Target aircraft large-attack-angle flight robust H-infinity control method and system

Abstract

The invention provides a target aircraft large-attack-angle flight robust H-infinity control method and system. The method comprises the steps that 1, the target aircraft speed, the target aircraft angular speed, the target aircraft track rolling angle and the target aircraft airflow angle are obtained; 2, setting a confinement domain of a closed-loop pole of a target aircraft large-attack-angle flight robust control system; 3, setting a tracking error model and a target aircraft uncertainty structure of a target aircraft large attack angle flight robust control system; 4, setting a control parameter linear matrix inequality group of the target aircraft large-attack-angle flight robust H-infinity control method; 5, setting a solving target of a linear matrix inequality group of the control parameters, and solving the control parameters by utilizing a linear matrix inequality toolbox; the parameters are applied to a target aircraft large-attack-angle flight robust control system, and the output of a target aircraft large-attack-angle flight robust H-infinity controller is obtained; and step 6, applying the values of the aileron, the elevator and the rudder output by the controller to the target aircraft to realize that the target aircraft tracks a large attack angle instruction, a sideslip angle instruction and a track roll angle instruction.

Description

Technical Field

[0001] The invention belongs to the field of target drone flight control, and in particular relates to a robust H∞ control method and system for target drone high-angle-of-attack flight. Background Art

[0002] In order to meet the test requirements of target drones with wide speed range, large envelope and high maneuverability, the target drones are required to have the ability of wide deceleration range, short turning time and small turning radius, so as to quickly change the direction of the nose and avoid missile attacks to significantly test the combat effectiveness of new weapons and equipment. Maneuverable flight is one of the ways for target drones to achieve the above capabilities.

[0003] The high-angle flight of the target drone is the basis of maneuverable flight, so it is necessary to study the high-angle flight of the target drone. However, when the target drone is in a high-angle state, its aerodynamic characteristics will change dramatically, mainly for the following reasons:

[0004] Nonlinear and unsteady aerodynamics: When the target aircraft is at a high angle of attack, its wings and fuselage will experience airflow separation and vortex breakage as the angle of attack and Mach number increase, causing a sudden change in its aerodynamic characteristics, showing unsteady and strong nonlinearity. At the same time, its dynamic and kinematic models themselves have strong nonlinear characteristics. The nonlinear and unsteady aerodynamics of the target aircraft are extremely unfavorable for its flight control at high angles of attack. The sudden change in aerodynamic characteristics means that the target aircraft no longer has a typical trim state, and the assumptions of the traditional small disturbance linearization model are no longer valid. The aerodynamic model is the basis for designing and analyzing the controller, so the linear controller developed on the basis of the linear model will also fail. Therefore, how to design a fast, accurate, and stable advanced nonlinear controller to achieve high angle of attack flight of the target aircraft is an important research direction at present.

[0005] Uncertainty and disturbance: The control surface of the target aircraft at high angles of attack will have reduced rudder efficiency due to airflow separation, resulting in uncertainty in the input matrix; complex external flight environments such as gusts, turbulence, etc. and unknown input gain matrices will also cause uncertain interference to the target aircraft; at the same time, since the current high-angle-of-attack target aircraft modeling theory is not perfect, its dynamic model itself has large deviations, including inaccurate aerodynamic data, unmodeled dynamics, etc. Therefore, improving the robustness and anti-interference ability of the nonlinear controller for the target aircraft model is the key to achieving high-angle-of-attack flight of the target aircraft.

[0006] Coupling effect: For conventional aircraft, the angle of attack range within the flight envelope is small, and the aerodynamic data can be regarded as a quasi-constant. Therefore, without considering the influence of external interference and brake delay characteristics, the dynamic inverse controller can accurately cancel the coupling of the target aircraft's roll and yaw directions. However, for target aircraft flying at large angles of attack, their aerodynamic data will change with the change of the angle of attack, especially at large angles of attack. Therefore, under the influence of nonlinear and unsteady aerodynamic data, coupled with its own modeling errors, the coupling of the target aircraft's roll and yaw directions will no longer be accurately eliminated, resulting in uncertainty in the roll and yaw directions. Therefore, how to suppress or compensate for the influence of the coupling effect of the target aircraft's roll and yaw directions and design an accurate and stable controller is a difficult problem that must be faced in order to achieve high-angle-of-attack flight of the target aircraft.

[0007] Due to the above characteristics, the lift coefficient of the target aircraft will decrease as the angle of attack increases at a large angle of attack, which is the opposite trend to that at a small angle of attack. If the target aircraft cannot be accurately corrected at the right time, it will enter a deep stall state, which can easily lead to serious consequences. If the target aircraft skids in a stall state, it will produce spontaneous yaw motion, and superimpose oscillations in the pitch, roll, and yaw directions, entering a tailspin state, which will seriously affect the stability and safety of the target aircraft.

[0008] Based on the above problems, the present invention provides a nonlinear robust control system with strong robustness, strong anti-interference ability and high precision to realize good flight of the target aircraft at a large angle of attack. Summary of the invention

[0009] The purpose of the present invention is to provide a robust H ∞ The control method can enable the target aircraft to quickly and accurately track large angle of attack, sideslip angle and track roll angle instructions when the target aircraft has model uncertainty, non-steady state, severe nonlinearity, external gust interference and severe yaw and roll direction coupling, and the closed-loop pole of the target aircraft is within the preset restriction domain.

[0010] The technical solution of the present invention:

[0011] In the first aspect, the present application provides a robust H ∞ A control method, the method is applied to a robust control system for a target drone flying at a high angle of attack, the method comprising:

[0012] Step 1, using an accelerometer, a gyroscope, a GPS and an airflow angle sensor to obtain a target drone speed, a target drone angular velocity, a target drone track roll angle and a target drone airflow angle; the target drone airflow angle is composed of a target drone attack angle and a target drone sideslip angle;

[0013] Step 2, setting the restriction domain of the closed-loop poles of the robust control system of the target aircraft at high angle of attack;

[0014] Step 3, setting the tracking error model of the robust control system of the target aircraft at high angle of attack and the target aircraft uncertainty structure;

[0015] Step 4: Set the robust H for the target aircraft to fly at high angles of attack ∞ A control parameter linear matrix inequality group of the control method; the control parameter linear matrix inequality group is composed of a parameter solving linear matrix inequality and a parameter restriction linear matrix inequality;

[0016] Step 5: Set the solution target of the control parameter linear matrix inequality group, and use the linear matrix inequality toolbox LMI in the Matlab simulation software to calculate the solution target to obtain the robust H of the target aircraft at high angle of attack. ∞ Parameters of the control method; the robust H ∞ The parameters of the control method are applied to the robust control system of the target aircraft at high angle of attack, and the robust control system H of the target aircraft at high angle of attack is obtained. ∞ The output of the controller; the robust H ∞ The output of the controller is the target aircraft aileron deflection value, the target aircraft elevator deflection value and the target aircraft rudder deflection value;

[0017] Step 6, applying the target aircraft's aileron deflection value, target aircraft's elevator deflection value and target aircraft's rudder deflection value to the target aircraft, so that the target aircraft can quickly and accurately track the large angle of attack command, sideslip angle command and track roll angle command at the same time; the large angle of attack command is a command with an angle of attack greater than 25°.

[0018] Furthermore, step 1 includes:

[0019] Step 11: Obtain the target drone velocity V in the target drone airflow coordinate system by using the accelerometer; the target drone airflow coordinate system has three axes: x, y, and z, and the directions of the three axes are forward, rightward, and downward respectively; the direction of the target drone velocity V is the x-axis direction;

[0020] Step 12: Obtain the target aircraft attack angle α and the target aircraft sideslip angle β from the airflow angle sensor;

[0021] Step 13: Obtain the target aircraft angular velocity ω in the target aircraft body coordinate system using the gyroscope b =[ω x ω y ω z ] T The target body coordinate system has three axes: x, y, and z, and the directions of the three axes are forward, right, and downward, respectively; the ω x ,ω y and ω z are the target aircraft angular velocity in the x-axis direction, the y-axis direction and the z-axis direction in the target aircraft body coordinate system respectively;

[0022] Step 14: Obtain the target aircraft track roll angle μ from GPS.

[0023] Furthermore, step 2 includes:

[0024] Step 21: Set the closed-loop pole restriction domain of the target aircraft high-angle-of-attack flight robust control system to a circular domain located to the left of the imaginary axis of the Laplace transformation complex plane; the specific form of the closed-loop pole restriction domain φ is:

[0025]

[0026] Wherein, σ>0, κ>0, -σ is the center position of the circle, κ is the radius of the circle, s is the complex number domain of the Laplace transformation, is the complex conjugate of s.

[0027] Furthermore, step 3 includes:

[0028] Step 31: Set the desired target attack angle α d , expected sideslip angle β d , expected target aircraft track roll angle μ d ;

[0029] Step 32: Set the target drone airflow state error e 1 ; The target drone airflow state error e 1 is the expected target aircraft attack angle α d , expected sideslip angle β d , expected target aircraft track roll angle μ d The difference between the target aircraft's angle of attack α, the target aircraft's sideslip angle β, the target aircraft's track roll angle μ, and the target aircraft's airflow state error e 1 The specific form is: 1 =[α d -αβ d -βμ d -μ] T ;

[0030] Step 33: Set the desired target drone angular velocity [ω xd ω yd ω zd ] T ;

[0031] Step 34: Set the target drone angular velocity error e 2 ; The target drone angular velocity error e 2 is the expected target drone angular velocity [ω xd ω yd ω zd ] T and the target aircraft angular velocity [ω x ω y ω z ] TThe difference between the target aircraft angular velocity error e 2 The specific form is: 2 =[ω xd -ω x ω yd -ω y ω zd -ω z ] T ;

[0032] Step 35: Setting the tracking error model D of the robust control system for the target aircraft at high angle of attack. The specific form of the tracking error model D of the robust control system for the target aircraft at high angle of attack is:

[0033]

[0034] Among them, the is the total tracking error of the target drone, is the derivative of the total tracking error of the target aircraft with respect to time, Φ(V) is the target aircraft state matrix related to the target aircraft speed V, Θ(V) is the target aircraft input matrix related to the target aircraft speed V, ΔΦ and ΔΘ are the target aircraft uncertainties, d represents the external gust interference of the target aircraft, and u represents the robustness of the target aircraft at high angle of attack. ∞ The output of the controller includes the target aircraft aileron rudder deflection value λ ail 、Target aircraft elevator rudder deviation value λ ele and the target aircraft rudder deflection value λ rud ;

[0035] Step 36: Set the target uncertainty structure of the target uncertainty ΔΦ and ΔΘ to: [ΔΦΔΘ] = QΓT(t)[Γ -1 R 1 Γ -1 R 2 ];

[0036] Among them, the matrices Q and R 1 and R 2 is a known constant matrix with a dimension of 6×6, representing the structural information of the uncertainties ΔΦ and ΔΘ; T(t) is a time-varying unknown matrix, representing the uncertainty of the uncertainties ΔΦ and ΔΘ; Γ is a diagonal matrix, and I is the unit matrix; where the matrices Q, R 1 and R 2 The value of should satisfy T(t)T T (t)≤I.

[0037] Furthermore, step 4 includes:

[0038] Step 41: Set the target drone's high angle of attack flight robust H ∞ The control method parameters solve the linear matrix inequality:

[0039]

[0040] Among them, the positive definite matrix Y, the diagonal matrix Γ, the matrix V and the constant τ are the robust H of the target aircraft at high angle of attack to be solved. ∞ The parameters of the control method, I is the unit matrix, the diagonal matrix D and the diagonal matrix E are the error weight matrix and input weight matrix of the robust control system of the target aircraft at high angle of attack, respectively, and ξ is the external gust disturbance d to the robust control system of the target aircraft at high angle of attack H ∞ norm index; the H ∞ The range of the norm index ξ is 0<ξ<0.5;

[0041] Step 42: Set the target drone's high angle of attack flight robust H ∞ The parameter restriction linear matrix inequality of the control method is:

[0042]

[0043] Wherein, W is a parameter restriction matrix, and I is an identity matrix;

[0044] Step 43: Solve the linear matrix inequality with parameters and the linear matrix inequality with parameter constraints to obtain the robust H of the target aircraft at high angle of attack ∞ The control parameters of the control method are linear matrix inequalities.

[0045] Furthermore, step 5 includes:

[0046] Step 51: Set the control parameter linear matrix inequality group to solve the target: minTrace(W)

[0047] Wherein, min represents a minimization operation, and Trace(W) represents the trace of the parameter restriction matrix W;

[0048] Step 52: Use the linear matrix inequality toolbox LMI in Matlab simulation software to solve the robust H of the target aircraft at high angle of attack with minTrace(W) as the target. ∞ The control parameters of the control method are linear matrix inequalities, and the robust H ∞ Parameters of the control method are the positive definite matrix Y, the diagonal matrix Γ, the matrix V and the constant τ;

[0049] Step 53: Set the target drone's high angle of attack flight robust H ∞ The output u of the controller is:

[0050] Get the target aircraft aileron rudder deviation value λ ail 、Target aircraft elevator rudder deviation value λ ele and the target aircraft rudder deflection value λ rud .

[0051] Furthermore, the structure of the closed-loop pole restriction domain φ of the robust control system for target aircraft high angle of attack flight is Where s refers to the complex field of the Laplace transform, is the conjugate complex number of s, and the symmetric matrices Ω and Ξ are used to describe the shape of the closed-loop pole restriction domain;

[0052] The closed-loop pole restriction domain of the target drone's high-angle-of-attack flight robust control system can ensure that the target drone's high-angle-of-attack flight robust control system meets the requirements of steady-state performance and transient performance.

[0053] Set the closed-loop pole restriction domain to a circular domain and set the matrix matrix Among them, σ>0, κ>0, -σ is the center position of the circular domain, and κ is the radius of the circular domain.

[0054] If the robust control system of the target aircraft's high-angle-of-attack flight requires fast convergence speed and small steady-state error, the range of parameter σ is: σ>10, and the range of parameter κ is: 0<κ<2; if the robust control system of the target aircraft's high-angle-of-attack flight requires small overshoot and fast rise speed, the range of parameter σ is: 4<σ<8, and the range of parameter κ is: 4<κ<6.

[0055] In the second aspect, the present application provides a high-angle-of-attack flight robust control system, the system comprising an accelerometer, a gyroscope, a GPS, an airflow angle sensor, a target drone high-angle-of-attack flight robust H ∞ Controller, aileron, elevator and rudder; Among them: the target aircraft speed V measured by the accelerometer, the target aircraft angular velocity ω measured by the gyroscope b =[ω x ω y ω z ] T The target aircraft track roll angle μ measured by GPS, the target aircraft attack angle α and the target aircraft sideslip angle β measured by the airflow angle sensor are the robust H of the target aircraft at high angle of attack. ∞ Controller input; Robust H for high angle of attack flight of target drone ∞ The output of the controller is the deflection values ​​of the aileron, elevator and rudder.

[0056] Advantages of the present invention:

[0057] The present invention provides a robust H-type target aircraft high-angle-of-attack flight control system. ∞ The control method can achieve the following when the target aircraft has model uncertainty, unsteadiness, serious nonlinearity, external gust interference, and serious yaw and roll direction coupling:

[0058] Ensure that the robust control system of the target drone flying at high angle of attack is asymptotically stable;

[0059] The target drone quickly and accurately tracks high angle of attack, sideslip angle and track roll angle instructions;

[0060] The control method is robust to the model parameters of the target aircraft, and does not require the precise model parameters of the target aircraft. It only needs an estimate of the range of parameter changes to implement the target aircraft tracking control instructions when the model parameters are uncertain.

[0061] The control method is robust to external gust disturbances, and the transfer function H of the external gust disturbance to the robust control system of the target aircraft at high angle of attack is realized. ∞ The norm is smaller than the index value, which means that the external gust interference has little effect on the robust control system of the target aircraft at high angle of attack.

[0062] The robust control system for target drone high angle flight is quadratically D-stable, that is, the closed-loop poles of the robust control system for target drone high angle flight are within the preset restriction domain;

[0063] The robust control system of target drone at high angle of attack meets the requirements of steady-state performance and transient performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a schematic diagram of a high angle of attack flight robust control system provided by the present application;

[0065] Figure 2 This is a flowchart of the steps of a high angle of attack flight robust control system provided by the present application;

[0066] Figure 3 This application provides a robust H-type high-angle-of-attack target aircraft flight. ∞ Schematic diagram of the control method;

[0067] Figure 4 It is the target aircraft tracking angle of attack command response curve diagram;

[0068] Figure 5 It is the target aircraft tracking sideslip angle command response curve diagram;

[0069] Figure 6 It is the roll angle command response curve of the target aircraft tracking track. Specific embodiments

[0070] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0071] Embodiment 1

[0072] The present application provides a robust H ∞ A control method is provided, wherein the method is applied to a robust control system for high angle of attack flight.

[0073] like Figure 1As shown, the target drone high angle flight robust control system includes an accelerometer, a gyroscope, a GPS, an airflow angle sensor, a target drone high angle flight robust H ∞ Controller, aileron, elevator and rudder; Among them: the target aircraft speed V measured by the accelerometer, the target aircraft angular velocity ω measured by the gyroscope b =[ω x ω y ω z ] T The target aircraft track roll angle μ measured by GPS, the target aircraft attack angle α and the target aircraft sideslip angle β measured by the airflow angle sensor are the robust H of the target aircraft at high angle of attack. ∞ Controller input; Robust H for high angle of attack flight of target drone ∞ The output of the controller is the deflection values ​​of the aileron, elevator and rudder.

[0074] like Figure 2 As shown, the target drone high angle of attack flight robust H ∞ Control methods include:

[0075] Step 1, using an accelerometer, a gyroscope, a GPS and an airflow angle sensor to obtain a target drone speed, a target drone angular velocity, a target drone track roll angle and a target drone airflow angle; the target drone airflow angle is composed of a target drone attack angle and a target drone sideslip angle;

[0076] Specifically, step 1 includes:

[0077] Step 11: Obtain the target drone velocity V in the target drone airflow coordinate system by using the accelerometer; the target drone airflow coordinate system has three axes: x, y, and z, and the directions of the three axes are forward, rightward, and downward respectively; the direction of the target drone velocity V is the x-axis direction;

[0078] Step 12: Obtain the target aircraft attack angle α and the target aircraft sideslip angle β from the airflow angle sensor;

[0079] Step 13: Obtain the target aircraft angular velocity ω in the target aircraft body coordinate system using the gyroscope b =[ω x ω y ω z ] T The target body coordinate system has three axes: x, y, and z, and the directions of the three axes are forward, right, and downward, respectively; the ω x ,ω y and ω z are the target aircraft angular velocity in the x-axis direction, the y-axis direction and the z-axis direction in the target aircraft body coordinate system respectively;

[0080] Step 14: Obtain the target aircraft track roll angle μ from GPS.

[0081] Step 2, setting the restriction domain of the closed-loop poles of the robust control system of the target aircraft at high angle of attack;

[0082] Specifically, step 2 includes:

[0083] Step 21: Set the closed-loop pole restriction domain of the target aircraft high-angle-of-attack flight robust control system to a circular domain located to the left of the imaginary axis of the Laplace transformation complex plane; the specific form of the closed-loop pole restriction domain φ is:

[0084]

[0085] Wherein, σ>0, κ>0, -σ is the center position of the circle, κ is the radius of the circle, s is the complex number domain of the Laplace transformation, is the complex conjugate of s;

[0086] Step 22: If the robust control system for the target aircraft's high-angle-of-attack flight requires fast convergence speed and small steady-state error, the range of parameter σ is: σ>10, and the range of parameter κ is: 0<κ<2; if the robust control system for the target aircraft's high-angle-of-attack flight requires small overshoot and fast rise speed, the range of parameter σ is: 4<σ<8, and the range of parameter κ is: 4<κ<6;

[0087] Step 23: The closed-loop pole restriction domain of the target drone's high-angle-of-attack flight robust control system can ensure that the target drone's high-angle-of-attack flight robust control system meets the index requirements of steady-state performance and transient performance.

[0088] Step 3, setting the tracking error model of the robust control system of the target aircraft at high angle of attack and the target aircraft uncertainty structure;

[0089] Specifically, step 3 includes:

[0090] Step 31: Set the desired target attack angle α d , expected sideslip angle β d , expected target aircraft track roll angle μ d ;

[0091] Step 32: Set the target drone airflow state error e 1 ; The target drone airflow state error e 1 is the expected target aircraft attack angle α d , expected sideslip angle β d , expected target aircraft track roll angle μ d The difference between the target aircraft's angle of attack α, the target aircraft's sideslip angle β, the target aircraft's track roll angle μ, and the target aircraft's airflow state error e 1 The specific form is: 1 =[α d -αβ d -βμ d -μ] T ;

[0092] Step 33: Set the desired target drone angular velocity [ω xd ω yd ω zd ] T ;

[0093] Step 34: Set the target drone angular velocity error e 2 ; The target drone angular velocity error e 2 is the expected target drone angular velocity [ω xd ω yd ω zd ] T and the target aircraft angular velocity [ω x ω y ω z ] T The difference between the target aircraft angular velocity error e 2 The specific form is: 2 =[ω xd -ω x ω yd -ω y ω zd -ω z [ T ;

[0094] Step 35: Setting the tracking error model D of the robust control system for the target aircraft at high angle of attack. The specific form of the tracking error model D of the robust control system for the target aircraft at high angle of attack is:

[0095]

[0096] Among them, the is the total tracking error of the target drone, is the derivative of the total tracking error of the target aircraft with respect to time, Φ(V) is the target aircraft state matrix related to the target aircraft speed V, Θ(V) is the target aircraft input matrix related to the target aircraft speed V, ΔΦ and ΔΘ are the target aircraft uncertainties, d represents the external gust interference of the target aircraft, and u represents the robustness of the target aircraft at high angle of attack. ∞ The output of the controller includes the target aircraft aileron rudder deflection value λ ail 、Target aircraft elevator rudder deviation value λ ele and the target aircraft rudder deflection value λ rud ;

[0097] Step 36: Set the target uncertainty structure of the target uncertainty ΔΦ and ΔΘ to: [ΔΦΔΘ] = QΓT(t)[Γ -1 R 1 Γ -1 R 2 ];

[0098] Among them, the matrices Q and R 1and R 2 is a known constant matrix with a dimension of 6×6, representing the structural information of the uncertainties ΔΦ and ΔΘ; T(t) is a time-varying unknown matrix, representing the uncertainty of the uncertainties ΔΦ and ΔΘ; Γ is a diagonal matrix, and I is the unit matrix; where the matrices Q, R 1 and R 2 The value of should satisfy T(t)T T (t)≤I.

[0099] Step 4: Set the robust H for the target aircraft to fly at high angles of attack ∞ A control parameter linear matrix inequality group of the control method; the control parameter linear matrix inequality group is composed of a parameter solving linear matrix inequality and a parameter restriction linear matrix inequality;

[0100] Specifically, step 4 includes:

[0101] Step 41: Set the target drone's high angle of attack flight robust H ∞ The control method parameters solve the linear matrix inequality:

[0102]

[0103] Among them, the positive definite matrix Y, the diagonal matrix Γ, the matrix V and the constant τ are the robust H of the target aircraft at high angle of attack to be solved. ∞ The parameters of the control method, I is the unit matrix, the diagonal matrix D and the diagonal matrix E are the error weight matrix and input weight matrix of the robust control system of the target aircraft at high angle of attack, respectively, and ξ is the external gust disturbance d to the robust control system of the target aircraft at high angle of attack H ∞ norm index; the H ∞ The range of the norm index ξ is 0<ξ<0.5;

[0104] Step 42: Set the target drone's high angle of attack flight robust H ∞ The parameter restriction linear matrix inequality of the control method is:

[0105]

[0106] Wherein, W is a parameter restriction matrix, and I is an identity matrix;

[0107] Step 43: Solve the linear matrix inequality with parameters and the linear matrix inequality with parameter constraints to obtain the robust H of the target aircraft at high angle of attack ∞ The control parameters of the control method are linear matrix inequalities.

[0108] Step 5: Set the solution target of the control parameter linear matrix inequality group, and use the linear matrix inequality toolbox LMI in the Matlab simulation software to calculate the solution target to obtain the robust H of the target aircraft at high angle of attack.∞ Parameters of the control method; the robust H ∞ The parameters of the control method are applied to the robust control system of the target aircraft at high angle of attack, and the robust control system H of the target aircraft at high angle of attack is obtained. ∞ The output of the controller; the robust H ∞ The output of the controller is the target aircraft aileron deflection value, the target aircraft elevator deflection value and the target aircraft rudder deflection value;

[0109] Specifically, step 5 includes:

[0110] Step 51: Set the control parameter linear matrix inequality group to solve the target: minTrace(W)

[0111] Wherein, min represents a minimization operation, and Trace(W) represents the trace of the parameter restriction matrix W;

[0112] Step 52: Use the linear matrix inequality toolbox LMI in Matlab simulation software to solve the robust H of the target aircraft at high angle of attack with minTrace(W) as the target. ∞ The control parameters of the control method are linear matrix inequalities, and the robust H ∞ Parameters of the control method are the positive definite matrix Y, the diagonal matrix Γ, the matrix V and the constant τ;

[0113] Step 53: Set the target drone's high angle of attack flight robust H ∞ The output u of the controller is:

[0114] Get the target aircraft aileron rudder deviation value λ ail 、Target aircraft elevator rudder deviation value λ ele and the target aircraft rudder deflection value λ rud .

[0115] Step 6, applying the target aircraft's aileron deflection value, target aircraft's elevator deflection value and target aircraft's rudder deflection value to the target aircraft, so that the target aircraft can quickly and accurately track the large angle of attack command, sideslip angle command and track roll angle command at the same time; the large angle of attack command is a command with an angle of attack greater than 25°.

[0116] In summary, the present invention provides a robust H ∞ Control method. In the case of model uncertainty, unsteadiness, serious nonlinearity, external gust interference and serious yaw and roll direction coupling in the target aircraft, the method relies on accelerometers, gyroscopes, GPS and airflow angle sensors to obtain the target aircraft speed, target aircraft angular velocity, target aircraft track roll angle and target aircraft airflow angle, and uses them as feedback signals to solve the target aircraft's aileron deflection value, elevator deflection value and rudder deflection value, which can achieve:

[0117] Ensure that the robust control system of the target drone flying at high angle of attack is asymptotically stable;

[0118] The target drone quickly and accurately tracks high angle of attack, sideslip angle and track roll angle instructions;

[0119] The control method is robust to the model parameters of the target aircraft, and does not require the precise model parameters of the target aircraft. It only needs an estimate of the range of parameter changes to implement the target aircraft tracking control instructions when the model parameters are uncertain.

[0120] The control method is robust to external gust disturbances, and the transfer function H of the external gust disturbance to the robust control system of the target aircraft at high angle of attack is realized. ∞ The norm is smaller than the index value, which means that the external gust interference has little effect on the robust control system of the target aircraft at high angle of attack.

[0121] The robust control system for target drone high angle flight is quadratically D-stable, that is, the closed-loop poles of the robust control system for target drone high angle flight are within the preset restriction domain;

[0122] The robust control system of target drone at high angle of attack meets the requirements of steady-state performance and transient performance.

[0123] Embodiment 2

[0124] The present application provides a robust H ∞ The control method is applied to a robust control system for high angle of attack flight. In this embodiment, a robust H control system for high angle of attack flight of a target aircraft is controlled on a Lenovo Savior laptop computer based on flight simulation software X-Plane and digital simulation software Matlab. ∞ The control method was experimented and useful conclusions were obtained. The specific steps are as follows:

[0125] Step 1: See Figure 1 The target aircraft velocity V and target aircraft angular velocity ω are obtained by accelerometer, gyroscope, GPS and airflow angle sensor. b =[ω x ω y ω z ] T , target aircraft track roll angle μ and target aircraft airflow angle [αβ] T .

[0126] Step 2: Set the closed-loop pole limit domain of the target aircraft high angle of attack flight robust control system to:

[0127]

[0128] Among them, the closed-loop pole restriction domain is a circular domain with the center at -12 and the half price being 1.5.

[0129] Step 3, setting the tracking error model D of the robust control system of the target aircraft at high angle of attack and the target aircraft uncertainty structure;

[0130] For details, see Figure 3 , step 3 includes:

[0131] Step 31: Set the desired target attack angle α d , expected sideslip angle β d , expected target aircraft track roll angle μ d ;

[0132] Step 32: Set the target drone airflow state error e 1 ; The target drone airflow state error e 1 is the expected target aircraft attack angle α d , expected sideslip angle β d , expected target aircraft track roll angle μ d The difference between the target aircraft's angle of attack α, the target aircraft's sideslip angle β, the target aircraft's track roll angle μ, and the target aircraft's airflow state error e 1 The specific form is: 1 =[α d -αβ d -βμ d -μ] T ;

[0133] Step 33: Set the desired target drone angular velocity [ω xd ω yd ω zd ] T ;

[0134] Step 34: Set the target drone angular velocity error e 2 ; The target drone angular velocity error e 2 is the expected target drone angular velocity [ω xd ω yd ω zd ] T and the target aircraft angular velocity [ω x ω y ω z ] T The difference between the target aircraft angular velocity error e 2 The specific form is: 2 =[ω xd -ω x ω yd -ω y ω zd -ω z ] T ;

[0135] Step 34: Set the tracking error model D of the robust control system of the target aircraft at high angle of attack to:

[0136]

[0137] Where t is the simulation time;

[0138] Step 35: Set the target uncertainty structure of the target uncertainty ΔΦ and ΔΘ as:

[0139]

[0140] Step 4: Set the robust H for the target aircraft to fly at high angles of attack ∞ A control parameter linear matrix inequality group of the control method; the control parameter linear matrix inequality group is composed of a parameter solving linear matrix inequality and a parameter restriction linear matrix inequality;

[0141] Specific, specific, see Figure 3 , step 4 includes:

[0142] Step 41: Set the target drone's high angle of attack flight robust H ∞ The control method parameters solve the linear matrix inequality:

[0143]

[0144] Among them, the positive definite matrix Y, the diagonal matrix Γ, the matrix V and the constant τ are the robust H of the target aircraft at high angle of attack to be solved. ∞ The parameters of the control method, I is the unit matrix, the diagonal matrix D and the diagonal matrix E are the error weight matrix and input weight matrix of the robust control system of the target aircraft at high angle of attack, respectively, and ξ is the external gust disturbance d to the robust control system of the target aircraft at high angle of attack H ∞ norm index; the H ∞ The range of the norm index ξ is 0<ξ<0.5;

[0145] Step 42: Set the target drone's high angle of attack flight robust H ∞ The parameter restriction linear matrix inequality of the control method is:

[0146]

[0147] Wherein, W is a parameter restriction matrix, and I is an identity matrix;

[0148] Step 43: Solve the linear matrix inequality with parameters and the linear matrix inequality with parameter constraints to obtain the robust H of the target aircraft at high angle of attack ∞ The control parameters of the control method are linear matrix inequalities.

[0149] Step 5: Set the solution target of the control parameter linear matrix inequality group, and use the linear matrix inequality toolbox LMI in the Matlab simulation software to calculate the solution target to obtain the robust H of the target aircraft at high angle of attack. ∞ Parameters of the control method; the robust H ∞ The parameters of the control method are applied to the robust control system of the target aircraft at high angle of attack, and the robust control system H of the target aircraft at high angle of attack is obtained. ∞ The output of the controller; the robust H ∞ The output of the controller is the target aircraft aileron deflection value, the target aircraft elevator deflection value and the target aircraft rudder deflection value;

[0150] For details, see Figure 3 , step 5 includes:

[0151] Step 51: Set the control parameter linear matrix inequality group to solve the target: minTrace(W)

[0152] Wherein, min represents a minimization operation, and Trace(W) represents the trace of the parameter restriction matrix W;

[0153] Step 52: Use the linear matrix inequality toolbox LMI in Matlab simulation software to solve the robust H of the target aircraft at high angle of attack with minTrace(W) as the target. ∞ The control parameters of the control method are linear matrix inequalities, and the robust H ∞ The parameters of the control method are positive definite matrix Y, diagonal matrix Γ, matrix V and constant τ; the target aircraft high angle flight robust H ∞ The value of the parameter positive definite matrix Y of the control method is solved as follows:

[0154]

[0155] The target drone high angle of attack flight robust H ∞ The parameter matrix V of the control method is solved to obtain the value:

[0156]

[0157] Step 53: Set the target drone's high angle of attack flight robust H ∞ The output u of the controller is:

[0158] Get the target aircraft aileron rudder deviation value λ ail 、Target aircraft elevator rudder deviation value λ ele and the target aircraft rudder deflection value λ rud .

[0159] Step 6, applying the target aircraft's aileron deflection value, target aircraft's elevator deflection value and target aircraft's rudder deflection value to the target aircraft, so that the target aircraft can quickly and accurately track the large angle of attack command, sideslip angle command and track roll angle command at the same time.

[0160] Simulation experiment results based on X-Plane and Matlab: Figure 4 The target aircraft tracking angle of attack command response curve is shown in FIG. 1 , where the red dotted line is the target aircraft's expected angle of attack command, and the blue solid line is the target aircraft's actual angle of attack. It can be seen that the robust H ∞ Under the control method, the target drone can overcome the uncertainty of the model and the nonlinearity and unsteadiness of the aerodynamic parameters caused by the large angle of attack, and can quickly track the angle of attack step instructions without overshoot or static error, including the 40° large angle of attack instructions. Figure 5 It is the target aircraft tracking sideslip angle command response curve, where the red dotted line is the target aircraft's expected sideslip angle command, and the blue solid line is the target aircraft's actual sideslip angle; Figure 5 is the target aircraft tracking track roll angle command response curve, where the red dotted line is the target aircraft's expected track roll angle command, and the blue solid line is the target aircraft's actual track roll angle; Figure 5 and Figure 6 It can be seen that the robust H of the target aircraft high angle of attack flight provided in this application ∞ Under the control method, the target drone can overcome the high coupling of yaw and roll directions, and realize tracking of slope sideslip angle and track roll angle instructions with a maximum amplitude of 5° under different attack angles, including under a large attack angle of 40°. The invention has strong engineering application value.

Claims

1. A robust H-based target aircraft high angle of attack flight ∞ The control method is characterized in that The method is applied to a robust control system for target drone high angle of attack flight, and the method comprises: Step 1, using an accelerometer, a gyroscope, a GPS and an airflow angle sensor to obtain a target drone speed, a target drone angular velocity, a target drone track roll angle and a target drone airflow angle; the target drone airflow angle is composed of a target drone attack angle and a target drone sideslip angle; Step 2, setting the restriction domain of the closed-loop poles of the robust control system of the target aircraft at high angle of attack; Step 3, setting the tracking error model of the robust control system of the target aircraft at high angle of attack and the target aircraft uncertainty structure; Step 4: Set the robust H for the target aircraft to fly at high angles of attack ∞ A control parameter linear matrix inequality group of the control method; the control parameter linear matrix inequality group is composed of a parameter solving linear matrix inequality and a parameter restriction linear matrix inequality; Step 5: Set the solution target of the control parameter linear matrix inequality group, and use the linear matrix inequality toolbox LMI in the Matlab simulation software to calculate the solution target to obtain the robust H of the target aircraft at high angle of attack. ∞ Parameters of the control method; the robust H ∞ The parameters of the control method are applied to the robust control system of the target aircraft at high angle of attack, and the robust control system H of the target aircraft at high angle of attack is obtained. ∞ The output of the controller; the robust H ∞ The output of the controller is the target aircraft aileron deflection value, the target aircraft elevator deflection value and the target aircraft rudder deflection value; Step 6, applying the target aircraft's aileron deflection value, target aircraft's elevator deflection value and target aircraft's rudder deflection value to the target aircraft, so that the target aircraft can quickly and accurately track the large angle of attack command, sideslip angle command and track roll angle command at the same time; the large angle of attack command is a command with an angle of attack greater than 25°.

2. The method according to claim 1, characterized in that: Step 1 includes: Step 11: Obtain the target drone velocity V in the target drone airflow coordinate system by using the accelerometer; the target drone airflow coordinate system has three axes: x, y, and z, and the directions of the three axes are forward, rightward, and downward respectively; the direction of the target drone velocity V is the x-axis direction; Step 12: Obtain the target aircraft attack angle α and the target aircraft sideslip angle β from the airflow angle sensor; Step 13: Obtain the target aircraft angular velocity ω in the target aircraft body coordinate system using the gyroscope b =[ω x ω y ω z ] T The target body coordinate system has three axes: x, y, and z, and the directions of the three axes are forward, right, and downward, respectively; the ω x ,ω y and ω z are the target aircraft angular velocity in the x-axis direction, the y-axis direction and the z-axis direction in the target aircraft body coordinate system respectively; Step 14: Obtain the target aircraft track roll angle μ from GPS.

3. The method according to claim 1, characterized in that Step 2 includes: Step 21: Set the closed-loop pole restriction domain of the target aircraft high-angle-of-attack flight robust control system to a circular domain located to the left of the imaginary axis of the Laplace transformation complex plane; the specific form of the closed-loop pole restriction domain φ is: Wherein, σ>0, κ>0, -σ is the center position of the circle, κ is the radius of the circle, s is the complex number domain of the Laplace transformation, is the complex conjugate of s.

4. The method according to claim 1, characterized in that: Step 3 includes: Step 31: Set the desired target attack angle α d , expected sideslip angle β d , expected target aircraft track roll angle μ d ; Step 32: Set the target aircraft airflow state error e1; the target aircraft airflow state error e1 is the desired target aircraft attack angle α d , expected sideslip angle β d , expected target aircraft track roll angle μ d The specific form of the target aircraft airflow state error e1 is: e1 = [α d -αβ d -βμ d -μ] T ; Step 33: Set the desired target drone angular velocity [ω xd ω yd ω zd ] T ; Step 34: Set the target aircraft angular velocity error e2; the target aircraft angular velocity error e2 is the expected target aircraft angular velocity [ω xd ω yd ω zd ] T and the target aircraft angular velocity [ω x ω y ω z ] T The specific form of the target aircraft angular velocity error e2 is: e2 = [ω xd -ω x ω yd -ω y ω zd -ω z ] T ; Step 35: Setting the tracking error model D of the robust control system for the target aircraft at high angle of attack. The specific form of the tracking error model D of the robust control system for the target aircraft at high angle of attack is: Among them, the is the total tracking error of the target drone, is the derivative of the total tracking error of the target aircraft with respect to time, Φ(V) is the target aircraft state matrix related to the target aircraft speed V, Θ(V) is the target aircraft input matrix related to the target aircraft speed V, ΔΦ and ΔΘ are the target aircraft uncertainties, d represents the external gust interference of the target aircraft, and u represents the robustness of the target aircraft at high angle of attack. ∞ The output of the controller includes the target aircraft aileron rudder deflection value λ ail 、Target drone elevator rudder deviation value λ ele and the target aircraft rudder deflection value λ rud ; Step 36: Set the target uncertainty structure of the target uncertainty ΔΦ and ΔΘ to: [ΔΦΔΘ] = QΓT(t)[Γ -1 R1Γ -1 R2]; Among them, the matrices Q, R1 and R2 are known constant matrices with a dimension of 6×6, representing the structural information of the uncertainties ΔΦ and ΔΘ; T(t) is a time-varying unknown matrix, representing the uncertainty of the uncertainties ΔΦ and ΔΘ; Γ is a diagonal matrix, and I is the unit matrix; Among them, the values ​​of the matrices Q, R1 and R2 should and satisfy T(t)T T (t)≤I.

5. The method according to claim 1, characterized in that Step 4 includes: Step 41: Set the target drone's high angle of attack flight robust H ∞ The control method parameters solve the linear matrix inequality: Among them, the positive definite matrix Y, the diagonal matrix Γ, the matrix V and the constant τ are the robust H of the target aircraft at high angle of attack to be solved. ∞ The parameters of the control method, I is the unit matrix, the diagonal matrix D and the diagonal matrix E are the error weight matrix and input weight matrix of the robust control system of the target aircraft at high angle of attack, respectively, and ξ is the external gust disturbance d to the robust control system of the target aircraft at high angle of attack H ∞ norm index; the H ∞ The range of the norm index ξ is 0<ξ<0.5; Step 42: Set the target drone's high angle of attack flight robust H ∞ The parameter restriction linear matrix inequality of the control method is: Wherein, W is a parameter restriction matrix, and I is an identity matrix; Step 43: Solve the linear matrix inequality with parameters and the linear matrix inequality with parameter constraints to obtain the robust H of the target aircraft at high angle of attack ∞ The control parameters of the control method are linear matrix inequalities.

6. The method according to claim 1, characterized in that Step 5 includes: Step 51: Set the control parameter linear matrix inequality group to solve the target: minTrace(W) Wherein, min represents a minimization operation, and Trace(W) represents the trace of the parameter restriction matrix W; Step 52: Use the linear matrix inequality toolbox LMI in Matlab simulation software to solve the robust H of the target aircraft at high angle of attack with minTrace(W) as the target. ∞ The control parameters of the control method are linear matrix inequalities, and the robust H ∞ Parameters of the control method are the positive definite matrix Y, the diagonal matrix Γ, the matrix V and the constant τ; Step 53: Set the target drone's high angle of attack flight robust H ∞ The output u of the controller is: Get the target aircraft aileron rudder deviation value λ ail 、Target drone elevator rudder deviation value λ ele and the target aircraft rudder deflection value λ rud .

7. The method according to claim 3, characterized in that The structure of the closed-loop pole restriction domain φ of the target drone high angle of attack flight robust control system is: Where s refers to the complex field of the Laplace transform, is the conjugate complex number of s, and the symmetric matrices Ω and Ξ are used to describe the shape of the closed-loop pole restriction domain; The closed-loop pole restriction domain of the robust control system for target drone high angle of attack flight can ensure that the robust control system for target drone high angle of attack flight meets the requirements of steady-state performance and transient performance. Set the closed-loop pole restriction domain to a circular domain and set the matrix matrix Among them, σ>0, κ>0, -σ is the center position of the circular domain, and κ is the radius of the circular domain. If the robust control system of the target aircraft flying at a high angle of attack requires fast convergence speed and small steady-state error, the range of parameter σ is: σ>10, and the range of parameter κ is: 0<κ<2; The robust control system of the target drone at high angle of attack requires small overshoot and fast ascent speed, so the range of parameter σ is: 4<σ<8, and the range of parameter κ is: 4<κ<6.

8. A robust control system for target drone high angle of attack flight, characterized in that: The system includes an accelerometer, a gyroscope, a GPS, an airflow angle sensor, a robust H ∞ Controller, aileron, elevator and rudder; Among them: the target aircraft speed V measured by the accelerometer, the target aircraft angular velocity ω measured by the gyroscope b =[ω x ω y ω z ] T The target aircraft track roll angle μ measured by GPS, the target aircraft attack angle α and the target aircraft sideslip angle β measured by the airflow angle sensor are the robust H of the target aircraft at high angle of attack. ∞ Controller input; Robust H for high angle of attack flight of target drone ∞ The output of the controller is the deflection values ​​of the aileron, elevator and rudder.

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