A fixed-time active disturbance rejection temperature and pressure decoupling control method for a high-altitude cabin air intake system

Abstract

The application relates to a high-altitude cabin air intake system fixed-time self-anti-interference temperature and pressure decoupling control method. Step 1: defining a high-altitude cabin air intake system, a self-anti-interference temperature and pressure decoupling control system and a novel fixed-time self-anti-interference controller; step 2: establishing a high-altitude cabin air intake system model; step 3: according to the established system model, a self-anti-interference temperature and pressure decoupling control system is designed to realize decoupling design of temperature and pressure environment parameters of the air intake system. Step 4: a novel fixed-time self-anti-interference decoupling controller is designed for the self-anti-interference temperature and pressure decoupling control system based on the fixed-time theory, and a novel fixed-time self-anti-interference temperature and pressure decoupling control system is obtained. Step 5: the novel fixed-time self-anti-interference temperature and pressure control system generates a control input signal according to system temperature and pressure environment parameter output signals. Step 6: the control input signal is input into the high-altitude cabin air intake system and the system is operated to obtain temperature and pressure environment parameter output signals. Step 7: steps 5-6 are repeated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-altitude simulation control of an aero-engine, and particularly relates to a fixed-time active disturbance rejection temperature and pressure decoupling control method for a high-altitude cabin air intake system. BACKGROUND

[0002] An aero-engine high-altitude simulation test bench simulates the working environment of an engine in the air on the ground to test the high-altitude working performance and stability of the engine, and mainly includes a gas supply system, an air intake and exhaust system, and an air extraction system. The air intake system in the air intake and exhaust system provides air intake conditions of specific pressure and temperature to simulate the flight state of the engine. In order to meet the airworthiness requirements of modern aero-engines, the air intake system must have the ability to quickly and accurately adjust the air intake pressure and temperature. With the development and evolution of the combat / use mode of new-generation aircraft and the test needs of new-type aero-engines, the engine transition state flight mission test to evaluate and examine the transition state working performance of the engine has become a research focus and focus.

[0003] The engine transition state test, as an important examination content for testing the operability and maneuverability of the engine, includes examination items such as constant Mach number climbing / descending and thrust transient. This kind of test has the significant characteristics of short task time, fast movement rate of the throttle lever, and drastic state change. This kind of transition state test requires that the air intake system must have the ability of rapid and accurate dynamic simulation. However, the current air intake system cannot meet the above requirements, and one of the important reasons is that there is a strong coupling between the pressure and temperature variables, the air intake temperature has the characteristics of large inertia and strong nonlinearity, and the rapid change of the air intake pressure or temperature in the rapid transition state flight mission test will greatly affect the control effect of the environmental parameters. It is extremely difficult for the air intake system to realize the multi-variable combined regulation and control of the air intake pressure and temperature under the engine transition state test mission. In addition, different types of engines need to be tested under different working conditions, and the characteristics of different types of engines are different. The differences between different working conditions make it difficult to accurately model the disturbance information in the system.

[0004] Therefore, how to design a strong disturbance rejection control method capable of realizing high-quality decoupling control of the pressure and temperature environmental parameters of the high-altitude cabin air intake system has become a problem to be solved. SUMMARY

[0005] The application aims at the strong disturbance problem caused by the sharp change of engine flow in the rapid transition state test in the air intake system, the multi-variable strong coupling control problem of pressure and temperature combination adjustment and the urgent need of realizing the rapid and stable control of pressure and temperature, and provides a high-altitude cabin air intake system fixed time active disturbance temperature and pressure decoupling control method.

[0006] To achieve the above object, the technical scheme of the application is as follows: a high-altitude cabin air intake system fixed time active disturbance temperature and pressure decoupling control method, comprising the following steps:

[0007] Step 1: defining the high-altitude cabin air intake system, the active disturbance temperature and pressure decoupling control system and the new fixed time active disturbance controller;

[0008] Step 2: establishing the high-altitude cabin air intake system model;

[0009] Step 3: designing the active disturbance temperature and pressure decoupling control system according to the established high-altitude cabin air intake system model;

[0010] Step 4: designing the new fixed time active disturbance controller for the active disturbance temperature and pressure decoupling control system based on the fixed time theory, and obtaining the new fixed time active disturbance temperature and pressure decoupling control system;

[0011] Step 5: the new fixed time active disturbance temperature and pressure decoupling control system generates the control input signal according to the system pressure and temperature environment parameter output signal;

[0012] Step 6: inputting the control input signal to the high-altitude cabin air intake system, and operating the high-altitude cabin air intake system to obtain the pressure and temperature environment parameter output signal;

[0013] Step 7: repeating steps 5-6.

[0014] In an embodiment of the application, the new fixed time active disturbance temperature and pressure decoupling control system decouples the pressure and temperature variables of the air intake system into single-input and single-output loops based on the active disturbance decoupling control framework, and designs the new fixed time active disturbance controller for each loop for the rapid and stable control of the pressure and temperature double variables of the high-altitude cabin air intake system.

[0015] In an embodiment of the application, step 2 is specifically implemented as follows:

[0016] The dynamic characteristic equation of the high-altitude cabin air intake system pressure and temperature is as follows:

[0017]

[0018]

[0019] In the formula, P, T, V, c p , h, C out , are the intake pressure, temperature, volume and gas constant pressure specific heat capacity, enthalpy, average flow rate, outflow mass flow rate, respectively, h in1 , C in1 are the mass flow rate and gas enthalpy, average flow rate of the hot flow path, h in2 , C in2 are the mass flow rate and gas enthalpy, average flow rate of the cold flow path, and R is the gas constant, is the convective heat transfer between the cavity and the outside world per unit time;

[0020] The engine's own flow rate variation is the largest disturbance source of the system. The engine air flow rate model is obtained through experimental data identification, as shown in the following formula:

[0021] Wa engine = f e (H, Ma, A pla )

[0022] In the formula, H is the flight altitude, Ma is the flight Mach number, A pla is the throttle lever angle, and f e is the engine flow rate function.

[0023] In order to realize decoupling control of the intake system pressure and temperature, the motion characteristics and flow characteristics of the control valve need to be modeled. The control valve motion characteristic model is essentially a third-order control system. Theoretical modeling and data identification methods are used to equivalent the control valve motion characteristic model to a first-order inertia link of the control signal and the real-time opening of the valve:

[0024]

[0025] In the formula, K a is the equivalent gain, T a is the time constant, s is the complex frequency, and u is the control amount.

[0026] The calculation formula of the control valve flow characteristic model is:

[0027]

[0028] In the formula, is the mass flow rate through the valve, is the flow coefficient, A0 is the total flow area of the valve, V a is the real-time opening of the valve, ρ is the air density, and p1 is the pressure before the valve;

[0029] The control amount of the control valve and the valve opening model are as follows:

[0030]

[0031] In the formula, K a,1 , T a,1 , V a,1 are the equivalent gain, time constant and real-time opening of the control valve 1 respectively, K a,2 , T a,2 , V a,2 are the equivalent gain, time constant and real-time opening of the control valve 2 respectively.

[0032] In an embodiment of the present application, in step 3, the self-disturbance temperature and pressure decoupling control system is designed, and the specific implementation is as follows:

[0033] In the high-altitude cabin air intake system, in order to eliminate the static coupling part of the control amount in the high-altitude cabin air intake system, a virtual control amount is introduced, and the control amount of the control valve 1 and the control valve 2 in the high-altitude cabin air intake system and the air intake pressure and temperature controlled object are decoupled; the system output is defined as [p T] T , and the system input is [u1 u2] T , wherein p and T are the air intake pressure and temperature respectively, and u1 and u2 are the control amount of the control valve 1 and the control valve 2 respectively; the nonlinear affine model of the system output and the system input is as follows:

[0034]

[0035] In the formula, f p (p,T) and f T (T,p) are the dynamic coupling part of the air intake pressure and the air intake temperature loop and the action amount of other unknown disturbances on the system, b 11 , b 12 , b 21 , b 22 are the control amount coefficients of the control valve 1 and the control valve 2;

[0036]

[0037]

[0038]

[0039]

[0040] The matrix U is defined as the virtual control amount of the system, the matrix F is the total disturbance of the system, and the matrix B is the static coupling matrix of the system;

[0041]

[0042] By introducing virtual control variables [U1 U2] T The nonlinear affine model of the system output and the system input is arranged as follows:

[0043]

[0044] In the formula, the virtual control variable U of the intake pressure and temperature loop i (i = 1, 2) and the controlled output [p T] T Has been calculated as a one-to-one correspondence, and the decoupling between the controlled output and the virtual control variable has been realized, that is, the static coupling part of the system control variable is eliminated, and a self-disturbance temperature and pressure decoupling control system is obtained.

[0045] In an embodiment of the present application, in step 4, a new fixed-time active disturbance rejection controller is designed for the self-disturbance temperature and pressure decoupling control system, that is, a new fixed-time active disturbance rejection controller based on a new fixed-time sliding mode controller and a fixed-time extended state observer is designed for the decoupled intake pressure and temperature loop, the fixed-time extended state observer is used to quickly and accurately estimate the system state and total disturbance of each loop, and the total disturbance is compensated into the new fixed-time sliding mode controller, so as to effectively cope with the complex and variable disturbance in the rapid transition state flight task of the engine and realize the rapid and stable control of the intake pressure and temperature.

[0046] In an embodiment of the present application, in order to realize complete decoupling of the system, the dynamic coupling caused by the rapid change of the intake pressure and temperature environmental parameters in the system can be considered as a part of the total disturbance and estimated and compensated into the new fixed-time sliding mode controller.

[0047] Define p, T as the system output pressure and temperature, p set ,T set As the target pressure and temperature, let Further, the intake pressure and temperature loop model can be expressed as

[0048]

[0049] Where d p ,d T Are the total disturbances (including system model errors, dynamic coupling parts other than system control variables, uncertainties, etc.) of the intake pressure and temperature loops in the high-altitude cabin intake system. The total disturbances d p ,d T Are considered as new states Assuming that the changes of d p ,d T are bounded, the state equation can be expanded as follows

[0050]

[0051] The fixed-time extended state observer for the above general second-order system is designed as follows:

[0052]

[0053]

[0054] wherein: is the intake pressure loop observer gain, is the intake temperature loop observer gain, are the estimated values of the intake pressure loop system states , respectively, are the estimated values of the intake temperature loop system states , respectively, p T are the amplification factors of the intake pressure and temperature loop observers, respectively, is the error feedback function of each state in the observer, is the exponential coefficient in the error feedback function, b p , b T are the virtual control quantity coefficients of the intake pressure and temperature loops, respectively;

[0055] The error estimates of the intake pressure and temperature loops are The differential error estimates are Let In order to have better rapid performance in practical applications, the fixed-time sliding mode surfaces of the system intake pressure and temperature loops are designed as follows:

[0056]

[0057]

[0058] wherein, γ p , γ T are the exponential term coefficients; λ1 p , μ1 p , λ1 T , μ1 T are the state-related variable exponential parameters; c p , c T are the error term coefficients, and sign is the sign function. Combined with the fixed-time sliding mode surface, the control law of the system intake pressure and temperature loops is designed as follows:

[0059]

[0060] ​

[0061] wherein, k p ,k T is a power term coefficient, ε p ,ε T is a sign function gain, The controller is designed based on the control law, and the system state can converge in a fixed time.

[0062] In an embodiment of the present application, the step 5 specifically comprises: estimating the system state and total disturbance of the high-altitude cabin air intake system pressure and temperature loop by using the fixed-time extended state observer, and compensating the total disturbance to the new fixed-time sliding mode controller of each loop to obtain the control input signal U i (i = 1, 2).

[0063] In an embodiment of the present application, the step 6 specifically comprises: inputting the control input signal to the high-altitude cabin air intake system, and operating the high-altitude cabin air intake system to obtain the air intake pressure and temperature signals.

[0064] In an embodiment of the present application, the step 7 specifically comprises: repeating the steps 5 to 6, combining the designed active disturbance rejection temperature and pressure decoupling control system, and using the new fixed-time active disturbance rejection controller based on the new fixed-time sliding mode controller and the fixed-time extended state observer to realize high-quality decoupling control of the pressure and temperature variables in the high-altitude cabin air intake system. The fixed-time active disturbance rejection controller can quickly converge and the maximum stable time is independent of the initial error, has the ability to effectively cope with short-time large load disturbance in the rapid transition state test of the high-altitude cabin air intake system, and can realize rapid and stable control of the pressure and temperature variables in the high-altitude cabin air intake system.

[0065] In an embodiment of the present application, the other unknown disturbances include system model errors and uncertainties.

[0066] In an embodiment of the present application, the total disturbance of the system includes system model errors, dynamic coupling parts other than system control quantities, and uncertainties.

[0067] The present application also provides a high-altitude cabin air intake system fixed-time active disturbance rejection temperature and pressure decoupling control system, which comprises a memory, a processor, and computer program instructions stored in the memory and capable of being executed by the processor, and when the processor executes the computer program instructions, the method steps described above can be realized.

[0068] The present application also provides a computer readable storage medium having computer program instructions capable of being executed by a processor stored thereon, and when the processor executes the computer program instructions, the method steps described above can be realized.

[0069] Compared with the prior art, the application has the following beneficial effects: the application can realize high-quality decoupling control of pressure and temperature variables of a high-altitude cabin air intake system. BRIEF DESCRIPTION OF DRAWINGS

[0070] Figure 1 High-altitude cabin air intake system

[0071] Figure 2 Active disturbance temperature and pressure decoupling control system

[0072] Figure 3 Transition state test mission profile

[0073] Figure 4 Air intake pressure and temperature control experimental results DETAILED DESCRIPTION

[0074] The technical solutions of the application will be specifically described below with reference to the drawings.

[0075] The application provides a high-altitude cabin air intake system fixed-time active disturbance temperature and pressure decoupling control method, comprising the following steps:

[0076] Step 1, defining a high-altitude cabin air intake system, an active disturbance temperature and pressure decoupling control system and a novel fixed-time active disturbance controller;

[0077] Step 2, establishing a high-altitude cabin air intake system model;

[0078] Step 3, designing an active disturbance temperature and pressure decoupling control system according to the established high-altitude cabin air intake system model;

[0079] Step 4, based on the fixed-time theory, designing a novel fixed-time active disturbance controller for the active disturbance temperature and pressure decoupling control system to obtain a novel fixed-time active disturbance temperature and pressure decoupling control system;

[0080] Step 5, the novel fixed-time active disturbance temperature and pressure decoupling control system generates a control input signal according to a system pressure and temperature environment parameter output signal;

[0081] Step 6, inputting the control input signal to the high-altitude cabin air intake system, and operating the high-altitude cabin air intake system to obtain a pressure and temperature environment parameter output signal;

[0082] Step 7, repeating steps 5-6.

[0083] The following is the specific implementation process of the application.

[0084] Step 1:

[0085] The application is defined as a high-altitude cabin air intake system (see Figure 1 ), an active disturbance temperature and pressure decoupling control system (see Figure 2) and fixed-time active disturbance rejection controller.

[0086] Step 2:

[0087] Wherein the dynamic characteristics equation of high altitude cabin intake system pressure and temperature is as follows:

[0088]

[0089]

[0090] In the formula, P, T, V, c p , h, C out , The intake pressure, temperature, volume and gas constant pressure specific heat, enthalpy, average flow rate, mass flow rate, h in1 , C in1 The mass flow rate and gas enthalpy, average flow rate of hot flow path, h in2 , C in2 The mass flow rate and gas enthalpy, average flow rate of cold flow path, R is the gas constant, The convection heat transfer between the content cavity and the outside world per unit time.

[0091] The engine flow rate variation is the largest disturbance source of the system, and the engine air flow model is obtained by experimental data identification, as shown in the following formula:

[0092] Wa engine = f e (H, Ma, A pla )

[0093] In the formula, H is the flight altitude, Ma is the flight Mach number, A pla is the throttle lever angle.

[0094] In order to realize the decoupling control of intake system pressure and temperature, the motion characteristics and flow characteristics of the control valve need to be modeled. The control valve motion characteristic model is essentially a third-order control system. The theoretical modeling and data identification method can be used to equivalent the control valve motion characteristic model to a first-order inertia link of control signal and valve real-time opening degree:

[0095]

[0096] In the formula, K a is the equivalent gain, T a is the time constant. The simplified model is checked by experimental data and meets the actual system characteristics and meets the engineering application requirements.

[0097] The control valve flow characteristic model calculation formula is:

[0098]

[0099] wherein, is the mass flow rate through the valve, is the flow coefficient, A0is the total flow area of the valve, V a is the real-time opening of the valve, p is the air density, p1is the pressure before the valve.

[0100] The control amount of the control valve and the valve opening model are as follows:

[0101]

[0102] wherein, K a,1 , T a,1 , V a,1 are the equivalent gain, time constant and real-time opening of the control valve 1 respectively, K a,2 , T a,2 , V a,2 are the equivalent gain, time constant and real-time opening of the control valve 2 respectively.

[0103] Step 3:

[0104] For the affine nonlinear model of the control amount and the system output of the high-altitude cabin air intake system, it is as follows:

[0105]

[0106]

[0107]

[0108]

[0109]

[0110] And the above formula is arranged as follows by introducing a virtual control amount:

[0111]

[0112] The virtual control amount U i (i = 1, 2) of the air intake pressure and temperature loop and the controlled output [p T] T has been calculated as a one-to-one correspondence, and the controlled output and the virtual control amount have been decoupled, that is, the static coupling part of the system control amount has been eliminated, obtaining a self-anti-disturbance temperature and pressure decoupling control system.

[0113] Step 4:

[0114] Based on the active disturbance rejection temperature and pressure decoupling control system, the fixed time active disturbance rejection controller is designed for the high altitude cabin intake system pressure and temperature loop respectively. A new fixed time sliding mode controller is used as the main controller. The fixed time extended state observer is used to quickly and accurately estimate the system state and total disturbance of each loop, and the total disturbance is compensated to the new fixed time sliding mode controller to effectively deal with the complex and variable disturbance in the engine rapid transition state flight mission, and realize the rapid and stable control of the intake pressure and temperature.

[0115] To realize the complete decoupling of the system, the dynamic coupling caused by the rapid change of the intake pressure and temperature environment parameters in the system can be designed as a part of the total disturbance and compensated to the new fixed time sliding mode controller.

[0116] Define p, T as the output pressure and temperature of the system, p set ,T set as the target pressure and temperature, let Then the intake pressure and temperature loop model can be expressed as

[0117]

[0118] Where d p ,d T are the total disturbances of the intake pressure and temperature loops in the high altitude cabin intake system (including system model error, dynamic coupling part except system control, uncertainty, etc.). The total disturbance d p ,d T is regarded as a new state Assuming that the change of d p ,d T is bounded, the state equation can be expanded as follows

[0119]

[0120] The fixed time extended state observer is designed for the above general second order system as follows

[0121]

[0122]

[0123] Where: is the intake pressure loop observer gain, is the intake temperature loop observer gain, are the estimated values of , respectively, are the estimated values of , respectively, θ p ,θ T are the magnification factors of the observer, is the error feedback function of each state in the observer, is the exponential coefficient in the error feedback function.

[0124] Based on the above fixed-time extended state observer, the intake pressure and temperature loop error estimates are The differential error estimate is Let In order to have better fast performance in practical applications, the new fixed-time sliding mode surface of the system intake pressure and temperature loop is designed as follows:

[0125]

[0126]

[0127] The above fixed-time sliding mode surface uses state-dependent variable exponential coefficients to avoid possible singular problems, and sets p ,c p and T ,c T as parameters to adjust the state convergence speed of the system.

[0128] Combined with the above fixed-time sliding mode surface, the control law of the system intake pressure and temperature loop is designed as follows:

[0129]

[0130]

[0131] where, Based on the above control law, a new fixed-time sliding mode controller is designed. Through the construction of Lyapunov function, it is proved that the new fixed-time active disturbance rejection controller based on the above new fixed-time sliding mode controller and fixed-time extended state observer can make the state of the active disturbance rejection temperature and pressure decoupling control system converge in fixed time.

[0132] Step 5:

[0133] The fixed-time extended state observer is used to estimate the system state and total disturbance of the high-altitude cabin intake system pressure and temperature loop, and the total disturbance is compensated to the new fixed-time sliding mode controller of each loop to obtain the control input signal U i (i = 1, 2).

[0134] Step 6:

[0135] The control input signal is input to the high-altitude cabin intake system, and the high-altitude cabin intake system runs to obtain the intake pressure and temperature signals.

[0136] Step 7:

[0137] Repeat the above steps 5 to step 6, combined with the designed self-disturbance temperature and pressure decoupling control system, the new fixed time self-disturbance controller based on the new fixed time sliding mode controller and the fixed time extended state observer is used to realize the high-quality decoupling control of the pressure and temperature variables in the high-altitude cabin air intake system. The fixed time self-disturbance controller can quickly converge and the maximum stable time is independent of the initial error, which has the ability to effectively cope with the short-time large load disturbance in the rapid transition state test of the high-altitude cabin air intake system, and can realize the rapid and stable control of the pressure and temperature variables of the high-altitude cabin air intake system.

[0138] Simulation and test description

[0139] In order to verify the decoupling control effect of the fixed time self-disturbance temperature and pressure decoupling control method proposed in the application on the pressure and temperature of the high-altitude cabin air intake system, a certain high-altitude cabin air intake system simulation based on simulink is carried out. The tested engine flight mission profile planning, such as Mach number climb / descend and thrust transient, two transition state flight missions, the flight Mach number, flight altitude, engine flow, and throttle lever angle corresponding to the test mission profile are shown in Figure 3

[0140] Task one: Mach number climb and descent, the flight Mach number remains 0.9 unchanged, and the flight altitude changes between 8km and 12km. This process needs to realize the continuous change of flight altitude under the premise of maintaining the flight Mach number unchanged, which greatly tests the dynamic tracking ability of the control method to the intake pressure and temperature (0-72 seconds).

[0141] Task two: thrust transient, simulate the Mach number to remain 0.5 unchanged, the flight altitude remains 5km unchanged, and the engine throttle lever rapidly acts between slow and maximum within 0.5 seconds, that is, the intake pressure and temperature remain unchanged, and the engine suction flow changes sharply between 43-85kg / s. This process basically represents the maximum load disturbance impact process currently faced by the intake system (102-150 seconds).

[0142] Figure 4 The intake pressure and temperature control experimental results.

[0143] The above is the preferred embodiment of the application, any changes made according to the technical solutions of the application, as long as the generated function does not exceed the scope of the technical solutions of the application, belongs to the protection scope of the application.​

Claims

1. A fixed-time active disturbance rejection temperature and pressure decoupling control method for a high-altitude cabin air intake system, characterized in that, The method comprises the following steps: Step 1, define the high-altitude cabin air intake system, the active disturbance rejection temperature and pressure decoupling control system and the new fixed-time active disturbance rejection controller; Step 2, establish a high-altitude cabin air intake system model; Step 3, according to the established high-altitude cabin air intake system model, design an active disturbance rejection temperature and pressure decoupling control system; Step 4, based on the fixed-time theory, design a new fixed-time active disturbance rejection controller for the active disturbance rejection temperature and pressure decoupling control system, and obtain a new fixed-time active disturbance rejection temperature and pressure decoupling control system; Step 5, the new fixed-time active disturbance rejection temperature and pressure decoupling control system generates a control input signal according to the system pressure and temperature environment parameter output signal; Step 6, input the control input signal into the high-altitude cabin air intake system, and operate the high-altitude cabin air intake system to obtain a pressure and temperature environment parameter output signal; Step 7, repeat steps 5-6; Step 2 is implemented as follows: The dynamic characteristic equation of the pressure and temperature of the high-altitude cabin air intake system is as follows: wherein p, T, V, c p , h, C out , are the intake pressure, temperature, volume and gas specific heat at constant pressure, enthalpy, average flow velocity, outflow mass flow rate, respectively, h in1 , C in1 are the mass flow rate and gas enthalpy, average flow velocity of the hot flow path, h in2 , C in2 are the mass flow rate and gas enthalpy, average flow velocity of the cold flow path, and R is the gas constant, is the convective heat transfer between the interior cavity and the outside environment per unit time; The engine's own flow rate change is the largest disturbance source of the system, and the engine's air flow rate model is obtained through experimental data identification, as shown in the following formula: Wa engine = f e (H, Ma, A pla ) where H is the flight altitude, Ma is the flight Mach number, A pla is the throttle lever angle, f e is the engine flow function; In order to realize the decoupling control of the pressure and temperature of the air intake system, the motion characteristic and flow characteristic of the control valve need to be modeled, the motion characteristic model of the control valve is essentially a third-order control system, and the motion characteristic model of the control valve is equivalent to a first-order inertia link of the control signal and the real-time opening of the valve by using the method of theoretical modeling and data identification: where K a is the equivalent gain, T a is the time constant, s is the complex frequency, and u is the control variable; The calculation formula of the flow characteristic model of the control valve is as follows: wherein, is the mass flow rate through the valve, is the flow coefficient, A0is the total flow area of the valve, V a is the real-time opening of the valve, p is the air density, p1is the pressure before the valve; The control amount and valve opening model of the control valve are as follows: where K a,1 , T a,1 , V a,1 are the equivalent gain, time constant and real-time opening of the control valve 1, respectively, and K a,2 , T a,2 , V a,2 are the equivalent gain, time constant and real-time opening of the control valve 2, respectively.

2. The fixed-time active disturbance rejection temperature and pressure decoupling control method for a high-altitude cabin air intake system according to claim 1, characterized in that, The new fixed-time active disturbance rejection temperature and pressure decoupling control system is based on the active disturbance rejection decoupling control framework, decouples the pressure and temperature variables of the air intake system into single-input and single-output loops, and designs a new fixed-time active disturbance rejection controller for each loop for the rapid and stable control of the pressure and temperature of the high-altitude cabin air intake system.

3. The fixed-time active disturbance rejection temperature and pressure decoupling control method for a high-altitude cabin air intake system according to claim 1, characterized in that, In step 3, the active disturbance rejection temperature and pressure decoupling control system is designed, and the implementation is as follows: In the high-altitude cabin intake system, in order to eliminate the static coupling part of the control quantity in the high-altitude cabin intake system, a virtual control quantity is introduced, and the control quantity of control valve 1 and control valve 2 and the intake pressure and temperature controlled object in the high-altitude cabin intake system are decoupled and designed; the system output is defined as [p T] T , the system input is [u1 u2] T , wherein p and T are the intake pressure and temperature respectively, u1 and u2 are the control quantity of control valve 1 and control valve 2 respectively; the nonlinear affine model of the system output and the system input is as follows: wherein f p (p, T), f T (T, p) are the dynamic coupling parts of the intake pressure and temperature loops and other unknown disturbances to the system, b 11 , b 12 , b 21 , b 22 are the control quantity coefficients of control valve 1 and control valve 2; Define the matrix U as the virtual control quantity of the system, the matrix F as the total disturbance of the system, and the matrix B as the static coupling matrix of the system; By introducing virtual control quantities [U1 U2] T The nonlinear affine model of the system output with respect to the system input is arranged in the following form: In the formula, the virtual control quantity U of the inlet pressure and temperature loop i (i = 1, 2) and the controlled output [p T] T has been calculated as a one-to-one correspondence, and the decoupling between the controlled output and the virtual control quantity has been achieved, that is, the static coupling part of the system control quantity is eliminated, and a self-anti-disturbance temperature and pressure decoupling control system is obtained.

4. The fixed-time active disturbance rejection temperature and pressure decoupling control method of a high-altitude cabin air intake system according to claim 3, characterized in that, In step 4, the new fixed-time active disturbance rejection controller for the active disturbance rejection temperature and pressure decoupling control system is designed, that is, the new fixed-time active disturbance rejection controller based on the new fixed-time sliding mode controller and the fixed-time extended state observer is designed for the air intake pressure and temperature loops after decoupling, the fixed-time extended state observer is used to quickly and accurately estimate the system state and total disturbance of each loop, and the total disturbance is compensated into the new fixed-time sliding mode controller, so as to effectively cope with the complex and variable disturbances in the rapid transition state flight task of the engine, and realize the rapid and stable control of the air intake pressure and temperature.

5. The fixed-time active-disturbance-rejection temperature-pressure decoupling control method for a high-altitude cabin air intake system according to claim 4, characterized in that, In step 4, the new fixed-time active disturbance rejection controller for the active disturbance rejection temperature and pressure decoupling control system is designed, and the new fixed-time active disturbance rejection temperature and pressure decoupling control system is obtained, and the implementation is as follows: Based on the active disturbance rejection temperature and pressure decoupling control system, the fixed-time extended state observer is constructed for the air intake pressure and temperature loops, the system state and the total disturbance containing dynamic coupling are estimated, and the specific form is as follows: where: is the intake pressure loop observer gain, is the intake temperature loop observer gain, are the estimated values of the intake pressure loop system states , are the estimated values of the intake temperature loop system states , p , T are the amplification factors of the intake pressure and temperature loop observers, is the error feedback function for each state in the observer, is the exponential coefficient in the error feedback function, p , T are the virtual control quantity coefficients of the intake pressure and temperature loops, respectively; The intake pressure and temperature loop error estimation is The differential error estimation is Let In order to have better fast performance in practical application, the fixed time sliding mode surface of the system intake pressure and temperature loop is designed respectively as where γ p ,γ T are the coefficients of the exponential terms; are the state-dependent variable exponential parameters; c p ,c T are the coefficients of the error terms, and sign is the sign function. Combining with the fixed time sliding mode surface, the control law of the system inlet pressure and temperature loop is designed as follows: wherein k p ,k T is a coefficient of the power term, ε p ,ε T is a sign function gain, γ p ,γ T > 0, c p ,c T > 0, the controller is designed based on the control law, and the system state converges within a fixed time.

6. The fixed-time active-disturbance-rejection temperature-pressure decoupling control method for a high-altitude cabin air intake system according to claim 3, characterized in that, Other unknown disturbances include system model errors and uncertainties.

7. The fixed-time active-disturbance-rejection temperature-pressure decoupling control method for a high-altitude cabin air intake system according to claim 3, characterized in that, The total disturbance of the system includes system model errors, dynamic coupling parts except for the system control quantity, and uncertainties.

8. A fixed-time active-disturbance-rejection temperature-pressure decoupling control system for a high-altitude cabin air intake system, characterized in that, A computer program product comprising a memory, a processor and computer program instructions stored on the memory and executable by the processor to implement the method steps of any one of claims 1-7.

9. A computer readable storage medium having stored thereon computer program instructions executable by a processor to implement the method steps of any one of claims 1-7.

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