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

Abstract

The application provides an aero-engine controller switching method based on a VPC-MPC dual architecture, and relates to the technical field of aero-engines, and comprises the following steps: when an engine is controlled by a model predictive control controller, acquiring real-time output values of the model predictive control controller, and updating the state of a valve position control controller based on the real-time output values; acquiring a real-time fuel flow rate variation of the engine; if the real-time fuel flow rate variation is lower than a preset switching threshold, switching the model predictive control controller to the valve position control controller. According to the real-time output values of the controller in the operation of the engine, the state of the to-be-switched controller is updated in real time, the instruction jump problem caused by the mismatch of the controller states is directly eliminated from the source, and the smoothness of the controller switching process is significantly improved. Meanwhile, the fuel flow is used as the judgment basis for switching, more accurate and timely switching triggering is realized, and the lag problem of the fuel control response is avoided.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and more specifically, to a method for switching aero-engine controllers based on a VPC-MPC dual architecture. Background Technology

[0002] Aero-engines are complex nonlinear systems, and with the ever-increasing demands on aircraft performance, the complexity of control systems has significantly increased. While advanced control algorithms such as Model Predictive Control (MPC) can handle multi-objective, complex-constraint control tasks, superior performance in complex situations inevitably comes with enormous computational overhead. The hardware performance of mainstream Full Authority Digital Aircraft Control Systems (FADEC) is insufficient for the real-time prediction and processing of operational states using simple model predictive algorithms, resulting in suboptimal control speed, accuracy, and economy. Since improving hardware performance is difficult, reducing computational costs at the algorithm level is a viable alternative.

[0003] At the algorithm level, the parallel valve position control (VPC) controller can be used to implement a multivariable performance optimization method based on a stabilization-optimization dual-loop system under steady-state conditions, thereby achieving efficient and economical operation of the aero-engine under stable operating conditions. The model predictive control (MPC) controller can focus solely on handling the dynamic process of the transient state, thus strictly ensuring safety boundaries (such as surge margin). In this way, the decoupled and complementary relationship between VPC and MPC on the time scale minimizes the large amount of complex computational overhead associated with a single MPC. However, since the operating state of the aero-engine changes with flight conditions, the controller also needs to switch according to the engine's operating state. During the controller switching process, there can be abrupt changes in control commands (i.e., "jumps"), which can cause the controller to fail to operate stably and efficiently. For example, the jump problem caused by switching can prevent the VPC controller from stably accepting and continuously executing the optimization task, reducing the VPC controller's performance under steady-state conditions.

[0004] At the same time, sudden changes in control commands can cause significant fluctuations in engine thrust, and may cause engine parameters to exceed the stability safety margin at certain instants, inducing unstable operation phenomena such as compressor surge. Summary of the Invention

[0005] The purpose of this invention is to provide a switching method for aero-engine controllers based on a VPC-MPC dual architecture, in order to improve the aforementioned problems. To achieve the above objective, the technical solution adopted by this invention is as follows:

[0006] This application provides a method for switching aero-engine controllers based on a VPC-MPC dual architecture, including:

[0007] When the engine is controlled by the model predictive control controller, the first information is acquired at each sampling time, and the state of the valve position control controller is updated based on the first information. The first information includes the first output value of the model predictive control controller, which includes the first nozzle throat area output, the first tail bypass injector area output, and the first fuel flow output of the engine.

[0008] Obtain the real-time fuel flow rate change rate of the engine;

[0009] If the real-time fuel flow rate change rate is lower than the preset switching threshold, the model prediction control controller will be switched to the valve position control controller.

[0010] As a preferred embodiment of the present invention, updating the state of the valve position control controller based on the first information includes:

[0011] The output reference value of the first control loop of the valve position control controller is calculated based on the output of the first nozzle throat area at the current moment.

[0012] The output reference value of the second control loop of the valve position control controller is calculated based on the area output of the first tail bypass injector at the current moment.

[0013] The rate of change of the integral term of the first controller in the third control loop of the valve position control controller is calculated based on the first fuel flow output at the current moment. The first controller is a PI controller.

[0014] As a preferred embodiment of the present invention, the rate of change of the integral term of the first controller is expressed as:

[0015] ;

[0016] in, The rate of change of the integral term of the first controller. For proportional gain, For integral gain, For the differential term of the error, For the current moment The error, The first time constant, and These are the first fuel flow output and the first controller output at the current moment, respectively.

[0017] As a preferred embodiment of the present invention, the aircraft engine controller switching method based on the VPC-MPC dual architecture further includes:

[0018] When the engine is controlled by the valve position control controller, third information is acquired at each sampling time, and the control sequence of the model prediction control controller is updated based on the third information. The third information includes the second output value of the valve position control controller. The second output value includes the engine's second nozzle throat area output, second tail bypass injector area output, and second fuel flow output.

[0019] If the real-time fuel flow rate change rate is higher than the preset switching threshold, the valve position control controller will be switched to the model prediction control controller.

[0020] As a preferred embodiment of the present invention, the control sequence of updating the model predictive control controller based on the third information includes:

[0021] The first control sequence is calculated based on the predictive model of the model predictive controller;

[0022] Construct a first objective function based on the second output value at the current moment and the preset objective function;

[0023] Calculate the objective function value corresponding to each control variable in the first control sequence based on the first objective function;

[0024] The control variables of the first control sequence are sorted in ascending order according to the objective function values ​​corresponding to the control variables to obtain the second control sequence.

[0025] As a preferred embodiment of the present invention, the first objective function is expressed as:

[0026] ;

[0027] in, To predict the step size, To control the step size, For the first The system output prediction of the step, For the first The reference trajectory of the step, This is the first weight matrix. This is the second weight matrix. , and These are the nozzle throat areas. Tail bypass injector area and fuel flow Weighting factors of external tracking items, For the first Step control increment, , and These are the nozzle throat areas. Tail bypass injector area and fuel flow The initial control input value, , and These are the output of the second nozzle throat area, the output of the second tail bypass injector area, and the output of the second fuel flow rate of the VPC at the current moment.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention eliminates command jumps caused by controller state mismatches by updating the state of the controller to be switched in real time based on the real-time output value of the controller during engine operation, significantly improving the smoothness of the controller switching process. Simultaneously, by using fuel flow as the switching criterion, it achieves more precise and timely switching triggering, thereby avoiding the lag problem in fuel control response.

[0030] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of a method for switching aero-engine controllers based on a VPC-MPC dual architecture, as described in an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the structure of an aero-engine controller switching method based on a VPC-MPC dual architecture as described in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the controller switching process of an aero-engine controller switching method based on a VPC-MPC dual architecture as described in an embodiment of the present invention.

[0035] Figure 4 This is a control principle diagram of an aero-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;

[0036] Figure 5This is a schematic diagram illustrating the changes in fuel flow output in the MPC controller and VPC controller of an aero-engine controller switching method based on a VPC-MPC dual architecture, as described in an embodiment of the present invention.

[0037] Figure 6 This is a schematic diagram illustrating the changes in thrust, high-pressure rotor, and low-pressure rotor in a VPC-MPC dual-architecture-based aero-engine controller switching method described in an embodiment of the present invention.

[0038] Figure 7 This is a schematic diagram illustrating the changes in engine fuel consumption rate, nozzle throat area opening, and tail bypass injector area opening of an aero-engine controller switching method based on a VPC-MPC dual architecture as described in an embodiment of the present invention.

[0039] Figure 8 This is a schematic diagram illustrating the changes in turbine inlet temperature, low-pressure compressor surge margin, and high-pressure compressor surge margin in a VPC-MPC dual-architecture-based aero-engine controller switching method described in this embodiment of the invention.

[0040] Figure label:

[0041] Figure 2 , Figure 3 and Figure 4 In this context, VPC stands for Valve Position Control Controller; MPC stands for Model Predictive Control Controller. -thrust; - Fuel flow rate; - Nozzle throat area; - Tail bypass injector area; - Output of nozzle throat area of ​​MPC controller; - Tail bypass injector area output of MPC controller; - Fuel flow output of the MPC controller; -VPC controller nozzle throat area output; -VPC controller tail bypass injector area output; - Fuel flow output from 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 in tail bypass injector area; - Reference change in nozzle throat area; - Steady-state value of fuel flow rate; - Steady-state value of nozzle throat area; - Steady-state value of tail bypass injector area; -Command value for real-time fuel flow rate change; - Command value for tail bypass injector area change; -Command value for change in nozzle throat area; The transfer function of the first controller in the third control loop; and These represent the transfer functions of the second and third controllers in the first control loop, respectively. and These represent the transfer functions of the fourth and fifth controllers in the third control loop, respectively. , and These are the transfer functions of the actuators in the first control loop, the third control loop, and the second control loop, respectively. , , These are the transfer functions of the controlled objects in the first control loop, the third control loop, and the second control loop, respectively. This is the first time constant. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0043] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0044] Example 1:

[0045] This embodiment provides a method for switching aero-engine controllers based on a VPC-MPC dual architecture.

[0046] like Figure 1 As shown in the figure, the method includes: when the engine is controlled by the model predictive control controller, acquiring first information at each sampling time and updating the state of the valve position control controller based on the first information. The first information includes the first output value of the model predictive control controller, and the first output value includes the first nozzle throat area output, the first tail bypass injector area output, and the first fuel flow output of the engine.

[0047] Obtain the real-time fuel flow rate change rate of the engine;

[0048] If the real-time fuel flow rate change rate is lower than the preset switching threshold, the model prediction control controller will be switched to the valve position control controller.

[0049] It should be noted that the acquisition of the output values ​​of the MPC controller and VPC controller at each sampling moment when controlling the engine is common knowledge to those skilled in the art. The focus of this embodiment is on the switching between the MPC controller and VPC controller, rather than on how to acquire the output values ​​of the controllers. Therefore, the acquisition of the output values ​​of the MPC controller and 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 to those skilled in the art and will not be described in detail.

[0050] It is understandable that, such as Figure 2 and Figure 3 As shown, firstly, based on the real-time fuel flow rate change... Switching between the MPC controller and VPC controller based on a preset fuel flow threshold of 5%. At that time, the engine is controlled by the MPC controller. At this time, the engine is controlled by the VPC controller. Regardless of whether the engine is controlled by the MPC or VPC, at each sampling moment, the engine receives the fuel flow rate output from the controller. nozzle throat area and tail bypass injector area Meanwhile, the fuel flow rate output at the current sampling time nozzle throat area and tail bypass injector area This will serve as the input value for both controllers at the next sampling time. The engine will operate based on the controller output value at each sampling time and feed back thrust. Engine fuel consumption rate (SFC) and fuel flow rate 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 ​​from the engine to calculate the output at the next sampling time, and the thrust fed back at the current sampling time. These values ​​will be directly used as the input values ​​for the VPC controller's output calculation at the next sampling time. The steady-state input and output are the inputs and outputs of the VPC controller during control; the transient input and output are the inputs and outputs of the MPC controller during control.

[0051] When the Model Predictive Control (MPC) controller is in operation, the MPC controller will output a preset thrust reference. Nozzle throat area reference output and tail bypass injector area reference output And the output of its own nozzle throat area at the previous sampling time. First tail bypass injector area output and first fuel flow output Calculate the nozzle throat area output at the current moment. First tail bypass injector area output and 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 to control the engine, thereby obtaining the engine fuel consumption rate (SFC) and fuel flow rate fed back by the engine based on the input value. Information such as engine feedback values ​​is used to monitor the engine's status and determine whether the current engine operation controller matches the current engine status. On the other hand, the valve position control (VPC) controller updates its own status based on the output value of the MPC controller at each sampling time.

[0052] Similarly, when the valve position is controlled by the VPC controller, the VPC controller will output according to the preset thrust reference. Nozzle throat area reference output and tail bypass injector area reference output And the output of its own nozzle throat area at the previous sampling time. Second tail bypass injector area output Second fuel flow output Calculate the nozzle throat area output at the current moment. Second tail bypass injector area output and 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 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 based on the output value of the VPC controller at each sampling moment.

[0053] Furthermore, it's understandable that when the engine is in a transitional state (steady-state or transient state), the MPC controller is more suitable. However, as the engine gradually approaches a steady state, the VPC controller should control the engine. Therefore, the timing of controller switching directly affects engine performance. Traditional Min-Max protection architectures have inherent hysteresis in their switching criteria (such as speed changes or load coefficients), thus reducing engine dynamic performance. Therefore, more effective switching criteria are needed to ensure the accuracy of controller switching timing, enabling rapid and accurate detection of changes in engine thrust demand and avoiding performance losses caused by fuel control response lag. Since fuel flow demand is directly related to engine status, for example, when the engine is in a transitional state, it needs to quickly and accurately switch to the next stable operating state, with high mobility requirements, resulting in rapid fuel flow changes, high consumption, and a large real-time fuel flow change rate. When the engine is in a steady state, which is a constant thrust state, i.e., constant speed cruise, it needs the most economical operating condition, resulting in slow fuel flow changes, low consumption, and a low real-time fuel flow change rate. Therefore, this embodiment uses the real-time feedback fuel flow change rate of the engine as a criterion to determine the current operating condition of the engine and the timing of controller switching based on a preset fuel flow threshold and the real-time fuel flow change rate. This solves the shortcoming of traditional criterion lag. The fuel flow threshold can be set according to the work experience and actual needs of those in the field, which will not be elaborated in this embodiment. In this embodiment, the fuel flow threshold is set to 5%.

[0054] In this embodiment, as Figure 2As shown, when the engine is operating in a constant or slowly varying state (i.e., steady state), the real-time fuel flow rate change is typically within 5%. Therefore, the control system should maintain VPC-based control at this time. Once a sharp change in fuel flow is detected, i.e., the real-time fuel flow rate change exceeds 5%, the system immediately responds and quickly switches to MPC control mode. This fuel flow-based criterion significantly enhances the system's ability to perceive changes in the engine's actual needs, effectively improving the accuracy and timeliness of switching actions in a high-inertia system. On the one hand, it ensures the accuracy of the switching timing; on the other hand, it ensures that the engine's operating point remains stable within a reasonable range, suppressing thrust fluctuations. This achieves the speed, accuracy, economy, and safety and reliability of the aero-engine control strategy in practical engineering applications.

[0055] As a preferred embodiment, updating the state of the valve position control controller based on the first information includes:

[0056] The output reference value of the first control loop of the valve position control controller is calculated based on the output of the first nozzle throat area at the current moment.

[0057] The output reference value of the second control loop of the valve position control controller is calculated based on the area output of the first tail bypass injector at the current moment.

[0058] The rate of change of the integral term of the first controller in the third control loop of the valve position control controller is calculated based on the first fuel flow output at the current moment. The first controller is a PI controller.

[0059] It should be noted that the VPC controller used in this embodiment for multivariate performance optimization under steady-state conditions has a core function based on a stabilization-optimization dual-loop multivariate performance optimization method. During the steady-state control phase, the VPC controller performs multivariate collaborative optimization of the nozzle throat area, the tail bypass injector area, and the fuel flow rate. This is the specific technical implementation of the "optimization loop," which can dynamically approach the highest fuel efficiency under specific flight conditions while meeting engine safety constraints (such as surge margin and turbine inlet temperature limits). This achieves the effect of online correction of the steady-state control plan to achieve optimal fuel efficiency.

[0060] Meanwhile, the VPC and MPC dual-architecture switching method designed in this embodiment provides key support for the VPC controller to perform the "soothing-optimization dual-loop" function: when the engine is in steady state, the VPC state is updated by tracking the MPC output in real time to ensure that the VPC can stably take over and continuously perform optimization tasks; when the operating condition switches to the transition state, the smooth switch to the MPC controller ensures the safety of the dynamic process, and after returning to steady state, the VPC can quickly restore its soothing-optimization function, thereby achieving stable and efficient operation in complex operating environments, laying the foundation for the overall system to achieve the optimal fuel efficiency target under specific flight conditions.

[0061] For the VPC controller in this embodiment, Figure 4 middle, The transfer function of the first controller in the third control loop; and These represent the transfer functions of the second and third controllers in the first control loop, respectively. and These represent the transfer functions of the fourth and fifth controllers in the third control loop, respectively. , and These are the transfer functions of the actuators in the first control loop, the third control loop, and the second control loop, respectively. , , These are the transfer functions of the controlled objects in the first control loop, the third control loop, and the second control loop, respectively. The controlled object is the engine. Indicates from arrive The transfer function; Indicates from arrive The transfer function; Indicates from arrive The transfer function. Figure 4 The design of the VPC controller shown meets the requirements. and It has the property of returning to the center, among which, and The return-to-center characteristic refers to, After the step jump, and It participates in the transient change process, but once the thrust stabilizes, and To return to its initial position. This requirement needs to be met. The circuit type is 1. and The circuit type is 1.

[0062] To meet this requirement, this embodiment will Choose a PI controller. and All are PD controllers (excluding integrators). The module parameters of the controller are determined according to the actual situation, which is common knowledge in this field. , At the same time respectively and The lead-lag compensator (without an integrator) in the control loop is used to improve the dynamic and steady-state performance of the system.

[0063] via PI controller ,Will and Reset to its optimal position to satisfy zero steady-state error, the formula is:

[0064] ;

[0065] in, The sensitivity index. This is the proportionality coefficient. The integral coefficient is... For controller In sensitivity index Transfer function under ;

[0066] Design controller , , ,and Excludes integrator and controller and Sensitivity Transfer function under and The formula is as follows:

[0067] ;

[0068] in, This is the proportionality coefficient. The differential coefficients are... and Sensitivity The controller below and controller The transfer function contains only proportional and derivative control, ensuring fast response and no integral effect.

[0069] It is understandable that, such as Figure 4As shown, when the MPC controller controls the engine, the VPC controller is inactive. If the VPC controller is directly switched to the MPC controller at the switching moment, a command jump will occur during the controller switching process, causing the engine operating parameters to exceed the normal operating range, seriously affecting the stable operation and safety of the aero-engine. Therefore, to solve the problem of efficient control of such complex nonlinear systems as aero-engines under varying operating conditions, it is necessary to solve the command jump problem during the switching process of dual control models, so as to quickly and accurately adapt to the changes in engine thrust demand with the change of operating state, and minimize the performance loss caused by fuel control response lag. The direct cause of this problem is that the two controllers, which handle steady state and transient state respectively, have differences in algorithms and objectives, resulting in controller state mismatch. This causes discontinuous output values ​​at the moment of switching, leading to violent thrust fluctuations and exceeding the limits of operating parameters at certain instants, and even the risk of unstable operation such as compressor surge.

[0070] In this embodiment, a feedforward correction technique is used. During the operation of the MPC controller, the VPC controller tracks the nozzle throat area output by the MPC controller at each sampling time. and tail bypass injector area output The values ​​are assigned to the nozzle throat area of ​​the VPC controller. Reference output of control loop and tail bypass injector area Reference output of 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. controller of the control loop The rate of change of the integral term. Thus, during the operation of the MPC controller, 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 the initial state of the VPC controller is also consistent with the output value of the MPC controller during controller switching, solving the problem of state mismatch at the moment of controller switching, eliminating the instruction jump problem caused by the moment of switching from the source, and significantly improving the smoothness of the controller switching process.

[0071] In a preferred embodiment, the rate of change of the integral term of the first controller is expressed as:

[0072] ;

[0073] in, The rate of change of the integral term of the first controller. For proportional gain, For integral gain, For the differential term of the error, The error at the current moment, The first time constant, A larger value indicates a faster tracking speed. and These are the current fuel flow output and the output of the first controller, respectively.

[0074] It is understandable that in the rate of change representation of the integral term of the first controller, The fuel flow output of the MPC controller at the current moment. and VPC controller Controller output The difference, through Integrating the difference, thus... Gradually approaching 0, reaching the VPC controller's... The control loop outputs fuel flow to the MPC controller. The tracking effect.

[0075] The above steps enable the switching from an MPC controller to a VPC controller.

[0076] As a preferred embodiment, the aircraft engine controller switching method based on the VPC-MPC dual architecture further includes:

[0077] When the engine is controlled by the valve position control controller, third information is acquired at each sampling time, and the control sequence of the model prediction control controller is updated based on the third information. The third information includes the second output value of the valve position control controller. The second output value includes the engine's second nozzle throat area output, second tail bypass injector area output, and second fuel flow output.

[0078] Obtain the real-time fuel flow rate change rate of the engine;

[0079] If the real-time fuel flow rate change rate is higher than the preset switching threshold, the valve position control controller will be switched to the model prediction control controller.

[0080] It is understandable that, such as Figure 2 As shown, when the engine's real-time fuel quantity change rate When the fuel flow rate is below the preset threshold by 5%, the engine is in a steady state. At this time, the VPC controller is better suited to the control requirements of the engine in a steady state, so the engine is controlled by the VPC controller. However, due to control requirements such as engine speed, the engine will enter a transition state. Therefore, when the VPC controller is controlling the engine, the MPC controller needs to track the VPC controller. That is, the MPC controller updates its control sequence based on the output value of the VPC controller at each sampling time, so that the initial control input of the MPC controller is close to the output value of the VPC controller at each sampling time.

[0081] As a preferred embodiment, the step of updating the control sequence of the model prediction control controller based on the third information includes:

[0082] The first control sequence is calculated based on the predictive model of the model predictive controller;

[0083] Construct a first objective function based on the second output value at the current moment and the preset objective function;

[0084] Calculate the objective function value corresponding to each control variable in the first control sequence based on the first objective function;

[0085] The control variables of the first control sequence are sorted in ascending order according to the objective function values ​​corresponding to the control variables to obtain the second control sequence.

[0086] The first objective function is expressed as:

[0087] ;

[0088] in, To predict the step size, To control the step size, For the first The system output prediction of the step, For the first The reference trajectory of the step, This is the first weight matrix. This is the second weight matrix. , and These are the nozzle throat areas. External tracking items Tail bypass injector area External tracking items and fuel flow External tracking items The weighting factor, the specific value of which is determined based on the actual tracking requirements, For the first Step control increment, , and These are the nozzle throat areas. Tail bypass injector area and fuel flow The initial control input value, , and These are the VPC's second nozzle throat area output, second tail bypass injector area output, and second fuel flow output at the current moment, respectively.

[0089] It should be noted that the MPC controller's rolling optimization mechanism includes:

[0090] At every moment The controller executes the following process:

[0091] S1, predicting the future based on models Step-by-step system behavior And solve the sequence of control variables. ;

[0092] S2, Solve for the minimum value of the objective function to obtain the complete control sequence, expressed by the formula:

[0093] ;

[0094] in, To predict the step size, To control the step size, For the first The system output prediction of the step, For the first The reference trajectory of the step, This is the first weight matrix. This is the second weight matrix. For the first Step control increment; The tracking error term is used to adjust the predicted output. Approximating the reference trajectory That is, the system "tracks the target"; To control the incremental smoothing term, which limits rapid changes in the control input and avoids drastic adjustments and actuator load; this makes the predicted output... As close as possible to the reference trajectory This also prevents excessive fluctuations in controller action, reducing actuator wear or system shock.

[0095] S3, only executes the first control input. The remaining parts are then re-optimized in the next moment (i.e., "rolling optimization").

[0096] S4, in the next moment Repeat steps S1-S3.

[0097] It is understandable that in this embodiment, by improving the rolling optimization mechanism of MPC, three external switching-free tracking terms are added to the original objective function. , and The three outputs of the VPC controller , , These serve as external commands corresponding to each initial control input; for each external switching disturbance-free tracking term, it ensures that its corresponding initial control input at each sampling time is... By closely following external commands, a seamless switching between the VPC controller and the MPC controller can be achieved at the switching moment.

[0098] This embodiment adds three external handover non-disruption tracking items. , and For any one of the external handover-free tracking terms Its role in rolling optimization is specifically manifested in:

[0099] The choice of initial control values ​​affects each optimization, since only the first control variable is executed in each MPC optimization. Therefore, the initial control input at the current moment The selection of this term is crucial for system execution. For each external switching non-perturbation tracking term, its term... This will make the optimization problem more inclined to choose the initial control input. ≈ The control input, i.e., the optimized solution of MPC, will automatically adjust its first control action to be close to the existing external control value, which is the output value of VPC at each time step. This ensures that each control input of the MPC controller is always close to the real-time output of the corresponding VPC controller during the operation of the VPC controller, fundamentally solving the problem of sudden jumps in controller switching instructions.

[0100] In summary, firstly, this embodiment uses a fuel flow threshold as a criterion to determine the timing of controller switching, improving the dynamic energy supply strategy of the engine and thus greatly enhancing the switching speed and accuracy of the control model. Secondly, to eliminate the command jump problem caused by the instant of switching and ensure that the initial state of the controller during switching is consistent with the output value of the previous controller, feedforward correction technology is adopted to solve the state mismatch problem during controller switching, thus resolving the problem at its source. Furthermore, the architecture of this embodiment fully leverages the MPC's ability to explicitly process the strong coupling relationships of numerous flight parameters in high-dynamic processes (i.e., high flight acceleration conditions) and ensure strict dynamic safety constraints. Overall, this embodiment significantly improves the smoothness of the controller switching process, greatly ensuring that the engine operating point remains stable within a reasonable range, suppressing thrust fluctuations, and achieving speed, accuracy, economy, and safety and reliability in practical engineering applications for aero-engine control strategies.

[0101] This embodiment conducts a simulation experiment based on the above controller switching method, as detailed below:

[0102] Under simulated near-sea level standard atmosphere (International Standard Atmosphere, ISA), during the engine's acceleration from a low-speed steady-state state to a high-thrust state, such as... Figure 5 and Figure 6 (as shown) Figure 5 This shows the change in fuel flow output by the MPC controller during engine operation. The curve and the fuel flow change output of the VPC controller The curve and the Switch signal curve of the output signal change, where a Switch signal of 0 indicates MPC controller control and 1 indicates VPC controller control; Figure 6 The thrust is shown in the figure. changing Curve, nozzle throat area opening changing Curve and tail bypass injector area opening changing curve.

[0103] As can be seen, the fuel flow command and actual output are smoothly and naturally connected throughout the acceleration process. There is no noticeable jerking sensation caused by sudden fuel volume jumps during gear shifts, a common issue with traditional switching methods. The advantage of this seamless switching scheme in terms of control continuity is very evident. Thrust increases almost linearly after the throttle command, approaching the target value in about 5 seconds. The entire process is clean and crisp, without fluctuations or overshoot. The high and low pressure rotor speeds also keep pace with the increase in fuel injection, with rapid speed increases followed by precise and accurate stabilization, demonstrating excellent dynamic response performance. With the increase in fuel flow, the speed quickly rises and stabilizes below the safe threshold (around 1700K), without any overheating issues throughout the process. While efficiently responding to acceleration commands and meeting multi-variable constraints, it successfully avoids surge and overheating risks, ensuring the safe and reliable dynamic operation of the engine.

[0104] To verify the effectiveness of the disturbance-free switching control strategy designed in this invention in practical engineering, a typical dual-axis multivariable aero-engine nonlinear model was built using the MATLAB / Simulink platform for simulation testing. The initial setup for this simulation selected a test scenario simulating the engine's acceleration from a low-speed steady-state to a high-thrust state under near-sea-level standard atmospheric (ISA) conditions. Furthermore, regarding model details, the model parameters were selected based on the engine's typical rated operating conditions. The high-pressure rotor speed was also given particular consideration. Low-pressure rotor speed Turbine inlet temperature And the compressor surge margin (SM) and other core parameters must adhere to strict limitations during 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... This serves as the sole basis for switching from the steady state to the transient state, and its accompanying non-disruptive switching mechanism ensures that the control output is free of sudden jumps. The total simulation time is set to 100 seconds, and the focus is on the response characteristics of the engine during the critical dynamic process of rapidly accelerating from the cruise thrust state (initial state) to the maximum thrust state.

[0105] Core performance indicators of the aircraft engine model: maximum thrust approximately 84.51 kN, high-pressure rotor. The design speed is 15000 r / min, low-pressure rotor. The design rotational speed is 9000 r / min, and a converging nozzle configuration is selected. Additionally, parameters such as the nozzle throat area and the aft duct ejector opening were considered. The calculation formula is:

[0106] ;

[0107] in, This represents the area of ​​the nozzle throat. This represents the nozzle area.

[0108] Rear duct ejector opening The calculation formula is:

[0109] ;

[0110] in, The area of ​​the tail bypass injector. The area of ​​the outer duct ejector.

[0111] The simulation settings mimic the process of a pilot rapidly pushing the throttle lever to its maximum position, where the engine initially operates at low speeds and then instantly receives a full acceleration command. For example... Figure 5 As shown, after the throttle command is issued, the fuel flow demand (command value) immediately surges, rapidly climbing from the initial steady-state of approximately 0.39 kg / s to about 1.05 kg / s. After a brief period of stabilization, the command value rises again to around 1.55 kg / s (reflecting the acceleration demand in the second stage). Simultaneously, the mode switching signal curve (Switch curve) clearly shows that Switch=0 indicates MPC operation, and Switch=1 indicates VPC operation. During the two periods of sharp increases in fuel demand, the designed value based on the real-time fuel flow rate change... The criteria are activated in a timely manner, and the control mode is smoothly switched from steady-state optimal to dynamic model prediction state. Figure 5 middle, curves and The curve changes closely follow the changes in the command switch signal curve. The curve trend clearly shows that the fuel flow command and actual output are smoothly and naturally connected throughout the acceleration process, completely eliminating the jerky feeling caused by sudden fuel volume jumps during gear shifts, a common problem with traditional switching methods. The advantage of this seamless switching scheme in terms of control continuity is very obvious.

[0112] like Figure 6 As shown, Figure 6 The thrust is shown in the figure. changing Curve, nozzle throat area opening changing Curve and tail bypass injector area opening changing The curves show that the thrust increases almost linearly after the throttle command, approaching the target value in about 5 seconds. The entire process is clean and crisp, without fluctuations or overshoot. The high and low pressure rotor speeds also keep pace with the increase in fuel injection, with rapid speed increase and precise final stabilization, demonstrating excellent dynamic response performance. These two sets of curves fully illustrate that the high accuracy of the switching timing selected as the criterion, coupled with the consistency between the MPC controller's initial position (initialization) and the VPC's output state before the switch, results in a crisp, smooth, and seamless engine thrust increase, without any sluggishness or sudden throttle jumps.

[0113] like Figure 7 As shown, Figure 7 The turbine inlet temperature is shown. changing Curve, high-pressure compressor surge margin changing Surge margin curve and low-pressure compressor surge margin changing The simulation results show that as the fuel flow rate increases, the temperature rises rapidly and stabilizes below the safe threshold (around 1700K), without any overheating. The high-pressure compressor surge margin narrows somewhat during acceleration, but its minimum value remains above the specified safe lower limit (approximately 20%). Conversely, the fan surge margin widens after thrust increases, remaining within the safe boundary. These findings demonstrate that the MPC controller effectively responds to acceleration commands and satisfies multivariate constraints while successfully mitigating surge and overheating risks, ensuring the safe and reliable dynamic operation of the engine.

[0114] like Figure 8 As shown, Figure 8 The diagram shows the SFC curve for the change in engine fuel consumption rate (SFC) and the area of ​​the exhaust nozzle throat. changing Curve and rear duct ejector opening changing The curves further illustrate the dynamic characteristics of engine fuel consumption rate and related efficiency parameters. During the initial acceleration phase, SFC (Self-Fuel Consumption Rate) briefly increases; subsequently, in the steady-state performance optimization phase, SFC significantly decreases and stabilizes at a low level (approximately 0.56 kg / (daN·h)), resulting in a combined fuel consumption reduction of approximately 5.03%. This indicates that after increasing thrust, the engine enters a more optimal operating range, effectively improving fuel economy. Simultaneously, the engine efficiency parameters under steady-state conditions (normalized to 100% baseline) are significantly better than those under initial cruise conditions, demonstrating that VPC steady-state optimization control successfully improves component-level efficiency, further corroborating the effectiveness of this control strategy in reducing fuel consumption.

[0115] In summary, the proposed VPC-MPC smooth switching control strategy demonstrates excellent performance during typical acceleration under simulated near-sea surface conditions. The controller achieves a continuous and smooth transition between fuel flow and thrust response, significantly improving the ability to stabilize the engine operating point within a safe range under harsh dynamic conditions. Furthermore, this strategy not only improves steady-state fuel economy but also optimizes component-level efficiency, fully demonstrating its practical value and application potential in engineering.

[0116] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0117] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An aero-engine controller switching method based on VPC-MPC dual architecture, characterized in that, include: When the engine is controlled by the model predictive control controller, the first information is acquired at each sampling time, and the state of the valve position control controller is updated based on the first information. The first information includes the first output value of the model predictive control controller, which includes the first nozzle throat area output, the first tail bypass injector area output, and the first fuel flow output of the engine. Obtain the real-time fuel flow rate change rate of the engine; If the real-time fuel flow rate change rate is lower than the preset switching threshold, the model prediction control controller will be switched to the valve position control controller. The step of updating the state of the valve position control controller based on the first information includes: The output reference value of the first control loop of the valve position control controller is calculated based on the output of the first nozzle throat area at the current moment. The output reference value of the second control loop of the valve position control controller is calculated based on the area output of the first tail bypass injector at the current moment. The rate of change of the integral term of the first controller in the third control loop of the valve position control controller is calculated based on the first fuel flow output at the current moment. The first controller is a PI controller. The rate of change of the integral term of the first controller is expressed as: ； wherein, is a rate of change of an integral term of the first controller, is a proportional gain, is an integral gain, is a derivative term of an error, is an error at a current time, is a first time constant, and is the first fuel flow output and an output of the first controller, respectively, at a current time.

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

3. The method for switching aero-engine controllers based on a VPC-MPC dual architecture according to claim 2, characterized in that... The control sequence for updating the model predictive control controller based on the third information includes: The first control sequence is calculated based on the predictive model of the model predictive controller; Construct a first objective function based on the second output value at the current moment and the preset objective function; Calculate the objective function value corresponding to each control variable in the first control sequence based on the first objective function; The control variables of the first control sequence are sorted in ascending order according to the objective function values ​​corresponding to the control variables to obtain the second control sequence.

4. The method for switching aero-engine controllers based on a VPC-MPC dual architecture according to claim 3, characterized in that... The first objective function is expressed as: ； in, To predict the step size, To control the step size, For the first The system output prediction of the step, For the first The reference trajectory of the step, This is the first weight matrix. This is the second weight matrix. , and These are the nozzle throat areas Tail bypass injector area and fuel flow Weighting factors of external tracking items, For the first Step control increment, , and These are the nozzle throat areas. Tail bypass injector area and fuel flow The initial control input value, , and These are the output of the second nozzle throat area, the output of the second tail bypass injector area, and the output of the second fuel flow rate of the VPC at the current moment.

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