CN101241369A - Flight control system executor deadlock trouble real-time detection method - Google Patents

Abstract

A real-time detection method for executor blocking fault in a flight control system pertains to flight control system field. The invented method uses a multi-model structure to build a set of observers UIOs each of which is based on a system model for describing a specific executor fault, UIOs are used for generating residual error signals depending on faults, UIO of a model matching with the system generates a residual error signal close to zero, and each UIO of a model mismatching with the system generates a big residual error signal driven by the mismatch signal. Aiming at unknown model parameter caused by that the executor blocking position can not be predicted, fault detection is implemented by using a model with a model of an uncertain parameter to online approach the executor blocking parameter by self-adaptation adjustment, to make the UIO model to match with the system status.

Description

A kind of real-time detection method of the stuck fault of actuator in the flight control system

Technical field

The present invention relates to the flight control system technical field, relate in particular to a kind of real-time detection method of the stuck fault of actuator in the flight control system.

Background technology

The reliably working of flight control system is the prerequisite of aircraft flight safety.In order to make flight control system under situation about breaking down, have fault-tolerant ability, present generation aircraft adopts the way of hardware redundancy usually, be that hardware devices such as controller, sensor and actuator all are parallel repetitions of overlapping more, the shortcoming of hardware redundancy is to the needs in space and increases load-carrying, at baby plane particularly on the unmanned plane, because the restriction of space and load-carrying, to adopt fault diagnosis technology based on analytical analysis or artificial intelligence approach be necessary and development potentiality is arranged.When flight control system adopted fault-tolerant control technology, the fast detecting of fault and the design of accurately orientating fault-tolerant controller as provided good basis and bigger method to select the space.

Since the last century the eighties, the troubleshooting issue of flight control system receives the concern of Many researchers.People such as Maybeck have delivered a series of papers about flight control system actuator and sensor FDI (Fault Detection and Isolation), for example, " K.A.Fisher and Peter S.Maybeck; Multiple model adaptive estimationwith filter spawning; IEEE Transactions on aerospace and electronic systems; Vol.38; No; 3, July 2002, pp.755-768 " and " T.E.Menke and Peter S.Maybeck, Sensor/Actuatorfailure detection in the Vista F-16 by multiple model adaptive estimation, IEEETransactions on aerospace and electronic systems, Vol.31, No, 4, October 1995, pp.1218-1229 "; their work is the adaptive estimation method that adopts based on multi-model; at first provide the model of system under the failure condition that may occur; design one group of Kalman wave filter then, each Kalman Filter Design is based on a specific fault situation of system.When system breaks down, provide minimum residual error with the pairing Kalman wave filter of this fault, thereby detect failure condition.The shortcoming of this method is in order to strengthen the recognition capability to fault, need add a pumping signal in system.In addition, this method can not the stuck situation of processing execution device, can not do the detection that continuous parameters changes to partial failure (loss ofeffectiveness).At document " Y.Zhang and J.Jiang; Integratedactive fault-tolerant control using IMM approach; IEEE Transactions on aerospace andelectronic systems; Vol.37; No; 4, October 2001, pp.1221-1235 " and " Y.Zhang andX.R.Li, Detection and diagnosis of sensor and actuator failures using IMM estimator, IEEE Transactions on aerospace and electronic systems, Vol.34, No, 4, October 1998, pp.1293-1313 " in, a kind of method based on Interactive Multiple-Model (Interacting Multiple Model) is suggested; for the situation of actuator partial failure; the author has taked the discretize disposal route, that is, it is divided several numerical value interval come modeling.In document " Y.Zhang and J.Jiang; Active fault-tolerant control system against partialactuator failures; IEE Proceedings-Control Theory Applications; Vol.149, No, 1; January 2002; pp.95-104 ", the author has proposed a kind of method can be with the mode processing section failure of removal of continuous parameter, but does not still propose effective method for the stuck situation of actuator.

Summary of the invention

A kind of real-time detection method that the purpose of this invention is to provide the stuck fault of actuator in the flight control system, this method can in time detect the stuck fault of actuator, determines the accurate position that actuator is stuck, ensures flight safety; The flight control system hardware configuration is simplified, reduced energy consumption and, reduce system cost the requirement in space.

In order to achieve the above object, technical scheme of the present invention is as follows:

A kind of real-time detection method of the stuck fault of actuator comprises the steps: in the flight control system

1) fault type that detects according to the number of actuator in the flight control system and desire is determined the number of observer in the fault detection system, under the situation of only considering the stuck fault of actuator, the number of observer is that actuator number p adds 1, the model of the normal operation of one of them corresponding system, p the stuck fault of difference actuation means;

2) set up the stuck fault model of p actuator;

3) the design stuck fault UIO of actuator (Unknown Input Observer) observer;

4) the self-adaptation regulation of design executor dead position Estimation of Parameters value;

5) output of each observer is compared with the actual measured value of system state obtain the residual signals of each observer, calculate the coupling index of corresponding each observer then;

6) programming performing step 3) observer, residual computations and the coupling index that designs in the step 5) calculated, and forms the multi-model fault detection system;

7) according to the detection principle of multi-model fault detection system, the fault diagnosis decision package compares all p+1 that obtain coupling indexs, and the current state of minimum coupling index representative system is consistent with corresponding malfunction, thereby realizes fault detect.

The present invention adopts the multi-model structure, sets up one group of UIO (observer), and the design of each UIO is based on one and describes the particular actuator fault and have system model under the situation.UIO is used to produce the residual signals that depends on fault, and the UIO of model and system matches produces the residual signals near null value, and unmatched all other the UIO of model and system's virtual condition produces big residual signals under the driving of mismatch signal.Design performance index of weighing residual error, can realize the real-time detection of the system failure.In existing UIO method for designing, all suppose UIO based on all parameters of model all be known, this condition is invalid under the stuck situation of actuator, because any point that actuator is stuck in may occurring between its motor area is the stuck position of there is no telling in advance.If to all modelings of every bit in interval, that will have infinite a plurality of model, be infeasible in practice.At this problem, the present invention has set up the method for designing of self-adaptation UIO, with a model that uncertain parameter is arranged, by the online adaptive adjustment, executor dead position parameter is approached by online, thereby make UIO model and system state coupling, reach the purpose of fault detect, have accurate numerical value to estimate to stuck position simultaneously.We have proved the convergence of the stable and residual signals of the self-adaptation adjustment rule assurance observer that we proposed under the situation of model and system state coupling.According to retrieval, thereby adaptive technique combined with UIO adaptive UIO is proposed, existing document does not appear in the newspapers, and is to propose first.

Beneficial effect of the present invention is as follows:

1) by the multi-model structure, the residual signals that the observer of more corresponding different faults model produces can in time detect the stuck fault of actuator;

2) estimate by online adaptive, can determine the accurate position that actuator is stuck;

3) owing to can accurately detect the executor dead position, system controller foundation failure message accurately can realize fault-tolerant operation, makes system stability, has ensured flight safety;

4) replace the existing hardware redundancy method that generally adopts, the present invention can make system hardware structure simplify, and reduces energy consumption, minimizing is to the requirement in space, reduce load-carrying, reduce system cost, the miniature self-service all very limited for space, load-carrying and energy supply drives an airplane extremely important.

Description of drawings

Fig. 1 is the structural representation of fault detection system of the present invention.

Fig. 2 is the measurement output curve diagram of simulation process of the present invention system.

Fig. 3 is the detection curve figure of executor of the present invention dead position.

Fig. 4 is the matching performance index curve map of corresponding six observers of the present invention.

Embodiment

Below in conjunction with accompanying drawing the present invention is done description in further detail:

The invention provides the detection method based on the stuck fault of actuator of multi-model observer, Fig. 1 has provided the structure of fault detection system.Design one group of observer and produce residual signals, the design of each observer is based on the model of system under a specific fault; Fault diagnosis is to make with the best model that determines current system, and promptly this method is to seek and the best model of current system matches in p model.For this purpose, the dreamboat of observer design is to produce residual signals vector r _i(t), i=1 ..., p, satisfy following condition: when i model and current system failure coupling, r _i(t)=0, simultaneously to all j ≠ i, r _j(t) ≠ 0.In order to eliminate the influence of external disturbance to residual signals, this paper adopts UIO (UnknownInput Observer) observer and according to the needs of problem standard UIO has been done necessary improvement in form, and the advantage of UIO is disturbing signal can be separated from residual signals.Specialize in the stuck situation of actuator at this, in the model uncertain parameter will be arranged, therefore propose self-adaptation UIO method, promptly, unknown parameter in UIO replaces with an estimated value, brings in constant renewal in estimated value by Adaptive adjusting algorithm, makes it converge on true value.Select the model best with system matches by designing performance index, the fault diagnosis decision package is exactly a link that provides diagnostic result according to performance index among Fig. 1.

Consider the linear time invariant system that following state-space model is described:

$\stackrel{\·}{x}\left(t\right)=\mathrm{Ax}\left(t\right)+\mathrm{Bu}\left(t\right)+\mathrm{Ed}\left(t\right)$

y(t)＝Cx(t) (1)

In the following formula, x (t) ∈ R ⁿBe system state, y (t) ∈ R ^mBe the measurement output of system, u (t) ∈ R ^pBe the control input, d (t) ∈ R ^qBe unknown external disturbance vector, A, B, C and E are the suitable known matrix of dimension, and disturbance input distribution matrix E is the row non-singular matrixs.

In the said system, when stuck fault took place i actuator, the model of system was changed to:

$\stackrel{\·}{x}\left(t\right)=\mathrm{Ax}\left(t\right)+B_{i}u\left(t\right)+b_i{\stackrel{\‾}{u}}_i+\mathrm{Ed}\left(t\right)---\left(2\right)$

B in the formula _i=BL _i, L _i∈ Ω ≡ { Li=diag[l ₁, l ₂..., l _p], l wherein _i=0; For j=0,1,2 ..., p and j ≠ i, l _j=1, b _iBe the i row of B, Be used for representing the pairing input action that system is formed in stuck position, place when i actuator is stuck.Because stuck position is unknown, Be unknown.

When taking into account system comprised the stuck failure condition of all possible actuator, the universal model of system can be expressed as:

$\stackrel{\·}{x}\left(t\right)=\mathrm{Ax}\left(t\right)+\stackrel{\‾}{B}u\left(t\right)+\stackrel{\‾}{b}\stackrel{\‾}{u}+\mathrm{Ed}\left(t\right)$

y(t)＝Cx(t) (3)

In the formula

With

Any situation of stuck fault takes place in any one in normal and p the actuator of representative system, and its possible value is as described in the formula (2).

Produce suitable residual signals and determine that the current running status of which model and system mates best in order to design one group of observer, a kind of UIO is proposed, this is the improvement on the basis of given UIO in the document " J.Chen; R.J, Patton and H.Zhang, design of unknowninput observers and robust fault detection filters; International Journal of Control; Vol.63 (1), 1996,85-105 ":

${\stackrel{\·}{w}}_i\left(t\right)={\mathrm{Fw}}_i\left(t\right)+G{B}_{i}u\left(t\right)+G{b}_i{\stackrel{\‾}{u}}_i+\mathrm{Ky}\left(t\right)$

${\hat{x}}_i\left(t\right)=w_i\left(t\right)+\mathrm{Hy}\left(t\right)---\left(4\right)$

In the formula

Be the state vector that estimation obtains, w _i(t) ∈ R ⁿBe the state vector of observer, the normal condition of the corresponding system of i=0, i=1 ..., corresponding i the actuator of p is stuck, and F, G, K and H need the matrix that designs, allow K=K ₁+ K ₂, K ₁And K ₂Undetermined, observer (4) is applied to system (3), state estimation error Provide by following formula:

${\stackrel{\·}{e}}_i\left(t\right)=(A-\mathrm{HCA}-K_{1}C)e_i\left(t\right)+[(A-\mathrm{HCA}-K_{1}C)-F]w_i\left(t\right)$

$+[(A-\mathrm{HCA}-K_{1}C)H-K_2]y\left(t\right)+[(I-\mathrm{HC})\stackrel{\‾}{B}-G{B}_i]u\left(t\right)---\left(5\right)$

$+(I-\mathrm{HC})\stackrel{\‾}{b}\stackrel{\‾}{u}-G{b}_i{\stackrel{\‾}{u}}_i+(I-\mathrm{HC})\mathrm{Ed}\left(t\right)$

The design observer makes parameter F, G, K ₁, K ₂Satisfy following relation with H:

(I-HC)E＝0 (6)

G＝I-HC (7)

F＝A-HCA-K ₁C (8)

K ₂＝FH (9)

The design of F (is selected K ₁) making that all eigenwerts of F are stable, the state estimation error is determined by following formula so:

${\stackrel{\·}{e}}_i\left(t\right)={\mathrm{Fe}}_i\left(t\right)+G(\stackrel{\‾}{B}-B_i)u+G(\stackrel{\‾}{b}\stackrel{\‾}{u}-b_i{\stackrel{\‾}{u}}_i)---\left(10\right)$

Because F is stable, e _i(t) steady-state value is only driven by the mismatch signal between system running state and i the model, is not subjected to the influence of disturbance and other signals.If e is mated fully in i model and system _i(t) steady-state value goes to zero, otherwise, e _i(t) steady-state value is driven by mismatch signal, will be remarkable non-zero.Like this, in one group of observer, have only observer with system matches to produce zero residual signals, can realize diagnosis the fault actuator.

In the above-mentioned observer that provides (4), represent the parameter of executor dead position

Be used as one of observer parameter.Because the stuck any point that may occur in its stroke range of actuator, when the design observer, it is stuck where, promptly to predict actuator

Be unknown, so this parameter can not be used for the observer design, this is a main problem to be solved by this invention.The present invention proposes one and comes the On-line Estimation location parameter with adaptive estimation method

Thereby solved this problem.In the adaptive approach that is proposed, self-adaptation UIO is provided by following formula:

${\stackrel{\·}{w}}_i\left(t\right)={\mathrm{Fw}}_i\left(t\right)+G{B}_{i}u+G{b}_i\hat{u}+\mathrm{Ky}\left(t\right)$

${\hat{x}}_i\left(t\right)=w_i\left(t\right)+\mathrm{Hy}\left(t\right)---\left(11\right)$

Contrast equation (4) can find that with formula (11) both unique differences are in formula (4) In formula (11), become

For

Estimated value, in self-adaptation UIO, use

Estimated value

Replace it.When system moves, at first give

Compose an initial value, adjust according to the self-adaptation regulation online in real time of design then Make it converge on its true value

Thereby reach self-adaptation and estimate

Purpose.

In this method,

The self-adaptation regulation provide by following formula:

${\stackrel{\·}{\hat{u}}}_i\left(t\right)={\mathrm{\α}}_i{e}_i^T\left(t\right)C^T\mathrm{PCG}{b}_i---\left(12\right)$

In the formula, α _iThe＞0th, self-adaptation is adjusted coefficient, and it can influence the speed of convergence that self-adaptation is estimated, P is a symmetric positive definite matrix, and it is the unique solution of following Lyapnov matrix equation:

F ^TP+PF＝-Q (13)

Q is any positive definite symmetric matrices in the following formula, and by formula (10) as can be known, when i actuator takes place when stuck, the output residual signals of i corresponding UIO is provided by following formula:

${\stackrel{\·}{e}}_i\left(t\right)={\mathrm{Fe}}_i\left(t\right)+G{b}_i({\stackrel{\‾}{u}}_i-{\hat{u}}_i)={\mathrm{Fe}}_i\left(t\right)+G{b}_i{\mathrm{\φ}}_i---\left(14\right)$

In the formula, ${\mathrm{\φ}}_i={\stackrel{\‾}{u}}_i-{\hat{u}}_i$ It is stuck position

Evaluated error.

Can draw such conclusion by above-mentioned: i stuck on the throne putting of actuator in the system (3) of setting up departments Formula (11) the auto-adaptive parameter adjustment algorithm that provides of the self-adaptation UIO that gives and formula (12) guarantee residual signals e _i(t) and the evaluated error φ of stuck position _iExponential convergence.

Document " K.S.Narendra and J.Balakrishnan; Adaptive control using multiple models; IEEE Transactions on automatic control; Vol.42; No; 2,1997, pp.171-187 " provided performance index in the following formula (15) and decided which has described the dynamic behaviour of system at current time best in a plurality of models in the system; according to these performance index; the model of obtaining minimum index value is the preferably description of system, because model and system matches are good, the residual signals that corresponding UIO produces goes to zero.

$S_i\left(t\right)=c_1{\left|\right|e_i\left(t\right)\left|\right|}^2+{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="S2008100105173E00021.png"\; state="\{\{state\}\}">c</figure-callout>}}_2\underset{t_0}{\overset{t}{\&Integral;}}\exp (-\mathrm{\&lambda;}(t-\mathrm{\&tau;})){\left|\right|e_i\left(\mathrm{\&tau;}\right)\left|\right|}^2\mathrm{d\&tau;},i=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,p,---\left(15\right)$

In the formula, c ₁＞0 and c ₂＞0 is respectively the current time and the weighting coefficient of signal constantly in the past, λ＞0th, forgetting factor, p is the number of UIO, at document " Jovan D.Boskovic and Raman K.Mehra; A robust adaptivereconfigurable fight control scheme for accommodation of control effector failures ", Journal of Guidance, Control, and Dynamics, Vol.25, No.4, July-August 2002, pp.712-724 " in above-mentioned performance index be used to the fault diagnosis of system.

In addition, because in residual vector, some component is more responsive for not matching of model and system than other component, and these components should be endowed bigger weights to increase the susceptibility of corresponding UIO.Weighted residual signal below so we have used:

e _i*(t)＝Q _ie _i(t) (16)

In the formula, Q _iBe a diagonal angle weighting matrix, Q _iValue can decide by emulation or sensitivity analysis.Correspondingly, (15) formula becomes:

${S^{*}}_i\left(t\right)=c_1{\left|\right|{e^{*}}_i\left(t\right)\left|\right|}^2+{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="S2008100105173E00021.png"\; state="\{\{state\}\}">c</figure-callout>}}_2\underset{t_0}{\overset{t}{\&Integral;}}\exp (-\mathrm{\&lambda;}(t-\mathrm{\&tau;})){\left|\right|{e^{*}}_i\left(\mathrm{\&tau;}\right)\left|\right|}^2\mathrm{d\&tau;},i=\mathrm{0,1},2,\&CenterDot;\&CenterDot;\&CenterDot;,p,---\left(17\right)$

(17) formula of utilization just can be determined and the best model of system dynamics behavior coupling by a simple logic determines, reaches the purpose of fault diagnosis.

Lift a specific embodiment below, self-adaptation UIO method proposed by the invention carried out emulation testing with the linear model of certain opportunity of combat, provide the numerical value of each matrix in system's correspondence model (1) below:

$A=\left[\begin{array}{cccccc}-0.0153& 0.0481& -5.9420& 0.0021& 0.0000& 0.0000\\ -0.0910& -0.9568& 1383608& 0.0163& 0.0000& 0.0000\\ 0.0002& 0.0046& -1.0220& -0.0005& 0.0000& -0.0029\\ 0.0000& 0.0000& 0.0000& -0.2804& 6.2667& -1511435\\ 0.0000& 0.0000& 0.0003& -0.1821& -3.4192& 0.6401\\ 0.0000& 0.0000& 0.0025& 0.0454& -0.0304& -0.4535\end{array}\right]$

$B=\left[\begin{array}{ccccc}0.0239& 0.0239& 0.0250& 0.0250& 0.000\\ -0.1722& -0.1722& -0.1799& -0.1799& 0.0000\\ -0.0873& -0.0873& -0.0076& -0.0076& 0.0000\\ -0.3149& 0.3149& 0.0233& -0.0233& 0.1205\\ -0.1892& 0.1892& -0.3464& 0.3464& 0.1237\\ 0.1678& 0.1678& -0.0147& 0.0147& -0.0587\end{array}\right]$

E＝[0.0481?-0.9568?0.0046?0?0?0] ^T；

$C=\left[\begin{array}{cccccc}0.0000& 0.0000& 57.2958& 0.0000& 0.0000& 0.0000\\ 0.0000& 0.0000& 0.0000& 0.0000& 57.2468& 2.3696\\ 0.0000& 0.0000& 0.0000& 0.0000& -2.3696& 57.2468\\ -0.0155& 0.3756& 0.0000& 0.0000& 0.0000& 0.0000\\ 0.0000& 0.0000& 0.0000& 0.3760& 0.0000& 0.0000\\ 0.0000& 1.0000& 0.0000& 0.0000& 0.0000& 0.0000\end{array}\right]$

Five actuators are arranged in this flight control system, in order to detect the stuck fault of each actuator, the multi-model fault detection system structure that proposes according to the present invention, need six self-adaptation UIO observers of design, the normal condition of one of them corresponding system, other five respectively corresponding five situations that actuator is stuck.By the stuck fault observer of formula (11) design actuator, observer parameter F, G, K ₁, K ₂With satisfy condition formula (6)～(9) and to make F by POLE PLACEMENT USING be stable of H, (12) and (13) design self-adaptation regulation by formula, the foundation of Fig. 1 structure press by system.Figure 2 shows that the measurement output of system in the simulation process, be in normal condition when system brings into operation, in 5 seconds, disturbing signal periodically joins in the system, during 10 seconds, actuator failures occurs.Fault in this example be the right elevator actuator stuck ${\stackrel{\&OverBar;}{u}}_1=1$ The position.Figure 3 shows that the estimation curve of output of corresponding self-adaptation UIO, as we can see from the figure, after the stuck fault of actuator occurs, promptly since 10 second actuator the position no longer change with its input instruction, the self-adaptation UIO method of utilizing the present invention to provide is carried out On-line Estimation to stuck position, the estimated value of stuck position very rapid convergence has realized the accurate estimation of stuck position in its true value.Figure 4 shows that six pairing six models of UIO and system matches performance index curve, because simulated failure is that the right elevator actuator is stuck, the corresponding therewith self-adaptation UIO of our expectations can provide the result of coupling, promptly obtains minimum performance index.From Fig. 4 as seen, system has realized our expection really, and corresponding performance index J1 is after 10 seconds, and numerical value is far smaller than the pairing performance index of other observer.Relatively six performance index can be diagnosed out the stuck fault of right elevator actuator rapidly and accurately.

Claims (1)

1, a kind of real-time detection method of the stuck fault of actuator in the flight control system is characterized in that this method comprises the steps:

1) fault type that detects according to the number of actuator in the flight control system and desire is determined the number of observer in the fault detection system, under the situation of only considering the stuck fault of actuator, the number of observer is that actuator number p adds 1, the model of the normal operation of one of them corresponding system, p the stuck fault of difference actuation means;

2) set up the stuck fault model of p actuator;

3) the stuck fault UIO observer of design actuator;

4) the self-adaptation regulation of design executor dead position Estimation of Parameters value;

5) output of each observer is compared with the actual measured value of system state obtain the residual signals of each observer, calculate the coupling index of corresponding each observer then;

6) programming performing step 3) observer, residual computations and the coupling index that designs in the step 5) calculated, and forms the multi-model fault detection system;

7) according to the detection principle of multi-model fault detection system, the fault diagnosis decision package compares all p+1 that obtain coupling indexs, and the current state of minimum coupling index representative system is consistent with corresponding malfunction, thereby realizes fault detect.

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