CN102929134A - Method for designing controller of multiple time lag aircraft model - Google Patents

Abstract

The invention discloses a method for designing a controller of a multiple time lag aircraft model, which is used for solving the technical problem that the existing robust control theory lacks the design step, so the flight controller is hard to design directly. The technical scheme is as follows: the multiple lag system segmentation robust stability and solvability conditions are given, selection of desired closed-loop poles of linear system state feedback is directly utilized and a constraint condition inequality direct design feedback matrix is given according to the characteristic that all the real parts of all the desired closed-loop poles are negative, so that the engineering technicians in the research field directly design the flight controller for the aircraft model with multiple time lag uncertainty obtained through wind tunnel or flight tests, thus solving the technical problem that the current research results only give the robust stability inequality but can not directly design the flight controller.

Description

The controller design method of aircraft a plurality of time lag of model

Technical field

The present invention relates to a kind of controller design method, particularly relate to the controller design method of a kind of aircraft a plurality of time lag of model.

Background technology

The aircraft robust control is one of emphasis problem of present international airline circle research, when the high performance airplane controller designs, must consider robust stability and kinds of robust control problems; Practical flight device model is the non-linear differential equation of very complicated Unknown Model structure, and in order to describe the non-linear of this complexity, people adopt wind-tunnel and flight test to obtain the test model of describing by discrete data usually; In order to reduce risks and to reduce experimentation cost, usually carry out the flight maneuver test according to differing heights, Mach number, like this, the discrete data of describing the aircraft test model is not a lot, aircraft is very practical preferably to static stability for this model.Yet the modern and following fighter plane has all relaxed restriction to static stability in order to improve " agility ", and fighter plane requires to work near open loop neutrality point usually; So just require well transaction module uncertain problem of flight control system; Will consider following subject matter in the practical flight Control System Design: (1) obtains discrete data with test and describes with a certain approximate model, exists not modeling dynamic in the model; (2) wind tunnel test can not be carried out the full scale model free flight, have constraint, the flight test discrete point is selected, the input action selection of initially state of flight, maneuvering flight etc. can not with all non-linear abundant excitations, adopt System Discrimination gained model to have various errors; (3) flight environment of vehicle and experimental enviroment are had any different, flow field change and interference etc. so that actual aerodynamic force, moment model and test model have any different; (4) there are fabrication tolerance in execution unit and control element, also have the phenomenons such as aging, wearing and tearing in system's operational process, and be not identical with the result of flight test; (5) in the Practical Project problem, need controller fairly simple, reliable, usually need to simplify for ground the mathematics model person, remove some complicated factors; Therefore, when the control problem of research present generation aircraft, just must consider robustness problem; Particularly a plurality of time lags of various degrees are uncertain in the aircraft angle of attack, yaw angle measurement and a lot of physics, the chemical process, if analysis or design process in system are ignored these a plurality of time lags, the result of mistake just may occur or cause the unstable of system.

After 1980, carried out in the world the control theory research of multiple uncertain system, the H-infinit theory that is particularly proposed by Canadian scholar Zames, Zames thinks, why robustness is bad for the LQG method of state-based spatial model, mainly is because represent that with White Noise Model uncertain interference is unpractical; Therefore, in the situation that disturbing, supposition belongs to a certain known signal collection, Zames proposes norm with its corresponding sensitivity function as index, design object is that the error of system is issued in this norm meaning is minimum, thereby will disturb the inhibition problem to be converted into to find the solution makes closed-loop system stable; From then on, the lot of domestic and international scholar has launched the research of H-infinit control method; At aeronautical chart, the method is in the exploratory stage always, U.S. NASA, and the state such as German aerospace research institute, Holland all is studied robust control method, has obtained a lot of emulation and experimental result; Domestic aviation universities and colleges have also carried out a series of research to the aircraft robust control method, such as document (Shi Zhongke, Wu Fangxiang etc., " robust control theory ", National Defense Industry Press, in January, 2003; Su Hongye. " robust control basic theory ", Science Press, in October, 2010) introduce, but the distance of these results and practical application also differs very large, is difficult to directly the practical flight controller be designed and uses; Particularly a lot of researchs have only provided uncertain a plurality of time-delay system Robust Stability according to Lyapunov theorem, but the problems such as existence condition for these solution of inequality relate to less, can not obtain specific implementation robust Controller Design time lag step, not have to solve the directly technical matters of design Robust Flight Control device.

Summary of the invention

Lack the technical deficiency that design procedure is difficult to directly design flight controller in order to overcome existing robust control theory, the invention provides the controller design method of a kind of aircraft a plurality of time lag of model; The method provides a plurality of time lag of the design conditions of real system Robust Stability Controller, directly utilize the closed loop expectation the selection of poles of State Feedback for Linear Systems, and all be the characteristics of negative according to the real part of all closed loops expectation limits, provided the direct design of feedback matrix of qualifications inequality, can directly design flight controller to a plurality of time lags uncertain dummy vehicle of containing that wind-tunnel or flight test obtain, solve that current research only provides the robust stability inequality and the technical matters that can't directly design flight controller.

The technical solution adopted for the present invention to solve the technical problems is: the controller design method of a kind of aircraft a plurality of time lag of model is characterized in may further comprise the steps:

Step 1, under assigned altitute, Mach number condition, obtain containing a plurality of time lags probabilistic dummy vehicles by wind-tunnel or flight test and be:

$\stackrel{\·}{x}\left(t\right)=\mathrm{Ax}\left(t\right)+\underset{i=1}{\overset{r}{\mathrm{\Σ}}}{A}_{\mathrm{\τi}}x(t-{\mathrm{\τ}}_i)+\mathrm{Bu}\left(t\right)---\left(1\right)$

In the formula, x ∈ R ⁿ, u ∈ R ^mBe respectively state and input vector, A, B are known matrix of coefficients, A _{τ i}Be the matrix of coefficients of a plurality of time lag of link, τ _iBe the time delay of the unknown, simple in order to write, x (t) is replaced x (t-τ with x _i) do not write a Chinese character in simplified form;

The selection flight controller is: u=-Kx

In the formula, K is feedback matrix;

Bring in (1) formula, have: $\stackrel{\·}{x}=(A-\mathrm{BK})x+\underset{i=1}{\overset{r}{\mathrm{\Σ}}}{A}_{\mathrm{\τi}}x(t-\mathrm{\τ})$

Step 2, choose the different and real part of the eigenwert of (A-B K) for negative, the design of feedback matrix K is so that satisfy condition:

$\mathrm{\Λ}>M^T\left(\underset{i=1}{\overset{r}{\mathrm{\Σ}}}{A}_{\mathrm{\τi}}^T{M}^{-T}{M}^{-1}{A}_{\mathrm{\τi}}\right)M;$

This controller so that $\stackrel{\·}{x}=(A-\mathrm{BK})x+\underset{i=1}{\overset{r}{\mathrm{\Σ}}}{A}_{\mathrm{\τi}}x(t-\mathrm{\τ})$ Robust stability;

In the formula, M is the matrix of a linear transformation,

M ^-1(A-B?K)M=diag[σ ₁+jω ₁，σ ₂+jω ₂，…，σ _n+jω _n]，

σ _i, ω _i(i=1,2 ..., n) be real number, j ω _i(i=1,2 ..., n) expression imaginary number, diag is the diagonal angle symbol,

$\mathrm{\Λ}=\mathrm{diag}[{\mathrm{\σ}}_1^2,{\mathrm{\σ}}_2^2,\·\·\·,{\mathrm{\σ}}_n^2];$

Δ A-Δ BK is assumed to be Δ A-Δ BK=HFW usually, and H, W all are assumed to be matrix, 0＜F≤I, and I=diag[1,1 ..., 1] and be unit matrix.

The invention has the beneficial effects as follows: can separate condition by a plurality of delay system segmentation robust stabilities provided by the invention, directly utilize the closed loop expectation the selection of poles of State Feedback for Linear Systems, and all be the characteristics of negative according to the real part of all closed loops expectation limits, provided the direct design of feedback matrix of qualifications inequality, so that the engineering technical personnel of this research field directly design flight controller to a plurality of time lags uncertain dummy vehicle of containing that wind-tunnel or flight test obtain, solved that the current research result only provides the robust stability inequality and the technical matters that can't directly design flight controller.

Below in conjunction with embodiment the present invention is elaborated.

Embodiment

The controller design method concrete steps of aircraft of the present invention a plurality of time lag of model are as follows:

1, obtaining containing a plurality of time lags probabilistic dummy vehicles by wind-tunnel or flight test under assigned altitute, Mach number condition is: contain r time lag

$\stackrel{\·}{x}\left(t\right)=\mathrm{Ax}\left(t\right)+\underset{i=1}{\overset{r}{\mathrm{\Σ}}}{A}_{\mathrm{\τi}}x(t-{\mathrm{\τ}}_i)+\mathrm{Bu}\left(t\right)---\left(1\right)$

In the formula, x ∈ R ⁿ, u ∈ R ^mBe respectively state and input vector, A, B are known matrix of coefficients, A _{τ i}Be the matrix of coefficients of a plurality of time lag of link, τ _iBe the time delay of the unknown, simple in order to write, x (t) is replaced x (t-τ with x _i) do not write a Chinese character in simplified form;

The selection flight controller is: u=-Kx

In the formula, K is feedback matrix;

Bring in (1) formula, have: $\stackrel{\·}{x}=(A-\mathrm{BK})x+\underset{i=1}{\overset{r}{\mathrm{\Σ}}}{A}_{\mathrm{\τi}}x(t-\mathrm{\τ})$

2, choose the different and real part of the eigenwert of (A-B K) for negative, the design of feedback matrix K is so that satisfy condition:

$M^T\left(\underset{i=1}{\overset{r}{\mathrm{\Σ}}}{A}_{\mathrm{\τ\ι}}^T{M}^{-T}{M}^{-1}{A}_{\mathrm{\τ\ι}}\right)M;$

This controller so that $\stackrel{\·}{x}=(A-\mathrm{BK})x+\underset{i=1}{\overset{r}{\mathrm{\Σ}}}{A}_{\mathrm{\τi}}x(t-\mathrm{\τ})$ Robust stability;

In the formula, M is the matrix of a linear transformation,

M ^-1(A-BK)M=diag[σ ₁+jω ₁，σ ₂+jω ₂，…，σ _n+jω _n]，

σ _i, ω _i(i=1,2 ..., n) be real number, j ω _i(i=1,2 ..., n) expression imaginary number, diag is the diagonal angle symbol,

$\mathrm{\Λ}=\mathrm{diag}[{\mathrm{\σ}}_1^2,{\mathrm{\σ}}_2^2,\·\·\·,{\mathrm{\σ}}_n^2];$

Δ A-Δ BK is assumed to be Δ A-Δ BK=HFW usually, and H, W all are assumed to be matrix, 0＜F≤I, and I=diag[1,1 ..., 1] and be unit matrix;

Getting the Flight Altitude Moving state variable is x=[a α θ] ^T, input variable is u=δ _e, wherein q is rate of pitch, and α is the air-flow angle of attack, and θ is the angle of pitch, δ _eBe the elevating rudder drift angle; The State Equation Coefficients matrix is:

$A=\left[\begin{array}{ccc}-0.5000& -8.6500& 0\\ 1.0000& -0.3800& 0\\ 1.0000& 0& 0\end{array}\right],$ $B=\left[\begin{array}{c}-6.5000\\ -0.1000\\ 0\end{array}\right],$

2 time lag uncertain part be:

$A_{\mathrm{\τ}1}=\left[\begin{array}{ccc}0.01000& -0.06000& 0\\ -0.13000& 0.14000& 0\\ 0& 0& 0\end{array}\right]F,$ $A_{\mathrm{\τ}2}=\left[\begin{array}{ccc}0.0000& -0.02000& 0\\ -0.23000& 0.074000& 0\\ 0& 0& 0\end{array}\right]F$

0<F≤I，

Selecting closed loop expectation limit is the eigenwert σ (A-BK)=diag[-0.5 of A-BK ,-1 ,-2], can get:

$A-\mathrm{BK}=\left[\begin{array}{ccc}-3.2738& 1.3482& -4.0502\\ 0.9573& -0.2262& -0.0623\\ 1.0000& 0& 0\end{array}\right],$ $M=\left[\begin{array}{ccc}-0.8005& -0.5173& 0.2203\\ 0.4461& 0.6817& -0.8703\\ 0.4003& 0.5173& -0.4406\end{array}\right]$

The controller of a plurality of time-delay systems is: K=[-0.3794 1.5382-0.6231].

Claims (1)

1. the controller design method of aircraft a plurality of time lag of a model is characterized in that may further comprise the steps:

Step 1, under assigned altitute, Mach number condition, obtain containing a plurality of time lags probabilistic dummy vehicles by wind-tunnel or flight test and be:

$\stackrel{\&CenterDot;}{x}\left(t\right)=\mathrm{Ax}\left(t\right)+\underset{i=1}{\overset{r}{\mathrm{\&Sigma;}}}{A}_{\mathrm{\&tau;i}}x(t-{\mathrm{\&tau;}}_i)+\mathrm{Bu}\left(t\right)---\left(1\right)$

In the formula, x ∈ R ⁿ, u ∈ R ^mBe respectively state and input vector, A, B are known matrix of coefficients, A _{τ i}Be the matrix of coefficients of a plurality of time lag of link, τ _iBe the time delay of the unknown, simple in order to write, x (t) is replaced x (t-τ with x _i) do not write a Chinese character in simplified form;

The selection flight controller is: u=-Kx

In the formula, K is feedback matrix;

Bring in (1) formula, have: $\stackrel{\&CenterDot;}{x}=(A-\mathrm{BK})x+\underset{i=1}{\overset{r}{\mathrm{\&Sigma;}}}{A}_{\mathrm{\&tau;i}}x(t-\mathrm{\&tau;})$

Step 2, choose the different and real part of the eigenwert of (A-B K) for negative, the design of feedback matrix K is so that satisfy condition:

$\mathrm{\&Lambda;}>M^T\left(\underset{i=1}{\overset{r}{\mathrm{\&Sigma;}}}{A}_{\mathrm{\&tau;i}}^T{M}^{-T}{M}^{-1}{A}_{\mathrm{\&tau;i}}\right)M;$

This controller so that $\stackrel{\&CenterDot;}{x}=(A-\mathrm{BK})x+\underset{i=1}{\overset{r}{\mathrm{\&Sigma;}}}{A}_{\mathrm{\&tau;i}}x(t-\mathrm{\&tau;})$ Robust stability;

In the formula, M is the matrix of a linear transformation,

M ^-1(A-B?K)M=diag[σ ₁+jω ₁，σ ₂+jω ₂，…，σ _n+jω _n]，

σ _i, ω _i(i=1,2 ..., n) be real number, j ω _i(i=1,2 ..., n) expression imaginary number, diag is the diagonal angle symbol,

$\mathrm{\&Lambda;}=\mathrm{diag}[{\mathrm{\&sigma;}}_1^2,{\mathrm{\&sigma;}}_2^2,\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{\&sigma;}}_n^2];$

Δ A-Δ BK is assumed to be Δ A-Δ BK=HFW usually, and H, W all are assumed to be matrix, 0＜F≤I, and I=diag[1,1 ..., 1] and be unit matrix.