A Cold and Hot State Flight Control Method for a Hypersonic Vehicle Engine

Abstract

This application belongs to the field of flight control technology and is a cold and hot state flight control method for a hypersonic vehicle engine. First, according to the flight characteristics of the hypersonic vehicle, longitudinal and lateral linearized modeling of the hypersonic vehicle is carried out. Then, corresponding controllers are designed at each independent operating point of the hypersonic vehicle. According to each controller, a linearized control model of the hypersonic vehicle before the scramjet engine ignition and a linearized control model of the hypersonic vehicle after the scramjet engine ignition are established respectively; since the control parameters at each operating point are matched with the corresponding controller, when the state of the engine changes, by first calling the controller corresponding to the state and then using the controller to control the control surface of the engine, the matching of the state and the corresponding control parameters can be achieved, so as to cope with the large changes in the aerodynamic parameters of the vehicle caused by the cold and hot states of the engine, avoid the mismatch between the control parameters and the aerodynamic mode of the vehicle, and ensure the attitude stability and flight safety of the hypersonic vehicle.

Description

Technical Field

[0001] This application belongs to the technical field of flight control, and particularly relates to a cold and hot state flight control method for a hypersonic vehicle engine. Background Art

[0002] A scramjet engine is a ramjet engine that organizes combustion in a supersonic airflow, and is generally applied to hypersonic vehicles with a flight Mach number higher than 6. The forces and moments of a scramjet engine change greatly under cold state (only the inlet starts) and hot state (the engine ignites) conditions, which can vary by several times. At the same time, a scramjet engine is usually integrated with the vehicle design. Except for thrust, the changes in other forces and moments in the cold and hot states will directly act on the airframe, resulting in large changes in the resultant force and moment received by the hypersonic vehicle under the cold and hot states of the scramjet engine. If the control strategy is not adjusted, problems such as poor flight quality will occur, and there is even a risk of out-of-control. Summary of the Invention

[0003] The purpose of this application is to provide a cold and hot state flight control method for a hypersonic vehicle engine to solve the problem that the resultant force and moment received by the hypersonic vehicle change greatly under the cold and hot states of the scramjet engine in the prior art.

[0004] The technical solution of this application is: A cold and hot state flight control method for a hypersonic vehicle engine, including:

[0005] Set the flight characteristics of the hypersonic vehicle, and perform longitudinal and lateral linearization modeling of the hypersonic vehicle;

[0006] Design corresponding controllers at each independent operating point of the hypersonic vehicle to obtain a cluster of controllers, and establish a linearized control model of the hypersonic vehicle before the scramjet engine ignites and a linearized control model of the hypersonic vehicle after the scramjet engine ignites according to each controller respectively;

[0007] Design a controller scheduling function. When the scramjet engine is in the cold state, control the hypersonic vehicle through the linearized control model of the hypersonic vehicle before the scramjet engine ignites; when the flight control system of the hypersonic vehicle issues an engine ignition command, perform controller scheduling and switch to the linearized control model of the hypersonic vehicle after the scramjet engine ignites to control the hypersonic vehicle; when the flight control system of the hypersonic vehicle issues an engine shutdown command, perform controller scheduling and switch to the linearized control model of the hypersonic vehicle before the scramjet engine ignites to control the hypersonic vehicle.

[0008] Preferably, the flight characteristics of the hypersonic vehicle are set as:

[0009] A hypersonic vehicle is a rigid body with six degrees of freedom;

[0010] Hypersonic vehicles have a symmetrical layout;

[0011] Hypersonic vehicles ignore the asymmetry of the fluid;

[0012] Hypersonic vehicles ignore the impact of engine mass changes on the dynamics of the vehicle;

[0013] The center of mass of a hypersonic vehicle always moves along the longitudinal axis of the fuselage.

[0014] Preferably, the longitudinal and lateral linearization modeling method of the hypersonic aircraft is:

[0015] Define hypersonic vehicle state variables S = [u,v,w,p,q,r,φ,θ] T , where u, v, w are the velocity of the aircraft body axis system, p, q, r are the attitude angular rates, φ, θ are the roll angle and pitch angle respectively; the aircraft control variable is U = [δ a ,δ e ,δ r ,Γ T ] T , where δ a ,δ e ,δ r are the control quantities of aileron, elevator and rudder channels respectively, Γ T ={0,1} are scramjet engine ignition and shutdown instructions respectively;

[0016] Then the three-axis force and torque balance equations of the hypersonic vehicle are:

[0017]

[0018] The equation is decoupled and linearized longitudinally and laterally at the Mach number and altitude operating point of the scramjet engine ignition start-up, and the longitudinal and lateral linearized models of the hypersonic aircraft are obtained as follows:

[0019]

[0020] Among them, S a =[ΔuΔwΔqΔθ] T In the vertical state, U a =[Δδ e Γ T T] T is the longitudinal control quantity, the coefficient matrix

[0021]

[0022] S l= [ΔvΔpΔrΔφ] T is the lateral state, U l = [Δδ a Δδ r T is the lateral control quantity, coefficient matrix

[0023]

[0024] Preferably, the linearized control model of the hypersonic vehicle before the scramjet engine ignition is:

[0025] The method for designing the pre-ignition controller based on this linearized control model includes: adopting a PID controller, designing a longitudinal attitude flight controller including a pitch angle / angle of attack PID controller Tuning the PID parameters K θ0 = {k θP0 , T θI0 , T θD0}; designing a lateral attitude flight controller including a roll angle controller Tuning the PID parameters K φ0 = {k φP0 , T φI0 , T φD0}; a heading angle controller, Tuning the PID parameters K ψ0 = {k ψP0 , T ψI0 , T ψD0}.

[0026] Preferably, the linearized control model of the hypersonic vehicle after the scramjet engine ignition is:

[0027] The method for designing the post-ignition controller based on this linearized control model is: adopting a PID controller, designing a longitudinal attitude flight controller including a pitch angle / angle of attack PID controller Tuning the PID parameters K θ1 = {k θP1 , T θI1 , T θD1}; designing a lateral attitude flight controller including a roll angle controller Tuning the PID parameters K φ1 = {k φP1 , T φI1 , T φD1}; a heading angle controller, Tuning the PID parameters K ψ1 = {k ψP1 , T​ψI1 ,T ψD1}。

[0028] Preferably, if the engine fails to ignite successfully after t seconds since the flight control system issues an engine ignition command, the flight control system issues an engine shutdown command, Γ T = 0, perform controller scheduling, and switch to the linearized control model of the hypersonic vehicle before scramjet engine ignition to control the hypersonic vehicle.

[0029] Preferably, during the engine ignition process, if the flight control system senses that the engine shuts down abnormally, the flight control system issues an engine shutdown command, Γ T = 0, perform controller scheduling, and switch to the linearized control model of the hypersonic vehicle before scramjet engine ignition to control the hypersonic vehicle.

[0030] A method for controlling the cold and hot states of an engine of a hypersonic vehicle according to the present application first performs longitudinal and lateral linearization modeling of the hypersonic vehicle according to the flight characteristics of the hypersonic vehicle, and then designs corresponding controllers at each independent operating point of the hypersonic vehicle. According to each controller, a linearized control model of the hypersonic vehicle before scramjet engine ignition and a linearized control model of the hypersonic vehicle after scramjet engine ignition are established respectively; since the control parameters at each operating point are matched with the corresponding controllers, when the state of the engine changes, by first calling the controller corresponding to the state and then using the controller to control the engine's control surfaces, the matching of the state and the corresponding control parameters can be achieved, thereby coping with the large changes in the aerodynamic parameters of the vehicle caused by the cold and hot states of the engine, avoiding the mismatch between the control parameters and the aerodynamic mode of the vehicle, and ensuring the attitude stability and flight safety of the hypersonic vehicle. Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions provided by the present application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application.

[0032] Figure 1 is the overall process schematic diagram of the present application;

[0033] Figure 2 is the schematic diagram of the cold and hot state controller scheduling of the engine of the present application. Detailed Embodiments

[0034] To make the purpose, technical solutions, and advantages of the implementation of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application.

[0035] A method for controlling the cold and hot states of an engine of a hypersonic vehicle, such asFigure 1 As shown, it includes the following steps:

[0036] Step S100, set the flight characteristics of the hypersonic vehicle, and conduct longitudinal and lateral linearized modeling of the hypersonic vehicle;

[0037] Preferably, the flight characteristics of the hypersonic vehicle are set as follows:

[0038] 1) The hypersonic vehicle is a six-degree-of-freedom rigid body;

[0039] 2) The hypersonic vehicle has a symmetric layout;

[0040] 3) The hypersonic vehicle ignores the asymmetry of the fluid;

[0041] 4) The hypersonic vehicle ignores the influence of engine mass change on the dynamics of the vehicle;

[0042] 5) The center of mass of the hypersonic vehicle always moves on the longitudinal axis of the airframe axis.

[0043] Preferably, the longitudinal and lateral linearized modeling method of the hypersonic vehicle is as follows:

[0044] Define the state variable S of the hypersonic vehicle as S = [u, v, w, p, q, r, φ, θ] T , where u, v, and w are the motion speeds of the vehicle in the body-axis system, p, q, and r are the attitude angular rates, and φ and θ are the roll angle and pitch angle respectively; the vehicle control variable is U = [δ a , δ e , δ r , Γ T T , where δ a , δ e , δ r are the control amounts of the aileron, elevator, and rudder channels respectively, and Γ T = {0, 1} are the ignition and extinguishing commands of the scramjet engine respectively;

[0045] Then the three-axis force and moment balance equations of the hypersonic vehicle are:

[0046]

[0047] At the Mach number and altitude operating points where the scramjet engine ignites and starts, decouple and linearize this equation longitudinally and laterally to obtain the longitudinal and lateral linearized models of the hypersonic vehicle as:

[0048]

[0049] Among them, S a = [Δu Δw Δq Δθ]​T is in the longitudinal state, U a = [Δδ e Γ T T] T is the longitudinal control quantity, coefficient matrix

[0050]

[0051] S l = [Δv Δp Δr Δφ] T is in the lateral state, U l = [Δδ a Δδ r T is the lateral control quantity, coefficient matrix

[0052]

[0053] By establishing the longitudinal and lateral linearized models of the hypersonic vehicle, it provides a basis for the flight control of the hypersonic vehicle.

[0054] Step S200, before and after the scramjet engine ignites, parameters such as thrust and pitching moment will change greatly, that is, the coefficient matrices of the control model change from A a0 , A l0 under cold engine conditions to A a1 , A l1 under hot conditions, where a0 and l0 are the operating points before the scramjet engine ignites, and a1 and l1 are the operating points after the scramjet engine ignites. For such a system with a state-space expression that changes dynamically with time-varying parameters, a gain-scheduling method is used for flight control.

[0055] Since there are multiple operating points both before and after the scramjet engine ignites, and even for different operating points before the scramjet engine ignites, their operating states will also be different. Therefore, how to control each independent operating point separately while ensuring that key parameters do not change greatly during control is a problem that needs to be solved.

[0056] The specific solution is as follows:

[0057] Design corresponding controllers for each independent operating point of the hypersonic vehicle to obtain a cluster of controllers, and establish a linearized control model of the hypersonic vehicle before the scramjet engine ignites and a linearized control model of the hypersonic vehicle after the scramjet engine ignites according to each controller respectively;

[0058] In this way, different operating points can be controlled separately through different controllers.

[0059] ​Preferably, the linearized control model of a hypersonic vehicle before the scramjet engine ignition is as follows:

[0060] As a specific implementation manner, the method for designing a controller based on the linearized control model of a hypersonic vehicle before the scramjet engine ignition includes: adopting a PID controller, and designing a longitudinal attitude flight controller including a pitch angle / angle of attack PID controller Tuning the PID parameters K θ0 ={k θP0 , T θI0 , T θD0}; designing a lateral attitude flight controller including a roll angle controller Tuning the PID parameters K φ0 ={k φP0 , T φI0 , T φD0}; a heading angle controller, Tuning the PID parameters K ψ0 ={k ψP0 , T ψI0 , T ψD0}.

[0061] Preferably, the linearized control model of a hypersonic vehicle after the scramjet engine ignition is as follows:

[0062] As a specific implementation manner, the method for designing a controller based on the linearized control model of a hypersonic vehicle after the scramjet engine ignition is: adopting a PID controller, and designing a longitudinal attitude flight controller including a pitch angle / angle of attack PID controller Tuning the PID parameters K θ1 ={k θP1 , T θI1 , T θD1}; designing a lateral attitude flight controller including a roll angle controller Tuning the PID parameters K φ1 ={k φP1 , T φI1 , T φD1}; a heading angle controller, Tuning the PID parameters K ψ1 ={k ψP1 , T ψI1 , T ψD1}.

[0063] It should be noted that the PID controller is only one embodiment of the present invention, and other controllers that can be adopted include active disturbance rejection controllers, robust controllers, adaptive controllers, non-linear controllers, controllers based on learning algorithms, etc.

[0064] It should be noted that in addition to the pitch angle, roll angle, and heading angle controllers, the included attitude controllers may also include an angle of attack controller, a pitch angle speed controller, an altitude hold controller, a sideslip angle controller, a heading angle rate controller, a reference line hold controller, etc. according to specific flight missions.

[0065] By using the controller and the linearized control model of the hypersonic vehicle to judge parameters such as thrust and pitch moment, the hypersonic vehicle can be enabled to have the ability to sense whether the scramjet engine ignites successfully.

[0066] Step S300, design a controller scheduling function. As Figure 2 shown, when the scramjet engine is in a cold state, the hypersonic vehicle is controlled by the linearized control model of the hypersonic vehicle before the scramjet engine ignites, that is, the control parameters K θ0 , K φ0 , K ψ0 are used for control; when the flight control system of the hypersonic vehicle issues an engine ignition command, controller scheduling is performed, and the control is switched to the linearized control model of the hypersonic vehicle after the scramjet engine ignites to control the hypersonic vehicle, that is, the control parameters are switched to K θ1 , K φ1 , K ψ1 ; after the test is completed, the flight control system of the hypersonic vehicle issues an engine shutdown command, and controller scheduling is performed. At this time, the control is switched to the linearized control model of the hypersonic vehicle before the scramjet engine ignites to control the hypersonic vehicle, that is, the control parameters K θ0 , K φ0 , K ψ0 are used for control.

[0067] Through the switching of the control parameters K θ0 , K φ0 , K ψ0 , K θ1 , K φ1 , K ψ1 in this step, the flight control system of the hypersonic vehicle has the ability to control the ignition of the scramjet engine.

[0068] Preferably, if the engine still fails to ignite successfully t time after the flight control system issues an engine ignition command, the flight control system issues an engine shutdown command, Γ TWhen =0, the controller is scheduled to switch to the linearized control model of the hypersonic vehicle before scramjet ignition to control the hypersonic vehicle.

[0069] Preferably, during the engine ignition operation process, if the flight control system senses that the engine has abnormal flameout, the flight control system issues an engine flameout command, Γ T When =0, the controller is scheduled to switch to the linearized control model of the hypersonic vehicle before scramjet ignition to control the hypersonic vehicle.

[0070] In this application, first, according to the flight characteristics of the hypersonic vehicle, longitudinal and lateral linearized modeling of the hypersonic vehicle is carried out. Then, corresponding controllers are designed at each independent operating point of the hypersonic vehicle. According to each controller, a linearized control model of the hypersonic vehicle before scramjet ignition and a linearized control model of the hypersonic vehicle after scramjet ignition are established respectively; since the control parameters at each operating point are matched with the corresponding controller, when the state of the engine changes, by first calling the controller in the corresponding state and then using the controller to control the rudder surface of the engine, the matching of this state and the corresponding control parameters can be achieved, so as to cope with the large changes in the aerodynamic parameters of the vehicle caused by the cold and hot states of the engine, avoid the mismatch between the control parameters and the aerodynamic mode of the vehicle, and ensure the attitude stability and flight safety of the hypersonic vehicle.

[0071] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A hot and cold state flight control method for a hypersonic vehicle engine, characterized in that Including: Set the flight characteristics of the hypersonic vehicle and conduct longitudinal and lateral linear modeling of the hypersonic vehicle; Design corresponding controllers for each independent operating point of the hypersonic vehicle to obtain a cluster of controllers, and establish a linearized control model of the hypersonic vehicle before scramjet ignition and a linearized control model of the hypersonic vehicle after scramjet ignition according to each controller respectively; Design a controller scheduling function. When the scramjet is in the cold state, control the hypersonic vehicle through the linearized control model of the hypersonic vehicle before scramjet ignition; when the flight control system of the hypersonic vehicle issues an engine ignition command, perform controller scheduling and switch to the linearized control model of the hypersonic vehicle after scramjet ignition to control the hypersonic vehicle; when the flight control system of the hypersonic vehicle issues an engine shutdown command, perform controller scheduling and switch to the linearized control model of the hypersonic vehicle before scramjet ignition to control the hypersonic vehicle.

2. The hot and cold state flight control method for a hypersonic vehicle engine according to claim 1, characterized in that The flight characteristics of the hypersonic vehicle are set as follows: The hypersonic vehicle is a six-degree-of-freedom rigid body; The hypersonic vehicle has a symmetric layout; The hypersonic vehicle ignores the fluid asymmetry; The hypersonic vehicle ignores the influence of engine mass change on the dynamics of the vehicle; The center of mass of the hypersonic vehicle always moves on the longitudinal axis of the airframe axis.

3. The hypersonic vehicle engine hot and cold state flight control method according to claim 1, characterized in that: If the engine fails to ignite successfully after \(t\) seconds since the flight control system issues the engine ignition command, the flight control system issues an engine shutdown command, \(\Gamma\) T \(= 0\), \(\Gamma\) T \(= \{0, 1\}\) are respectively the ignition and shutdown commands for the scramjet engine; perform controller scheduling and switch to the linearized control model of the hypersonic vehicle before scramjet engine ignition to control the hypersonic vehicle.

4. The hot and cold state flight control method for a hypersonic vehicle engine according to claim 1, characterized in that: During the engine ignition working process, if the flight control system senses that the engine has abnormal flameout, the flight control system issues an engine flameout command, Γ T = 0, Γ T = {0, 1} are respectively the ignition and flameout commands for the scramjet engine; perform controller scheduling and switch to the linearized control model of the hypersonic vehicle before scramjet engine ignition to control the hypersonic vehicle.

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