Aero-engine controller switching method based on VPC-MPC double architecture

Abstract

The invention provides an aero-engine controller switching method based on VPC-MPC double architecture, and relates to the technical field of aero-engines, comprising: when an engine is controlled by a model predictive control controller, acquiring a real-time output value of the model predictive control controller, and updating the state of a valve position control controller based on the real-time output value; the real-time fuel flow change rate of the engine is obtained; and if the real-time fuel flow change rate is lower than a preset switching threshold value, the model prediction control controller is switched to the valve position control controller. According to the method, the state of the controller to be switched is updated in real time according to the real-time output value of the controller in the running process of the engine, the problem of instruction jump caused by mismatching of the states of the controller is directly eliminated from the source, and the smoothness of the controller switching process is remarkably improved. Meanwhile, the fuel oil flow serves as the judgment basis of switching, more accurate and timely switching triggering is achieved, and therefore the problem of delay of fuel oil control response is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft engines, and in particular to a method for switching aircraft engine controllers based on a VPC-MPC dual architecture. Background Art

[0002] Aircraft engines are complex, nonlinear systems, and with the increasing demand for aircraft performance, the complexity of control systems has increased significantly. While advanced control algorithms such as model predictive control (MPC) can achieve multi-objective, complex constraint control tasks, excellent performance in complex situations inevitably comes with significant computational overhead. Simple model predictive algorithms, capable of real-time prediction and processing of operating states, are insufficient for the hardware performance of the current mainstream onboard full authority digital control system (FADEC), resulting in poor control speed, accuracy, and economy. While improving hardware performance is difficult, reducing computational overhead at the algorithmic level is an effective approach.

[0003] At the algorithmic level, the parallel valve position control (VPC) controller can be used to implement a multivariable performance optimization method based on a dual stabilization-optimization loop under steady-state conditions, thereby achieving efficient and economical operation of aircraft engines under stable operating conditions. The model predictive control (MPC) controller can be used to focus solely on transient dynamic processes, thereby strictly ensuring safety margins (such as surge margin). This decoupled and complementary relationship between VPC and MPC on a time scale minimizes the extensive and complex computational overhead associated with a single MPC. However, since aircraft engine operating conditions vary with flight conditions, the controller must also switch accordingly. This switching process can result in abrupt changes in control commands (i.e., "kicks"), which can lead to unstable and inefficient controller operation. For example, these jumps can prevent the VPC controller from stably accepting and continuously executing the optimization task, reducing its performance under steady-state conditions.

[0004] At the same time, the jump in control instructions will also cause significant fluctuations in engine thrust, and may cause engine parameters to exceed the stability safety margin at certain instantaneous moments, inducing unstable working phenomena such as compressor surge. Summary of the Invention

[0005] The present invention aims to provide an aircraft engine controller switching method based on a VPC-MPC dual architecture to address the aforementioned issues. To achieve this objective, the present invention employs the following technical solutions: This application provides an aircraft engine controller switching method based on the VPC-MPC dual architecture, including: When the engine is controlled by a model predictive control controller, first information is acquired at each sampling moment, and a state of a valve position control controller is updated based on the first information, wherein the first information includes a first output value of the model predictive control controller, and the first output value includes a first nozzle throat area output, a first tail bypass injector area output, and a first fuel flow output of the engine; Get the real-time fuel flow rate change rate of the engine; If the real-time fuel flow rate change rate is lower than a preset switching threshold, the model predictive control controller is switched to the valve position control controller.

[0006] As a preferred solution of the present invention, updating the state of the valve position control controller based on the first information includes: Calculating an output reference value of a first control loop of the valve position control controller based on the first nozzle throat area output at a current moment; calculating an output reference value of a second control loop of the valve position control controller based on the area output of the first tail bypass injector at a current moment; The change rate of the integral term of the first controller of the third control loop of the valve position control controller is calculated based on the first fuel flow output at the current moment, and the first controller is a PI controller.

[0007] As a preferred solution of the present invention, the rate of change of the integral term of the first controller is expressed as: ; in, is the rate of change of the integral term of the first controller, is the proportional gain, is the integral gain, is the differential term of the error, For the current moment The error, is the first time constant, and They are respectively the first fuel flow output and the output of the first controller at the current moment.

[0008] As a preferred embodiment of the present invention, the aircraft engine controller switching method based on the VPC-MPC dual architecture further includes: When the engine is controlled by the valve position control controller, third information is acquired at each sampling moment, and a control sequence of the model predictive control controller is updated based on the third information, wherein the third information includes a second output value of the valve position control controller, and the second output value includes a second nozzle throat area output, a second tail bypass injector area output, and a second fuel flow output of the engine; If the real-time fuel flow rate change rate is higher than a preset switching threshold, the valve position control controller is switched to the model predictive control controller.

[0009] As a preferred solution of the present invention, the control sequence of updating the model predictive control controller based on the third information includes: calculating a first control sequence based on a prediction model of the model predictive control controller; Constructing a first objective function based on the second output value at the current moment and a preset objective function; Calculating an objective function value corresponding to each control variable of the first control sequence based on the first objective function; Each control variable of the first control sequence is sorted in ascending order according to the objective function value corresponding to the control variable to obtain a second control sequence.

[0010] As a preferred solution of the present invention, the first objective function is expressed as: ; in, is the prediction step length, To control the step size, For the The system output prediction of the step For the The reference trajectory of the step, is the first weight matrix, is the second weight matrix, 、 and The nozzle throat area , Tail bypass injector area and fuel flow The weight factor of the external tracking term, For the The control increment of the step, 、 and The nozzle throat area , Tail bypass injector area and fuel flow The initial control input value is 、 and are respectively the second nozzle throat area output, the second tail bypass injector area output and the second fuel flow output of VPC at the current moment.

[0011] The beneficial effects of the present invention are: This invention updates the state of the controller to be switched in real time based on the real-time output values ​​of the engine's operating controller, eliminating command jumps caused by controller state mismatches at the source and significantly improving the smoothness of the controller switching process. Furthermore, by using fuel flow as the basis for switching, more accurate and timely switching triggering is achieved, thereby avoiding the problem of delayed fuel control response.

[0012] Other features and advantages of the present invention will be set forth in the following description, and in part will be apparent from the description, or may be learned by practicing embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 A schematic flow chart of a method for switching an aircraft engine controller based on a VPC-MPC dual architecture according to an embodiment of the present invention; Figure 2 Schematic diagram of the structure of an aircraft engine controller switching method based on a VPC-MPC dual architecture according to an embodiment of the present invention; Figure 3 Schematic diagram of a controller switching process of an aircraft engine controller switching method based on a VPC-MPC dual architecture according to an embodiment of the present invention; Figure 4 This is a control principle diagram of an aircraft engine controller switching method based on a VPC-MPC dual architecture described in an embodiment of the present invention when the VPC controller is not activated; Figure 5 Schematic diagram of changes in fuel flow output in an MPC controller and a VPC controller in an aircraft engine controller switching method based on a VPC-MPC dual architecture described in an embodiment of the present invention; Figure 6 Schematic diagram of changes in thrust, high-pressure rotor, and low-pressure rotor in an aircraft engine controller switching method based on a VPC-MPC dual architecture described in an embodiment of the present invention; Figure 7 Schematic diagram of changes in engine fuel consumption rate, nozzle throat area opening, and tail bypass injector area opening in an aircraft engine controller switching method based on a VPC-MPC dual architecture described in an embodiment of the present invention; Figure 8 Schematic diagram of changes in turbine inlet temperature, low-pressure compressor surge margin, and high-pressure compressor surge margin in an aircraft engine controller switching method based on a VPC-MPC dual architecture described in an embodiment of the present invention.

[0015] Reference numerals: Figure 2 、 Figure 3 and Figure 4 Among them, VPC-valve position control controller; MPC-model predictive control controller; -thrust; -Fuel flow; - nozzle throat area; - Tail bypass injector area; -Nozzle throat area output from the MPC controller; -The tail bypass injector area output of the MPC controller; -Fuel flow output of the MPC controller; -Nozzle throat area output from the VPC controller; -Tail bypass injector area output of the VPC controller; -Fuel flow output of the VPC controller; -Engine fuel consumption rate; -Thrust reference output; -Nozzle throat area reference output; -Tail bypass injector area reference output; -Real-time fuel flow rate change; -Thrust change; - Change in nozzle throat area; -Change in the area of ​​the tail bypass injector; -Thrust reference change; -Reference change of tail bypass injector area; -Reference change of nozzle throat area; - Steady-state value of fuel flow rate; - Steady-state value of nozzle throat area; - Steady-state value of the tail bypass injector area; -Real-time fuel flow rate change command value; - Tail bypass injector area change command value; -Nozzle throat area change command value; a transfer function representing the first controller of the third control loop; and denote the transfer functions of the second and third controllers of the first control loop, respectively; and denote the transfer functions of the fourth and fifth controllers of the third control loop, respectively; 、 and are the transfer functions of the actuators of the first control loop, the third control loop, and the second control loop, respectively; 、 、 are the transfer functions of the controlled objects of the first control loop, the third control loop and the second control loop respectively; is the first time constant. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0017] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are used only to distinguish the description and should not be understood as indicating or implying relative importance.

[0018] Example 1: This embodiment provides an aircraft engine controller switching method based on the VPC-MPC dual architecture.

[0019] like Figure 1 As shown in the figure, the method includes: when the engine is controlled by a model predictive control controller, acquiring first information at each sampling moment, and updating the state of the valve position control controller based on the first information, the first information includes a first output value of the model predictive control controller, and the first output value includes a first nozzle throat area output, a first tail bypass injector area output, and a first fuel flow output of the engine; Get the real-time fuel flow rate change rate of the engine; If the real-time fuel flow rate change rate is lower than a preset switching threshold, the model predictive control controller is switched to the valve position control controller.

[0020] It should be noted that obtaining the output values ​​of the MPC controller and the VPC controller at each sampling moment when controlling the engine is common knowledge among those skilled in the art. The focus of this embodiment is on switching between the MPC controller and the VPC controller, rather than on how to obtain the output values ​​of the controllers. Therefore, obtaining the output values ​​of the MPC controller and the VPC controller will not be described in detail. At the same time, the real-time fuel flow rate change rate of the engine can be calculated based on the real-time thrust of the engine. This calculation is common knowledge among those skilled in the art and will not be described in detail.

[0021] It is understandable that if Figure 2 and Figure 3 As shown, first, according to the real-time fuel flow rate change The MPC controller and VPC controller are switched when the preset fuel flow threshold is 5%. When the engine is controlled by the MPC controller, When the engine is controlled by the VPC controller, the engine will receive the fuel flow output by the controller at each sampling moment regardless of whether the engine is controlled by MPC or VPC. , nozzle throat area and tail bypass injector area At the same time, the fuel flow output at the current sampling moment , nozzle throat area and tail bypass injector area It will be used as the input value of the two controllers at the next sampling moment. The engine will run according to the output value of the controller at each sampling moment and feedback thrust , engine fuel consumption rate SFC, fuel flow , turbine inlet temperature , high pressure compressor surge margin , low-pressure compressor surge margin , high pressure rotor and low-pressure rotor The controller will refer to these feedback values ​​of the engine to calculate the output at the next sampling moment, and the thrust feedback at the current sampling moment The values ​​are used directly as inputs for the VPC controller's output calculation at the next sampling moment. The steady-state input and steady-state output are the inputs and outputs of the VPC controller; the transient-state input and transient-state output are the inputs and outputs of the MPC controller.

[0022] When the model predictive control (MPC) controller is in control, the model predictive control (MPC) controller will output the preset thrust reference , nozzle throat area reference output and tail bypass injector area reference output And the nozzle throat area output at the last sampling moment , the first tail bypass injector area output and the first fuel flow output Calculate the nozzle throat area output at the current moment , the first tail bypass injector area output and the first fuel flow output On the one hand, the output value of the MPC at the current moment is used as the input value of the engine and input into the engine to control the engine, thereby obtaining the engine fuel consumption rate SFC and fuel flow rate fed back by the engine according to the input value The engine status is monitored according to the engine feedback value, and this is used as a basis to determine whether the current engine operation controller matches the current engine status; on the other hand, the valve position control VPC controller will update its own status according to the output value of the MPC controller during operation at each sampling moment.

[0023] Similarly, if the valve position control VPC controller is in control, the valve position control VPC controller will output the preset thrust reference , nozzle throat area reference output and tail bypass injector area reference output And the nozzle throat area output at the last sampling moment , the second tail bypass injector area output and second fuel flow output Calculate the nozzle throat area output at the current moment , the second tail bypass injector area output and the first fuel flow output On the one hand, the output value of the VPC at the current moment is used as the input value of the engine and input into the engine to control the engine. In particular, the VPC controller will directly use the engine state as a basis to determine whether the current engine operation controller matches the current engine state; on the other hand, the model predictive control MPC controller will update its own state according to the output value of the VPC controller at each sampling moment.

[0024] Furthermore, it's understandable that when the engine's operating conditions (steady or transient) are in a transitional state, the MPC controller is more suitable. However, as the engine gradually approaches steady state, the VPC controller should be used to control the engine. Therefore, the timing of controller switching also directly affects engine performance. The switching criteria of the traditional Min-Max protection architecture (such as speed changes or load factors) have inherent hysteresis, which reduces the engine's dynamic performance. Therefore, more effective switching criteria are needed to ensure the accuracy of controller switching timing, so as to quickly and accurately sense changes in engine thrust demand and avoid performance losses caused by delayed fuel control response. Since the fuel flow demand is directly related to the engine state, for example, when the engine is in a transition state, it needs to switch quickly and accurately to the next stable working state, and the maneuverability requirement is high, so the fuel flow changes quickly, the consumption is high, and the real-time fuel flow change rate is large; while when the engine is in a steady state, the steady state is a constant thrust state, that is, constant speed cruise, which requires the most economical working condition, so the fuel flow changes slowly, the consumption is low, and the real-time fuel flow change rate is low. Therefore, this embodiment uses the fuel flow change rate fed back by the engine in real time as a criterion, and determines the current working condition of the engine and the timing of controller switching according to a pre-set fuel flow threshold and the real-time fuel flow change rate, thereby solving the shortcoming of the traditional criterion lag. The fuel flow threshold can be set according to the work experience and actual needs of people in the field, which will not be elaborated in this embodiment. This embodiment sets the fuel flow threshold to 5%.

[0025] In this embodiment, Figure 2 As shown in the figure, since the real-time fuel flow rate change rate is usually within 5% when the engine is operating in a constant or slowly changing state, that is, in steady state, the control system at this time should maintain VPC-based control. Once a sharp change in fuel flow is detected, that is, the real-time fuel flow rate change rate exceeds 5%, the system responds immediately and quickly switches to MPC control mode. This fuel flow-based judgment significantly enhances the system's ability to perceive changes in actual engine demand and effectively improves the accuracy and timeliness of switching actions in high-inertia systems. On the one hand, it ensures the accuracy of switching timing, and on the other hand, it ensures that the engine operating state point is stable within a reasonable range, suppresses thrust fluctuations, and achieves the speed, accuracy, economy, and safety and reliability of aviation engine control strategies in actual engineering applications.

[0026] As a preferred solution of this embodiment, updating the state of the valve position control controller based on the first information includes: Calculating an output reference value of a first control loop of the valve position control controller based on the first nozzle throat area output at a current moment; calculating an output reference value of a second control loop of the valve position control controller based on the area output of the first tail bypass injector at a current moment; The change rate of the integral term of the first controller of the third control loop of the valve position control controller is calculated based on the first fuel flow output at the current moment, and the first controller is a PI controller.

[0027] It should be noted that the VPC controller used in this embodiment for multivariable performance optimization under steady-state conditions embodies a core multivariable performance optimization method based on a dual stabilization-optimization loop. During the steady-state control phase, the VPC controller implements this "optimization loop" through multivariable coordinated optimization of the nozzle throat area, the tail bypass injector area, and the fuel flow rate. This is the specific technical implementation of this "optimization loop." While meeting engine safety constraints (such as surge margin and turbine inlet temperature limit), the controller dynamically approaches the maximum fuel efficiency under specific flight conditions, thereby achieving online correction of the steady-state control plan to achieve optimal fuel efficiency.

[0028] At the same time, the VPC and MPC dual-architecture switching method designed in this embodiment provides key support for the VPC controller to perform its "stabilization-optimization dual-loop" function: when the engine is in steady state, the VPC status is updated by real-time tracking of the MPC output, ensuring that the VPC can stably undertake and continuously execute the optimization task; when the operating condition switches to the transition state, a smooth switch to the MPC controller is performed to ensure dynamic process safety. After returning to steady state, the VPC can quickly resume its stabilization-optimization function, thereby achieving stable and efficient operation in complex operating environments, laying the foundation for the overall system's adaptability to operating conditions, enabling it to achieve optimal fuel efficiency under specific flight conditions.

[0029] For the VPC controller of this embodiment, Figure 4 middle, a transfer function representing the first controller of the third control loop; and denote the transfer functions of the second and third controllers of the first control loop, respectively; and denote the transfer functions of the fourth and fifth controllers of the third control loop, respectively; 、 and are the transfer functions of the actuators of the first control loop, the third control loop, and the second control loop, respectively; 、 、 are the transfer functions of the controlled objects of the first control loop, the third control loop and the second control loop respectively, and the controlled object is the engine; Indicates from arrive The transfer function of Indicates from arrive The transfer function of Indicates from arrive The transfer function of . Figure 4 The VPC controller shown is designed to meet and Has a return to center characteristic, where and The return-to-center characteristic means that After the step, and Participate in the transient change process, but when the thrust is stable, and To return to its initial position. The circuit type is 1, and The loop type is 1.

[0030] To meet this requirement, this embodiment will Take as PI controller, and All are PD controllers (without integrators), and the module parameters of the controllers are determined according to actual conditions, which is common knowledge in the art. 、 At the same time, they are and The lead-lag compensator of the control loop (without integrator) is used to improve the dynamic and steady-state performance of the system.

[0031] Through PI controller ,Will and Reset to its optimal position to meet zero steady-state error, the formula is: ; in, is the sensitivity index, is the proportionality coefficient, is the integration coefficient, For controller In the sensitivity index The transfer function under ; Designing the controller 、 、 ,and Does not include integrator, controller and In sensitivity The transfer function under and The formula is as follows: ; in, is the proportionality coefficient, is the differential coefficient, and Sensitivity Controller under and controller The transfer function only contains proportional and derivative control, ensuring fast response and no integral effect.

[0032] It is understandable that if Figure 4 As shown in the figure, when the MPC controller is controlling the engine, the VPC controller is inactive. If the VPC controller is directly switched to the MPC controller at the switching moment, command jumps will occur during the controller switching process, causing the engine operating parameters to exceed the normal operating range, seriously affecting the stable operation and operational safety of the aircraft engine. Therefore, to achieve efficient control of complex nonlinear systems such as aircraft engines under variable operating conditions, it is necessary to solve the command jump problem during the dual control model switching process. This can quickly and accurately adapt to the changes in engine thrust demand caused by changes in operating conditions and minimize the performance loss caused by fuel control response lag. The direct cause of this problem is that the two controllers that handle steady-state and transient states have different algorithms and objectives, resulting in controller state mismatch. This causes discontinuous output values ​​at the switching moment, leading to severe thrust fluctuations and operating parameter violations at certain instants. There is even the risk of unstable operation such as compressor surge.

[0033] In this embodiment, the feedforward correction technology is used, that is, when the MPC controller is running, the VPC controller tracks the nozzle throat area output by the MPC controller at each sampling moment. and tail bypass injector area output The values ​​of are assigned to the nozzle throat area of ​​the VPC controller Reference output of the control loop and tail bypass injector area Reference output of the control loop In addition, it is also based on the fuel flow output of the MPC controller at the current moment Calculate the fuel flow rate of the valve position control controller Control loop controller The rate of change of the integral term. In this way, when the MPC controller is running, the initial state of the VPC controller is kept consistent with the output value of the MPC controller at each sampling moment. This ensures that when the controller switches, the initial state of the VPC controller is also consistent with the output value of the MPC controller. This solves the state mismatch problem at the moment of controller switching, eliminates the command jump problem caused by the switching moment from the source, and significantly improves the smoothness of the controller switching process.

[0034] As a preferred solution of this embodiment, the rate of change of the integral term of the first controller is expressed as: ; in, is the rate of change of the integral term of the first controller, is the proportional gain, is the integral gain, is the differential term of the error, is the error at the current moment, is the first time constant, The larger the value, the faster the tracking speed. and They are respectively the fuel flow output at the current moment and the output of the first controller.

[0035] It can be understood that in the expression of the rate of change of the integral term of the first controller, is the fuel flow output of the MPC controller at the current moment and VPC controller Controller output The difference, through Integrate the difference so that Gradually approaches 0, reaching the VPC controller The control loop outputs the fuel flow to the MPC controller tracking effect.

[0036] Through the above, the switch from MPC controller to VPC controller can be achieved.

[0037] As a preferred solution of this embodiment, the aircraft engine controller switching method based on the VPC-MPC dual architecture further includes: When the engine is controlled by the valve position control controller, third information is acquired at each sampling moment, and a control sequence of the model predictive control controller is updated based on the third information, wherein the third information includes a second output value of the valve position control controller, and the second output value includes a second nozzle throat area output, a second tail bypass injector area output, and a second fuel flow output of the engine; Get the real-time fuel flow rate change rate of the engine; If the real-time fuel flow rate change rate is higher than a preset switching threshold, the valve position control controller is switched to the model predictive control controller.

[0038] It is understandable that if Figure 2 As shown, when the engine's real-time fuel quantity change rate When the fuel flow rate falls below the preset threshold by 5%, the engine is in steady state. At this point, the VPC controller better matches the steady-state control requirements, so the engine is controlled by the VPC controller. However, due to control requirements such as engine speed, the engine enters a transient state. Therefore, when the VPC controller is in control, the MPC controller needs to track the VPC controller. This means updating the MPC controller's control sequence based on the VPC controller's output value at each sampling time, ensuring that the MPC controller's initial control input is close to the VPC controller's output value at each sampling time.

[0039] As a preferred solution of this embodiment, the control sequence of updating the model predictive control controller based on the third information includes: calculating a first control sequence based on a prediction model of the model predictive control controller; Constructing a first objective function based on the second output value at the current moment and a preset objective function; Calculating an objective function value corresponding to each control variable of the first control sequence based on the first objective function; Each control variable of the first control sequence is sorted in ascending order according to the objective function value corresponding to the control variable to obtain a second control sequence.

[0040] Wherein, the first objective function is expressed as: ; in, is the prediction step length, To control the step size, For the The system output prediction of the step For the The reference trajectory of the step, is the first weight matrix, is the second weight matrix, 、 and The nozzle throat area External tracking items , Tail bypass injector area External tracking items and fuel flow External tracking items The weight factor is determined according to the actual tracking requirements. For the The control increment of the step, 、 and The nozzle throat area , Tail bypass injector area and fuel flow The initial control input value is 、 and They are the second nozzle throat area output, the second tail bypass injector area output and the second fuel flow output of VPC at the current moment respectively.

[0041] It should be noted that the rolling optimization mechanism of the MPC controller includes: At every moment , the controller performs the following process: S1, predicting the future based on models Step system behavior , and solve the control variable sequence ; S2, solve the minimum value of the objective function and obtain the complete control sequence, which is expressed as: ; in, is the prediction step length, To control the step size, For the The system output prediction of the step For the The reference trajectory of the step, is the first weight matrix, is the second weight matrix, For the Control increment of step; is the output tracking error term, which is used to make the predicted output Approximating the reference trajectory , that is, the system "tracks the target"; It is a control increment smoothing term used to limit the rapid change of control input to avoid drastic adjustment and actuator load; thus, the predicted output As close to the reference trajectory as possible At the same time, it can avoid large jumps in controller action, reduce actuator wear or system impact.

[0042] S3, only execute the first control input , and the rest will be re-optimized at the next moment (i.e. "rolling optimization"); S4, at the next moment Repeat steps S1-S3.

[0043] It is understandable that in this embodiment, by improving the rolling optimization mechanism of MPC, three external switching non-disturbance tracking items are added on the basis of the original objective function. 、 and , the three outputs of the VPC controller 、 、 As the external instructions corresponding to each initial control input respectively; for each external switching disturbance-free tracking item, it is possible to make the corresponding initial control input at each sampling moment It is close to the external command, thus achieving disturbance-free switching from the VPC controller to the MPC controller at the switching moment.

[0044] This embodiment adds three external switching non-disruptive tracking items: 、 and , for any external switching undisturbed tracking item The role of rolling optimization is specifically manifested as follows: Affects the selection of the control initial value in each optimization, since each MPC optimization is performed only on the first control variable , so the initial control input at the current moment is The selection of is crucial to the system performance. For each external switching undisturbed tracking item, the item This will make the optimization problem more inclined to choose the initial control input ≈ The control input of MPC will automatically adjust its first control action to be close to the existing external control value, that is, the output value of VPC at each moment. , so that during the operation of the VPC controller, each control input of the MPC controller is always close to the real-time output of the corresponding VPC controller, fundamentally solving the command jump problem of controller switching.

[0045] In summary, this embodiment uses fuel flow thresholds as a criterion for determining controller switching timing, improving the dynamic engine energy supply strategy and significantly enhancing the control model's switching speed and timing accuracy. Secondly, to eliminate the command jump problem caused by switching instants and ensure that the initial state of the controller at the time of switching remains consistent with the output value of the previous controller, a feedforward correction technique is employed to address the state mismatch problem at the moment of controller switching, thus addressing the problem at its source. Furthermore, the architecture of this embodiment fully leverages the MPC's ability to explicitly handle the strong coupling relationships between numerous flight parameters in highly dynamic processes (i.e., high flight acceleration conditions) and to ensure strict dynamic safety constraints. Overall, this embodiment significantly improves the smoothness of the controller switching process, significantly ensuring that the engine operating state point remains stable within a reasonable range, suppressing thrust fluctuations, and achieving the rapidity, accuracy, and economy of the aircraft engine control strategy, as well as the safety and reliability in practical engineering applications.

[0046] This embodiment conducts a simulation experiment based on the above controller switching method, as follows: Under the conditions of the simulated near-sea-level standard atmosphere (International Standard Atmosphere, ISA), the engine accelerates from a low-speed steady state to a high-thrust state. Figure 5 and Figure 6 shown), Figure 5 The figure shows the fuel flow rate change output by the MPC controller during engine operation. Curve and fuel flow rate change of VPC controller output The curve and the Switch signal curve of the output signal change. The Switch signal of 0 indicates MPC controller control, and 1 indicates VPC controller control; Figure 6 The thrust is shown in Changing Curve, nozzle throat area opening Changing Curve and tail bypass injector area opening Changing curve.

[0047] Throughout the acceleration process, the transition between fuel flow command and actual output is smooth and natural, with no noticeable jerks or jerkiness associated with conventional shifting methods. This seamless shifting approach demonstrates the intuitive control continuity advantage of this system. Thrust increases almost linearly upon throttle command, approaching the target value in approximately 5 seconds. The entire process is seamless, with no fluctuations or overshoot. The high- and low-pressure rotor speeds closely track the increase in fuel injection, accelerating rapidly and ultimately stabilizing accurately, demonstrating excellent dynamic response. With increased fuel flow, the engine's speed rapidly rises and stabilizes below the safe threshold (around 1700K), with no overheating observed throughout the entire process. While efficiently responding to acceleration commands and meeting multivariable constraints, it successfully avoids surge and overheating risks, ensuring safe and reliable engine dynamic operation.

[0048] In order to test the effect of the disturbance-free switching control strategy designed in this invention in actual engineering, a typical dual-axis multivariable aircraft engine nonlinear model was built with the help of MATLAB / Simulink platform for simulation testing. The test scenario in the initialization setting of this simulation was selected to simulate the process of the engine accelerating from a low-speed steady state to a high-thrust state under the conditions of a standard atmosphere near sea level (International Standard Atmosphere, ISA). In addition, regarding the model details, the model parameters were selected from the typical rated operating point of the engine. At the same time, the high-pressure rotor speed was given priority consideration. , low pressure rotor speed , turbine inlet temperature The core parameters such as compressor surge margin (SM) must comply with the hard limits in actual operation. The control architecture here adopts the VPC-MPC dual-mode control structure designed in this paper. Among them, the real-time fuel flow rate change rate The simulation is conducted for 100 seconds, focusing on the engine's response during the critical dynamic process of rapidly accelerating from cruise thrust (initial state) to maximum thrust.

[0049] Core performance indicators of the aircraft engine model: maximum thrust of approximately 84.51 kN, high-pressure rotor The design point speed is 15000r / min, the low pressure rotor The design point speed is 9000 r / min, and the nozzle configuration is a convergent nozzle. In addition, the tail nozzle throat area opening and the rear duct ejector opening are also considered. The calculation formula is: ; in, is the nozzle throat area, is the nozzle area.

[0050] Rear duct ejector opening The calculation formula is: ; in, is the area of ​​the tail bypass injector, is the area of ​​the external duct ejector.

[0051] The simulation setting simulates the process of the pilot quickly pushing the throttle lever to the maximum position, that is, the engine is initially running at a low speed and instantly receives a full acceleration command. Figure 5 As shown in the figure, after the throttle command is issued, the fuel flow demand (command value) increases sharply, climbing rapidly from the initial steady-state value of about 0.39 kg / s to about 1.05 kg / s. After a short period of stabilization, the command value is raised again to around 1.55 kg / s (reflecting the second stage of afterburner demand). At the same time, it can be clearly seen from the mode switching signal curve Switch curve that Switch=0 is MPC operation and Switch=1 is VPC operation. During the two periods of sharp increase in fuel demand, the designed real-time fuel flow rate change rate The judgment criteria are started in time and the control mode is smoothly switched from the steady-state optimal state to the dynamic model prediction state. Figure 5 middle, Curve and The curve closely tracks the changes in the command switch signal curve. This clearly shows the smooth and natural transition between the fuel flow command and actual output throughout the acceleration process, with no visible jerks or sudden jumps in fuel flow that occur with traditional switching methods. The advantage of this non-disruptive switching solution in terms of control continuity is readily apparent.

[0052] like Figure 6 As shown, Figure 6 The thrust is shown in Changing Curve, nozzle throat area opening Changing Curve and tail bypass injector area opening Changing The curves show that thrust increases almost linearly after the throttle command is received, approaching the target value in approximately 5 seconds. The entire process is clean and seamless, without fluctuations or overshoot. The high- and low-pressure rotor speeds also closely track the increase in fuel injection, increasing rapidly and ultimately stabilizing accurately, demonstrating excellent dynamic response. These two sets of curves clearly demonstrate that the precise timing of the switchover is used as the criterion, and that the MPC controller's starting position (initialization) is consistent with the VPC output state before the switchover. As a result, the entire engine thrust buildup process is crisp and smooth, without any drag or throttle jumps.

[0053] like Figure 7 As shown, Figure 7 Shows the turbine inlet temperature Changing curve, high pressure compressor surge margin Changing curves and low-pressure compressor surge margin Changing curve. Simulation results show that as the fuel flow rate increases, it rapidly rises and stabilizes below the safety threshold (near 1700K), with no overheating occurring throughout the entire process. The high-pressure compressor surge margin narrows somewhat during acceleration, but its minimum value remains above the specified safety lower limit (approximately 20%). Conversely, the fan surge margin widens with increased thrust, remaining within the safety margin. This demonstrates that the MPC controller successfully avoids surge and overtemperature risks while efficiently responding to acceleration commands and satisfying multivariable constraints, ensuring safe and reliable dynamic engine operation.

[0054] like Figure 8 As shown, Figure 8 The SFC curve of the engine fuel consumption SFC and the tail nozzle throat area are shown in Changing Curve and rear duct ejector opening Changing The curve further illustrates the dynamic characteristics of the engine's fuel consumption rate and associated efficiency parameters. During the initial acceleration phase, the SFC briefly rises; then, entering the steady-state performance optimization phase, the SFC drops significantly and stabilizes at a low level (approximately 0.56 kg / (daN·h)), resulting in a reduction in overall fuel consumption of approximately 5.03%. This indicates that the increased thrust has enabled the engine to enter a more optimal operating range, effectively improving fuel efficiency. Furthermore, the engine efficiency parameters under steady-state conditions (normalized to a 100% baseline) are significantly better than those under initial cruise conditions, demonstrating that VPC steady-state optimization control successfully improves component-level efficiency, further demonstrating the effectiveness of this control strategy in reducing fuel consumption.

[0055] In summary, the proposed VPC-MPC smooth-switching control strategy performed excellently during a typical acceleration process simulating near-sea level conditions. The controller achieved continuous and smooth conversion of fuel flow and thrust response, significantly enhancing the ability to stabilize the engine operating point within a safe range under demanding dynamic conditions. Furthermore, this strategy not only improved steady-state fuel economy but also optimized component-level efficiency, fully demonstrating its practical value and potential in engineering applications.

[0056] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0057] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. An aircraft engine controller switching method based on a VPC-MPC dual architecture is characterized by: include: When the engine is controlled by a model predictive control controller, first information is acquired at each sampling moment, and a state of a valve position control controller is updated based on the first information, wherein the first information includes a first output value of the model predictive control controller, and the first output value includes a first nozzle throat area output, a first tail bypass injector area output, and a first fuel flow output of the engine; Get the real-time fuel flow rate change rate of the engine; If the real-time fuel flow rate change rate is lower than a preset switching threshold, the model predictive control controller is switched to the valve position control controller.

2. The method for switching an aircraft engine controller based on a VPC-MPC dual architecture according to claim 1, characterized in that The updating of the state of the valve position control controller based on the first information includes: Calculating an output reference value of a first control loop of the valve position control controller based on the first nozzle throat area output at a current moment; calculating an output reference value of a second control loop of the valve position control controller based on the area output of the first tail bypass injector at a current moment; The change rate of the integral term of the first controller of the third control loop of the valve position control controller is calculated based on the first fuel flow output at the current moment, and the first controller is a PI controller.

3. The method for switching an aircraft engine controller based on a VPC-MPC dual architecture according to claim 2, characterized in that , the rate of change of the integral term of the first controller is expressed as: ； in, is the rate of change of the integral term of the first controller, is the proportional gain, is the integral gain, is the differential term of the error, is the error at the current moment, is the first time constant, and They are respectively the first fuel flow output and the output of the first controller at the current moment.

4. The method for switching aircraft engine controllers based on the VPC-MPC dual architecture according to claim 1, characterized in that , also includes: When the engine is controlled by the valve position control controller, third information is acquired at each sampling moment, and a control sequence of the model predictive control controller is updated based on the third information, wherein the third information includes a second output value of the valve position control controller, and the second output value includes a second nozzle throat area output, a second tail bypass injector area output, and a second fuel flow output of the engine; If the real-time fuel flow rate change rate is higher than a preset switching threshold, the valve position control controller is switched to the model predictive control controller.

5. The method for switching aircraft engine controllers based on the VPC-MPC dual architecture according to claim 4 is characterized in that The control sequence of updating the model predictive control controller based on the third information includes: calculating a first control sequence based on a prediction model of the model predictive control controller; Constructing a first objective function based on the second output value at the current moment and a preset objective function; Calculating an objective function value corresponding to each control variable of the first control sequence based on the first objective function; Each control variable of the first control sequence is sorted in ascending order according to the objective function value corresponding to the control variable to obtain a second control sequence.

6. The method for switching aircraft engine controllers based on the VPC-MPC dual architecture according to claim 5, characterized in that ,The first objective function is expressed as: ； in, is the prediction step length, To control the step size, For the The system output prediction of the step For the The reference trajectory of the step, is the first weight matrix, is the second weight matrix, 、 and The nozzle throat area , Tail bypass injector area and fuel flow The weight factor of the external tracking term, For the The control increment of the step, 、 and The nozzle throat area , Tail bypass injector area and fuel flow The initial control input value is 、 and are respectively the second nozzle throat area output, the second tail bypass injector area output and the second fuel flow output of VPC at the current moment.

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