CN111176252A - Fault diagnosis method for concurrent actuator of hypersonic reentry overdrive system - Google Patents

Abstract

The invention discloses a hypersonic reentry overdrive system concurrent actuator fault diagnosis method, which comprises the following steps: step 1, constructing a hypersonic overdrive system mathematical model with concurrent actuator faults; step 2, designing a concurrent actuator fault isolation detection threshold design algorithm, and proposing hypothesis testing according to residual error characteristics to determine a fault detection threshold; and 3, designing a self-adaptive fault estimation algorithm to estimate a fault value in the system. The fault diagnosis method is simple and feasible and can aim at the fault of the concurrent actuator.

Description

Fault diagnosis method for concurrent actuator of hypersonic reentry overdrive system

Technical Field

The invention relates to a fault diagnosis method for a hypersonic reentry overdrive system with a concurrent actuator fault based on an adaptive technology.

Background

The fault is an abnormal phenomenon that the dynamic characteristic and the system parameter of the system deviate from the standard value of the system, so that the normal work of the system is influenced, and any automatic control system can be in fault.

Systems with redundant actuators, i.e. actuators having the same or similar physical characteristics, leading to severe coupling between the actuators, are becoming increasingly competitive due to the reduced cost of the physical components of the control system. The effect of the single control surface actuator of the reentry attitude system on the attitude system is not redundant in pairs, but redundancy exists between the combined actuators, which makes the detection and isolation of the system when concurrent actuator faults occur difficult.

The overdrive system is a system with more control input quantity than output quantity, which brings great difficulty to the design of a controller, and the overdrive system is often processed by control distribution, and the method has certain fault tolerance to actuator faults. Therefore, in the present case, we perform the research of FDI and fault-tolerant control allocation problem for the concurrent actuator failure situation in the HRV overdrive system. Many researchers also research the problem of fault detection of an overdrive system, but most of them decompose the coefficient matrix of the fault to obtain a newly defined full rank coefficient matrix, and then design a fault detection isolation algorithm with the coefficient matrix, and actually the detection result is not the position of the real actuator which is not required by us.

Disclosure of Invention

The invention aims to provide a hypersonic reentry overdrive system concurrent actuator fault diagnosis method which is simple and feasible and can aim at concurrent actuator faults.

In order to achieve the above purpose, the solution of the invention is:

a hypersonic reentry overdrive system concurrent actuator fault diagnosis method comprises the following steps:

step 1, constructing a hypersonic overdrive system mathematical model with concurrent actuator faults;

step 2, designing a concurrent actuator fault isolation detection threshold design algorithm, and proposing hypothesis testing according to residual error characteristics to determine a fault detection threshold;

and 3, designing a self-adaptive fault estimation algorithm to estimate a fault value in the system.

In the step 1, the digital model of the constructed hypersonic overdrive system with concurrent actuator faults is as follows:

wherein f (ω) ═ J^-1ΩJω，

γ＝[φ,β,α]^Tis an attitude angle vector, phi, β, alpha respectively representing the tilt angle, sideslip angle and angle of attack, omega ═ p, q, r]^TIs the angular rate vector, p, q, R are the roll rate, pitch rate and yaw rate, respectively, J ∈ R^3×3Is a symmetrical positive definite inertial matrix,

representing independent Gaussian noise signals with a mean value of zero, B ∈ R^3×8Is the sensitivity matrix, δ_cIs the desired rudder plane deflection vector, Ψ ∈ R^3×10Is a weight matrix, u_rcsIs an input signal of a reaction control system, L_iAs a fault feature vector, f_i(t) is a fault value of the ith control surface, and the matrix Ω and R are as follows:

in step 2 above, for a given confidence level

Acceptance intervals for hypothesis testing are:

wherein the content of the first and second substances,

representing a standard Gaussian distribution variable having

Has a probability of falling into the interval

In the interior of said container body,

representing a residual signal r_{ij_2}(t) standard deviation; when r is_ij∈Ω_ijWhen the system is not in fault, or the fault occurs at L_iOr L_jA channel; when r is_ij≠Ω_ijWhen the actuator fails, the failure is at L_kIn the channel, k is not equal to i, j; therefore, Ω_ijIs for detecting the input channel L_iOr L_jIs detected, and is detected.

In the step 2, detectable factors are introduced to determine the maximum number of the concurrent faults which can be isolated, and then a series of residual signals are designed through a space projection operator, so that each residual is sensitive to some faults.

In the step 3, the adaptive fault estimation algorithm is designed as follows:

wherein the content of the first and second substances,

denotes the fault estimate, G ∈ R^n×3Representing the gain matrix of the estimation algorithm, n representing the number of concurrent actuator faults,

is the error in the state of the device,

an estimate representing ω; ω ═ p, q, r]^TIs the angular rate vector, and p, q, r are the roll rate, pitch rate and yaw rate, respectively.

After adopting the scheme, compared with the prior art, the invention has the following technical effects: and the application of a fault diagnosis algorithm of the concurrent actuator is convenient for positioning the fault position.

Drawings

FIGS. 1-1 through 1-28 are output residual response curves for each channel using the present invention without failure;

FIGS. 2-1 through 2-28 show the application of a single fault f in the present invention to each channel₂(t) an output residual response curve for the case;

FIGS. 3-1 through 3-28 illustrate the application of concurrent faults f in the present invention to each channel₁(t) and f₃(t) an output residual response curve for the case;

FIG. 4 shows a fault f in the present invention₂(t) an estimated response curve;

FIG. 5 shows a fault f in the present invention₁(t) and f₃(t) an estimated response curve;

fig. 6 is a control schematic of the present invention.

Detailed Description

The technical solution and the advantages of the present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 6, the present invention provides a method for diagnosing a fault of a concurrent actuator of a hypersonic reentry overdrive system, which integrally includes the following steps:

step 1, setting characteristic information of concurrent actuator faults and constructing a hypersonic overdrive system mathematical model with the concurrent actuator faults;

step 2, introducing detectable factors to determine the maximum number of concurrent faults which can be isolated, and then designing a series of residual error signals through a space projection operator to enable each residual error to be sensitive to certain faults only; designing a concurrent actuator fault isolation detection threshold design algorithm, and providing hypothesis test according to residual error characteristics to determine a fault detection threshold;

and 3, designing a self-adaptive fault estimation algorithm to estimate a fault value in the system.

Firstly, in step 1, the mathematical model of the constructed hypersonic overdrive system with concurrent actuator faults is as follows:

wherein f (ω) ═ J^-1ΩJω，

γ＝[φ,β,α]^Tis an attitude angle vector, phi, β, alpha respectively representing the tilt angle, sideslip angle and angle of attack, omega ═ p, q, r]^TIs the angular rate vector, p, q, R are the roll rate, pitch rate and yaw rate, respectively, J ∈ R^3×3Is a symmetrical positive definite inertial matrix,

representing independent Gaussian noise signals with a mean value of zero, B ∈ R^3×8Is the sensitivity matrix, δ_cIs the desired rudder plane deflection vector, Ψ ∈ R^3×10Is a weight matrix, u_rcsIs an input signal of a reaction control system, L_iAs a fault feature vector, f_i(t) is a fault value of the ith control surface, and the matrix Ω and R are as follows:

in the step 2, a fault detection algorithm is designed for the hypersonic aircraft, and the fault detection algorithm is obtained by adopting the following proving method:

a detectability index, which represents the maximum number of simultaneous faults that can be detected and isolated, i.e., the maximum number of concurrent faults. μ is defined as the maximum number of faults that can be detected at the same time, where μ < m, which is the number of actuators. A necessary condition for the overdrive system to be mu-detectable is the combination of L per mu +1 fault feature vector_i1,...,L_iμ+1The following conditions are satisfied:

it can be calculated that the detectable index of the studied hypersonic reentry attitude system is 2, so that the case where two faults occur at most simultaneously, that is, n is less than or equal to 2, and n represents the number of faults occurring is considered.

Subspace, reentry to hypersonic velocityWhen two faults occur in the drive system at most simultaneously, the condition for detection and isolation is that any two vector combinations L are combined_iAnd L_jThe following subspaces exist: s_ij＝span{L_i,L_jAnd the subspace satisfies:

the following C (m, μ) residual generators were constructed. Wherein with respect to L_iAnd L_jIs designed to:

where i, j ∈ {1, 2., m } and

is the state vector of the residual generator, n_ij＝dim(ω)-dim(S_ij)，

λ_ij< 0, wherein P_ij:Rⁿ→Rⁿ/S_ijIs a space projection operator and is the key of the residual error generator; e_ij＝F_ijP_ij,g(ω)＝P_ijf(ω),h(T)＝P_ijJ^-1And T. Definition e_ij＝z_ij-P_ijω, then the error dynamic equation of the residual error generator and the original system is:

analysis shows that when the input channel L is used_kWhen a fault occurs, the control unit controls the operation of the control unit,

so the residual r_kjWithout being affected by the fault, the remaining residual signals will all be affected by the fault, where k, j ∈ {1,2, …, m }. Thus, for each actuator failure, there is a unique set of residual errors subject to the failureThe effect of the barrier, and therefore the fault can be detected and isolated by looking at these residuals. For two input channels L_i，L_jIn the event of simultaneous failure, P_ijL_i＝P_ijL_j0, residual r_ijThe two simultaneous faults will be decoupled and the remaining residuals will be affected by them, so the location of the fault occurrence can be easily detected.

N is obtained by calculation_ij＝dim(ω)-dim(S_ij) Let e 1_ij(0) The residual can then be expressed as:

definition of

Note that v (t) is independent white Gaussian noise, with zero mean and R_ν＝E(νν^T) So r_{ij_2}(t) obeys a Gaussian distribution with a mean value of zero, i.e. E [ r ]_{ij_2}(t)]＝0。r_{ij_2}The variance of (t) is:

thus, it is possible to provide

Φ (-) represents a gaussian distribution function. r is_{ij_1}The characteristic of (t) can be expressed as: when t < t_f，r_{ij_1}(t) ═ 0; when t > t_fThe fault occurs in the input channel L_k，k∈{i,j},r_{ij_1}(t) ═ 0; when t > t_fThe fault occurs in the input channel L_k，

r_{ij_1}(t) ≠ 0. We introduce the following hypothesis testing:

for a given confidence level

We can get acceptance intervals for hypothesis testing as:

wherein the content of the first and second substances,

representing a standard Gaussian distribution variable having

Has a probability of falling into the interval

In the interior of said container body,

representing a residual signal r_{ij_2}(t) standard deviation, so we can conclude that when r is_ij∈Ω_ijWhen the system is not in fault, or the fault occurs at L_iOr L_jA channel. When r is_ij≠Ω_ijWhen the actuator fails, the failure is at L_kIn the channel, k ≠ i, j. Therefore, Ω_ijIs for detecting the input channel L_iOr L_jIs detected, and is detected.

The self-adaptive fault estimation algorithm is carried out on the hypersonic aircraft, and the self-adaptive fault estimation algorithm is obtained by adopting the following proving method:

the system model may be represented as:

wherein the content of the first and second substances,

is a system matrix that represents the characteristics of the fault,F＝[f₁；f₂；…；f_n]∈R^{n ×1}representing a fault vector. Then, the following observer was designed to estimate actuator failure:

wherein

Is the state vector of the observer, K ∈ R^3×3Is a matrix of the gains that are,

is an estimate of F. The error dynamics equation of the observer is expressed as:

wherein

It is the error in the estimation of the fault,

is the state error. The adaptive fault estimation algorithm is designed as follows:

wherein the content of the first and second substances,

denotes the fault estimate, G ∈ R^n×3Representing the gain matrix of the estimation algorithm, n representing the number of concurrent actuator faults,

to representAn estimate of ω. The following error-augmenting systems were constructed:

wherein

The Lyapunov function is chosen to be:

V_ζ＝ζ^TPζ

the derivative is in the form:

taking function

The time derivative can be:

wherein H is [0 ═_3×3,I_n×n]. According to Schur's theorem of complement, a proper parameter matrix is selected to obtain

And is

Due to V_ζ＞0，

This is true. Thus we can get

I.e. the fault estimation error is finally bounded and the interference suppression level is met.

First, we consider the system fault-free case, and FIG. 1 depicts the various channel groupsAnd combining the corresponding output residual response curves, the fact that all the residual errors do not exceed the designed threshold interval can be seen, and therefore the fact that no fault exists in the system can be obtained. Then, we consider the input channel L₂There is a fault, i.e. when t is 10s, f₂(t) 0.2sin (t). Fig. 2 depicts the output residual response curves for each channel combination. From these figures it can be seen that the residual signal r₁₂，r₁₃，r₁₄，r₁₅，r₁₆，r₁₇，r₁₈，r₂₃，r₂₄，r₂₅，r₂₆，r₂₇，r₂₈，r₃₄，r₃₅，r₃₆，r₃₇，r₃₈，r₄₅，r₄₆，r₄₇，r₄₈，r₅₆，r₅₇，r₅₈，r₆₇，r₆₈And r₇₈Exceeding the designed threshold interval. Finally, we consider the case of a concurrent failure of the system, two input channels L₁And L₃Presence of fault f₁(t) and f₃(t), wherein when t is 10s, f₁(t) 0.3 and f₃(t) 0.4. Fig. 3 depicts the output residual response curves for each channel combination. As shown, after t is 10s, only r₁₃Without exceeding the threshold curve, all other residuals would be affected by the fault beyond the threshold interval. Simulation results of fault estimation as shown in fig. 4 and 5, response curves indicate that the adaptive fault estimation law can effectively and quickly estimate fault values.

The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the protection scope of the present invention.

Claims (5)

1. A hypersonic reentry overdrive system concurrent actuator fault diagnosis method is characterized by comprising the following steps:

step 1, constructing a hypersonic overdrive system mathematical model with concurrent actuator faults;

step 2, designing a concurrent actuator fault isolation detection threshold design algorithm, and proposing hypothesis testing according to residual error characteristics to determine a fault detection threshold;

and 3, designing a self-adaptive fault estimation algorithm to estimate a fault value in the system.

2. The hypersonic reentry overdrive system concurrent actuator fault diagnosis method of claim 1, wherein: in the step 1, the digital model of the constructed hypersonic overdrive system with concurrent actuator faults is as follows:

wherein f (ω) ═ J^-1ΩJω，γ＝[φ,β,α]^Tis an attitude angle vector, phi, β, alpha respectively representing the tilt angle, sideslip angle and angle of attack, omega ═ p, q, r]^TIs the angular rate vector, p, q, R are the roll rate, pitch rate and yaw rate, respectively, J ∈ R^3×3Is a symmetric positive definite inertial matrix, v (t),

representing independent Gaussian noise signals with a mean value of zero, B ∈ R^3×8Is the sensitivity matrix, δ_cIs the desired rudder plane deflection vector, Ψ ∈ R^3×10Is a weight matrix, u_rcsIs an input signal of a reaction control system, L_iAs a fault feature vector, f_i(t) is a fault value of the ith control surface, and the matrix Ω and R are as follows:

3. the hypersonic reentry overdrive system concurrent actuator fault diagnosis method of claim 1, wherein: in said step 2, for a given confidence level

Acceptance intervals for hypothesis testing are:

wherein the content of the first and second substances,

representing a standard Gaussian distribution variable having

Has a probability of falling into the interval

In the interior of said container body,

representing a residual signal r_{ij_2}(t) standard deviation; when r is_ij∈Ω_ijWhen the system is not in fault, or the fault occurs at L_iOr L_jA channel; when r is_ij≠Ω_ijWhen the actuator fails, the failure is at L_kIn the channel, k is not equal to i, j; therefore, Ω_ijIs for detecting the input channel L_iOr L_jIs detected, and is detected.

4. The hypersonic reentry overdrive system concurrent actuator fault diagnosis method of claim 1, wherein: in the step 2, detectable factors are introduced to determine the maximum number of the concurrent faults which can be isolated, and then a series of residual signals are designed through a space projection operator, so that each residual is sensitive to some faults.

5. The hypersonic reentry overdrive system concurrent actuator fault diagnosis method of claim 1, wherein: in step 3, designing a self-adaptive fault estimation algorithm as follows:

wherein the content of the first and second substances,

denotes the fault estimate, G ∈ R^n×3Representing the gain matrix of the estimation algorithm, n representing the number of concurrent actuator faults,

is the error in the state of the device,

an estimate representing ω; ω ═ p, q, r]^TIs the angular rate vector, and p, q, r are the roll rate, pitch rate and yaw rate, respectively.

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