CN103324202A - Fault tolerance flight control system and method based on control surface faults - Google Patents

Abstract

The invention provides a fault tolerance flight control system based on control surface faults. The fault tolerance flight control system based on control surface faults comprises a sensor, a fault detection and insulation module, a monitor module, a controller module and a control distribution module, wherein the sensor is arranged at the corresponding part of an airplane body; the fault detection and insulation module transmits an airplane state parameter estimation value to the controller module, judges the health situation of control surfaces and the types of the generated faults, calculates the probability of the type of faults on each control surface, transmits the probability to the monitor module, detects the deviation angle of each control surface to obtain a deviation angle estimation value of each control surface, and transmits the deviation angle estimation value of each control surface to the monitor module; the monitor module determines the faults positions of the control surfaces, and provides a control distribution basis for the control distribution module; the controller module generates a virtual control command vector, and transmits the vector to the control distribution module as virtual control input; the control distribution module calculates the control surface deviation angle vector of each control surface deviation angle given value. When the control surface faults occur, based on fault detection and diagnosis results, the fault tolerance flight control system based on control surface faults provided by the invention compensates faults, thereby guaranteeing the continuous and safe flight of an airplane.

Description

Fault-tolerant flight control system and method based on control surface fault

Technical Field

The invention belongs to the technical field of airplane fault-tolerant control, and particularly relates to a fault-tolerant flight control system and method based on control surface faults.

Background

The fault-tolerant flight control system is a flight control system with redundancy capability, and when some parts of an airplane are in failure or even fail, the fault-tolerant flight control system can still safely complete control tasks according to the original performance index or slightly reduced performance index (within an acceptable range). Common methods of fault tolerant flight control system design include: multi-model switching and setting, multi-model adaptive control, model reference adaptive control, interactive multi-model, control distribution, sliding mode control, model prediction control, characteristic structure configuration, model reference and dynamic inverse, neural network and the like. The multi-model switching and setting method has the advantages of high speed and stability when the actually-occurring faults are consistent with the predefined faults, but certain defects exist if undefined faults or multi-fault and structural faults occur. The advantage of the multi-model adaptive control method is that it can respond quickly when parameters change, thus providing faster fault isolation than other methods that do not have a multi-model structure, but this method results in an increased amount of computation required for each filter and produces less than satisfactory results when insufficient compliance with predefined fault assumptions is encountered. The model reference adaptive control method is used for the situation that damage faults or structural faults need to be subjected to fault tolerance, and aims to enable the output of a system to track the output of a reference model.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides a fault-tolerant flight control system and method based on control surface faults. When the control surface has faults, the faults are compensated based on the results of fault detection and diagnosis, so that the airplane can continuously and safely fly. The technical scheme adopted by the invention is as follows:

a fault tolerant flight control system based on control surface faults, comprising:

the sensors are arranged at corresponding positions of the airplane body: outputting the measured parameter value;

fault detection and isolation module: the estimated value of the flight state parameter of the airplane is obtained by detecting the output of a sensor arranged at the corresponding position of the airplane body

The estimated value of the flight state parameter

Including roll, pitch, yaw, angle of attack, and sideslip of the aircraft; will fly awayLine state parameter estimation

Transmitting to the controller module; simultaneously estimating the value according to the flight state parameter

Judging the health condition of the control surface and the type of the fault; calculating the probability of the fault of each control surface, and calculating the probability calculation value p of the fault of each control surface₁～p_iTransmitting the data to a monitor module, and detecting the deflection angle of each control surface through a control surface sensor to obtain the estimated value of the deflection angle of each control surface

And estimating the deflection angle of each control surfaceTransmitting to the monitor module; i denotes a total of i control surfaces, i>1；

A monitor module: based on the result sent by the fault detection and isolation module, the position of the control surface fault is determined, and a basis for control distribution is provided for the control distribution module, and the method comprises the following steps:

a) resetting the upper/lower limits of the control surfaces 1-i according to the type of the fault of the control surfaces, and sending the new deflection limiting parameters of the control surfaces to a control distribution module;

b) for monitoring the probability p of failure of each control surface transmitted by the failure detection and isolation module₁～p_iAnd an estimated value of deflection angleIf the probability of the fault of a certain control surface exceeds a set threshold value within a certain detection time, the monitor module determines that the control surface has the fault, decides which corresponding control surface can be activated specifically to compensate the fault, and calculates the control for compensationSignalSuperimposing the control signal on the respective control surface

If the control surface is confirmed to have a locking fault, the monitor module estimates a value according to the deflection angle

Determining the locking angle of the fault control surface and estimating the deflection angle

Transmitting to a control distribution module;

c) selecting a control surface actuating mode corresponding to the fault according to the fault state of the control surface, and simultaneously sending the serial number of the actuating mode to a control distribution module;

a controller module: according to given state reference input Ref and the estimated value of the flight state parameter of the airplane sent by the fault detection and isolation module

To calculate a virtual control command vector C_vAnd a virtual control command vector C_vTransmitting the data to a control distribution module as virtual control input; generating a control command of the thrust of the aircraft engine;

a control distribution module: according to the control plane actuation mode and the control plane deflection limit sent by the monitor module and the virtual control input C sent by the controller module_vTo calculate a control surface deflection angle vector delta containing a given value of each control surface deflection angle_c；

A plurality of control surfaces for controlling the flight state of the aircraft: when there is no failure in the event of a failure,

each rudder surface is according to the rudderPlane deflection angle vector δ_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the normal flight of the airplane; when a fault occurs in a certain control surface, the control surface corresponding to the fault is activated toDeflecting, the other control surface still uses the deflection angle vector delta of the control surface_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the airplane to continuously keep normal flight.

Further, the sensors arranged at the corresponding positions of the airplane body comprise: the gyroscope is arranged in an inertial navigation system of the airplane body and is used for measuring and outputting the roll rate, the pitch rate and the yaw rate of the airplane; and the attack angle and sideslip angle sensor is arranged on the side surface of the aircraft nose and is used for measuring and outputting the attack angle and the sideslip angle of the aircraft.

A fault-tolerant flight control method based on control surface faults comprises the following steps:

s1, transmitting measured parameter values to a fault detection and isolation module by sensors arranged at corresponding positions of an airplane body;

s2, the fault detection and isolation module obtains the flight state parameter estimation value of the airplane by detecting the output of a sensor arranged at the corresponding position of the airplane body

Judging the health condition of the control surface and the type of the fault; calculating the probability of the fault of each control surface, and calculating the probability calculation value p of the fault of each control surface₁～p_iTransmitting the data to a monitor module, and detecting the deflection angle of each control surface through a control surface sensor to obtain the estimated value of the deflection angle of each control surface

And estimating the deflection angle of each control surface

Transmitting to the monitor module; estimating flight state parameters

Transmitting to the controller module;

s3, the monitor module determines the position of the fault of the control surface based on the result sent by the fault detection and isolation module, and provides a control distribution basis for the control distribution module, wherein the basis comprises control surface deflection limiting parameters and a control surface actuation mode;

s4, the controller module inputs Ref according to the given state reference and the estimated value of the flight state parameter of the airplane sent by the fault detection and isolation module

To calculate a virtual control command vector C_vAnd a virtual control command vector C_vTransmitting the data to a control distribution module as virtual control input; generating a control command of the thrust of the aircraft engine;

s5, the control distribution module controls the control plane actuation mode, the control plane deflection limit and the virtual control input C sent by the controller module according to the control plane actuation mode and the control plane deflection limit provided by the monitor module_vTo calculate a control surface deflection angle vector delta containing a given value of each control surface deflection angle_cThereby obtaining the given value of the deflection angle of each control surface.

Further, the step S3 specifically includes:

s3-1, the monitor module resets the upper/lower limits of the control surfaces 1 to i according to the type of the fault of the control surfaces and sends the new deflection limiting parameters of the control surfaces to the control distribution module;

s3-2, the monitor module monitors the probability p of each control surface fault sent by the fault detection and isolation module₁～p_iAnd an estimated value of deflection angle

If the probability of the fault of a certain control surface exceeds a set threshold value within a certain detection time, the monitor module determines that the control surface has the fault, decides which corresponding control surface can be activated specifically to compensate the fault, and calculates a control signal for compensation

Superimposing the control signal on the respective control surface

If the control surface is confirmed to have a locking fault, the monitor module estimates a value according to the deflection angle

Determining the locking angle of the fault control surface and estimating the deflection angle

Transmitting to a control distribution module;

s3-3, the monitor module selects a control surface actuating mode corresponding to the fault according to the fault state of the control surface, and sends the number of the actuating mode to the control distribution module.

Further, after step S5, the method further includes:

s6, when no fault occurs, controlling each control surface to perform vector delta according to control surface deflection angle_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the normal flight of the airplane; when a certain control surface has a fault, the corresponding activated control surface of the fault is controlled toDeflecting, the other control surface still uses the deflection angle vector delta of the control surface_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the airplane to continuously keep normal flight.

When the airplane control surface has a fault, according to the method disclosed by the invention, the deflection angle of each control surface can be obtained through simple calculation, so that the control is redistributed. The method does not need to adjust a complex control law, thereby greatly reducing the design difficulty of the control system. Specifically, the invention mainly has the following three advantages:

(1) the control surface restriction (such as control surface position restriction) is also taken as a consideration factor, and if a certain control surface reaches a saturation state, the deflection angles for generating the required control effect can be obtained by the other control surfaces through simple calculation.

(2) The redundancy of a control surface system is fully utilized, and the safe flight of the airplane can be still kept after the control surface fails.

(3) In the case of a fault of the control surface, the control distribution module can automatically compensate the fault by a method of redistributing the control proportion without redefining the control law.

Drawings

Fig. 1 is an aircraft configuration of the present invention.

FIG. 2 is a schematic diagram of a fault tolerant flight control system of the present invention.

Detailed Description

The invention is further illustrated by the following specific figures and examples.

As shown in fig. 1, the aircraft has five major control surfaces, a left aileron, a right aileron, a left elevator, a right elevator, and a rudder. All control surfaces are completely independent, i.e. the ailerons (or elevators) can be deflected independently upwards, downwards or both ailerons (or both elevators) can be deflected simultaneously in the same direction. This configuration enables the ailerons to generate a pitch moment, while the rudder generates a roll moment.

As shown in fig. 2: a fault tolerant flight control system based on control surface faults, comprising:

the sensors are arranged at corresponding positions of the airplane body: outputting the measured parameter value; the sensor arranged at the corresponding position of the airplane body comprises: the gyroscope is arranged in an inertial navigation system of the airplane body and is used for measuring and outputting the roll rate, the pitch rate and the yaw rate of the airplane; and the attack angle and sideslip angle sensor is arranged on the side surface of the aircraft nose and is used for measuring and outputting the attack angle and the sideslip angle of the aircraft.

Fault detection and isolation module: the estimated value of the flight state parameter of the airplane is obtained by detecting the output of a sensor arranged at the corresponding position of the airplane body

The estimated value of the flight state parameter

Including roll, pitch, yaw, angle of attack, and sideslip of the aircraft; estimating flight state parameters

Transmitting to the controller module; simultaneously estimating the value according to the flight state parameter

Adopting an extended multi-model adaptive estimation algorithm EMMAE to judge the health condition of the control surface and the type of the fault; calculating the probability of the fault of each control surface, and calculating the probability calculation value p of the fault of each control surface₁～p_iTransmitting the data to a monitor module, and detecting the deflection angle of each control surface through a control surface sensor to obtain the estimated value of the deflection angle of each control surface

And estimating the deflection angle of each control surfaceTransmitting the data to the monitor module so that the monitor module can confirm the fault position; i denotes a total of i control surfaces, i>1；

A monitor module: based on the result sent by the fault detection and isolation module, the position of the control surface fault is determined, and a basis for control distribution is provided for the control distribution module, and the method comprises the following steps:

a) resetting the upper/lower limits of the control surfaces 1-i according to the type (locking fault or loose fault) of the control surface fault judged by the fault detection and isolation module, and sending a new control surface deflection limiting parameter to the control distribution module;

b) for monitoring the probability p of failure of each control surface transmitted by the failure detection and isolation module₁～p_iAnd an estimated value of deflection angle

If the probability of the fault of a certain control surface exceeds a set threshold value within a certain detection time, the monitor module determines that the control surface has the fault (the fault type is determined by the fault detection and isolation module), determines which corresponding control surface can be activated specifically to compensate the fault, and calculates a control signal for compensation

Superimposing the control signal on the respective control surface

If the control surface is confirmed to have a locking fault, the monitor module estimates a value according to the deflection angle

Determining the locking angle of the fault control surface and estimating the deflection angleTransmitting to a control distribution module;

c) selecting a control surface actuation mode corresponding to the fault according to the fault state of the control surface (the control surface actuation mode is used for controlling the deflection of the aileron and the elevator), and simultaneously sending the number of the actuation mode to the control distribution module;

a controller module: according to given state reference input Ref and the estimated value of the flight state parameter of the airplane sent by the fault detection and isolation module

To calculate a virtual control command vector C_vAnd a virtual control command vector C_vTransmitting the data to a control distribution module as virtual control input; generating a control command of the thrust of the aircraft engine;

a control distribution module: according to the control plane actuation mode and the control plane deflection limit sent by the monitor module and the virtual control input C sent by the controller module_vTo calculate a control surface deflection angle vector delta containing a given value of each control surface deflection angle_c；

A plurality of control surfaces for controlling the flight state of the aircraft: when there is no failure in the event of a failure,

vector delta of each control surface according to deflection angle of control surface_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the normal flight of the airplane; when a fault occurs in a certain control surface, the control surface corresponding to the fault is activated to

Deflecting, the other control surface still uses the deflection angle vector delta of the control surface_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the airplane to continuously keep normal flight.

A fault-tolerant flight control method based on control surface faults comprises the following steps:

s1, transmitting measured parameter values to a fault detection and isolation module by a sensor arranged at a corresponding position of an airplane body.

Firstly, a gyroscope installed in an inertial navigation system of an airplane body sends measured roll rate, pitch rate and yaw rate of the airplane to a fault detection and isolation module; and the measured attack angle and sideslip angle of the airplane are sent to a fault detection and isolation module by an attack angle sideslip angle sensor arranged on the side surface of the airplane nose.

S2, the fault detection and isolation module obtains the flight state parameter estimation value of the airplane by detecting the output of a sensor arranged at the corresponding position of the airplane body

Judging the health condition of the control surface and the type of the fault; calculating the probability of the fault of each control surface, and calculating the probability calculation value p of the fault of each control surface₁～p_iTransmitting the data to a monitor module, and detecting the deflection angle of each control surface through a control surface sensor to obtain the estimated value of the deflection angle of each control surface

And estimating the deflection angle of each control surface

Transmitting to the monitor module; estimating flight state parameters

Transmitting to the controller module;

the details are as follows:

the fault detection and isolation module adopts an extended multi-model adaptive estimation algorithm (EMMAE) to judge the health condition of the control surface. Firstly, respectively establishing a model and a Kalman filter for the normal working state of a control surface and the state of various faults. On the basis, the fault detection and isolation module calculates parameters of the roll rate, the pitch rate, the yaw rate, the attack angle and the sideslip angle of the airplane measured by the sensors to obtain the Bayesian posterior probability of each model, and selects the class model with the maximum posterior probability as the state of the control surface: if the posterior probability of the normal state model is the maximum, each control surface is considered to be in a normal state; and if the posterior probability of a certain type of fault state is the maximum, the type of fault (locking fault or loose fault) of the control surface is considered to occur.

The fault detection and isolation module can only judge which type of fault occurs on the control surface, but cannot judge which specific control surface has the type of fault. Therefore, the monitor module is also required to confirm the location of the failure. Assuming that the aircraft has i control surfaces in total, the fault detection and isolation module needs to calculate the probability of the faults of the control surfaces 1 to i, and calculate the calculated value p₁～p_iThe deflection angle of the control surface is detected by a control surface sensor to obtain the estimated deflection angle value of each control surface

And estimating the deflection angle of each control surface

To the monitor module.

Meanwhile, the fault detection and isolation module combines the parameters of the roll rate, the pitch rate, the yaw rate, the attack angle and the sideslip angle of the airplane measured by the sensors into an estimated value of the flight state parameter of the airplaneAnd the flight state parameters

To the controller module.

S3, the monitor module determines the position of the control surface fault based on the result sent by the fault detection and isolation module and provides a basis for control distribution for the control distribution module; the method specifically comprises the following steps:

s3-1, the monitor module resets the upper/lower limits of the control surfaces 1 to i according to the type (locking fault or loosening fault) of the control surface fault judged by the fault detection and isolation module, and sends a new control surface deflection limiting parameter to the control distribution module;

s3-2, the monitor module monitors the probability p of each control surface fault sent by the fault detection and isolation module₁～p_iAnd an estimated value of deflection angle

If the probability of the fault of a certain control surface exceeds a set threshold value within a certain detection time, the monitor module determines that the control surface has the fault (the fault type is determined by the fault detection and isolation module), determines which corresponding control surface can be activated specifically to compensate the fault, and calculates a control signal for compensationSuperimposing the control signal on the respective control surface

If the control surface is confirmed to have a locking fault, the monitor module estimates a value according to the deflection angle

Determining the locking angle of the fault control surface and estimating the deflection angle

Transmitting to a control distribution module;

the details are as follows: probability p of the monitor module generating a certain type of fault on each control surface transmitted by the fault detection and isolation module₁～p_iMonitoring is performed. If the probability of a certain fault occurring on a certain control surface exceeds a certain threshold value within a certain detection time (although the probability does not mean that the certain fault occurs on the control surface, sometimes the detection value of a sensor has errors due to the influence of strong gust, and therefore comprehensive judgment needs to be carried out), the monitor module determines which control surfaces (1-i) are to be activated specifically to compensate the fault, and the probability p of the certain fault occurring on each control surface is used for compensating the fault₁～p_iCalculating control signals

(t represents the time of occurrence of the failure, p_i(t) represents the probability of the control surface having such a fault, f_iRepresenting the frequency of the excitation signal) to superimpose a control signal on the corresponding control surface

If the control surface does have a fault, the superposed control signals do not influence the dynamic characteristics of the airplane, but can help the fault detection and isolation module to confirm the fault state of the control surface more quickly; if the control surface does not actually have a fault, the aircraft responds according to the superposed control signals, and then the fault detection and isolation module eliminates the fault on the control surface. If the probability of the control surface failing is below a certain threshold for a predefined period of time, the monitor module will cancel the superimposed control signal

Meanwhile, if it is confirmed that the control surface has a lock-up failure, the monitor module estimates a value according to the deflection angleDetermining the locking angle of the fault control surface and estimating the deflection angle

And the data is transmitted to a control distribution module.

S3-3, the monitor module selects a control plane actuation mode corresponding to the fault (this control plane actuation mode will be used to control the deflections of the ailerons and elevators) according to the fault state of the control plane (as shown in table 1), and sends the number of the actuation mode to the control distribution module.

S4, the controller module inputs Ref according to the given state reference and the estimated value of the flight state parameter of the airplane sent by the fault detection and isolation module

To calculate a virtual control command vector C_vAnd a virtual control command vector C_vTransmitting the data to a control distribution module as virtual control input; and generates control commands for aircraft engine thrust. The details are as follows:

the controller module is used for inputting Ref according to given state and the estimated value of the flight state parameter of the airplane sent by the fault detection and isolation module

And the controller module generates a virtual control command vector C by taking the aerodynamic coefficient related to the generated roll, pitch and yaw moments as a reference value_v=[C_L C_M C_N]^T（C_LFor roll moment, C_MFor pitching moment, C_LIs the yaw moment).

The controller module maps the virtual control command vector C_vThe control command is transmitted to the control distribution module to be used as a virtual control input, and the control command of the thrust of the aircraft engine is obtained through calculation, so that the power for flying is provided for the aircraft.

S5, the control distribution module controls the control plane actuation mode, the control plane deflection limit and the virtual control input C sent by the controller module according to the control plane actuation mode and the control plane deflection limit provided by the monitor module_vTo calculate a control surface deflection angle vector delta containing a given value of each control surface deflection angle_cThereby obtaining the given value of the deflection angle of each control surface;

s6, when no fault occurs, controlling each control surface to perform vector delta according to control surface deflection angle_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the normal flight of the airplane; when a certain control surface has a fault, the corresponding activated control surface of the fault is controlled to

Deflecting, the other control surface still uses the deflection angle vector delta of the control surface_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the airplane to continuously keep normal flight.

The following examples describe in detail step S5 and step S6:

control vector C according to virtual command provided by controller module_vAnd the control plane actuation mode and the control plane deflection limit provided by the monitor module are combined, and the control distribution module is used for calculating the deflection angle of each control plane. The following are assumed conditions for solving each control surface deflection angle:

let a given value of the control surface deflection angle vector be denoted delta_c=[δ_a1 δ_a2 δ_e1 δ_e2 δ_r]^T（δ_a1Given value of deflection angle of left aileron, delta_a2Given value of right aileron deflection angle, delta_e1Given value of left elevator deflection angle, delta_e2Given value of right elevator deflection angle, delta_rA given value for the rudder deflection angle). For ailerons and elevators, the sign is positive when their control surfaces deflect upwards and negative when they deflect downwards; for a rudder, the sign is positive when the rudder is deflected to the right (looking forward from the aircraft tail). In order to ensure flight safety, the deflection angle and the deflection rate of each control surface need to have certain limits, namely the deflection angle of the ith control surface has an upper limit delta_i,maxAnd a lower limit δ_i,minHaving an upper limit of the deflection rate ρ_i,upAnd a lower limit ρ_i,down。

Based on the above assumptions, a virtual control command vectorC_vCan be expressed as:

$C_v=\left(\begin{array}{c}{C}_L\\ C_M\\ C_N\end{array}\right)=\left(\begin{array}{c}{C}_{L_{a1}}{\mathrm{\δ}}_{a1}+C_{L_{a2}}{\mathrm{\δ}}_{a2}+C_{L_{e1}}{\mathrm{\δ}}_{e1}+C_{L_{e2}}{\mathrm{\δ}}_{e2}\\ C_{M_{a1}}{\mathrm{\δ}}_{a1}+C_{M_{a2}}{\mathrm{\δ}}_{a2}+C_{M_{e1}}{\mathrm{\δ}}_{e1}+C_{M_{e2}}{\mathrm{\δ}}_{e2}\\ C_{N_{{\mathrm{\δ}}_r}}{\mathrm{\δ}}_r+C_{\mathrm{Ndrag}}\left({\mathrm{\δ}}_{a2}\right)-C_{\mathrm{Ndrag}}\left({\mathrm{\δ}}_{a1}\right)\end{array}\right)$

wherein:

generating roll torque C for left and right ailerons and left and right elevators_LThe aerodynamic coefficient of (a);

generating pitching moment C for left and right ailerons and left and right elevators_MIn a pneumatic train ofCounting;

generating a yawing moment C for a rudder-needle pair_NThe aerodynamic coefficient of (a);

C_Ndrag(δ_a2)-C_Ndrag(δ_a1) Indicating a reverse yaw action. The aerodynamic coefficients are determined to be constant values when the airplane configuration design is finished.

Based on the above assumptions, given C_vOn the premise of each aerodynamic coefficient, the control surface deflection angle vector delta can be obtained through calculation_cIs given only to the value given. Given value delta for calculating deflection angle vector of control surface_cPreviously, it was necessary to first determine the control surface actuation pattern and, when a fault occurs, compensate for the fault by controlling the deflections of the ailerons and the elevator (i.e. fault tolerant control). The control surface operation mode is determined by the fault conditions shown in table 1:

TABLE 1 Fault states

Note: x represents the failure of the corresponding control surface.

Taking the no-fault mode 0 and the no-fault mode 1 as examples, a method for calculating the deflection angle of the control surface is explained as follows:

(1) mode 0: failure free mode

In mode 0, the system is not malfunctioning and the ailerons are driven differentially according to the following equation:

(gamma is a differential coefficient)

The sign of each aerodynamic coefficient may be determined as:

$C_{L_{a2}}=-C_{L_{a1}}=C_{\mathrm{La}}>0,C_{L_{e2}}=-C_{L_{e1}}=C_{\mathrm{Le}}>0,$

$C_{M_{a2}}=C_{M_{a1}}=C_{\mathrm{Ma}}>0,C_{M_{e2}}=C_{M_{e1}}=C_{\mathrm{Me}}>0,C_{N_{{\mathrm{\δ}}_r}}>0$

wherein,

is the absolute value of each aerodynamic coefficient.

Thus, in mode 0, if the effect of the reverse yaw is not taken into account, the vector C is commanded according to the virtual control_vThe system moment equation can be simplified to be:

$C_L=C_{L_a}({\mathrm{\δ}}_{a2}-{\mathrm{\δ}}_{a1})+C_{L_e}({\mathrm{\δ}}_{e2}-{\mathrm{\δ}}_{e1}),$

$C_M=C_{M_a}=({\mathrm{\δ}}_{a2}+{\mathrm{\δ}}_{a1})+C_{M_e}({\mathrm{\δ}}_{e2}+{\mathrm{\δ}}_{e1}),$

$C_N=C_{N_{{\mathrm{\δ}}_r}}{\mathrm{\δ}}_r$

the above equations are 3 in number but contain 5 unknowns. To obtain a unique solution to the equation, the number of unknowns must be reduced to 3. In the no-fault mode 0, the following equation holds:

δ_a1=-γ·δ_a2,

δ_e1=δ_e2

substituting the above equations into a system moment equation, the system moment equation can be simplified into three unknowns, and has a unique solution, so that the deflection angle of each control surface can be obtained:

${\mathrm{\δ}}_{a1}=-\frac{\mathrm{\γ}\·C_L}{C_{L_a}(1+\mathrm{\γ})},$

${\mathrm{\δ}}_{a2}=\frac{C_L}{C_{L_a}(1+\mathrm{\γ})},$

${\mathrm{\δ}}_{e1}={\mathrm{\δ}}_{e2}=\frac{C_M}{{2C}_{M_e}}-\frac{(1-\mathrm{\γ})C_L{C}_{M_a}}{2(1+\mathrm{\γ})C_{L_a}{C}_{M_e}}$

the deflection angle values of the control surfaces obtained by the above equations are combined to obtain the given value delta of the deflection angle vector of the control surfaces under the fault-free mode 0_c=[δ_a1 δ_a2 δ_e1 δ_e2 δ_r]^T. At this time, the process of the present invention,vector delta of each control surface according to deflection angle of control surface_cThe given values in the control system deflect, and the given values and the engine thrust jointly control the normal flight of the airplane.

(2) Mode 1: left aileron failure

If the left aileron has a lock-up failure (mode 1), the control distribution module estimates the yaw angle of the left aileron at that time

And assigning a given value of the deflection angle of the left aileron. At the moment, the right aileron is used for generating rolling moment required by the stability of the airplane, and the left elevator and the right elevator are activated for compensating redundant pitching moment generated by the locking of the left aileron. The deflection angle of each control surface can be derived from the following equation:

${\mathrm{\δ}}_{a1}={\widehat{\mathrm{\δ}}}_{a1},$

δ_a2=δ_a1-C_L/C_La,

${\mathrm{\δ}}_{e1}={\mathrm{\δ}}_{e2}=(C_M-C_{M_a}({\mathrm{\δ}}_{a1}+{\mathrm{\δ}}_{a2}))/\left({2C}_{M_e}\right),$

${\mathrm{\δ}}_r=(C_N-[C_{\mathrm{Ndrag}\left({\mathrm{\δ}}_{a2}\right)}-C_{\mathrm{Ndrag}\left({\mathrm{\δ}}_{a1}\right)}\left]\right)/C_{N_{{\mathrm{\δ}}_r}}$

checking the Right aileron deflection Angle delta_a2If the given value of (a) is within the actuation range of the right aileron (the actuation range is determined by the new control plane deflection limiting parameter sent by the monitor module), and if the given value of (a) is beyond the actuation range, the deflection angle of the right aileron should be set as the limit value of the actuation range, namely delta_a2=δ_a2,minOr delta_a2,max. At this time, an unknown quantity can be removed from the equation, and only the deflection angle of the elevator is required to be calculatedAnd (4) calculating. The angle at which each control surface should be deflected can be calculated according to the following equation:

${\mathrm{\δ}}_{a1}={\widehat{\mathrm{\δ}}}_{a1},{\mathrm{\δ}}_{a2}={\mathrm{\δ}}_{a2,\min }$ or delta_a2,max,

${\mathrm{\θ}}_1=(C_M-C_{M_a}({\mathrm{\δ}}_{a1}+{\mathrm{\δ}}_{a2}))/C_{M_e},{\mathrm{\θ}}_2=(C_L-C_{L_a}({\mathrm{\δ}}_{a1}-{\mathrm{\δ}}_{a2}))/C_{L_e},$

δ_e1=(θ₁+θ₂)/2,δ_e2=(θ₁-θ₂)/2,

${\mathrm{\δ}}_r=(C_N-[C_{\mathrm{Ndrag}\left({\mathrm{\δ}}_{a2}\right)}-C_{\mathrm{Ndrag}\left({\mathrm{\δ}}_{a1}\right)]})/C_{N_{{\mathrm{\δ}}_r}}$

Wherein, theta₁,θ₂Is an intermediate parameter for calculating the deflection angle of each control surface.

The deflection angle values of the control surfaces obtained by the above equations are combined to obtain the given value delta of the deflection angle vector of the control surface under the left aileron fault mode 1_c=[δ_a1 δ_a2 δ_e1 δ_e2 δ_r]^T. At this time, the left and right elevators (i.e., the activated control surfaces corresponding to the left aileron failure) are driven by the control unitAnd

deflection in which ${\mathrm{\δ}}_{{\mathrm{ex}}_1}\left(t\right)=[1+3(1-p_1\left(t\right))]\cos \left(2\mathrm{\π}{f}_{1}t\right),{\mathrm{\δ}}_{{\mathrm{ex}}_2}\left(t\right)=[1+3(1-p_2\left(t\right))]\cos \left(2\mathrm{\π}{f}_{2}t\right).$ The other control surfaces, namely the right aileron and the rudder still have a vector delta according to the deflection angle of the control surfaces_cGiven values of δ_a2,δ_rThe deflection and the engine thrust jointly control the airplane to keep normal flight.

Claims (5)

1. A fault tolerant flight control system based on control surface faults, comprising:

the sensors are arranged at corresponding positions of the airplane body: outputting the measured parameter value;

fault detection and isolation module: the estimated value of the flight state parameter of the airplane is obtained by detecting the output of a sensor arranged at the corresponding position of the airplane body

The flight state parameterEstimated value

Including roll, pitch, yaw, angle of attack, and sideslip of the aircraft; estimating flight state parameters

Transmitting to the controller module; simultaneously estimating the value according to the flight state parameter

Judging the health condition of the control surface and the type of the fault; calculating the probability of the fault of each control surface, and calculating the probability calculation value p of the fault of each control surface₁～p_iTransmitting the data to a monitor module, and detecting the deflection angle of each control surface through a control surface sensor to obtain the estimated value of the deflection angle of each control surface

And estimating the deflection angle of each control surface

Transmitting to the monitor module; i denotes a total of i control surfaces, i>1；

A monitor module: based on the result sent by the fault detection and isolation module, the position of the control surface fault is determined, and a basis for control distribution is provided for the control distribution module, and the method comprises the following steps:

a) resetting the upper/lower limits of the control surfaces 1-i according to the type of the fault of the control surfaces, and sending the new deflection limiting parameters of the control surfaces to a control distribution module;

b) for monitoring the probability p of failure of each control surface transmitted by the failure detection and isolation module₁～p_iAnd an estimated value of deflection angle

If it is detected at a certain levelWithin the time, the probability of a certain control surface failing exceeds a set threshold value, the monitor module determines that the control surface fails, determines which corresponding control surfaces can be activated specifically to compensate the failure, and calculates a control signal for compensation

Superimposing the control signal on the respective control surface

If the control surface is confirmed to have a locking fault, the monitor module estimates a value according to the deflection angle

Determining the locking angle of the fault control surface and estimating the deflection angle

Transmitting to a control distribution module;

c) selecting a control surface actuating mode corresponding to the fault according to the fault state of the control surface, and simultaneously sending the serial number of the actuating mode to a control distribution module;

a controller module: according to given state reference input Ref and the estimated value of the flight state parameter of the airplane sent by the fault detection and isolation module

To calculate a virtual control command vector C_vAnd a virtual control command vector C_vTransmitting the data to a control distribution module as virtual control input; generating a control command of the thrust of the aircraft engine;

a control distribution module: according to the control plane actuation mode and the control plane deflection limit sent by the monitor module and the virtual control input C sent by the controller module_vTo calculate a control surface deflection angle vector delta containing a given value of each control surface deflection angle_c；

For controlling the flight of aircraftMultiple control surfaces of state: when there is no failure in the event of a failure,

vector delta of each control surface according to deflection angle of control surface_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the normal flight of the airplane; when a fault occurs in a certain control surface, the control surface corresponding to the fault is activated to

Deflecting, the other control surface still uses the deflection angle vector delta of the control surface_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the airplane to continuously keep normal flight.

2. The fault-tolerant flight control system based on control surface faults as claimed in claim 1, wherein the sensors disposed at respective positions of the aircraft body comprise: the gyroscope is arranged in an inertial navigation system of the airplane body and is used for measuring and outputting the roll rate, the pitch rate and the yaw rate of the airplane; and the attack angle and sideslip angle sensor is arranged on the side surface of the aircraft nose and is used for measuring and outputting the attack angle and the sideslip angle of the aircraft.

3. A fault-tolerant flight control method based on control surface faults is characterized by comprising the following steps:

s1, transmitting measured parameter values to a fault detection and isolation module by sensors arranged at corresponding positions of an airplane body;

s2, the fault detection and isolation module obtains the flight state parameter estimation value of the airplane by detecting the output of a sensor arranged at the corresponding position of the airplane body

Judging the health condition of the control surface and the type of the fault; calculating the probability of the fault of each control surface, and calculating the probability calculation value p of the fault of each control surface₁～p_iTo surveillanceThe device module detects the deflection angle of each control surface through the control surface sensor to obtain the estimated value of the deflection angle of each control surface

And estimating the deflection angle of each control surface

Transmitting to the monitor module; estimating flight state parameters

Transmitting to the controller module;

s3, the monitor module determines the position of the fault of the control surface based on the result sent by the fault detection and isolation module, and provides a control distribution basis for the control distribution module, wherein the basis comprises control surface deflection limiting parameters and a control surface actuation mode;

s4, the controller module inputs Ref according to the given state reference and the estimated value of the flight state parameter of the airplane sent by the fault detection and isolation module

To calculate a virtual control command vector C_vAnd a virtual control command vector C_vTransmitting the data to a control distribution module as virtual control input; generating a control command of the thrust of the aircraft engine;

s5, the control distribution module controls the control plane actuation mode, the control plane deflection limit and the virtual control input C sent by the controller module according to the control plane actuation mode and the control plane deflection limit provided by the monitor module_vTo calculate a control surface deflection angle vector delta containing a given value of each control surface deflection angle_cThereby obtaining the given value of the deflection angle of each control surface.

4. The fault-tolerant flight control method based on control surface faults as claimed in claim 3, wherein the step S3 specifically comprises:

s3-1, the monitor module resets the upper/lower limits of the control surfaces 1 to i according to the type of the fault of the control surfaces and sends the new deflection limiting parameters of the control surfaces to the control distribution module;

s3-2, the monitor module monitors the probability p of each control surface fault sent by the fault detection and isolation module₁～p_iAnd an estimated value of deflection angle

If the probability of the fault of a certain control surface exceeds a set threshold value within a certain detection time, the monitor module determines that the control surface has the fault, decides which corresponding control surface can be activated specifically to compensate the fault, and calculates a control signal for compensation

Superimposing the control signal on the respective control surface

If the control surface is confirmed to have a locking fault, the monitor module estimates a value according to the deflection angle

Determining the locking angle of the fault control surface and estimating the deflection angle

Transmitting to a control distribution module;

s3-3, the monitor module selects a control surface actuating mode corresponding to the fault according to the fault state of the control surface, and sends the number of the actuating mode to the control distribution module.

5. The fault-tolerant flight control method based on control surface faults as claimed in claim 4, further comprising, after the step S5:

s6, when no fault occurs, controlling each control surface to perform vector delta according to control surface deflection angle_cEach control surface deflection angle inThe given value deflects, and the given value deflects and the engine thrust jointly control the normal flight of the airplane; when a certain control surface has a fault, the corresponding activated control surface of the fault is controlled to

Deflecting, the other control surface still uses the deflection angle vector delta of the control surface_cThe given deflection angle of each control surface deflects, and the given deflection angle and the engine thrust jointly control the airplane to continuously keep normal flight.

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