A hierarchical architecture fault tolerance method and device for aircraft flight control system

Abstract

A hierarchical architecture fault tolerance method and device for an aircraft flight control system, the method comprising: using a triple-redundant flight control system to establish a redundant flight control system architecture, designing three independently operated flight control channels, and using a triple-redundant voting mechanism; designing a hierarchical fault-tolerant architecture for the aircraft system; simulating actuator failures and injecting aircraft actuator failures; designing a Kalman filter fault detection method based on actuator control command signal difference for actuator failures; transmitting the detection results of the actuator fault detection algorithm to a controller to adjust the flight trajectory of the aircraft; the reconstructed controller adjusts the flight state of the aircraft and feeds the flight state back to a top-level task reconstruction unit to adjust the aircraft task; simulating controller failures; designing redundant controller voting logic for controller failures; injecting controller failures, and designing experiments to verify the correctness of the redundant controller voting logic.

Description

Technical Field

[0001] The present invention relates to the safety and reliability technology of an aircraft flight control system, and in particular to a fault tolerance method and device for an aircraft flight control system based on a layered architecture. Background Art

[0002] The design and manufacture of intelligent vehicles can not only improve the intelligence level of products, but also effectively alleviate urban traffic pressure and improve urban operation efficiency. With the acceleration of urbanization, urban population density continues to increase, and traffic congestion problems are becoming increasingly prominent, especially in first-tier cities. Traditional urban transportation methods can no longer meet the growing travel needs, and a new mode of transportation is urgently needed to improve the current situation. The low-altitude economy has huge development potential and market space, and is expected to become a new engine to promote economic growth. As a new type of urban air traffic vehicle, the electric vertical take-off and landing aircraft provides new ideas and solutions for solving urban traffic congestion problems with its unique advantages and potential. Compared with traditional helicopters, the aircraft has lower operating costs and maintenance difficulties, and is more environmentally friendly and efficient. Its electric drive mode greatly reduces dependence on aviation fuel, reduces carbon emissions, and meets the requirements of green development. In addition, the electric vertical take-off and landing aircraft has a low noise level, has less impact on the urban environment, and improves the quality of life of residents. Its vertical take-off and landing characteristics enable it to take off and land in small spaces such as city centers, providing a "last mile" solution for large passenger aircraft to transport passengers, effectively alleviating urban traffic pressure.

[0003] In today's low-altitude manned aircraft field, facing the complexity of operating scenarios, the risks of air operations and the uncertainty of the operating environment, ensuring the high safety of aircraft has become a prerequisite for its commercialization and popularization. In order to achieve this goal, international aviation regulators have set strict safety standards. As the nerve center of the aircraft, the safety and reliability of the flight control system (flight control system) are crucial to the safe operation of the entire aircraft and are directly related to the promotion and application of the aircraft. Therefore, the present invention aims to propose a systematic hierarchical architecture flight control system fault tolerance method to cope with various abnormal situations that may occur during the flight process, ensuring that the aircraft can still maintain stable flight performance when facing faults or abnormalities. The core of the hierarchical fault-tolerant architecture design is to enhance the reliability and fault-tolerant capability of the system through system redundancy, modularization and hierarchical control. In traditional designs, the various parts of the system are highly integrated and interdependent. The failure of one part may affect the entire system, making it difficult to repair or replace it locally. The fault-tolerant design only uses a single control logic or strategy, lacks a multi-level control and decision-making mechanism to deal with different fault situations, and lacks self-adaptation and self-healing capabilities. The traditional design method is static design. In contrast to the dynamic and flexible design of the layered fault-tolerant architecture, the static design cannot be adjusted according to the system operating status or environmental changes, and lacks the ability to respond to emergencies.

[0004] At present, a key challenge facing my country in promoting low-altitude manned aircraft and ensuring their safe application is the lack of a mature and reliable integrated fault-tolerant control strategy solution. This challenge not only limits the stable operation capability of aircraft in complex environments, but also affects its performance in terms of safety and reliability, thus restricting the healthy development of the entire industry. The lack of an effective fault-tolerant control strategy means that the aircraft may not be able to respond in time when encountering unexpected situations, which not only increases the risk of accidents, but also reduces the public's trust in the safety of low-altitude manned aircraft. Summary of the invention

[0005] The present invention aims to overcome the above-mentioned shortcomings of the prior art and proposes a fault tolerance method and device for a hierarchical architecture of an aircraft flight control system.

[0006] In order to overcome this problem, the present invention proposes a fault tolerance method for a flight control system with a layered architecture. This strategy can ensure that the aircraft can maintain safe operation even when some systems fail by implementing fault tolerance mechanisms at different levels. The strategy includes but is not limited to real-time monitoring of system status, intelligent diagnosis of potential faults, and rapid response control reconstruction technology. The integrated application of these technologies will greatly improve the adaptability and stability of the aircraft in the face of various abnormal situations. By implementing this innovative control strategy, not only can the reliability and safety of the aircraft be significantly improved, but it will also provide strong technical support for the implementation and development of my country's advanced air traffic aircraft industry, accelerate the maturity of the industry and market recognition. This research not only has important exploratory significance in theory, and provides a new research direction and methodology for the field of aircraft safety control, but also has broad prospects in practical applications, and can directly promote the innovation of related technologies and the upgrading of the industry. With the deepening of this research, it is expected to provide a solid technical foundation for the safe application of low-altitude manned aircraft in my country and even the world, promote the formulation of relevant laws and regulations and standards, and lay the foundation for the realization of future urban air traffic, which is of great strategic significance.

[0007] The present invention adopts a triple-redundant flight control system to establish a redundant flight control system architecture, designs three independently operated flight control channels; designs a hierarchical fault-tolerant architecture for the aircraft system; simulates actuator failures, and adjusts the flight state of the aircraft after the aircraft is reconstructed, and feeds back the flight state to the top-level task reconstruction unit to adjust the aircraft task; if the failure is more serious and reduces the flight quality, the aircraft is allowed to land smoothly. If there is a redundant replacement unit, the flight quality is not affected, and the aircraft can continue to fly and perform tasks; simulates controller failures; designs redundant controller voting logic for controller failures; injects controller failures, and designs experiments to verify the correctness of the redundant controller voting logic. The present invention adopts a redundant flight control system architecture, which improves the robustness of a single flight control system by increasing the redundancy of the system.

[0008] A first aspect of the present invention relates to a layered architecture fault tolerance method for an aircraft flight control system, comprising the following steps:

[0009] Step 1: Use a triple-redundant flight control system to establish a redundant flight control system architecture, design three independently operated flight control channels, and through the triple-redundant voting mechanism, the aircraft can still maintain safe flight in the event of one or two flight control computer failures;

[0010] Step 2: Design a hierarchical fault-tolerant architecture for the aircraft system, which includes the bottom-level fault detection unit layer, the control strategy adjustment unit layer, the trajectory replanning unit layer, and the top-level task reconstruction unit layer from bottom to top;

[0011] Step 3: Simulate actuator failure and inject aircraft actuator fault;

[0012] Step 4: Design a Kalman filter fault detection method based on actuator control command signal difference for actuator faults;

[0013] Step 5: The detection result of the actuator fault detection algorithm is passed to the controller, and the control method based on gain scheduling is used to perform fault-tolerant response of the actuator in the flight control system, and the flight status is fed back to the trajectory replanning unit layer to adjust the flight trajectory of the aircraft;

[0014] Step 6: The reconstructed controller adjusts the flight state of the aircraft and feeds back the flight state to the top-level task reconstruction unit to adjust the aircraft mission. If the fault is serious and reduces the flight quality, the aircraft is landed smoothly. If there is a redundant replacement unit, the flight quality is not affected and the aircraft can continue to fly and perform the mission.

[0015] Step 7: Simulate controller failure;

[0016] Step 8: Design redundant controller voting logic for controller failure;

[0017] Step 9: Inject controller failure and design experiments to verify the correctness of the redundant controller voting logic.

[0018] Among them, the aircraft system layered fault-tolerant architecture described in step 2 realizes systematic and progressive control of fault management through layered design, and smoothly transitions from instant identification and processing of local faults to real-time adaptive adjustment of the aircraft's global mission.

[0019] Among them, the simulated actuator fault described in step 3 and the aircraft actuator fault injection are performed, and the actuator fault model expression is:

[0020] (1)

[0021] in, is the actuator fault signal, is the actuator fault gain factor, when When it is equal to 1, the actuator has no fault; when When the value is smaller, the actuator fails. The smaller the value, the more serious the failure.

[0022] Among them, in step 4, for the actuator fault, a Kalman filter fault detection method based on the actuator control command signal difference is designed, which specifically includes:

[0023] The fault detection method is verified using a quadrotor aircraft. The actuator fault signal is injected into the fourth motor. The difference between the second actuator control command signal and the fourth actuator control command signal is calculated and the absolute value is taken:

[0024] (2)

[0025] is the second actuator control command signal ( ) and the fourth actuator control command signal ( ), the state space equation of the actuator is:

[0026] (3)

[0027] (4)

[0028] Output signal difference of the controller , is the state variable; A and C are unit matrices, is the process noise, with variance Q, is the measurement noise, the variance is R, k represents the time; the posterior estimate of the state variable of the Kalman filter is:

[0029] (5)

[0030] Equation (5) represents the Kalman filter estimation of the state variable x(k), is the new information of Kalman filter;

[0031] (6)

[0032] Among them, K(k) is the Kalman gain, P(k|k-1) is the corresponding prior state error covariance in the Kalman filter; the final detection link compares x(k|k) with the set threshold. If it is greater than the threshold, the output fault flag is 1, otherwise it is 0.

[0033] The actuator failure described in step 5 triggers the attitude controller and the altitude controller in the controller to reconfigure the control parameters, adjust the flight state of the aircraft, and feed the flight state back to the trajectory replanning unit layer to adjust the flight trajectory of the aircraft, specifically including:

[0034] When an actuator failure is detected, the controller is reconfigured to stabilize pitch and roll at 0 radians and land at a low speed; since yaw is uncontrolled, the aircraft rotates around the vertical axis; the configured pitch-roll angle controller is:

[0035] (7)

[0036] (8)

[0037] In formula (7), are the reference values ​​of pitch angle and roll angle, angle and angel_rate are the state feedback values ​​of aircraft attitude angle and corresponding angular velocity, is the angle outer loop proportional gain parameter, which is obtained by looking up the table according to the fault flag bit. is the outer ring angle information difference; in formula (8), is the inner loop proportional gain coefficient, is the inner loop integral gain coefficient, which is obtained by looking up the table according to the fault flag bit. Output signal to the pitch-roll controller to adjust the moment change of the aircraft.

[0038] Wherein, the step six realizes the adjustment of the flight mission by reconstructing the top-level mission; the top-level mission is reconstructed to minimize the risk of mission failure and maximize the mission success rate, specifically including:

[0039] (9)

[0040] (10)

[0041] Among them, S represents the flight mission execution strategy, including decision variables such as flight path, speed, and altitude. The mission success rate (S) is the probability of mission completion based on strategy S; the mission risk (S) is the probability of mission failure based on strategy S; is a weight parameter used to balance the trade-off between mission success rate and risk; g is a constraint function, which represents the constraints that strategy S must meet, such as aircraft performance limitations, safety requirements, etc.; flight status includes the aircraft's position, speed, attitude and other status information; redundant configuration refers to the remaining schedulable redundant resources of the aircraft after a fault occurs;

[0042] Among them, the simulated controller failure described in step seven is set through programming, and a preset signal mode is introduced into the enable signal of the flight control system in a simulated environment, thereby simulating the sudden failure encountered by the controller in actual operation; the jump of the enable signal triggers the fault detection mechanism of the flight control system, thereby activating the preset fault-tolerant control strategy.

[0043] Among them, the redundant controller voting logic described in step eight specifically includes: among the three redundant controllers, each controller is assigned a priority based on its performance and reliability factors; during normal operation, the high-priority controller plays a leading role, and when a fault occurs, the system switches to other controllers according to the priority order.

[0044] Among them, the verification of the voting logic of the redundant controller described in step nine is verified by simulating normal working conditions and fault conditions of all three redundancies; the fault conditions include: injecting the first flight control fault into the flight control system respectively to verify the output logic of the voting mechanism; injecting the first flight control and the second flight control faults to verify that the output of the voting mechanism is the output of the third flight control.

[0045] A second aspect of the present invention relates to a layered architecture fault tolerance device for an aircraft flight control system, comprising a memory and one or more processors, wherein the memory stores executable code, and when the one or more processors execute the executable code, they are used to implement a layered architecture fault tolerance method for an aircraft flight control system of the present invention.

[0046] A third aspect of the present invention relates to a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements a layered architecture fault tolerance method for an aircraft flight control system of the present invention.

[0047] The core innovation of the present invention is to adopt a multi-level, modular fault-tolerant design concept to significantly improve the robustness of the flight control system. The specific implementation strategy is as follows: The present invention configures a redundant flight control hardware system, which realizes the redundancy of key components through modular design. When some system components fail, the remaining redundant components can take over immediately to ensure that the aircraft can maintain basic flight functions, thereby ensuring flight safety. In terms of software, the present invention introduces an advanced hierarchical fault-tolerant strategy, which can monitor and effectively handle potential faults of key components such as actuators and flight control controllers in real time during flight, ensuring rapid response and system recovery when faults occur. Through the deep integration of software and hardware, the present invention not only significantly enhances the fault-tolerant performance of the flight control system, but also provides a solid theoretical foundation and innovative technical support for the safety and reliability of the system. The designed aircraft system hierarchical fault-tolerant architecture can be divided into four layers, including the bottom fault detection unit layer, the control strategy adjustment unit layer, the trajectory replanning unit layer and the top task reconstruction unit layer from bottom to top. Finally, it is verified and explained by simulating actuator failure and controller failure respectively.

[0048] The fault-tolerant control strategy of the hierarchical architecture designed by the present invention ensures that the backup system can quickly and seamlessly take over control when the key system components fail through layer-by-layer analysis and evaluation. This hierarchical control strategy not only improves the response speed of the system, but also enhances the adaptive ability of the system. Through the integrated application of the above-mentioned innovative technologies and methods, the present invention not only provides a high-safety and high-reliability flight control system for low-altitude manned aircraft, but also provides solid theoretical and technical support for the safe operation of aircraft in complex and uncertain operating environments. The implementation of the present invention will open up new paths for the commercialization and popularization of low-altitude manned aircraft, promote the innovation and development of the aviation industry, and provide technical guarantees for the realization of future urban air traffic. The present invention breaks through the traditional limitations in design, constructs an integrated hierarchical architecture system, and adopts a methodology from local to global. This method not only focuses on the robustness of individual components, but also focuses on the stability and reliability of the overall system, ensuring that when a local failure occurs, the system can maintain the safe flight and stable control of the aircraft through a global coordination mechanism. Through this comprehensive method, the solution of the present invention can comprehensively improve the performance of the flight control system and enhance its adaptability and resilience in the face of various failures and abnormal situations.

[0049] The beneficial effects of the present invention are:

[0050] (1) Redundant flight control hardware architecture: By designing a redundant flight control hardware architecture, even if the reliability of a single flight control unit is low, the overall system can meet strict safety indicators through redundant design. This design not only significantly improves the safety and stability of the system, but also enhances the system's fault tolerance for potential failures. Hardware redundancy is implemented in key control units and computing resources to ensure that the system can still maintain normal operation in the face of partial hardware failures, reducing the probability of system or equipment failure, thereby improving the reliability of the entire flight control system. In addition, this redundant design also allows the system to quickly switch to a backup unit in the event of a failure, minimizing the impact of the failure on the flight mission, ensuring that the aircraft can operate safely in all situations, and providing a higher level of protection for the aircraft.

[0051] (2) Hierarchical fault-tolerant control architecture: Based on hardware redundancy, the present invention further proposes a hierarchical fault-tolerant control architecture. This architecture realizes step-by-step response and effective implementation of the fault-tolerant process by quickly detecting and locating faults and matching corresponding safety control strategies and fault-tolerant methods. The hierarchical fault-tolerant architecture design of the aircraft system is divided into four levels from bottom to top: first, the bottom-level fault detection unit layer is responsible for real-time monitoring and preliminary diagnosis; second, the control strategy adjustment unit layer adjusts the control algorithm according to the detection results to adapt to the fault situation; then, the trajectory replanning unit layer dynamically adjusts the flight trajectory of the aircraft to avoid the impact of the fault; and finally, the top-level mission reconstruction unit layer is responsible for replanning and decision-making of the entire flight mission when necessary. This hierarchical approach ensures that the system can respond appropriately to faults of different levels and types, maintaining the flight safety of the aircraft and the continuity of the mission. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a fault tolerance diagram of the layered architecture of the aircraft flight control system of the present invention.

[0053] Figure 2 It is a flow chart of the Kalman filter fault detection method based on actuator control command signal difference of the present invention.

[0054] Figure 3 It is a flow chart of the actuator fault tolerance algorithm based on gain scheduling of the present invention.

[0055] Figure 4 It is a diagram of actuator fault injection signal of the present invention.

[0056] Figure 5 This is the actuator fault detection-Kalman filter input signal diagram of the present invention.

[0057] Figure 6 It is the actuator fault detection-Kalman filter output diagram of the present invention.

[0058] Figure 7 It is a diagram of the actuator fault detection result of the present invention.

[0059] Figure 8 It is the roll angle variation curve of the gain-scheduled fault-tolerant control of the present invention.

[0060] Fig. 9 It is the pitch angle variation curve of the gain-scheduled fault-tolerant control of the present invention.

[0061] Fig.10 It is the gain-scheduled fault-tolerant control yaw angle variation curve of the present invention.

[0062] Fig.11 It is the gain scheduling fault-tolerant control height variation curve of the present invention.

[0063] Fig.12 It is a voting logic flow chart of the redundant flight control system of the present invention.

[0064] Fig.13 It is the triple-redundant flight control-x position change curve of the present invention.

[0065] Fig.14 It is the -y position change curve of the triple-redundant flight control of the present invention.

[0066] Fig.15 It is the -z position change curve of the triple-redundant flight control of the present invention.

[0067] Fig.16 It is a structural diagram of the device of the present invention. DETAILED DESCRIPTION

[0068] The present invention relates to a hierarchical fault tolerance method for an aircraft flight control system. The method is based on a hierarchical architecture design and is intended to improve the safety and reliability of the flight control system during the flight of an aircraft. Although a large number of studies on fault diagnosis methods and fault-tolerant control algorithms have emerged, an integrated architecture has not yet been formed to ensure that these methods can be efficiently implemented and promoted in practical applications. In response to the above challenges, the present invention proposes an innovative systematic solution. In terms of hardware design, the present invention adopts a redundant flight control system architecture, which significantly improves the robustness of a single flight control system by increasing the redundancy of the system. In terms of software, the present invention introduces an advanced hierarchical fault-tolerant strategy, which can monitor and effectively handle potential faults of key components such as actuators and flight control controllers in real time during flight, ensuring rapid response and system recovery when faults occur. Through the deep integration of software and hardware, the implementation of the present invention not only significantly improves the fault tolerance and overall performance of the flight control system, but also provides a solid theoretical basis and technical support for the future development of urban air traffic. With the acceleration of urbanization and the growth of air traffic demand, the promotion and application of the present invention will have important strategic significance for promoting the healthy development of the low-altitude manned aircraft industry and improving the safety and efficiency of urban air traffic.

[0069] Example 1

[0070] like Figure 1A hierarchical architecture fault tolerance method for an aircraft flight control system is shown, and its architecture can be divided into four layers, including, from bottom to top, a bottom fault detection unit layer, a control strategy adjustment unit layer, a trajectory replanning unit layer, and a top task reconstruction unit layer. The purpose of the architecture is to achieve fault-tolerant control of faults at the "local-global" level. A quadcopter is used as the simulation experimental object, with a mass of m=0.1kg. The simulation run time is set to 40s. The time when the actuator fault is injected is the 30th second, and the fault state continues until the end. Example 1 illustrates the specific execution process of hierarchical architecture fault tolerance based on actuator faults:

[0071] First, the actuator failure is simulated and the aircraft actuator fault is injected. The actuator failure model expression is:

[0072] (1)

[0073] in, is the actuator fault signal, is the actuator fault gain factor; when =1, the actuator has no fault; when When the value is smaller, the actuator fails. The smaller the value, the more serious the fault. In order to simulate the fourth motor fault, the fault parameter FG is set to 0.3, so the motor fault signal , k represents the time, such as Figure 4 As shown, the FG of the other three motors is 1. For actuator failure, a Kalman filter fault detection method based on the actuator control command signal difference is designed, as shown in Figure 2 As shown, the difference between motor control command signal 2 and motor control command signal 4 is calculated and the absolute value is taken:

[0074] (2)

[0075] Motor control command signal 2 ( ) and motor control command signal 4 ( ), the curve is as follows Figure 5 As shown; the state space equation of the motor is:

[0076] (3)

[0077] (4)

[0078] Output signal difference of the controller , is the state variable; A and C are unit matrices, is process noise, with a variance of Q=0.002; To measure noise, the variance is R=0.05; k represents the time.

[0079] The Kalman filter is known as an optimal linear estimator that minimizes the mean square error and provides a recursive calculation of the state variables. Based on the state space equation and the measurement equation, the estimation process is as follows:

[0080] (5)

[0081] Wherein, equation (5) represents the Kalman filter prior estimate of the state variable x(k|k-1), and x(k-1|k-1) is the posterior minimum mean square error estimate of the state variable x(k-1) in the Kalman filter estimator.

[0082] (6)

[0083] Equation (6) represents the calculation process of the prior covariance P(k|k-1) in the Kalman filter. P(k|k-1) and P(k-1|k-1) are the corresponding prior and posterior state error covariances in the Kalman filter. Q is the variance of the system noise w(k), and its value is 0.002.

[0084] (7)

[0085] Where K(k) is the Kalman gain and R is 0.05. The posterior estimate of the state variable of the Kalman filter is:

[0086] (8)

[0087] Equation (8) represents the Kalman filter estimation of the state variable x(k), and its calculation result is as follows: Figure 6 As shown; z(k)-Cx(k|k-1) is the new information of the Kalman filter. The posterior covariance calculation formula of the Kalman filter is:

[0088] (9)

[0089] The final detection step compares x(k|k) with the set threshold, where th=200; if it is greater than the threshold, the output fault flag is 1, otherwise it is 0.

[0090] (10)

[0091] Test results such as Figure 7As shown, it can be seen that after the fault occurs, the bottom detection unit can effectively detect the fault. For actuator faults, the detection result detection (fault flag signal) of the actuator fault detection algorithm is passed to the controller, and the control method based on gain scheduling is used to perform fault-tolerant response of the actuator in the flight control system. The occurrence of actuator failure triggers the attitude controller and altitude controller in the controller to reconfigure the control parameters, adjust the flight state of the aircraft, and feed back the flight state to the trajectory replanning unit layer to adjust the flight trajectory of the aircraft. Specifically:

[0092] When an actuator failure is detected, the controller reconfigures the pitch and roll to stabilize at 0 radians and land at a low speed. Since yaw is uncontrolled, the vehicle rotates around the vertical axis. The calculation flow is as follows Figure 3 The configured pitch-roll angle controller is:

[0093] (11)

[0094] (12)

[0095] In formula (11), is the pitch angle and roll angle When the fault signal detection detects a fault, =0; angle and angel_rate are the pitch angles of the aircraft and roll angle And the corresponding pitch angular velocity q and roll angular velocity p state feedback values; is the angle outer loop proportional gain parameter, which is obtained by looking up the table according to the fault flag bit =11.02, =11.42; is the outer ring angle information difference. In formula (12), is the inner loop proportional gain coefficient, is the inner loop integral gain coefficient, which is obtained by looking up the table according to the fault flag bit. The pitch angular velocity loop gain =0.006416, =0.01; Roll angular velocity loop gain =0.005209, =0.01; It is the output signal of the pitch-roll angular velocity controller, which is mainly used to adjust the torque change of the aircraft. Figure 8-Figure 10 It is the attitude angle change curve of the aircraft during the fault tolerance process. When the aircraft loses some power, it can be seen that the deflection of the aircraft is uncontrolled, but the pitch and roll angles can be effectively controlled. The calculation process of the reconstructed altitude controller is:

[0096] (13)

[0097] is the height difference, As a height reference, when the fault flag signal detection detects a fault , h is the height feedback value of the state estimation; because the height is the displacement in the z-axis direction, the vertical velocity is expressed as It means that the control law of the height control loop is as follows:

[0098] (14)

[0099] In formula (14), is the height loop control law output command, , Obtained by looking up the table according to the fault flag bit =1.667, =0.01 and =4.098. The reconstructed controller adjusts the flight state of the aircraft through the trajectory replanning unit layer and the top-level task reconstruction unit layer to make it land smoothly. Fig.11 It can be seen from the altitude curve that when the aircraft loses some power, the aircraft can adjust its control strategy and land smoothly by controlling the pitch, roll angle and altitude information.

[0100] Example 2

[0101] The present embodiment relates to a redundant flight control system architecture using a triple-redundant flight control system to implement a hierarchical architecture fault tolerance method for an aircraft flight control system.

[0102] The flight control system is the core of the aircraft flight control system, and its performance is directly related to the stability and safety of the aircraft. In order to improve the reliability of the flight control system, the industry generally adopts two methods: error avoidance and fault tolerance. Error avoidance reduces the probability of failure by selecting high-reliability components, but this method is not enough to ensure that the overall system reaches the expected high reliability level. In contrast, fault tolerance technology significantly improves the fault tolerance and overall reliability of the system by implementing redundant design at the software and hardware levels. In the redundant design of the flight control system, designers need to follow the principle of minimizing the number of redundancies and reducing system complexity, while ensuring that the reliability and safety requirements of the aircraft mission are met. This design strategy aims to achieve cost-effectiveness and performance optimization through precise redundant configuration. The three-redundancy voting mechanism is a key link in the redundant design of the flight control system, which can ensure the efficient operation of the redundant system and improve the flexibility and fault tolerance of the system.

[0103] The multi-redundant flight control hardware architecture design proposed in the present invention adopts "n c Flight control computer + n s Sensor+n a The architecture of the "actuator" forms a high-efficiency redundant flight control system. Through the triple-redundant flight control system architecture, the design of the triple-redundant voting mechanism realizes the priority judgment, state arbitration and switching between the flight control channels, ensuring that when any single flight control unit fails, the system can quickly switch to the normal unit to ensure the stable operation of the aircraft. The voting logic flow of the triple-redundant flight control system of the present invention is as follows Fig.12 shown.

[0104] Based on the above, a three-redundant flight control architecture is built, and its priority order is set as follows:

[0105] (15)

[0106] The logic voting process is as follows. By adding an enable signal to each controller to simulate the controller failure, if the enable signals are all 1, the controller works normally, otherwise it simulates a failure. On this basis, first simulate the normal working condition of the three flight controllers. According to the priority setting, the signal of Controller1 is output by default. First simulate the normal working condition of the aircraft, so in each flight controller, the attitude loop gain parameter is, =9.669, =9.572; the pitch angular velocity loop gain parameter is =0.004296, =0.01; the roll angular velocity loop gain parameter is =0.003493, =0.01; height ring =3.004, =0.01 and =3.308; the simulation time is 40s, and the displacement curves of the aircraft in the three axis directions are as follows Figure 13-Figure 15 The figure shows the constant altitude flight of the quadrotor under normal working conditions. Fig.13 It means that the aircraft is flying from the negative semi-axis to the positive semi-axis on the x-axis. Fig.14 It means that the aircraft is flying from the negative semi-axis to the positive semi-axis on the y-axis. Fig.15 It means that the aircraft flies from the negative semi-axis away from the positive semi-axis on the z-axis, and finally the coordinates in the z-axis direction are stable, indicating that the aircraft finally flies at a constant altitude.

[0107] Among the three redundant controllers, each controller is assigned a priority based on its performance, reliability and other factors. In normal operation, the high-priority controller plays a leading role, and when a failure occurs, the system will switch to other controllers according to the priority order. The triple-redundant flight control system improves the reliability of the system through the design of three independent channels. Even if one or two channels fail, the remaining channels can still maintain the normal operation of the system.

[0108] Simulate Controller1 fault, its enable signal =0, judged by the fault detection module The state is detected =0, it is judged that Controller1 is faulty; the triple-redundant flight control system detects the enable signal of Controller2 according to the priority order. Status (normally The default value is 1); first simulate the condition where only Controller1 fails, so =1, the three-redundancy voting mechanism is compared and Finally, the control signal of Controller2 is output to the actuator system. The controller gain parameter configuration remains unchanged, and the simulation time is 40s. The aircraft's trajectory is consistent with the aircraft's trajectory under normal conditions, indicating that even if Controller1 fails, the aircraft will automatically switch to Controller2 in the three-redundant flight control system and can still fly normally at a constant altitude. The y-axis flight speed =3.72m / s, flight altitude h=15m.

[0109] Based on the above, inject faults into Controller2, that is, =0, the detection unit detects that the enable signals of Controller1 and Controller2 are both 0, and determines that both of them are faulty at the same time; the three-redundant flight control system outputs the Controller3 control signal to the execution system according to the priority order and function voting; the controller gain parameter configuration remains unchanged, the simulation time is 40s, and the aircraft operation trajectory of the entire controller fault tolerance process is consistent with the aircraft operation trajectory under normal conditions; it means that even if Controller1 and Controller2 fail at the same time, the aircraft can still fly normally at a fixed altitude, and the y-axis flight speed =3.72m / s, flight altitude h=15m.

[0110] Finally, by injecting two fault conditions: Controller1 failure and simultaneous failure of Controller1 and Controller2, simulation experiments verify the correctness and effectiveness of the voting logic of the three redundant controllers.

[0111] Example 3

[0112] Reference Figure 1 to Figure 16 This embodiment relates to a layered architecture fault tolerance device for an aircraft flight control system, including a memory and one or more processors, wherein the memory stores executable code, and when the one or more processors execute the executable code, they are used to implement a layered architecture fault tolerance method for an aircraft flight control system of the present invention.

[0113] Example 4

[0114] This embodiment relates to a computer-readable storage medium on which a program is stored. When the program is executed by a processor, a layered architecture fault tolerance method for an aircraft flight control system of embodiment 1 is implemented.

[0115] Each embodiment of the present invention is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0116] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A layered architecture fault tolerance method for an aircraft flight control system, characterized in that: The following steps are involved: Step 1: Use a triple-redundant flight control system to establish a redundant flight control system architecture, design three independently operated flight control channels, and through the triple-redundant voting mechanism, the aircraft can still maintain safe flight in the event of one or two flight control computer failures; Step 2: Design a hierarchical fault-tolerant architecture for the aircraft system, which includes the bottom-level fault detection unit layer, the control strategy adjustment unit layer, the trajectory replanning unit layer, and the top-level task reconstruction unit layer from bottom to top; Step 3: Simulate actuator failure and inject aircraft actuator fault; Step 4: For actuator failure, design a Kalman filter fault detection method based on the control command signal difference between different actuators; Step 5: The detection result of the actuator fault detection algorithm is passed to the controller, and the control method based on gain scheduling is used to perform fault-tolerant response of the actuator in the flight control system, and the flight status is fed back to the trajectory replanning unit layer to adjust the flight trajectory of the aircraft; Step 6: The reconstructed controller adjusts the flight state of the aircraft and feeds back the flight state to the top-level task reconstruction unit to adjust the aircraft mission. If the fault is serious and reduces the flight quality, the aircraft will land smoothly. If there is a redundant replacement unit, the flight quality will not be affected and the aircraft will continue to fly and perform the mission. Step 7: Simulate controller failure; Step 8: Design redundant controller voting logic for controller failure; Step 9: Inject controller failure and design experiments to verify the correctness of the redundant controller voting logic.

2. The layered architecture fault tolerance method of an aircraft flight control system according to claim 1, characterized in that: The aircraft system layered fault-tolerant architecture described in step 2; through layered design, the systematic and progressive control of fault management is realized; from the instant identification and processing of local faults, a smooth transition is made to the real-time adaptive adjustment of the global mission of the aircraft.

3. The layered architecture fault tolerance method of an aircraft flight control system according to claim 1, characterized in that: The simulated actuator fault described in step 3 is injected into the aircraft actuator fault. The actuator fault model expression is: （1） in, is the actuator fault signal, is the actuator fault gain factor, when When it is equal to 1, the actuator has no fault; when When , the actuator fails, and the smaller the value, the more serious the fault.

4. The layered architecture fault tolerance method of an aircraft flight control system according to claim 1, characterized in that: In step 4, for the actuator fault, a Kalman filter fault detection method based on the actuator control command signal difference is designed, which specifically includes: The fault detection method is verified using a quadrotor aircraft. The actuator fault signal is injected into the fourth motor. The difference between the second actuator control command signal and the fourth actuator control command signal is calculated and the absolute value is taken: （2） Control command signal for the second actuator and the fourth actuator control command signal The absolute value of the difference between the two, the state space equation of the actuator is: （3） （4） The absolute value of the controller output signal difference , is the state variable; A and C are unit matrices, is the process noise, with variance Q, is the measurement noise, the variance is R, k represents the time; the posterior estimate of the state variable of the Kalman filter is: （5） Equation (5) represents the Kalman filter estimation of the state variable x(k), is the new information of Kalman filter; （6） Among them, K(k) is the Kalman gain, P(k|k-1) is the corresponding prior state error covariance in the Kalman filter; the final detection link is Compared with the set threshold, if it is greater than the threshold, the output fault flag is 1, otherwise it is 0.

5. The layered architecture fault tolerance method of an aircraft flight control system according to claim 1, characterized in that: The actuator failure described in step 5 triggers the attitude controller and the altitude controller in the controller to reconfigure the control parameters, adjust the flight state of the aircraft, and feed the flight state back to the trajectory replanning unit layer to adjust the flight trajectory of the aircraft, specifically including: When an actuator failure is detected, the controller is reconfigured to stabilize pitch and roll at 0 radians and land at a low speed; since yaw is uncontrolled, the aircraft rotates around the vertical axis; the configured pitch-roll angle controller is: （7） （8） In formula (7), are the reference values ​​of pitch angle and roll angle, angle and is the aircraft attitude angle and the corresponding angular velocity state feedback value, is the angle outer loop proportional gain parameter, which is obtained by looking up the table according to the fault flag bit. is the outer ring angle information difference; in formula (8), is the inner loop proportional gain coefficient, is the inner loop integral gain coefficient, which is obtained by looking up the table according to the fault flag bit. Output signal to the pitch-roll controller to adjust the moment change of the aircraft.

6. The layered architecture fault tolerance method of an aircraft flight control system according to claim 1, characterized in that: Step 6 adjusts the flight mission by reconfiguring the top-level mission; the top-level mission is reconfigured to minimize the risk of mission failure and maximize the mission success rate, specifically including: （9） （10） Among them, S represents the flight mission execution strategy, including the decision variables of flight path, speed, and altitude. The mission success rate (S) is the probability of mission completion based on strategy S; the mission risk (S) is the probability of mission failure based on strategy S; is a weight parameter used to balance the trade-off between mission success rate and risk; g is a constraint function, which indicates the constraint conditions that strategy S must satisfy; the flight state includes the state information of the position, speed, and attitude of the aircraft; the redundant configuration refers to the remaining schedulable redundant resources of the aircraft after a failure occurs.

7. The layered architecture fault tolerance method of an aircraft flight control system according to claim 1, characterized in that: The simulated controller failure described in step seven is set through programming, and a preset signal mode is introduced into the enable signal of the flight control system in a simulated environment, thereby simulating the sudden failure encountered by the controller in actual operation; the jump of the enable signal triggers the fault detection mechanism of the flight control system, thereby activating the preset fault-tolerant control strategy.

8. The layered architecture fault tolerance method of an aircraft flight control system according to claim 1, characterized in that: The redundant controller voting logic described in step eight specifically includes: among the three redundant controllers, each controller is assigned a priority based on its performance and reliability factors; during normal operation, the high-priority controller plays a leading role, and when a fault occurs, the system switches to other controllers according to the priority order.

9. The layered architecture fault tolerance method of an aircraft flight control system according to claim 1, characterized in that: The verification of the redundant controller voting logic described in step nine is verified by simulating normal operating conditions and fault conditions of all three redundancies; the fault conditions include: injecting the first flight control fault into the flight control system to verify the output logic of the voting mechanism; injecting the first flight control and the second flight control faults to verify that the voting mechanism output is the third flight control output.

10. A hierarchical architecture fault tolerance device for an aircraft flight control system, characterized in that: It comprises a memory and one or more processors, wherein the memory stores executable code, and when the one or more processors execute the executable code, it is used to implement a layered architecture fault tolerance method for an aircraft flight control system according to any one of claims 1 to 9.

11. A computer-readable storage medium, characterized in that: A program is stored thereon, and when the program is executed by a processor, a layered architecture fault tolerance method for an aircraft flight control system according to any one of claims 1 to 9 is implemented.

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