Hybrid propulsion system cross-coupling fault diagnosis method and system

Abstract

The application discloses a hybrid propulsion system cross-coupling fault diagnosis method and system, comprising the following steps: step one: by analyzing the motion state data of the flying car in the air-ground conversion process, a coupling model between the air and ground working conditions is established; step two: based on the flying car motion state coupling result in step one, the functional coupling relationship between the turboshaft engine and the motor executor is studied; step three: based on the fault prediction characteristic value in step two, the system will continuously monitor the sensor data and the executor state, and carry out real-time fault diagnosis based on the cross-coupling characteristics, and obtain system real-time diagnosis feedback and adjustment suggestions. The application realizes accurate coupling analysis between the air and ground working conditions, and can also carry out fault diagnosis and early warning on the coupling characteristics of the air take-off and ground landing stages through real-time monitoring of the motion state data.

Description

Technical Field

[0001] This invention relates to the technical field of fault diagnosis of flying car power systems, and in particular to a method and system for diagnosing cross-coupling faults in hybrid propulsion systems. Background Technology

[0002] Flying cars, representing the future of transportation, combine the characteristics of automobiles and aircraft, effectively alleviating ground traffic congestion. With technological advancements and electrification, hybrid propulsion systems are increasingly being applied to the flying car field, playing a crucial role. In flying car hybrid propulsion systems, there is a significant coupling between the motion states in the air and on the ground, and complex coupling exists between the functions of various actuators in the propulsion system (such as turboshaft engines and electric motors). How to fully consider these cross-coupling relationships and effectively apply them to system fault prediction has become a pressing technical challenge for the industry. Currently, research on fault diagnosis for flying car hybrid propulsion systems is not yet comprehensive, but some existing related technical solutions can provide some reference for research in this field. For example, Chinese invention patent application number CN202310030052.2, entitled "A Flying Car Drive-by-Wire Chassis Control System," mentions that flying cars should be suitable for both land and air use; therefore, the chassis system structure should have redundancy characteristics to function in fault diagnosis and special circumstances. The fault diagnosis module of its drive-by-wire chassis system considers the coupling relationship between the air and the ground. It obtains the expected data input through signal reception and processing, acquires real-time data input through the detection system, and performs fault diagnosis after preprocessing. Chinese invention patent application number CN 202210917909.8, entitled "Self-testing method, device and computer-readable storage medium for flying car", proposes to divide the flying car system into a flight system and a land system. Each of the two systems contains multiple subsystems. The parameters of each subsystem are diagnosed separately to form a target control strategy. Chinese invention patent application number CN 202410916533.8, entitled "Diagnostic method, device and medium for hybrid vehicle", proposes to use the coupling of the engine and drive motor and the separate coupling of the processor to perform fault diagnosis of vehicle components, engine components and drive motor components.

[0003] However, while these existing technologies have addressed the fault diagnosis problem in hybrid propulsion systems to some extent, they still have two main shortcomings: First, in terms of fault prediction, existing technologies mostly focus on fault prediction for a single actuator or under specific operating conditions, neglecting the functional coupling between different actuators and the interactive effects during air-to-ground transitions. Because they fail to fully utilize the coupling characteristics within and outside the system, these solutions often cannot accurately predict fault occurrences in complex operating conditions. Second, in the design of fault diagnosis methods, existing technologies typically perform fault diagnosis on a single component or under a single operating condition, failing to fully consider the functional cross-coupling between actuators within the system. This approach ignores the possibility of maintaining the overall system function by utilizing the functional coupling of other actuators when some system functions fail, resulting in lower reliability of diagnostic results under complex operating conditions.

[0004] Therefore, developing a fault diagnosis method that can comprehensively utilize the coupling characteristics between actuators and between air and ground conditions in a hybrid propulsion system has become an important issue for improving the reliability and safety of hybrid propulsion systems. This invention aims to provide a fault diagnosis method for hybrid propulsion systems based on cross-coupling characteristics. Through in-depth analysis of the system's coupling characteristics, it improves the accuracy of fault prediction and diagnosis, ensuring efficient operation and stability of the system under complex conditions. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the current methods and systems for diagnosing cross-coupling faults in hybrid propulsion systems, this invention is proposed.

[0007] Therefore, the purpose of this invention is to provide a method and system for cross-coupling fault diagnosis of hybrid propulsion systems. This method and system solve the problem in the prior art that, when performing system fault prediction and diagnosis, it is difficult to effectively utilize the coupling characteristics between various actuators and air-to-ground operating conditions, resulting in inaccurate fault prediction and unreliable diagnosis results in hybrid propulsion systems under complex operating conditions, and the inability to fully leverage the advantages of internal functional coupling for efficient fault diagnosis.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for diagnosing cross-coupling faults in a hybrid propulsion system, comprising the following steps:

[0009] Step 1: By analyzing the motion state data of the flying car during the air-to-ground transition, a coupling model between air and ground conditions is established to obtain the coupling characteristic data of the influence of the ground acceleration process on the air takeoff phase or the influence of the air flight attitude on the ground landing stability, so as to carry out fault diagnosis and monitor the motion state coupling results of the flying car in real time.

[0010] Step 2: Based on the coupling results of the flying car motion state in Step 1, study the functional coupling relationship between the turboshaft engine and the motor actuator. By analyzing the impact of the fluctuation of the motor output power on the working state of the turboshaft engine, obtain the specific impact range of the functional coupling between the turboshaft engine and the motor, and establish a fault prediction model based on historical data and real-time monitoring data to predict the probability and time of potential faults, set fault thresholds, and output fault prediction feature values.

[0011] Step 3: Based on the fault prediction feature values ​​in Step 2, the system will continuously monitor sensor data and actuator status, and perform real-time fault diagnosis based on cross-coupling characteristics to obtain real-time diagnostic feedback and adjustment suggestions. When an anomaly is detected, the system will automatically adjust the operating mode of the hybrid propulsion system and output the adjusted propulsion system parameters to ensure flight safety and prevent the fault from escalating further.

[0012] As a preferred embodiment of the cross-coupling fault diagnosis method for the hybrid propulsion system described in this invention, step one specifically includes:

[0013] 11) By analyzing the motion state data of the flying car during ground acceleration and its attitude angles during takeoff, a coupling model between ground and air conditions is established to obtain the influence coefficients α1 and β1, and a preliminary coupling equation is constructed: Among them, M c V represents the combined effect of the coupled model. g It is the ground acceleration, θ a It is the attitude angle in the air;

[0014] 12) Based on the coupling model M obtained in step 11), c Further analysis of the impact of flight attitude on ground landing stability yielded coupling characteristic parameters γ1 and γ2, and the coupling formula was updated as follows: , where S c A represents the landing stability after coupling. a These are the aerial attitude parameters.

[0015] As a preferred embodiment of the cross-coupling fault diagnosis method for the hybrid propulsion system described in this invention, step two specifically includes:

[0016] 21) Based on the coupling model M in step one cand S c This study investigates the coupling relationship between the output power of a turboshaft engine and the output power of an electric motor, analyzes the impact of motor power fluctuations on the turboshaft engine, obtains coupling coefficients λ1 and λ2, and establishes coupling equations: , where P t It is the output power of the turboshaft engine, P e It is the output power of the motor;

[0017] 22) Based on the coupling equation in step 21), using historical data H d and real-time monitoring data R m Establish a fault prediction model F p The probability P of a potential failure occurring is calculated using machine learning algorithms or physics-based models. f and time T f : Where f(, ) is the probability calculation function and g(, ) is the time calculation function;

[0018] 23) Based on the fault prediction model F in step 22) p Set the fault threshold δ f When P f ≥δ f At that time, the system will output a fault prediction report R. f And recommends taking preventive measures: .

[0019] As a preferred embodiment of the cross-coupling fault diagnosis method for the hybrid propulsion system described in this invention, step three specifically includes:

[0020] 31) Based on the fault prediction report R in step 23) f The system continuously monitors data from various sensors. d and actuator state A s Using the coupling model M c and functional coupling equation P t Real-time diagnosis of fault sources and assessment of fault impact range, yielding fault impact parameter η and fault source location parameter λ. s : , where f() is the fault impact parameter calculation function and g() is the fault source location parameter calculation function;

[0021] 32) Based on the diagnostic results in step 31), generate a fault diagnosis report R. d The system automatically adjusts the operating mode of the hybrid propulsion system based on the report, and the adjusted propulsion system parameters P adj satisfy: ;

[0022] 33) Based on the adjustment results in step 32), the system updates the control strategy of the propulsion system in real time to ensure that the adjusted parameter P is maintained. adj Meets flight safety requirements.

[0023] A cross-coupling fault diagnosis system for a hybrid propulsion system includes: a turboshaft engine module, an electric motor module, a power coupler, a power management module, an air-to-ground conversion control module, a sensor unit module, and a fault diagnosis controller based on cross-coupling characteristics.

[0024] The turboshaft engine module includes: an intake device, a compressor, a combustion chamber, a power turbine, an exhaust device, a turboshaft reduction mechanism, and an output shaft. The intake device is connected to the compressor, introducing external air and feeding it into the compressor. The compressor is connected to the combustion chamber. The combustion chamber is connected to the power turbine, where high-temperature, high-pressure gas is generated by mixing and igniting air and fuel to drive the power turbine. The power turbine is connected to the exhaust device, discharging combustion exhaust gas, and simultaneously connected to the turboshaft reduction mechanism via the output shaft, converting gas energy into mechanical energy and transmitting it to the turboshaft reduction mechanism. The turboshaft reduction mechanism adjusts the speed of the output shaft to adapt to different operating conditions and environmental requirements.

[0025] The motor module includes: a motor, a reducer, and a motor control unit; the motor is connected to the reducer; the reducer adjusts the output speed of the motor to adapt to different working conditions and environmental requirements; the motor control unit is connected to the motor and the reducer, and monitors and controls them in real time.

[0026] The turboshaft engine module features a compact integrated design for the intake device, compressor, and combustion chamber to improve power output efficiency and response speed. The motor module employs a modular design for the reducer and motor control unit, facilitating maintenance and functional expansion. The outputs of the turboshaft engine module and motor module are connected to the output drive shaft via a power coupler to achieve synchronous power output.

[0027] The power management module connects the turboshaft engine module, the motor module, and the power coupler. It is responsible for coordinating the power distribution and conversion between the turboshaft engine module and the motor module, and adopts an integrated design.

[0028] The air-to-ground switching control module monitors the current environmental conditions and smoothly switches between air and ground operating conditions. The output signal of the air-to-ground switching control module is transmitted to the power management module and the fault diagnosis controller to achieve power coordination and fault monitoring during the switching of operating conditions.

[0029] The sensor unit module is used to continuously monitor the turboshaft engine module, motor module and power coupler. Its inputs include combustion chamber temperature, compressor pressure, output speed of turboshaft engine module, output speed of motor module and bus current parameters. After the above data is collected and processed, it is output to the fault diagnosis controller.

[0030] The fault diagnosis controller adopts a design based on cross-coupling characteristics. Through feedback from the sensor unit module and the air-to-ground conversion control module, it monitors in real time the functional coupling status between the turboshaft engine module and the motor module, as well as the conversion between air and ground operating conditions.

[0031] As a preferred embodiment of the cross-coupling fault diagnosis system for the hybrid propulsion system described in this invention, in the air, the power management module prioritizes the output of the turboshaft engine module and adjusts the auxiliary output of the motor module as needed; in the ground, the power management module prioritizes the power output of the motor module and provides additional power through the assistance of the turboshaft engine module to meet the needs of ground operation.

[0032] As a preferred embodiment of the cross-coupling fault diagnosis system for the hybrid propulsion system described in this invention, when a potential fault is detected, the fault diagnosis controller can issue a fault warning based on the coupling characteristics and initiate appropriate emergency measures to ensure the stability and safety of the system.

[0033] As a preferred embodiment of the hybrid propulsion system cross-coupling fault diagnosis system described in this invention, during system operation, the power management module adjusts the output ratio of the turboshaft engine module and the motor module through the power coupler to adapt to the power requirements under different operating conditions; when the fault diagnosis controller detects a fault, it can adjust the distribution ratio of the power coupler and reconfigure the power output path through the power management module to continue to maintain the normal operation of the system and ensure the reliability and safety of the system under complex operating conditions.

[0034] The beneficial effects of this invention are:

[0035] 1. This invention not only considers the motion state coupling of flying cars during the air-to-ground transition process and realizes accurate coupling analysis between air and ground conditions, but also can perform fault diagnosis and early warning of the coupling characteristics of the air take-off and ground landing phases by real-time monitoring of motion state data, so as to ensure the stability and safety of flying cars under complex conditions.

[0036] 2. This invention delves into the functional coupling relationship between turboshaft engines and actuators such as electric motors, and establishes a fault prediction model based on historical and real-time monitoring data. By introducing key coupling parameters and fault thresholds, accurate monitoring and early warning of functional coupling between actuators are achieved, providing predictive reports before potential faults occur, thus improving the system's fault prediction capability and response speed.

[0037] 3. This invention also considers real-time diagnosis and system adjustment after a fault occurs. Through the established fault diagnosis model, the system can quickly locate the fault source and assess its impact range, automatically adjusting the operating mode of the hybrid propulsion system to ensure flight safety. Even in the event of partial actuator failure, the system can still achieve functional control of the propulsion system through adjusted parameters, improving the fault tolerance and system safety of the flying car under fault conditions. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0039] Figure 1 This is a schematic diagram of the hybrid propulsion system of the present invention;

[0040] Figure 2 This is a schematic diagram of a turboshaft engine module.

[0041] Figure 3 This is a schematic diagram of the motor module structure;

[0042] Figure 4 This is a flowchart illustrating the principle of the method of the present invention;

[0043] In the diagram: 1. Turboshaft engine module; 2. Motor module; 3. Power coupler; 4. Power management module; 5. Air-to-ground conversion control module; 6. Sensor unit module; 7. Fault diagnosis controller; 101. Intake device; 102. Compressor; 103. Combustion chamber; 104. Power turbine; 105. Exhaust device; 106. Turboshaft reduction mechanism; 107. Output shaft; 201. Electric motor; 202. Reducer; 203. Motor control unit. Detailed Implementation

[0044] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0045] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0046] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0047] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0048] Reference Figures 1-4 A method for diagnosing cross-coupling faults in a hybrid propulsion system is provided, comprising the following steps:

[0049] Step 1: By analyzing the motion state data of the flying car during the air-to-ground transition, a coupling model between air and ground conditions is established to obtain the coupling characteristic data of the influence of the ground acceleration process on the air takeoff phase or the influence of the air flight attitude on the ground landing stability, so as to carry out fault diagnosis and monitor the motion state coupling results of the flying car in real time.

[0050] Step 2: Based on the coupling results of the flying car motion state in Step 1, study the functional coupling relationship between the turboshaft engine and the motor actuator. By analyzing the impact of the fluctuation of the motor output power on the working state of the turboshaft engine, obtain the specific impact range of the functional coupling between the turboshaft engine and the motor, and establish a fault prediction model based on historical data and real-time monitoring data to predict the probability and time of potential faults, set fault thresholds, and output fault prediction feature values.

[0051] Step 3: Based on the fault prediction feature values ​​in Step 2, the system will continuously monitor sensor data and actuator status, and perform real-time fault diagnosis based on cross-coupling characteristics to obtain real-time diagnostic feedback and adjustment suggestions. When an anomaly is detected, the system will automatically adjust the operating mode of the hybrid propulsion system and output the adjusted propulsion system parameters to ensure flight safety and prevent the fault from escalating further.

[0052] Step one specifically includes:

[0053] 11) By analyzing the motion state data of the flying car during ground acceleration and its attitude angles during takeoff, a coupling model between ground and air conditions is established to obtain the influence coefficients α1 and β1, and a preliminary coupling equation is constructed: Among them, M c V represents the combined effect of the coupled model. g It is the ground acceleration, θ a It is the attitude angle in the air;

[0054] 12) Based on the coupling model M obtained in step 11), c Further analysis of the impact of flight attitude on ground landing stability yielded coupling characteristic parameters γ1 and γ2, and the coupling formula was updated as follows: , where S c A represents the landing stability after coupling. a These are the aerial attitude parameters.

[0055] Furthermore, step two specifically includes:

[0056] 21) Based on the coupling model M in step one c and S c This study investigates the coupling relationship between the output power of a turboshaft engine and the output power of an electric motor, analyzes the impact of motor power fluctuations on the turboshaft engine, obtains coupling coefficients λ1 and λ2, and establishes coupling equations: , where P t It is the output power of the turboshaft engine, P e It is the output power of the motor;

[0057] 22) Based on the coupling equation in step 21), using historical data H d and real-time monitoring data R m Establish a fault prediction model F p The probability P of a potential failure occurring is calculated using machine learning algorithms or physics-based models. f and time T f : Where f(, ) is the probability calculation function and g(, ) is the time calculation function;

[0058] 23) Based on the fault prediction model F in step 22) p Set the fault threshold δ f When P f ≥δ f At that time, the system will output a fault prediction report R. f And recommends taking preventive measures: .

[0059] Step three specifically includes:

[0060] 31) Based on the fault prediction report R in step 23) f The system continuously monitors data from various sensors. d and actuator state A s Using the coupling model M c and functional coupling equation P t Real-time diagnosis of fault sources and assessment of fault impact range, yielding fault impact parameter η and fault source location parameter λ. s : , where f() is the fault impact parameter calculation function and g() is the fault source location parameter calculation function;

[0061] 32) Based on the diagnostic results in step 31), generate a fault diagnosis report R. d The system automatically adjusts the operating mode of the hybrid propulsion system based on the report, and the adjusted propulsion system parameters P adj satisfy: ;

[0062] 33) Based on the adjustment results in step 32), the system updates the control strategy of the propulsion system in real time to ensure that the adjusted parameter P is maintained. adj Meets flight safety requirements.

[0063] Specifically, the hybrid propulsion system cross-coupling fault diagnosis system includes: turboshaft engine module 1, motor module 2, power coupler 3, power management module 4, air-to-ground conversion control module 5, sensor unit module 6, and fault diagnosis controller based on cross-coupling characteristics 7.

[0064] The turboshaft engine module 1 includes: an intake device 101, a compressor 102, a combustion chamber 103, a power turbine 104, an exhaust device 105, a turboshaft reduction mechanism 106, and an output shaft 107. The intake device 101 is connected to the compressor 102, introducing external air and sending it into the compressor 102. The compressor 102 is connected to the combustion chamber 103. The combustion chamber 103 is connected to the power turbine 104, where high-temperature and high-pressure gas is generated by mixing air and fuel and igniting it, driving the power turbine 104. The power turbine 104 is connected to the exhaust device 105 to discharge the combustion exhaust gas, and is also connected to the turboshaft reduction mechanism 106 through the output shaft 107, converting the gas energy into mechanical energy and transmitting it to the turboshaft reduction mechanism 106. The turboshaft reduction mechanism 106 regulates the rotational speed of the output shaft 107 to adapt to different operating conditions and environmental requirements.

[0065] The motor module 2 includes: a motor 201, a reducer 202, and a motor control unit 203; the motor 201 is connected to the reducer 202; the reducer 202 adjusts the output speed of the motor to adapt to different working conditions and environmental requirements; the motor control unit 203 is connected to the motor 201 and the reducer 202 to monitor and control them in real time.

[0066] In turboshaft engine module 1, the intake device 101, compressor 102, and combustion chamber 103 adopt a compact integrated design to improve power output efficiency and response speed; in motor module 2, the reducer 202 and motor control unit 203 adopt a modular design for easy maintenance and functional expansion; the outputs of turboshaft engine module 1 and motor module 2 are connected to the output drive shaft through power coupler 3 to achieve synchronous power output.

[0067] The power management module 4 connects the turboshaft engine module 1, the motor module 2 and the power coupler 3. It is responsible for coordinating the power distribution and conversion between the turboshaft engine module 1 and the motor module 2, and adopts an integrated design.

[0068] The air-to-ground transition control module 5 monitors the current environmental conditions and smoothly transitions between air and ground operating conditions. The output signal of the air-to-ground transition control module 5 is transmitted to the power management module 4 and the fault diagnosis controller 7 to achieve power coordination and fault monitoring during the transition between operating conditions.

[0069] The sensor unit module 6 is used to continuously monitor the turboshaft engine module 1, the motor module 2 and the power coupler 3. Its inputs include the combustion chamber 103 temperature, the compressor 102 pressure, the output speed of the turboshaft engine module 1, the output speed of the motor module 2 and the bus current parameters. After summarizing and processing the above data, it is output to the fault diagnosis controller 7.

[0070] The fault diagnosis controller 7 adopts a design based on cross-coupling characteristics. Through feedback from the sensor unit module 6 and the air-to-ground conversion control module 5, it monitors in real time the functional coupling status between the turboshaft engine module 1 and the motor module 2, as well as the conversion between air and ground operating conditions.

[0071] In the air, the power management module 4 prioritizes the output of the turboshaft engine module 1 and adjusts the auxiliary output of the motor module 2 as needed. In the ground, the power management module 4 prioritizes the power output of the motor module 2 and provides additional power through the assistance of the turboshaft engine module 1 to meet the needs of ground operation.

[0072] Furthermore, when a potential fault is detected, the fault diagnosis controller 7 can issue a fault warning based on the coupling characteristics and initiate appropriate emergency measures to ensure the stability and safety of the system. During system operation, the power management module 4 adjusts the output ratio of the turboshaft engine module 1 and the motor module 2 through the power coupler 2 to adapt to the power requirements under different operating conditions. When the fault diagnosis controller 7 detects a fault, it can adjust the distribution ratio of the power coupler 3 and reconfigure the power output path through the power management module 4 to continue to maintain the normal operation of the system and ensure the reliability and safety of the system under complex operating conditions.

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A hybrid propulsion system cross-coupling fault diagnostic method characterized by, The method comprises the following steps: Step one: by analyzing the motion state data of the air car during the air-ground conversion process, a coupling model between the air and ground working conditions is established, the influence of the ground acceleration process on the air take-off stage or the influence of the air flight attitude on the ground landing stability is obtained, and the coupling characteristic data is obtained, so as to perform fault diagnosis and monitor the motion state coupling result of the air car in real time; Step two: based on the motion state coupling result of the air car in step one, the functional coupling relationship between the turboshaft engine and the motor actuator is studied, the influence of the fluctuation of the motor output power on the working state of the turboshaft engine is analyzed, the specific influence range of the functional coupling between the turboshaft engine and the motor is obtained, and a fault prediction model based on historical data and real-time monitoring data is established to predict the occurrence probability and time of potential faults, set a fault threshold, and output a fault prediction characteristic value; Step three: based on the fault prediction characteristic value in step two, the system will continuously monitor the sensor data and the actuator state, and perform real-time fault diagnosis based on the cross-coupling characteristics, obtain the system real-time diagnosis feedback and adjustment suggestion, and when an abnormality is detected, automatically adjust the working mode of the hybrid propulsion system, output the adjusted propulsion system parameters, so as to ensure flight safety and avoid further expansion of the fault.

2. The cross-coupling fault diagnostic method of a hybrid propulsion system of claim 1, wherein: The step one specifically comprises: 11) By analyzing the motion state data of the flying car during the ground acceleration process and the attitude angle in the air take-off stage, a coupling model between the ground and air working conditions is established, and the influence coefficient α 1and β 1, and a preliminary coupling equation is constructed: ； wherein M c denotes the overall influence of the coupling model, V g is the ground acceleration, θ a is the air attitude angle; 12) Coupling model based on step 11) M c Further analysis of the influence of the flight attitude on the landing stability on the ground, coupling characteristic parameters γ 1 and γ 2 are obtained, and the coupling formula is updated as: ； wherein, S c represents the coupled landing stability, A a is the air attitude parameter.

3. The cross-coupling fault diagnostic method of a hybrid propulsion system of claim 2, wherein: The step two specifically comprises: 21) Based on the coupling model in step one M c and S c , the coupling relationship between the output power of the turboshaft engine and the output power of the motor is studied, the influence of the motor power fluctuation on the turboshaft engine is analyzed, the coupling coefficients λ 1 and λ 2 are obtained, and the coupling equation is established: ； wherein, P t is the output power of the turboshaft engine, P e is the output power of the electric machine; 22) Based on the coupled equations in step 21), utilize historical data H d and real-time monitoring data R m to build a failure prediction model F p By machine learning algorithms or physics-based models, calculate the probability of potential failure occurrence P f and time T f : ； wherein f (, ) is a probability calculation function, g (, ) is a time calculation function; 23) According to the failure prediction model in step 22) F p , set the failure threshold δ f When P f ≥ δ f , the system will output a failure prediction report R f , and recommend taking preventive measures: 。 4. The cross-coupling fault diagnostic method of a hybrid propulsion system according to claim 3, characterized in that: The step three specifically comprises: 31) Based on the failure prediction report in step 23) R f , the system continuously monitors each sensor data S d and actuator status A s , using the coupling model M c and the functional coupling equation P t , diagnose the failure source in real time and evaluate the failure impact range, obtain the failure impact parameter η and the failure source positioning parameter λ s : ； wherein, f ( ) is a fault impact parameter calculation function, g ( ) is a fault source localization parameter calculation function; 32) generating a fault diagnosis report based on the diagnosis result in step 31) R d , the system automatically adjusts the working mode of the hybrid propulsion system according to the report, and the adjusted propulsion system parameters P adj satisfy: ； 33) According to the adjustment result in step 32), the system updates the control strategy of the propulsion system in real time, ensuring that the adjusted parameters P adj safety requirements.

5. A hybrid propulsion system cross-coupling fault diagnostic system employing the diagnostic method of any one of claims 1 to 4, characterized by: It comprises: a turboshaft engine module (1), a motor module (2), a power coupler (3), a power management module (4), an air-ground conversion control module (5), a sensor unit module (6), and a fault diagnosis controller based on cross-coupling characteristics (7); The turboshaft engine module (1) comprises: an air intake device (101), a compressor (102), a combustion chamber (103), a power turbine (104), an exhaust device (105), a turboshaft reduction mechanism (106), and an output shaft (107); the air intake device (101) is connected with the compressor (102) to introduce external air into the compressor (102); the compressor (102) is connected with the combustion chamber (103); the combustion chamber (103) is connected with the power turbine (104) to mix air and fuel and ignite to produce high-temperature and high-pressure gas to drive the power turbine (104); the power turbine (104) is connected with the exhaust device (105) to discharge combustion exhaust gas, and at the same time, the output shaft (107) is connected with the turboshaft reduction mechanism (106) to convert gas energy into mechanical energy and transmit it to the turboshaft reduction mechanism (106); the turboshaft reduction mechanism (106) adjusts the speed of the output shaft (107) to adapt to different working conditions and environmental requirements; The motor module (2) comprises: a motor (201), a reducer (202), and a motor control unit (203); the motor (201) is connected with the reducer (202); the reducer (202) adjusts the output speed of the motor to adapt to different working conditions and environmental requirements; the motor control unit (203) is connected with the motor (201) and the reducer (202) to monitor and control them in real time; The turbo-shaft engine module (1) adopts a compact integrated design for the intake device (101), the compressor (102), and the combustion chamber (103) to improve the efficiency and response speed of power output; the reducer (202) and the motor control unit (203) in the motor module (2) adopt a modular design, which is convenient for maintenance and functional expansion; the outputs of the turbo-shaft engine module (1) and the motor module (2) are connected to the output transmission shaft through the power coupler (3) to realize synchronous output of power. The power management module (4) is connected to the turbo-shaft engine module (1), the motor module (2), and the power coupler (3), and is responsible for coordinating the power distribution and conversion between the turbo-shaft engine module (1) and the motor module (2), adopting an integrated design. The air-ground conversion control module (5) performs smooth conversion between the air and ground working conditions by monitoring the current environmental state; the output signal of the air-ground conversion control module (5) is transmitted to the power management module (4) and the fault diagnosis controller (7) to realize power coordination and fault monitoring during working condition conversion. The sensor unit module (6) is used for continuous monitoring of the turbo-shaft engine module (1), the motor module (2), and the power coupler (3), and its input includes the combustion chamber (103) temperature, the compressor (102) pressure, the output speed of the turbo-shaft engine module (1), the output speed of the motor module (2), and the bus current parameters; after processing the combustion chamber (103) temperature, the compressor (102) pressure, the output speed of the turbo-shaft engine module (1), the output speed of the motor module (2), and the bus current parameters, the parameters are output to the fault diagnosis controller (7). The fault diagnosis controller (7) adopts a design based on cross-coupling characteristics, and monitors the functional coupling state between the turbo-shaft engine module (1) and the motor module (2), and the conversion between the air and ground working conditions in real time through the feedback of the sensor unit module (6) and the air-ground conversion control module (5).

6. The hybrid propulsion system cross-coupling fault diagnostic system of claim 5, wherein: In the air working condition, the power management module (4) preferentially uses the output of the turbo-shaft engine module (1), while adjusting the auxiliary output of the motor module (2) as needed; in the ground working condition, the power management module (4) preferentially uses the power output of the motor module (2), and provides additional power through the auxiliary turbo-shaft engine module (1) to adapt to the requirements of ground operation.

7. The hybrid propulsion system cross-coupling fault diagnostic system of claim 5, wherein: When a potential fault is detected, the fault diagnosis controller (7) can make a fault warning according to the coupling characteristics, and start appropriate emergency measures to ensure the stability and safety of the system.

8. The hybrid propulsion system cross-coupling fault diagnostic system of claim 5, wherein: During system operation, the power management module (4) adjusts the output ratio of the turbo-shaft engine module (1) and the motor module (2) through the power coupler (3) to adapt to the power requirements in different working conditions; when a fault is detected, the fault diagnosis controller (7) can adjust the distribution ratio of the power coupler (3) and reconfigure the power output path through the power management module (4) to continue normal operation of the system, ensuring the reliability and safety of the system in complex working conditions.

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