CN115437259A - Airplane attitude fault-tolerant control system and control method for control surface fault - Google Patents

Abstract

The invention discloses an airplane attitude fault-tolerant control system and method for control plane faults, belongs to the technical field of aircraft control, and aims to solve the problem that the fault-tolerant control complexity of airplane attitudes is high in the prior art. The fault-tolerant control of the attitude of the airplane is realized by the modular design under the condition that multiple surfaces of the airplane have faults in the flying process. The self-adaptive multi-model observer module improves the efficiency of fault detection and isolation of the control surface and provides estimated state and deflection estimation of the control surface; the control surface behavior adjusting module determines a control surface behavior mode according to the fault; the nonlinear dynamic inverse fault-tolerant controller module uses a nonlinear dynamic inverse fault-tolerant controller to perform closed-loop attitude fault-tolerant control; the control distributor module combines the fault control plane deflection estimation, the control plane behavior mode and the control plane virtual input control to generate actual control plane control input information, and the problem of high complexity of airplane attitude fault-tolerant control is solved through the combination of the control distributor module and the control plane virtual input control.

Description

Aircraft attitude fault-tolerant control system and control method for rudder surface failure

technical field

The invention belongs to the technical field of aircraft control, in particular to an aircraft attitude fault-tolerant control system and control method for rudder surface failure.

Background technique

When the new generation of UAVs completes the assigned missions, it must not only be efficient, but also have better safety. Monitoring the health status of the aircraft rudder surface and taking corresponding actions according to the health status of the rudder surface will become a necessary part of the UAV. However, it is difficult for a small, low-cost UAV fault-tolerant control system to significantly increase the number of actuators and sensors to achieve safer flight. There are technical limitations of fault-tolerant control systems and methods. For example, when the rudder surface is stuck at a non-zero position, the output of the filter will be deviated, resulting in a decrease in detection accuracy; control redistribution requires redesign of the controller, This greatly increases the complexity of fault-tolerant control; the linear controller needs to perform variable parameter processing to cover the entire operating range of the aircraft.

Contents of the invention

In order to overcome the shortcomings of the above-mentioned prior art, the object of the present invention is to provide an aircraft attitude fault-tolerant control system and control method for rudder surface failure, aiming to solve the defective technology of high complexity in the fault-tolerant control of aircraft attitude in the prior art question.

In order to achieve the above object, the present invention adopts the following technical solutions to achieve:

In a first aspect, the present invention provides a method for aircraft attitude fault-tolerant control facing rudder surface failure, comprising the following steps:

Continuously receiving the aircraft attitude information of the aircraft under the condition of rudder surface failure, and inputting the aircraft attitude information as the desired attitude to the nonlinear dynamic inverse fault-tolerant controller module, the nonlinear dynamic inverse fault-tolerant controller module calculates the virtual control input of the rudder surface, and Throttle control input information;

The control allocator module receives the virtual control input information issued by the nonlinear dynamic inverse fault-tolerant controller module, the rudder surface behavior mode issued by the rudder surface behavior adjustment module and the deflection estimation of the rudder surface, and releases the actual control input information of each rudder surface, In the self-adaptive multi-model observer module, calculate the estimated attitude of each rudder surface, the rudder deflection estimate of each rudder surface, and the conditional probability of failure;

The rudder surface behavior adjustment module receives the conditional probability of rudder surface failures issued by the adaptive multi-model observer module and the rudder surface deflection estimates of each rudder surface, and calculates the new rudder surface deflection limit, according to the current aircraft rudder surface health status Adjust the behavior mode of the rudder surface;

The control allocator module receives the new rudder surface deflection limit, and calculates the actual control input information of each rudder surface according to the adjusted behavior mode of the rudder surface, and at the same time inputs the actual rudder surface control input information to the adaptive multi-model observer module.

In a second aspect, the present invention provides an aircraft attitude fault-tolerant control system facing rudder surface failure, including:

The nonlinear dynamic inverse fault-tolerant controller module, the input of the nonlinear dynamic inverse fault-tolerant controller module is connected with the adaptive multi-model observer module, which is used to continuously receive the aircraft attitude information, and calculate the virtual control input of the rudder surface, and the throttle control input information;

A control allocator module, the input of the control allocator module is connected to the nonlinear dynamic inverse fault-tolerant controller module and the rudder surface behavior adjustment module, and is used to receive the virtual control input information issued by the nonlinear dynamic inverse fault-tolerant controller module, And the rudder surface behavior pattern issued by the rudder surface behavior adjustment module and the deflection estimator of the rudder surface; the output end of the control distributor module is connected to the self-adaptive multi-model observer module, which is used to calculate the actual control input of each rudder surface information, and simultaneously input actual rudder surface control input information to the adaptive multi-model observer module;

The rudder surface behavior adjustment module, the input end of the rudder surface behavior adjustment module is connected with the adaptive multi-model observer module, and is used to receive the conditional probability of the rudder surface failure issued by the adaptive multi-model observer module, and each The rudder deflection estimate for the rudder surface and calculates the new rudder deflection limit.

In a third aspect, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and operable on the processor. When the processor executes the computer program, the above-mentioned method steps.

In a fourth aspect, the present invention provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

Compared with the prior art, the present invention has the following beneficial effects:

An aircraft attitude fault-tolerant control system and control method for rudder surface faults proposed by the present invention adopts an adaptive multi-model observer module to realize monitoring and isolation of rudder surface faults, which can work on the entire flight envelope and can cope with Jamming and swing failures at any position on the rudder surface. Model the failure of the rudder surface, estimate the conditional probability of possible failure, and isolate the failure when the probability exceeds the warning value. The control allocator module is combined with the nonlinear dynamic inverse fault-tolerant controller module to compensate the failure of the rudder surface, adjust the attitude of the UAV and keep it stable. The nonlinear dynamic inverse fault-tolerant controller module can well deal with the nonlinear UAV system and its wide range of working attitudes. The rudder surface behavior adjustment module uses the failure condition probability information of each rudder surface and the deflection of each rudder surface The estimator is used to determine the rudder surface behavior model that should be used to compensate the attitude effect caused by the faulty rudder surface, which solves the problem of high complexity of aircraft attitude fault-tolerant control.

Furthermore, all rudder surfaces can operate independently, the ailerons or elevators can move up and down independently or together in one direction, the ailerons can generate pitching moments, and the elevators can generate rolling moments.

Furthermore, mode 1 is left aileron failure, mode 2 is the case of right aileron failure, the healthy aileron is used to generate rolling moment to stabilize the attitude of the aircraft, and the elevator is used to correct the undesirable aileron produced by the faulty aileron. pitching torque, so as not to affect the pitching attitude of the aircraft.

Furthermore, when mode 3 is left elevator failure and mode 4 is right elevator failure, firstly, in order to generate the desired pitching moment, calculate the deflection of the other elevator, and then use the differential aileron to correct the rolling torque to Stabilize the attitude of the aircraft.

Furthermore, in mode 5, when two rudder surfaces fail at the same time, if two rudder surfaces of different types fail, the attitude of the aircraft can still be compensated, but if the two elevators are stuck up or down at the same time, the auxiliary It is impossible for the wings to compensate for the resulting pitching motion. In this case, the subsequent emergency procedures of mode 6 and mode 7 will be entered. Mode 6 is three rudder surface failures at the same time, and mode 7 is all rudder surface failures. The occurrence of these two modes means that the aircraft is no longer under control and the engine is turned off and the parachute is opened.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

FIG. 1 is a schematic diagram of the composition and structure of the aircraft attitude fault-tolerant control system facing rudder surface failures according to the present invention.

Fig. 2 is a flow chart of the aircraft attitude error-tolerant control method facing rudder surface failure in the present invention.

Fig. 3 is the rudder surface fault modeling of the rudder surface fault-oriented aircraft attitude fault-tolerant control system of the present invention.

Fig. 4 is a working flow diagram of the self-adaptive multi-model observer module of the present invention.

Fig. 5 is a working flowchart of the nonlinear dynamic inverse fault-tolerant controller module of the present invention.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations.

Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

It should be noted that like numerals and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "horizontal", "inside" etc. is based on the orientation or positional relationship shown in the drawings , or the orientation or positional relationship that the product of the invention is usually placed in use is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed in a specific orientation and operation, and therefore should not be construed as limiting the invention. In addition, the terms "first", "second", etc. are only used for distinguishing descriptions, and should not be construed as indicating or implying relative importance.

In addition, when the term "horizontal" appears, it does not mean that the part is required to be absolutely horizontal, but may be slightly inclined. For example, "horizontal" only means that its direction is more horizontal than "vertical", and it does not mean that the structure must be completely horizontal, but can be slightly inclined.

In the description of the embodiments of the present invention, it should also be noted that, unless otherwise specified and limited, the terms "setting", "installation", "connection" and "connection" should be interpreted in a broad sense, for example, It can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In order to overcome the technical limitations of the fault-tolerant control system and method, for example: when the rudder surface is stuck at a non-zero position, the output of the filter will be deviated, resulting in a decrease in the accuracy of detection; control redistribution requires redesign of the controller , which greatly increases the complexity of fault-tolerant control; the linear controller needs to perform variable parameter processing to cover the entire operating range of the aircraft. The present invention provides a fault-tolerant control system and control method for rudder surface faults, wherein the self-adaptive multi-model observer module utilizes the nonlinear online estimation of the deflection amount when the rudder surface fails, and successfully detects the stuck or swaying fault of the rudder surface , and reduces the number of required filters. Model the failure of the rudder surface, estimate the conditional probability of possible failure, and isolate the failure when the probability exceeds the warning value. The Control Distributor module will recalculate the desired dynamic parameters needed to stabilize the attitude in the event of multifaceted failure. The nonlinear dynamic inverse fault-tolerant controller module can well deal with the nonlinear UAV system and its wide range of working attitudes.

An aircraft attitude fault-tolerant control system for rudder surface faults, as shown in Figure 1, includes a nonlinear dynamic inverse fault-tolerant controller module, a control distributor module, an adaptive multi-model observer module, and a rudder surface behavior adjustment module.

The nonlinear dynamic inverse fault-tolerant controller module continuously receives aircraft attitude information, and calculates the virtual control input of the rudder surface, and the throttle control input information;

The control allocator module receives the virtual control input information issued by the nonlinear dynamic inverse fault-tolerant controller module, and receives the rudder surface behavior pattern issued by the rudder surface behavior adjustment module and the deflection estimate of the rudder surface; the control distribution The controller module calculates actual control input information of each rudder surface, and simultaneously inputs the actual rudder surface control input information to the adaptive multi-model observer module;

The rudder surface behavior adjustment module receives the conditional probability of rudder surface failures issued by the adaptive multi-model observer module and the rudder surface deflection estimates of each rudder surface, and calculates a new rudder surface deflection limit.

specific:

Non-linear dynamic inverse fault-tolerant controller module: The nonlinear dynamic inverse fault-tolerant controller module is installed in the onboard computer, subscribes to the expected attitude information released by the adaptive multi-model observer module, and subscribes to the flight control task module and publishes it inside the aircraft Expected attitude information of the communication module. The nonlinear dynamic inverse fault-tolerant controller is used, combined with the subscribed reconstructed attitude information and expected attitude information, to perform closed-loop control, and obtain safe and stable aircraft rudder surface virtual control input information and throttle control input information.

Adaptive multi-model observer module: installed in the onboard computer, through the internal communication module of the aircraft, subscribes to the information from the traditional sensors necessary for the aircraft, that is, the attitude information of the aircraft. It also needs to subscribe to the desired attitude information from the mission module of the flight control system. This module is composed of multiple parallel filters, each filter corresponds to a specific rudder surface fault, and calculates the estimated attitude and the deflection of the rudder surface in the case of the fault. Then, according to the residual error of each filter and the error covariance matrix, the conditional probability of the estimated rudder surface failure is calculated. The estimated attitude value is used to calculate the reconstructed attitude information, and the attitude reconstruction is performed to isolate the faulty rudder surface, which is convenient for the nonlinear dynamic inverse fault-tolerant controller module to perform fault-tolerant control.

Control surface behavior adjustment module: fixed-wing aircraft configurations generally have five control surfaces: a left aileron, a right aileron, a left elevator, a right elevator, and a rudder. All control surfaces are independently operable, which means that the ailerons or elevators can move up and down independently or together in one direction. Thus, the ailerons create a pitching moment and the elevators create a rolling moment.

The rudder surface behavior adjustment module subscribes to the failure condition probability information of each rudder surface and the deflection estimator of each rudder surface issued by the self-adaptive multi-model observer module, and uses these information to determine the rudder surface behavior model that should be used to compensate Attitude effects due to faulty rudder surfaces.

Control allocator module: The control allocator module receives the virtual control input information released by the nonlinear dynamic inverse fault-tolerant controller module and the rudder surface deflection estimate after the rudder surface behavior processing released by the rudder surface behavior adjustment module, and uses these information to combine The new rudder surface deflection limit issued by the rudder surface behavior adjustment module generates the actual rudder surface control input information.

A kind of aircraft attitude fault-tolerant control method facing the rudder surface fault that the present invention proposes, as shown in Figure 2, comprises the following steps:

Continuously receiving the aircraft attitude information of the aircraft under the condition of rudder surface failure, and inputting the aircraft attitude information as the desired attitude to the nonlinear dynamic inverse fault-tolerant controller module, the nonlinear dynamic inverse fault-tolerant controller module calculates the virtual control input of the rudder surface, and Throttle control input information;

The control allocator module receives the virtual control input information issued by the nonlinear dynamic inverse fault-tolerant controller module, the rudder surface behavior mode issued by the rudder surface behavior adjustment module and the deflection estimation of the rudder surface, and releases the actual control input information of each rudder surface, In the self-adaptive multi-model observer module, calculate the estimated attitude of each rudder surface, the rudder deflection estimate of each rudder surface, and the conditional probability of failure;

The rudder surface behavior adjustment module receives the conditional probability of rudder surface failures issued by the adaptive multi-model observer module and the rudder surface deflection estimates of each rudder surface, and calculates the new rudder surface deflection limit, according to the current aircraft rudder surface health status Adjust the behavior mode of the rudder surface;

The control allocator module receives the new rudder surface deflection limit, and calculates the actual control input information of each rudder surface according to the adjusted behavior mode of the rudder surface, and at the same time inputs the actual rudder surface control input information to the adaptive multi-model observer module.

specific:

Step 1. Model the rudder surface failure. The rudder surface of the UAV is stuck or swings at an unknown position. The failure can be regarded as the loss of the expected input rudder angle control signal, which is caused by a wrong rudder angle control signal. Replaced, resulting in the instability of aircraft flight attitude control. Refer to Figure 3 for modeling of rudder surface failure.

In order to make the adaptive multi-model observer module applicable to all flight attitudes and flight states, and to isolate the actuator from stuck or swing faults, it will continue to receive the attitude information of the aircraft, which in the present invention is the three-axis angular velocity of the aircraft , and the angle of attack and heading angle.

Step 2: Combining the rudder surface control input information released by the control allocator module, use sufficient filters to calculate the estimated attitude of each rudder surface in the event of failure, the estimated amount of rudder deflection of each rudder surface, and the conditional probability of failure. The number of filters corresponds to the type of fault being detected. Then use the error state covariance matrix and filter residuals to calculate the conditional probability of the rudder surface failure. If the probability of failure exceeds the warning value, mark it. Then use the conditional probability to weight the estimated state of each rudder surface failure, and get The final total estimated state. Referring to FIG. 4, it is a working flowchart of the adaptive multi-model observer module.

The expression of the adaptive multi-model observer module is shown in formula (1):

y _i = F _i ( z _i ( k ), δ _i ( k ))+ w _k

，集合变量z _i (k)代替

，

。

, the set variable z _i ( k ) replaces

,

.

为总估计姿态，z _i (k)为集合变量。 Among them, k is the discrete current moment, i is the fault, x _k is the aircraft attitude at the current moment, u _k is the expected input of the mission module, x _i ( k ) is the estimated attitude based on the filter output of fault i , δ _i ( k ) is the deflection estimation of the rudder surface, F _i is the filter based on the fault i , p _i ( k ) is the conditional probability of the fault, Σ _k is the error covariance matrix, y _i is the observation output, w _k is the random noise, ri ( k ₎ is the filter residual,

is the total estimated pose, z _i ( k ) is a set variable.

Step 3, the rudder surface behavior adjustment module receives the conditional probability of rudder surface failures issued by the adaptive multi-model observer module and the rudder surface deflection estimates of each rudder surface. A new rudder deflection limit is then calculated. The adaptive multi-model observer module has marked and isolated the faulty rudder surface, and the rudder surface behavior adjustment module can adjust the rudder surface behavior mode according to the current aircraft rudder surface health status. The following examples of modes are given.

Mode 1 to Mode 4 are single rudder surface failure modes. Mode 1 is left aileron failure, mode 2 is right aileron failure. in this mode. The healthy ailerons are used to generate rolling moment to stabilize the aircraft attitude, and the elevator is used to correct the undesired pitching torque produced by the faulty ailerons, so as not to affect the pitching attitude of the aircraft.

Mode 3 is left elevator failure and mode 4 is right elevator failure. In this mode, the faulty elevator will cause a rolling motion if the healthy elevator does not deflect by the same angle as the faulty elevator. Allowing the healthy elevator to deflect the same amount to compensate for this undesired roll motion also produces an undesired pitching torque. And it is very difficult to compensate for this undesired pitching motion with only the control of the ailerons. The proposed solution is to first calculate the deflection of the other elevator in order to produce the desired pitching moment. Then, the differential aileron is used to correct the roll torque to stabilize the attitude of the aircraft.

Mode 5 is two rudder surfaces failure at the same time. If two rudder surfaces of different types fail, the attitude of the aircraft can still be compensated by the above method, but if two elevators are stuck up or down at the same time, the ailerons cannot compensate the resulting pitching motion. In this case, the subsequent emergency procedures of mode 6 and mode 7 will be entered.

Mode 6 is failure of three control surfaces at the same time, and mode 7 is failure of all control surfaces. The emergence of these two modes means that the aircraft is no longer under control, and the emergency plan is to turn off the engine and open the parachute.

Step 4, the nonlinear dynamic inverse fault-tolerant controller module will use the estimated aircraft attitude released by the adaptive multi-model observer module and combine the expected attitude information given by the mission module, and then calculate the error between the current state and the expected attitude, and linearize Afterwards, the attitude generated by the aircraft model is used to calculate the error again, and the error is combined with the inverse model to calculate the virtual control input of the rudder surface and the input information of the throttle control, as shown in Figure 5.

The expression of the nonlinear dynamic inverse fault-tolerant controller module is shown in formula (2):

（2）

(2)

Among them, σ _i ( k ) is the virtual control input information of the rudder surface, G ^-1 ( x ) is the dynamic inverse model, L ( x ) is the linearization model, k _p is the proportional coefficient _, and ki is the integral coefficient.

Step 5, the control allocator module receives the virtual control input information issued by the nonlinear dynamic inverse fault-tolerant controller module, the behavior mode of the steering surface issued by the behavior adjustment module of the steering surface, and the deflection estimation of the steering surface. Then calculate the actual control input information of each rudder surface, and at the same time input the actual rudder surface control input information to the adaptive multi-model observer module to complete the closed-loop detection and control.

A control system for an aircraft attitude fault-tolerant control method for rudder surface failures proposed by the present invention, comprising:

A nonlinear dynamic inverse fault-tolerant controller module, the nonlinear dynamic inverse fault-tolerant controller module is used to continuously receive the aircraft attitude information of the aircraft in the case of a rudder surface failure, and input the aircraft attitude information as a desired attitude to the nonlinear dynamic inverse fault-tolerant The controller module, the nonlinear dynamic inverse fault-tolerant controller module calculates the virtual control input of the rudder surface, and the throttle control input information;

The receiving and estimating module of the rudder surface information, the receiving and estimating module of the rudder surface information is used to control the distributor module to receive the virtual control input information issued by the nonlinear dynamic inverse fault-tolerant controller module, and the rudder surface behavior adjustment module issued by the control surface Behavior mode and deflection estimates of rudder surfaces, and publish the actual control input information of each rudder surface, and calculate the estimated attitude of each rudder surface failure, the rudder surface deflection estimation of each rudder surface, and The conditional probability of the failure occurring;

The behavior mode adjustment module of the rudder surface, the behavior mode adjustment module of the rudder surface is used for the rudder surface behavior adjustment module to receive the conditional probability of the rudder surface failure issued by the self-adaptive multi-model observer module and the rudder surface deflection estimation of each rudder surface and calculate the new rudder surface deflection limit, and adjust the behavior mode of the rudder surface according to the current aircraft rudder surface health;

A control allocator module, the control allocator module is used to receive the new rudder surface deflection limit, and calculate the actual control input information of each rudder surface according to the adjusted behavior mode of the rudder surface, and at the same time input the actual rudder surface control input The information is input to the adaptive multi-model observer module.

A terminal device provided by an embodiment of the present invention includes: a processor, a memory, and a computer program stored in the memory and operable on the processor. When the processor executes the computer program, the steps in the foregoing method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of the modules/units in the above device embodiments are implemented.

The computer program may be divided into one or more modules/units, which are stored in the memory and executed by the processor to implement the present invention.

The terminal device may be computing devices such as desktop computers, notebooks, palmtop computers, and cloud servers. The terminal device may include, but not limited to, a processor and a memory.

The processor can be a central processing unit (Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field- ProgrammableGateArray, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

The memory can be used to store the computer programs and/or modules, and the processor implements the terminal by running or executing the computer programs and/or modules stored in the memory and calling the data stored in the memory various functions of the device.

If the integrated modules/units of the terminal equipment are realized in the form of software function units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the present invention realizes all or part of the processes in the methods of the above embodiments, and can also be completed by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer When the program is executed by the processor, the steps in the above-mentioned various method embodiments can be realized. Wherein, the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, removable hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM, Read-OnlyMemory), Random access memory (RAM, RandomAccessMemory), electrical carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, computer-readable media Excludes electrical carrier signals and telecommunication signals.

An aircraft attitude fault-tolerant control system for rudder surface failure proposed by the present invention has the following key points: 1) The fault-tolerant control system must have certain robustness, and can cope with the uncertainty of the aircraft model and external interference when a fault occurs ;2) The supporting fault detection and isolation system can monitor the state of the rudder surface better and more efficiently, and assist the fault-tolerant control system to adjust the UAV attitude; 3) The UAV mission module should take the failure of the rudder surface into consideration, In the case of reduced flight performance, choose a gentle flight attitude for flight missions.

The invention discloses an aircraft attitude fault-tolerant control method facing rudder surface faults. The method adopts an adaptive multi-model observer module to realize monitoring and isolation of rudder surface faults. It can work on the entire flight envelope and can deal with rudder surface faults. Stuck and swing faults at any position on the surface. The control allocator module is combined with the nonlinear dynamic inverse fault-tolerant controller module to compensate the failure of the rudder surface, adjust the attitude of the UAV and keep it stable.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. An aircraft attitude fault-tolerant control method for control surface faults is characterized by comprising the following steps of:

continuously receiving airplane attitude information of an airplane under the condition of a fault of a control surface, and inputting the airplane attitude information serving as an expected attitude into a nonlinear dynamic inverse fault-tolerant controller module, wherein the nonlinear dynamic inverse fault-tolerant controller module calculates virtual control input of the control surface and throttle control input information;

the control distributor module receives virtual control input information issued by the nonlinear dynamic inverse fault-tolerant controller module, control surface behavior modes issued by the control surface behavior adjusting module and deflection estimators of the control surfaces, issues actual control input information of each control surface, and calculates estimated postures of each control surface under the condition of faults, deflection estimators of the control surfaces of each control surface and conditional probability of fault occurrence in the self-adaptive multi-model observer module;

the control surface behavior adjusting module receives the conditional probability of control surface fault occurrence and the control surface deflection estimators of all the control surfaces, which are issued by the self-adaptive multi-model observer module, calculates new control surface deflection limits, and adjusts the behavior mode of the control surfaces according to the current control surface health condition of the airplane;

and the control distributor module receives the new deflection limit of the control surface, calculates the actual control surface control input information according to the adjusted behavior mode of the control surface, and inputs the actual control surface control input information to the self-adaptive multi-model observer module.

2. The control surface fault-tolerant control method for aircraft attitude of claim 1, characterized in that the calculation of the estimated attitude under each control surface fault is as follows:

wherein,

in order to estimate the attitude as a whole,kin order to be a discrete current time instant,iin order to be a fault,x _i (k) Based on failureiThe estimated pose of the output of the filter of (2),p _i (k) Is a conditional probability of failure, and

，λ _i (k) Is a conditional probability coefficient, and

，

to solve for the fixed formula part of the conditional probability,r _i (k) Is a filter residual, an

，TIs the length of time between the two moments in time,y _i to observe the output, andy _i =F _i (z _i (k),δ _i (k))+w _k ，F _i in order for the filter to be fault-based,z _i (k) Is a collection of variables, and

，δ _i (k) For the estimation of the amount of deflection of the control surface,w _k in order to be uncertain and the amount of error,u _k as desired input to the task module, sigma _k Is an error covariance matrix, and

and E is a mean value function,x _k the attitude quantity of the airplane at the current moment.

3. The fault-tolerant control method for the attitude of an aircraft facing a control surface fault according to claim 2, characterized in that the virtual control input of the control surface is calculated as follows:

wherein,σ _i (k) Information is input for the virtual control of the control surface,G ^-1 (x) In order to be a dynamic inverse model,L(x) In order to linearize the model, the model is,k _p is a coefficient of proportionality that is,k _i is an integral coefficient.

4. An aircraft attitude fault-tolerant control system for control plane faults is characterized by comprising:

the nonlinear dynamic inverse fault-tolerant controller module is connected with the input of the nonlinear dynamic inverse fault-tolerant controller module and the adaptive multi-model observer module, and is used for continuously receiving the attitude information of the airplane and calculating the virtual control input of a control surface and the control input information of an accelerator;

the control distributor module is connected with the nonlinear dynamic inverse fault-tolerant controller module and the control surface behavior adjusting module through the input of the control distributor module, and is used for receiving the virtual control input information issued by the nonlinear dynamic inverse fault-tolerant controller module, the control surface behavior mode issued by the control surface behavior adjusting module and the deflection estimator of the control surface; the output end of the control distributor module is connected with the self-adaptive multi-model observer module and is used for calculating actual control surface control input information and inputting the actual control surface control input information to the self-adaptive multi-model observer module;

and the input end of the control surface behavior adjusting module is connected with the self-adaptive multi-model observer module and is used for receiving the conditional probability of control surface fault occurrence issued by the self-adaptive multi-model observer module and the control surface deflection estimator of each control surface and calculating new control surface deflection limit.

5. The control surface fault-tolerant aircraft attitude control system according to claim 4, further comprising an estimated attitude calculation module and a virtual control input calculation module;

the estimation attitude calculation module is used for calculating the estimation attitude under the condition of each control surface fault, and specifically comprises the following steps:

wherein,

in order to estimate the attitude as a whole,kin order to be a discrete current time instant,iin order to be a fault,x _i (k) Based on failureiThe estimated pose of the output of the filter of (2),p _i (k) Is a conditional probability of failure, and

，λ _i (k) Is a conditional probability coefficient, and

，

to solve for the fixed formula part of the conditional probability,r _i (k) Is the filter residual, an

，TIs the length of time between the two moments in time,y _i to observe the output, andy _i =F _i (z _i (k),δ _i (k))+w _k ，F _i in order to be a fault-based filter,z _i (k) Is a collection of variables, and

，δ _i (k) For the estimation of the amount of deflection of the control surface,w _k in order to be uncertain and the amount of error,u _k as desired input to the task module, sigma _k Is an error covariance matrix, and

and E is a mean value function,x _k the attitude quantity of the airplane at the current moment;

the virtual control input calculation module is used for calculating virtual control input of the control surface, and specifically comprises the following steps:

wherein,σ _i (k) Information is input for the control surface virtual control,G ^-1 (x) In order to be a dynamic inverse model,L(x) In order to linearize the model, the model is,k _p is a coefficient of proportionality that is,k _i is an integration coefficient.

6. The control plane fault-tolerant control system for aircraft attitude of claim 4, wherein the adaptive multi-model observer module is loaded in an on-board computer and subscribes to information from conventional sensors necessary for the aircraft and expected attitude information through an aircraft internal communication module.

7. The aircraft attitude fault-tolerant control system for rudder surface faults according to claim 4, wherein the rudder surface behavior adjusting module subscribes fault condition probability information of each rudder surface issued by the adaptive multi-model observer module and a deflection estimator of each rudder surface, and determines a rudder surface behavior model which should be used by using the fault condition probability information of each rudder surface and the deflection estimator of each rudder surface to compensate attitude influence caused by the faulted rudder surface;

the control surface behavior adjustment module issues the required control surface behavior modes comprising a mode 1, a mode 2, a mode 3, a mode 4, a mode 5, a mode 6 and a mode 7;

the modes 1 to 4 are single control surface fault modes: a mode 1 is a left aileron fault, a mode 2 is a right aileron fault, a mode 3 is a left elevator fault, and a mode 4 is a right elevator fault;

the mode 5 is that two control surface faults occur simultaneously;

the mode 6 is that three control surface faults occur simultaneously;

the mode 7 is that all control surfaces are in failure.

8. The control surface fault-tolerant control system for airplane attitude of aircraft according to claim 4, characterized in that the nonlinear dynamic inverse fault-tolerant controller module is loaded in an on-board computer and subscribes to expected attitude information and estimated state information issued by the adaptive multi-model observer module; and performing closed-loop control by using a nonlinear dynamic inverse fault-tolerant controller module and combining the expected attitude information and the estimated state information to obtain virtual control input information of the control surface of the airplane and control input information of the accelerator.

9. A computer arrangement comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the method according to any of claims 1-3 when executing the computer program.

10. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1-3.

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