

[0033] Step S100: Based on the input from the upper level (user, aircraft design and development department), define the working state / mode of each level of the aero-engine. Then, based on the design input of the aero-engine and considering the specific operation and use requirements of the engine, divide the top-level working state / mode of the aero-engine.

[0034] like Figure 2As shown, this example uses the design inputs and operational requirements of a typical low-bypass turbofan engine to determine the engine's top-level operating states / modes as static mode, operational mode, and emergency mode. In static mode, this example only illustrates the installed engine shutdown state. Operational mode further analyzes and refines the ground start-up mode and operational operating states. The operational operating states encompass the idle state, throttle state, maximum state, afterburner state required for normal aircraft use, as well as the transition modes required for state transitions. The emergency mode in this example lists the emergency action mode and the in-flight start-up mode.

[0035] Step S200: Based on the defined working states / modes at each level, initially define the state transition logic between the engine's various working states / modes;

[0036] The implementation of specific logic may involve the combined application of external operation commands, external environment variables, relevant system parameters, engine parameters, etc. Through design definition, between the divided states / modes, this information of commands, variables, parameters, etc., is converted into a set of logical conditions, and a preliminary range of variable values ​​or conditions that can represent the design intent is given. When some logical conditions cannot be precisely quantified at this step, a rough estimate can be given temporarily.

[0037] If the logical condition fails the logical error check in step S300, or if a logical defect is found in the logical condition after analysis in step S700, the iterative design of the logical condition needs to be repeated.

[0038] This example uses a specific "emergency action mode" as an example. A set of combined variables that can satisfy the jump to this mode is defined as "logic variable 1 (L1) + engine parameter variable 1 (V1) + aircraft parameter variable 2 (V2)". The variable ranges for L1, V1, and V2 are initially given; in this example, they are "L1==1&&V1".<xx&&V2> xx".

[0039] like Figure 3 As shown, in step S300, based on the defined working states / modes at each level and the state transition modes between the engine's working states / modes, a state machine model is initially constructed, including the modular definition of states / modes and the preliminary definition of logical conditions. Logical condition analysis is performed on the constructed state machine model to determine whether there are any logical errors. If not, the next step is executed; if there are, the process returns to step S200 to redefine the state transition logic of the corresponding working states / modes.

[0040] The logical error analysis here includes confirming whether the state / mode transition process is consistent with the design intent, whether the specific combination of logical parameters can meet the specific logical transition requirements, and whether there are contradictions, errors, or omissions between the transition logical conditions, which may lead to failure to execute or jump to the wrong state / mode.

[0041] Step S400: Analyze the relationship between the engine operating state / mode and the corresponding engine function operating state, and determine the function execution and switching logic under any operating state / mode;

[0042] Specifically, this includes analyzing which functions will be executed when the engine is in a specific state / mode, and analyzing how the specific function operation status, such as "execution", "execution interruption", "not executed" and "disabled", is switched when the engine is in a given state / mode or during state / mode switching.

[0043] In this example, under the "emergency action mode", the engine's "engine communication", "signal measurement", "signal processing" and "mechanical adjustment limit" functions are all in the "execution" state. When the "emergency operation mode" switches back to the "operational operation state", the emergency limit function will be in the "disabled" state.

[0044] Step S500: After determining the function execution and switching logic of all working states / modes, conduct engine functional architecture design and performance simulation tests, determine the parameters and threshold range of variables in any state transition logic, and then perform quantitative design of all state transition logics.

[0045] If the parameter variables in the defined combination conditions involve the functional implementation of the engine itself or related systems (such as aircraft or equipment), then it is often necessary to use appropriate simulation (or co-simulation) calculations or testing methods to design and optimize the quantification range. The simulation or testing content generally includes the function and its degree of implementation (such as performance, speed, accuracy, capability, etc.). At this stage, the parameters and thresholds required by the logical conditions should be considered in detail, and the quantified logical conditions should be given. If, after analysis in step S700, it is found that the specific parameter definitions or threshold settings in the logical conditions do not meet the design requirements, then iterative design work of selecting specific parameters and setting thresholds needs to be repeated.

[0046] This example combines engine functional architecture design and performance simulation calculation results to conduct a detailed design of the pre-defined combinational logic condition "Logic Variable 1 (L1) + Engine Parameter Variable 1 (V1) + Aircraft Parameter Variable 2 (V2)" and the initially given variable range or value conditions. It involves the measurement functions and implementation accuracy of variables L1, V1, and V2, signal transmission functions and transmission rates, signal processing functions and processing capabilities, as well as the performance simulation calculation results or test results generated for the corresponding parameter variables themselves. For example, if the engine parameter variable in this example is "high-pressure speed," then the speed change curve in the performance simulation should be given in conjunction with the engine functional architecture design process, and the quantitative analysis results of the variable range in the combinational logic should be provided, refining the preliminary design results given in step 2). At this stage, the quantitative design results of all logic conditions are given.

[0047] Step S600: Based on the quantitative design results of all state transition logics, refine the corresponding logical conditions and reconfigure the state machine model to obtain a new state machine model.

[0048] When refining the logical conditions corresponding to the state transition logic, if there is a need for further decomposition, the sub-working states / modes are further refined, and the process of setting their logical conditions is to repeat steps S200 to S500.

[0049] Step S700: For the new state machine model, conduct state deviation analysis by performing engine whole machine tests to determine whether there are defects in the existing state transition logic. If so, determine the type of defect again. If the parameter setting or threshold range deviates from the engine whole machine test data, conduct engine functional architecture design and performance simulation tests again until the parameter setting or threshold range requirements are met. If there are logic defects, change the corresponding state transition logic and repeat the state deviation separation until no logic defects are found.

[0050] When conducting state deviation analysis, the following steps are taken: First, a deviation analysis is performed between the given logical conditions and the theoretical design intent. Modern engines generally employ a segmented multivariable control strategy to adapt to complex operating conditions. Under different operating conditions, the reasons for deviations between variables and theoretical values ​​differ. Second, the possible deviation range is calculated and evaluated. The factors leading to these deviations are often complex, involving control strategies, design tolerances, product characteristics, manufacturing deviations, and product characteristic dispersion. Third, the conditions or probabilities of unexpected transitions are analyzed and examined. On the one hand, the probability that the threshold range of variables in the given logical conditions meets the allowable deviation range is analyzed; in this example, whether the probability that the actual deviation of the high-pressure speed falls within the given logical interval meets the requirements is analyzed. On the other hand, the possibility of unexpected erroneous jumps is analyzed. Based on the analysis results, it is confirmed whether there are defects in the existing logical design. If there are logical defects, they can be resolved by adjusting and optimizing specific parameter settings or threshold ranges, then the process returns to step S500 for iteration. If there are logical defects, they need to be resolved by changing the logical conditions, then the process returns to step S200 for iteration. If no logical defects are found, the process proceeds to step S800.

[0051] This example uses the engine's "high-pressure speed" as the V1 variable in the logic condition. First, it analyzes the possible influencing factors causing deviations in V1 implementation under various operating conditions. In some conditions, the high-pressure speed variable is used as the control target, and the deviation from the theoretical value mainly stems from control accuracy deviation. In other conditions, the low-pressure speed variable is used as the control target, and the deviation from the theoretical value must consider not only control accuracy deviation but also the influence of the engine's complex aerodynamic matching characteristics and the slip dispersion between different engine products. Second, it calculates the deviation range of the high-pressure speed. In this example, using the low-pressure speed variable as the control target, the possible deviation range affecting the high-pressure speed includes: the control tolerance of the low-pressure speed, the engine's high and low-pressure rotor matching characteristics, and the product's possible slip dispersion. These deviations need to be obtained through simulation, measurement, or evaluation based on existing design experience. Third, it analyzes and checks the threshold range of the high-pressure speed variable given in the combinational logic condition, on the one hand, to confirm whether the actual possible deviation range affects the normal execution of the logic condition. On the other hand, analyzing the probability of false jumps in other states / modes with the same logical conditions can lead to complex situations where it's necessary to set the priority of state / mode jumps. In this example... Figure 4 As shown, the combinational logic condition model in the fusion state machine model and the characteristic calculation module of the system simulation are used to analyze the probability that the actual speed meets the V2 threshold range of the given distribution law. If the probability that the actual deviation of the high-pressure speed does not meet the expectation is found, the process returns to step S500. After readjusting the variable range of the optimization logic condition, steps S500-S700 are repeated until it is confirmed that there is no logic defect, and then the process proceeds to step S800.

[0052] Step S800: If no defects exist, the design results of the engine functional logic scheme are output by integrating the engine operating state / mode definition and decomposition refinement results, functional state analysis results, state deviation analysis results, and state machine model refinement results. When multiple alternative schemes that meet the conditions exist, a trade-off must be made at a higher level.

[0053] This application first divides the top-level operating states / modes of the aero-engine based on the design input of the aero-engine. Then, it preliminarily defines the state transition logic between the various operating states / modes of the engine. A state machine model is initially constructed, and logical condition analysis is performed on the constructed state machine model to determine whether there are any logical errors. If not, the relationship between the engine operating states / modes and the corresponding engine functional operation states is analyzed to determine the functional execution and switching logic under any operating state / mode. Then, the engine functional architecture design and performance simulation test are carried out. After that, all state transition logics are quantitatively designed, and the state machine model is reconfigured to obtain a new state machine model. The new state machine model is subjected to state deviation analysis through engine whole-machine testing to determine whether there are any defects in the existing state transition logic. If there are no defects, the functional logic scheme of the completed design is output. Improve the standardization of the design and optimization process of aero-engine functional logic schemes to reduce the probability of design defects; reduce ambiguity in the setting of logical combination conditions by using state machine models to improve the efficiency of professional collaboration; replace experience-based text analysis with model-based and simulation analysis techniques to enhance the design analysis and response capabilities for the increased complexity in the engine functional logic design process.

[0054] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An aeroengine functional logic scheme design method, characterized in that, include: Based on the upper-level input, the operating states / modes of each level of the aero-engine are defined, and then the top-level operating states / modes of the aero-engine are divided according to the design input of the aero-engine. Based on the defined working states / modes at each level, the initial state transition logic between the engine's various working states / modes is defined; Based on the defined working states / modes at each level and the state transition modes between the engine's working states / modes, a preliminary state machine model is constructed. Logical condition analysis is performed on the constructed state machine model to determine if there are any logical errors. If not, the next step is executed; if so, the state transition logic for the corresponding working states / modes is redefined. Analyze the relationship between engine operating state / mode and corresponding engine function operating state, and determine the function execution and switching logic for any operating state / mode; After determining the functional execution and switching logic of all working states / modes, engine functional architecture design and performance simulation tests are carried out to determine the parameters and threshold range of variables within any state transition logic, and then the quantitative design of all state transition logic is performed. Based on the quantitative design results of all state transition logics, the corresponding logical conditions are refined, and the state machine model is reconfigured to obtain a new state machine model. For the new state machine model, state deviation analysis is carried out by conducting engine whole machine tests to determine whether there are defects in the existing state transition logic. If so, the type of defect is determined again. If the parameter setting or threshold range deviates from the engine whole machine test data, the engine functional architecture design and performance simulation test are carried out again until the parameter setting or threshold range requirements are met. If there are logic defects, the corresponding state transition logic is changed and the state deviation separation is repeated until no logic defects are found. If there are no defects, output the completed functional logic solution.

2. The method of claim 1, wherein, The specific analysis method of the state deviation analysis is as follows: conduct a deviation analysis between the given logical conditions and the theoretical design intention, determine whether there are influencing factors that cause deviations in the state transition logic under different working conditions, and if so, evaluate the deviation range of the corresponding influencing factors through simulation or measurement. Then, the threshold range of variables within the state transition logic is analyzed and checked to determine whether the deviation range of the above-mentioned influencing factors affects the normal execution of the corresponding state transition logic and to calculate the probability of false jumps in other working states / logics under the same logic conditions. If the deviation range of the influencing factors affects the normal execution of the state transition logic or the probability of false jumps in the state transition logic is greater than the expected probability, then the engine functional architecture design and performance simulation test are carried out again, and a new threshold range is redefined.

3. The method of claim 1, wherein: When conducting engine functional architecture design and performance simulation tests, run any state transition logic to determine the degree of its function execution and implementation, and then obtain the parameters and threshold range required for its execution switching logic, thereby providing quantified logical conditions.

4. The method of claim 1, wherein: When refining the logical conditions corresponding to the state transition logic, if there is a need for further decomposition, the sub-working states / modes are further refined.

5. The design method for the functional logic scheme of an aero-engine as described in claim 1, characterized in that: The top-level operating states / modes of the aero-engine include a stationary mode, an operating mode, and an emergency mode. The operating modes include an idle state, a throttling state, a maximum state, an afterburner state, and a transition mode required for state transitions.

6. The design method for the functional logic scheme of an aero-engine as described in claim 1, characterized in that: The logic error analysis includes confirming whether the state / mode transition process is consistent with the design intent, whether the specific combination of logic parameters can meet the specific logic transition requirements, and whether there are contradictions, errors, or omissions among the transition logic conditions; if not, a logic error is determined to have occurred.

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