An aircraft engine control system and method based on adaptive specified interference elimination

Abstract

The present invention discloses an aircraft engine control system and method based on adaptive specified interference elimination, which belongs to the field of aircraft engine control. The nonlinear mathematical model of the aircraft engine with disturbance in affine form is obtained through system identification, a fixed-time disturbance observer is designed to estimate the lumped interference of the system in real time, and an adaptive specified interference elimination composite controller is constructed based on the nonlinear backstepping method and the dynamic inverse method to achieve precise control of the engine speed. The system adjusts the control quantity in real time based on the backstepping method and the dynamic inverse method. The controller adopts a non-smooth command filter and an adaptive dynamic weight distribution mechanism to achieve effective compensation for system uncertainty. The method can effectively deal with the uncertainty caused by system parameter perturbation, unmodeled dynamics and external load fluctuations, taking into account both dynamic and static performance, and has high control accuracy, good anti-interference ability and closed-loop stability, and is suitable for aircraft engine speed control under complex working conditions.

Description

Technical Field

[0001] The present invention belongs to the field of aircraft engine control, and relates to an aircraft engine control method, and in particular to a control system and method based on adaptive specified interference elimination technology. The aircraft engine control method combines the advantages of backstepping method, dynamic inversion method, and adaptive specified interference elimination technology, and fully considers the favorable or harmful effects of interference on control performance under different circumstances. It has the advantages of clear physical meaning, fast disturbance estimation, adaptive specified interference elimination, closed-loop stability, good control performance, etc. Background Art

[0002] As the core power unit of aircraft, aircraft engines have extremely complex working environments, including high temperature, high pressure, rapidly changing load conditions and the influence of various meteorological factors. In addition, as the service time of aircraft engines increases, wear and aging of their internal components are inevitable, and this performance degradation further aggravates the complexity of the control system. Therefore, there are many complex factors such as unmodeled dynamics, uncertainty and external disturbances in aircraft engine control systems. These uncertainties can be uniformly described by using lumped disturbances. The existence of lumped disturbances inevitably affects the control performance of aircraft engines, making it difficult for the system to simultaneously meet the control index requirements such as stability, rapidity, accuracy, robustness and reliability.

[0003] In traditional control methods, it is usually assumed that the system model is accurately known and the disturbance is negligible or can be simply compensated. However, in reality, since the lumped disturbance has a significant impact on the system dynamics, if these disturbances are not fully considered when designing the control system, there may be a large deviation between the system output and the expected value. This deviation will not only reduce the quality of the control system, but also endanger the stability of the system. Although a variety of advanced control methods have been developed, such as adaptive or robust control methods, these methods still have limitations. For example, adaptive control methods are usually based on the assumption that system parameters change slowly and regularly, while robust control methods rely on the assumption that disturbances are bounded (i.e., assuming that the uncertainty of the system changes within a fixed range). These assumptions are often difficult to meet in the actual operation of aircraft engines. Therefore, the controllers designed based on these methods are often very conservative and it is difficult to obtain ideal control effects.

[0004] In addition, traditional control methods often adopt an indiscriminate compensation strategy when dealing with disturbances, that is, all disturbances are regarded as harmful factors for compensation. This approach ignores the positive effects that certain disturbances may have under specific conditions. For example, when an aircraft engine is operating under different operating conditions, some external disturbances may have a certain positive effect on the closed-loop performance of the system, especially in improving the system response speed and reducing fuel consumption. Under other operating conditions, disturbances may have a negative impact on system performance, causing the system output to deviate from the expected value and even affecting the stability of the system. However, traditional control methods fail to effectively distinguish between beneficial and harmful disturbances, resulting in the failure to fully optimize the control performance of the system, especially in terms of the rapidity and fuel efficiency of aircraft engines.

[0005] In summary, the existing aircraft engine control technology has many shortcomings when dealing with lumped disturbances in complex working environments, including high conservatism of disturbance compensation strategies, insufficient utilization of favorable factors of disturbances, harsh assumptions of control methods, and high complexity of controller design. Therefore, how to effectively deal with complex disturbances in aircraft engine systems, make full use of engine model information, achieve real-time estimation of lumped disturbances and adaptive elimination of specified disturbances, and improve the dynamic and static performance and robustness of the control system are technical issues that need to be solved in the current field of aircraft engine control. Summary of the invention

[0006] 1. Purpose of the invention

[0007] In order to solve the above defects and deficiencies existing in the existing aircraft engine control system and method, the present invention aims to provide an aircraft engine control system and method based on adaptive specified interference elimination technology. This control system and method do not need to provide an accurate mathematical model. By introducing an extended observer based on fixed time to monitor and estimate the lumped interference in the system in real time, and combining the dynamic inversion method, backstepping method and adaptive specified interference elimination technology, an adaptive specified interference elimination composite controller is designed to achieve the rational use and effective compensation of system interference. This idea utilizes the beneficial effect of lumped interference in the aircraft engine system on tracking control, improves the convergence speed of the closed-loop system, takes into account the static characteristics, reduces the static error and control ripple, and achieves excellent speed tracking control performance of the aircraft engine. It has the advantages of conditional disturbance estimation and compensation, closed-loop stability, high control accuracy, and no reliance on accurate models. The closed-loop system obtained by this method is theoretically uniformly bounded and stable, and reasonable selection of controller parameters can effectively improve the control quality of the system.

[0008] (II) Technical solution

[0009] In order to achieve the purpose of the invention and solve the technical problems, the present invention adopts the following technical solutions:

[0010] The first invention object of the present invention is to provide an aircraft engine control system based on adaptive specified disturbance elimination, which is used to realize the speed control of the aircraft engine, improve its speed tracking control accuracy and system robustness under different working conditions, and logically includes at least one instruction generator, one adaptive specified disturbance elimination composite controller and one fixed time disturbance observer, wherein:

[0011] The command generator, whose output end is connected to the input end of the adaptive specified interference elimination composite controller, is used to generate a dynamic command signal that meets the index requirements according to the control target set by the system, and the dynamic command signal has a preset speed tracking trajectory characteristic to guide the speed regulation of the engine;

[0012] The fixed-time disturbance observer has an input end connected to the output end of the adaptive specified interference elimination composite controller and the state feedback end and system output end of the downstream aircraft engine, respectively, and is used to input the output control quantity of the adaptive specified interference elimination composite controller, the state feedback value representing the shaft speed of the aircraft engine, and the system output quantity; and an output end connected to the input end of the adaptive specified interference elimination composite controller, and is used to estimate the lumped interference in real time within a fixed time according to the state feedback information of the aircraft engine and the output control instruction of the controller, and output the lumped interference estimation value to the adaptive specified interference elimination composite controller;

[0013] The adaptive specified disturbance elimination composite controller has its input end connected to the output end of the instruction generator, the output end of the fixed time disturbance observer and the state feedback end of the downstream aircraft engine, and its output end connected to the control instruction input end of the downstream aircraft engine and the input end of the fixed time disturbance observer, and wherein:

[0014] The adaptive specified interference elimination composite controller combines the dynamic instructions from the instruction generator, the lumped interference estimation value of the fixed-time disturbance observer and the state feedback information of the aircraft engine, adjusts the control quantity in real time based on the backstepping method and the dynamic inverse method, and combines the adaptive specified interference elimination method to generate adaptive control instructions through real-time estimation and feedback compensation of the lumped interference and output them to the aircraft engine and the fixed-time disturbance observer, thereby realizing real-time tracking control of the aircraft engine speed and adaptive elimination of specified interference.

[0015] The second invention object of the present invention is to provide an aircraft engine control method based on adaptive specified interference elimination, based on the aircraft engine control system based on adaptive specified interference elimination provided by the first invention object, for improving the speed tracking control accuracy and system robustness of the engine under different working conditions. The control method at least comprises the following steps when implemented:

[0016] SS1. Control model establishment

[0017] The aircraft engine is modeled systematically, and its input and output data are used to construct a nonlinear mathematical model with disturbance in the form of affine through system identification method in response to the needs of control design:

[0018]

[0019] In the formula, x represents the shaft speed state vector of the aircraft engine and x= [ x 1 x 2] T , x 1 represents the increment of the aircraft engine shaft speed, x 2 represents the acceleration of the aircraft engine. They are x 1. x 2 Differentiation with respect to time and , d is the aggregate interference in the system, f ( x ), g ( x ) are all about the state vector x A nonlinear function of y Represents the system output value of the aircraft engine, which is the increment of the aircraft engine shaft speed here x 1, u is the system input value of the aircraft engine, which is the output control quantity of the adaptive specified disturbance elimination composite controller;

[0020] SS2. Trace instruction generation

[0021] Based on given reference instructions r d , through a transfer function G ( s ) to adjust and arrange the process and generate dynamic instructions that meet the requirements of preset control indicators x 1d , and find the differential of the instruction with respect to time To ensure that the dynamic response of the system under different working conditions can maintain good tracking performance;

[0022] SS3. Fixed-time interference observation

[0023] Based on the fixed-time extended state interference observation method, the observation and real-time estimation of the aggregate interference within a fixed time are realized by extending the state observation method, and the estimated value of the aggregate interference is obtained. , the fixed-time disturbance observer is designed as follows:

[0024]

[0025] in Corresponding to The observed value of represents the observation error, represents the coefficient of the nonlinear term, l represents the order of the observer, The coefficient representing the observer convergence speed, The specific matrix constructed satisfies the Hurwitz condition to ensure the stability of the system;

[0026] SS4. Adaptive Specified Disturbance Cancellation Composite Control Calculation

[0027] Firstly, the nonlinear backstepping method is used to design the virtual control quantity based on the system error feedback and the differential of the dynamic command signal. x Expected value of 2 x 2d , whose expression is:

[0028]

[0029] in K 1, K 2, K 3 is a positive gain parameter, which is used to control the response speed and stability of the system; u 1 and u 2 is the weight parameter and satisfies 0< u 1<1, u 2>1, to achieve the convergence characteristics of the closed-loop system; e 1= x 1 -x 1d , which represents the tracking error between the current state and the target state; at the same time, in order to improve the dynamic performance and anti-interference ability of the controller in practical applications, the following non-smooth command filter is designed to smooth the output of the control quantity:

[0030]

[0031] in, is the time constant and is used to control the response speed of the command filter. k 1. k 2. k 3 are filter parameters and are all positive numbers. x 2c is the command filter output, by adjusting the parameters k 1. k 2. k 3 to ensure the smoothness of the controlled quantity and the stability and smoothness of the output after filtering, and in the above two formulas, , α is the power exponent;

[0032] Secondly, based on the dynamic inversion method and combined with the observed output of the fixed-time interferer, an adaptive specified disturbance elimination composite control law is designed to achieve closed-loop control of the aircraft engine system:

[0033]

[0034] in e 2= x 2 -x 2c , represents the error between the current state and the expected state; K 4. K 5. K 6 is an appropriate positive number, which represents the control law gain parameter, which is used to adjust the feedback strength of the error and its nonlinear term to ensure the stability and rapid response capability of the system under different working conditions; exp(•) represents the power function with Euler number as the base, is the differential of the command filter output with respect to time, The composition weights of the interference compensation components in different tracking stages are adjusted for the pre-given adaptive parameters;

[0035] SS5. Closed-loop control judgment

[0036] The system performs closed-loop control to determine whether an instruction to end control is received. If so, the control is ended. If not, the process jumps to step SS2 and executes the loop to continue tracking control and interference estimation to ensure that the engine maintains stable control performance under complex working conditions.

[0037] (III) Technical Effect

[0038] Compared with the prior art, the aircraft engine control system and method based on adaptive specified interference elimination of the present invention have the following significant technical effects:

[0039] (1) Closed-loop stability: Compared with traditional model-free control methods such as PID, the present invention can theoretically explain the bounded stability of the system. Through a fixed-time disturbance observer, the present invention can quickly and accurately describe and compensate for the internal and external disturbance factors of the aircraft engine system. Compared with traditional asymptotically convergent observers, it has a certain convergence time and better dynamic performance, thereby ensuring that the system can still maintain stable operation in the face of complex disturbances. Through the disturbance observation and compensation mechanism within a fixed time, the system is guaranteed to have theoretically consistent bounded stability, thereby improving the robustness and reliability of the control system.

[0040] (2) Good control performance: The adaptive specified interference elimination of model uncertainty in the present invention takes into account both dynamic and static performance and robustness, so the method proposed in the present invention has good control performance. During the dynamic change process, the system can quickly adjust and adapt to the interference, thereby reducing the steady-state error and improving the stability and accuracy of the control. This design shows good dynamic and static performance under different working conditions, especially when facing complex and nonlinear disturbances, ensuring efficient and accurate control performance.

[0041] (3) No reliance on precise models: Another significant advantage of the present invention is that it has low reliance on precise mathematical models. It only needs to use the input and output data of the aircraft engine and construct its nonlinear affine mathematical model with disturbance through the system identification method. The modeling error and the unmodeled dynamic characteristics of the system are described by lumped disturbance, and the lumped disturbance is observed and compensated in real time through a fixed-time disturbance observer. This method avoids the high requirements for precise models, can effectively handle complex actual working conditions, and greatly simplifies the complexity of controller design.

[0042] (4) The present invention enhances the anti-interference capability of the system. In actual operation, aircraft engines are often affected by unmodeled dynamics, uncertainties, and external disturbances. The present invention, by designing a fixed-time extended state disturbance observer, can observe and estimate the aggregated disturbance in real time within a limited time. By accurately estimating the aggregated disturbance, the system can adaptively adjust the control strategy to effectively eliminate the disturbance, thereby significantly improving the stability and robustness of the aircraft engine in an interference environment. In addition, by designing a nonlinear backstepping method and an adaptive filter, the present invention can quickly respond to the dynamic needs of the aircraft engine and ensure that the control instructions can take effect in real time. In particular, through the dynamic inverse method, combined with the non-smooth design of the filter, the system can dynamically adjust the output control amount according to the real-time error, reduce the response lag, and improve the dynamic performance of the system.

[0043] (5) More importantly, the important innovation of this method is that it proposes a control method based on adaptive specified disturbance elimination technology, which breaks through the indiscriminate treatment of disturbances by traditional control methods. By dynamically observing the disturbances, it fully utilizes the beneficial effect of the lumped disturbances in the aero-engine system on tracking control and improves the convergence speed of the closed-loop system. This design not only improves the tracking accuracy of the system for the target command, but also takes into account the static characteristics, including static error and control ripple. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a principle block diagram of an aircraft engine control system based on adaptive specified interference elimination according to Embodiment 1 of the present invention;

[0045] Figure 2 is a flow chart of an aircraft engine control method based on adaptive specified interference elimination according to embodiment 2 of the present invention;

[0046] Figure 3 The figure shows the control effect diagram of the tracking step instruction of the aircraft engine control method based on adaptive specified interference elimination of the present invention;

[0047] Figure 4 Shown is a control effect diagram of tracking sinusoidal instructions of the aviation engine control method based on adaptive specified interference elimination of the present invention.

[0048] Description of reference numerals:

[0049] 10-command generator, 20-adaptive specified disturbance elimination composite controller, 30-fixed time disturbance observer, 40-aircraft engine. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the implementation of the present invention clearer, the technical scheme in the embodiment of the present invention will be described in more detail below in conjunction with the drawings in the embodiment of the present invention. The described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and should not be understood as limiting the present invention. Based on the embodiments in 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.

[0051] The present invention aims to provide an aircraft engine control system and method based on adaptive specified interference elimination technology. By introducing an extended observer based on fixed time to monitor and estimate the lumped interference in the system in real time, and combining the dynamic inversion method, backstepping method and adaptive specified interference elimination technology, an adaptive specified interference elimination composite controller is designed to achieve reasonable use and effective compensation of system interference. This idea utilizes the beneficial effect of lumped interference in the aircraft engine system on tracking control, improves the convergence speed of the closed-loop system, takes into account static characteristics, reduces static errors and control ripples, and achieves superior speed tracking control performance of aircraft engines. It has the advantages of conditional disturbance estimation and compensation, closed-loop stability, high control accuracy, and no reliance on accurate models.

[0052] Example 1

[0053] As a specific example, Figure 1 As shown, logically, the aircraft engine control system based on the adaptive specified interference elimination technology of the present invention includes at least the following parts:

[0054] Instruction generator 10: generates corresponding dynamic instructions according to the overall given indicator requirements, used to generate given instructions x d , for use in control design.

[0055] Adaptive specified disturbance cancellation compound controller 20: Based on the instruction generator 10 and the fixed-time disturbance observer 30, it realizes the adaptive disturbance cancellation compound control of the aircraft engine.

[0056] Fixed-time disturbance observer 30: Design of a disturbance observer with fixed-time convergence properties for observing aggregate disturbances d .

[0057] In addition, an aircraft engine 40 is included, and a mathematical model is established from the input and output data of the aircraft engine to complete the control design. The present invention is mainly aimed at the speed control of a single-shaft aircraft engine, which is an essential component of the present invention but does not belong to the content of the present invention.

[0058] Figure 1 middle, x Represents the state vector describing the aircraft engine system, which is x represents the state vector of the aircraft engine and x =[ x 1 x 2] T , x 1 represents the increment of the aircraft engine shaft speed ΔN = N - N e ,in N is the actual speed of the current engine, No is the engine speed under static or reference conditions, x 2 represents the acceleration of the aircraft engine. u The output of the adaptive specified disturbance elimination compound controller 20, whose physical meaning is the increase of fuel flow ΔW f = W f - W fe ,in W f is the current fuel flow of the engine, W fe is the base fuel flow. d is the total interference of the system, y Output of the aircraft engine system.

[0059] More specifically, Figure 1As shown, in the aircraft engine control system based on the adaptive specified interference elimination technology proposed by the present invention, the instruction generator 10 is connected to the adaptive specified interference elimination composite controller 20, which will generate corresponding dynamic instructions according to the overall given index requirements. x d The disturbance is input into the adaptive specified disturbance cancellation compound controller 20 for use in control design; the fixed time disturbance observer 30 is also connected to the adaptive specified disturbance cancellation compound controller 20, and the estimated value of the disturbance is used for the adaptive specified disturbance cancellation compound control. x Input to the adaptive specified disturbance elimination composite controller 20 and the fixed time disturbance observer 30 as state feedback, and u and y It is also input into the fixed-time disturbance observer 30 for use in disturbance estimation.

[0060] As for the connection relationship between the components in the system, in the aircraft engine control system based on the adaptive specified interference elimination technology proposed in the present invention, the output end of the command generator 10 is connected to the input end of the adaptive specified interference elimination composite controller 20, which is used to generate a dynamic command signal that meets the index requirements according to the control target set by the system. The dynamic command signal has a preset speed tracking trajectory characteristic to guide the engine speed regulation.

[0061] The fixed time disturbance observer 30 has an input terminal connected to the output terminal of the adaptive specified disturbance elimination composite controller 20 and the state feedback terminal and system output terminal of the downstream aircraft engine 40, and is used to input the output control quantity of the adaptive specified disturbance elimination composite controller 20 and the state feedback value representing the shaft speed of the aircraft engine. x And system output y , whose output end is connected to the input end of the adaptive specified interference elimination compound controller 20, and is used to estimate the aggregate interference in real time within a fixed time according to the state feedback information of the aircraft engine and the output control instruction of the controller, and output the aggregate interference estimation value to the adaptive specified interference elimination compound controller 20.

[0062] The adaptive specified interference elimination composite controller 20 has its input end connected to the output end of the instruction generator 10, the output end of the fixed-time disturbance observer 30 and the state feedback end of the downstream aircraft engine 40, and its output end is connected to the control instruction input end of the downstream aircraft engine 40 and the input end of the fixed-time disturbance observer 30, and wherein: the adaptive specified interference elimination composite controller 20 combines the dynamic instructions from the instruction generator 10, the lumped interference estimation value of the fixed-time disturbance observer 30 and the state feedback information of the aircraft engine 40, adjusts the control quantity in real time based on the backstepping method and the dynamic inverse method, and combines with the adaptive specified interference elimination method, through the real-time estimation and feedback compensation of the lumped interference, generates adaptive control instructions and outputs them to the aircraft engine 40 and the fixed-time disturbance observer 30, so as to realize real-time tracking control of the aircraft engine speed and adaptive elimination of specified interference.

[0063] In a preferred example of the present invention, the aircraft engine 40 includes an input end, a state feedback end and a system output end, wherein the input end is connected to the output end of the adaptive specified interference elimination compound controller 20, and is used to receive control instructions and adjust the engine speed in real time accordingly, and the state feedback end is connected to the fixed-time disturbance observer 30 and the adaptive specified interference elimination compound controller 20, and is used to feed back its shaft speed state information to the fixed-time disturbance observer 30 and the adaptive specified interference elimination compound controller 20 to achieve closed-loop control, and the system output end is connected to the fixed-time disturbance observer 30, and provides engine output information to assist the observer in estimating the lumped interference.

[0064] In a preferred embodiment of the present invention, the aircraft engine 40 is a single-shaft aircraft engine. For the single-shaft aircraft engine system, the input and output data thereof are used to meet the needs of control design and obtain the affine nonlinear mathematical model with disturbance through the system identification method:

[0065]

[0066] In the formula, x represents the shaft speed state vector of the aircraft engine and x =[ x 1 x 2] T , x 1 represents the increment of the aircraft engine shaft speed, x 2 represents the acceleration of the aircraft engine. They are x 1. x 2 Differentiation with respect to time and , d is the total interference of the system, f ( x ),g ( x ) are all about the state vector x A nonlinear function of y Represents the system output value of the aircraft engine, which is the increment of the aircraft engine shaft speed here x 1, u is the system input value of the aircraft engine, which is the output control quantity of the adaptive specified disturbance elimination composite controller.

[0067] In a preferred embodiment of the present invention, the instruction generator 10 is used to generate a given dynamic instruction signal according to the control index requirements of the overall system, based on the known given reference instruction r d , through a transfer function G ( s ) to adjust and arrange the process and generate dynamic instructions that meet the requirements of preset control indicators x 1d , and find the differential of the instruction with respect to time To ensure that the system's dynamic response under different working conditions can maintain good tracking performance.

[0068] In a preferred embodiment of the present invention, the fixed-time disturbance observer 30 is based on the fixed-time extended state disturbance observation method, and realizes the observation and real-time estimation of the aggregate interference within a fixed time by extending the state observation method, and obtains the estimated value of the aggregate interference. , the fixed-time disturbance observer is designed as follows:

[0069]

[0070] in Corresponding to The observed value of represents the observation error, represents the coefficient of the nonlinear term, l represents the order of the observer, The coefficient representing the observer convergence speed, The specific matrix formed satisfies the Hurwitz condition to ensure the stability of the system. In this way, the aggregate interference can be observed in real time. d And its derivatives of various orders, the final output is the estimated value of the aggregate interference , which provides a basis for disturbance compensation for the adaptive specified disturbance elimination composite controller.

[0071] In a preferred embodiment of the present invention, the adaptive specified disturbance elimination composite controller 20 adopts a two-step control law design strategy based on the backstepping method, and generates an output control quantity based on the input information of the command generator and the fixed time disturbance observer. uAnd output to the aircraft engine and fixed-time disturbance observer to realize the adaptive specified disturbance elimination composite control of the aircraft engine. The control law design includes two steps:

[0072] Firstly, the nonlinear backstepping method is used to design the virtual control quantity based on the system error feedback and the differential of the dynamic command signal. x Expected value of 2 x 2d , whose expression is:

[0073]

[0074] in K 1, K 2, K 3 is a positive gain parameter, which is used to control the response speed and stability of the system; u 1 and u 2 is the weight parameter and satisfies 0< u 1<1, u 2>1, to achieve the convergence characteristics of the closed-loop system; e 1= x 1- x 1d , which represents the tracking error between the current state and the target state; at the same time, in order to improve the dynamic performance and anti-interference ability of the controller in practical applications, the following non-smooth command filter is designed to smooth the output of the control quantity:

[0075]

[0076] in, is the time constant and is used to control the response speed of the command filter. k 1. k 2. k 3 are filter parameters and are all positive numbers. x 2c is the command filter output, by adjusting the parameters k 1. k 2. k 3 to ensure the smoothness of the controlled quantity and the stability and smoothness of the output after filtering, and in the above two formulas, , α is the power exponent;

[0077] Secondly, based on the dynamic inversion method and combined with the observed output of the fixed-time interferer, an adaptive specified disturbance elimination composite control law is designed to achieve closed-loop control of the aircraft engine system:

[0078]

[0079] in e 2=x 2- x 2c , represents the error between the current state and the expected state; K 4. K 5. K 6 is an appropriate positive number, which represents the control law gain parameter, which is used to adjust the feedback strength of the error and its nonlinear term to ensure the stability and rapid response capability of the system under different working conditions; exp(•) represents the power function with Euler number as the base, Output of the command filter x 2c Differentiation with respect to time, The adaptive parameters are given in advance to adjust the composition weights of the disturbance compensation components in different tracking stages. This control law effectively combines error feedback and disturbance compensation. The design of nonlinear terms and adaptive compensation terms enhances the system's adaptability to external disturbances, effectively improves the system's robustness to unmodeled dynamics and external disturbances, and realizes precise tracking control of aircraft engine speed.

[0080] Example 2

[0081] Based on the aircraft engine control system based on the adaptive specified interference elimination technology shown in the above embodiment 1, as a further supplement, Figure 2 As shown, the present invention also provides a corresponding aircraft engine control method based on adaptive specified interference elimination technology, which mainly includes:

[0082] SS1. Control model establishment

[0083] For the single-shaft aircraft engine system, using its input and output data, facing the needs of control design, and through the method of system identification, its affine form nonlinear mathematical model with disturbance is obtained:

[0084]

[0085] In the formula, x represents the shaft speed state vector of the aircraft engine and x =[ x 1 x 2] T , x 1 represents the increment of the aircraft engine shaft speed, x 2 represents the acceleration of the aircraft engine. They are x 1. x 2 Differentiation with respect to time and , d is the aggregate interference in the system, f ( x ), g( x ) are all about the state vector x A nonlinear function of y Represents the system output value of the aircraft engine, which is the increment of the aircraft engine shaft speed here x 1, u is the system input value of the aircraft engine, which is the output control quantity of the adaptive specified disturbance elimination composite controller.

[0086] As a preference, x 1 represents the increment of the aircraft engine shaft speed ΔN = N - N e ,in N is the actual speed of the current engine, N e The speed of the engine under static or reference conditions. This increment is used to reflect the change in the speed of the engine under different working conditions. u The output control quantity of the adaptive specified disturbance elimination compound controller is the increment of fuel flow. ΔW f = W f - W fe ,in W f is the current fuel flow of the engine, W fe is the base fuel flow.

[0087] In addition, in order to improve the system modeling accuracy and model applicability, the lumped interference d At least it includes the uncertainty effects caused by system parameter perturbations, unmodeled dynamics, external load fluctuations, and environmental factors; at the same time, f ( x )and g ( x ) all satisfy the local Lipschitz continuity condition, and the control gain function g ( x ) remains non-singular throughout the entire operating range.

[0088] SS2. Trace instruction generation

[0089] Based on given reference instructions r d , through a transfer function G ( s ) to adjust and arrange the process and generate dynamic instructions that meet the requirements of preset control indicators x 1d, and find the differential of the instruction with respect to time to ensure that the dynamic response of the system under different working conditions can maintain good tracking performance.

[0090] SS3. Fixed-time interference observation

[0091] Based on the fixed-time extended state disturbance observation method, the observation and real-time estimation of the aggregate interference within a fixed time are realized by extending the state observation method, and the estimated value of the aggregate interference is obtained. The fixed-time disturbance observer is designed as follows:

[0092]

[0093] in Corresponding to The observed value of represents the observation error, represents the coefficient of the nonlinear term, l represents the order of the observer, The coefficient representing the observer convergence speed, The specific matrix constructed satisfies the Hurwitz condition to ensure the stability of the system.

[0094] As a preference, the order of the fixed-time disturbance observer l The selection must meet l ≥2, the design of the observer parameters needs to ensure that the system converges within a finite time, that is, there is a finite time T >0, so that for any t ≥ T At this moment, the observation error satisfies , is the estimated value of the fixed-time disturbance observer output; at the same time, the nonlinear term coefficient r i and d i The selection must satisfy 0< r i <1, d i >1, i =1,2,…, l , to ensure that the observer has fixed-time convergence characteristics.

[0095] SS4. Adaptive Specified Disturbance Cancellation Composite Control Calculation

[0096] The above adaptive specified disturbance elimination composite control calculation is divided into two steps:

[0097] Firstly, the nonlinear backstepping method is used to design the virtual control quantity based on the system error feedback and the differential of the dynamic command signal. x Expected value of 2 x2d , whose expression is:

[0098]

[0099] in K 1, K 2, K 3 is a positive gain parameter, which is used to control the response speed and stability of the system; u 1 and u 2 is the weight parameter and satisfies 0< u 1<1, u 2>1, to achieve the convergence characteristics of the closed-loop system; e 1= x 1- x 1d , which represents the tracking error between the current state and the target state; at the same time, in order to improve the dynamic performance and anti-interference ability of the controller in practical applications, the following non-smooth command filter is designed to smooth the output of the control quantity:

[0100]

[0101] in, is the time constant and is used to control the response speed of the command filter. k 1. k 2. k 3 are filter parameters and are all positive numbers. x 2c is the command filter output, by adjusting the parameters k 1. k 2. k 3 to ensure the smoothness of the controlled quantity and the stability and smoothness of the output after filtering, and in the above two formulas, , α is the power exponent;

[0102] Secondly, based on the dynamic inversion method and combined with the observed output of the fixed-time interferer, an adaptive specified disturbance elimination composite control law is designed to achieve closed-loop control of the aircraft engine system:

[0103]

[0104] in e 2= x 2- x 2c , represents the error between the current state and the expected state; K 4. K 5. K6 is an appropriate positive number, which represents the control law gain parameter, which is used to adjust the feedback strength of the error and its nonlinear term to ensure the stability and rapid response capability of the system under different working conditions; exp(•) represents the power function with Euler number as the base, Output of the command filter x 2c Differentiation with respect to time, The adaptive parameters are given in advance and the composition weights of the interference compensation components in different tracking stages are adjusted.

[0105] SS5. Closed-loop control judgment

[0106] The system performs closed-loop control to determine whether an instruction to end control is received. If so, the control is ended. If not, the process jumps to step SS2 to execute the loop and continue tracking control and interference estimation to ensure that the engine maintains stable control performance under complex working conditions.

[0107] Through the above steps, the control method of the present invention can effectively realize the precise control of the aircraft engine system, improve its robustness and dynamic response speed under various complex working conditions, and ensure that the system has high-precision speed tracking control capability and anti-interference ability.

[0108] Figure 3 The figure shows the control effect diagram of the tracking step instruction of the aircraft engine control method based on the adaptive specified interference elimination technology of the present invention. The figure reflects the tracking performance of the actual response (solid line) of the aircraft engine speed and the preset reference speed (dashed line) under the step input condition, and intuitively demonstrates the excellent performance of the aircraft engine control method of the present invention when processing step input, including fast response, low overshoot, high tracking accuracy and strong anti-interference ability. Specifically:

[0109] from Figure 3It can be seen that when the reference speed of the step input changes, the actual speed can quickly track the given speed target, showing good dynamic response performance. In about 1 second, the actual speed quickly tracks the given speed, verifying the efficiency of the control method in processing sudden changes. In addition, there is no obvious overshoot phenomenon when the actual speed tracks the step input. Even in the dynamic adjustment stage of the system, the actual speed can smoothly approach the given speed and remain stable, which shows that the present invention effectively suppresses the overshoot caused by disturbances and model uncertainties through the adaptive specified interference elimination technology. The figure also shows that in the steady-state stage after the step input, the actual speed basically coincides with the given speed, indicating that the system has extremely high tracking accuracy. This high-precision tracking control benefits from the fixed-time extended state disturbance observer and the adaptive specified interference elimination control strategy used in the present invention, which can estimate and compensate for the uncertainty and interference in the system in real time, ensuring the stability and accuracy of the system. The tracking curve in the figure also shows that even under complex dynamic conditions, the present invention can effectively eliminate the influence of internal and external interference in the system, and the actual speed can always maintain stable tracking performance, which shows that the adaptive specified interference elimination method enhances the anti-interference ability of the system by observing and compensating for the lumped interference.

[0110] Figure 4 The figure shows the control effect diagram of tracking sinusoidal instructions of the aircraft engine control method based on the adaptive specified interference elimination technology of the present invention. The figure shows the tracking performance of the system under sinusoidal input conditions, and the actual speed (solid line) is compared with the given speed (dashed line) to evaluate the responsiveness and stability of the control system. It can be seen from the figure that the actual speed response curve is highly coincident with the given instruction signal, which proves the accurate tracking ability of the system under complex input conditions (sine wave), indicating that the control method of the present invention has extremely high tracking accuracy when processing continuously changing inputs. In addition, the fluctuation process of the actual speed curve is very smooth, without obvious mutations or jitters, indicating that the system has good smoothness when tracking dynamically changing instructions, which is due to the adaptive specified interference elimination composite controller in the present invention, which combines the non-smooth instruction filter and the dynamic inverse control method to effectively reduce the dynamic fluctuations caused by interference. Figure 4 The actual speed displayed can maintain a fluctuation curve that is highly consistent with the reference speed under interference conditions, indicating that the system can effectively suppress the influence of interference, thanks to the real-time observation and compensation of the lumped interference by the fixed-time interference observer, ensuring that the system can maintain high stability under dynamic conditions. At the same time, from the observation of multiple cycles of the sine wave, the system can not only quickly track the given instructions in the dynamic response stage, but also accurately maintain the given speed in steady state, indicating that the method of the present invention can maintain good control performance under different conditions during the operation of the aircraft engine, taking into account the needs of dynamic response and steady-state tracking.

[0111] pass Figure 4 It can be seen from the simulation results that the control method proposed in the present invention can not only achieve accurate tracking of the step signal (such as Figure 3 As shown in the figure, it is also possible to achieve high-quality tracking control of continuously changing periodic signals. This fully verifies the superiority of this control method in dealing with the complex dynamic characteristics of aircraft engines, especially in practical application scenarios where continuous adjustment of engine speed is required.

[0112] The above embodiments 1 and 2 provide detailed descriptions of the aircraft engine conditional anti-interference composite control system and method proposed in the present invention. Compared with the prior art, the aircraft engine conditional anti-interference composite control system and method proposed in the present invention have significant technical effects such as closed-loop stability, high control accuracy, and independence from precise models. At the same time, it also has the following innovations: ① A control method based on adaptive specified interference elimination technology is proposed, which utilizes the beneficial effect of the lumped interference in the aircraft engine system on tracking control, improves the convergence speed of the closed-loop system, and takes into account the static characteristics, including static errors and control ripples; ② An aircraft engine control scheme based on adaptive specified interference elimination technology is designed to achieve superior speed tracking control performance of the aircraft engine by benefiting from beneficial interference and compensating for adverse interference.

[0113] Through the above embodiments, the purpose of the present invention is fully and effectively achieved. Those skilled in the art can understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Although the present invention has been described with respect to the most practical and preferred embodiments currently considered, it should be understood that the present invention is not limited to the disclosed embodiments, and any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. An aircraft engine control system based on adaptive specified disturbance elimination, comprising a command generator, an adaptive specified disturbance elimination composite controller and a fixed-time disturbance observer, characterized in that: The command generator, whose output end is connected to the input end of the adaptive specified interference elimination composite controller, is used to generate a dynamic command signal that meets the index requirements according to the control target set by the system, and the dynamic command signal has a preset speed tracking trajectory characteristic to guide the speed regulation of the engine; The fixed-time disturbance observer has an input end connected to the output end of the adaptive specified interference elimination composite controller and the state feedback end and system output end of the downstream aircraft engine, respectively, and is used to input the output control quantity of the adaptive specified interference elimination composite controller, the state feedback value representing the shaft speed of the aircraft engine, and the system output quantity; and an output end connected to the input end of the adaptive specified interference elimination composite controller, and is used to estimate the lumped interference in real time within a fixed time according to the state feedback information of the aircraft engine and the output control instruction of the controller, and output the lumped interference estimation value to the adaptive specified interference elimination composite controller; The adaptive specified disturbance elimination composite controller has its input end connected to the output end of the instruction generator, the output end of the fixed time disturbance observer and the state feedback end of the downstream aircraft engine, and its output end connected to the control instruction input end of the downstream aircraft engine and the input end of the fixed time disturbance observer, and wherein: The adaptive specified disturbance elimination composite controller combines the dynamic instructions from the instruction generator, the lumped disturbance estimation value of the fixed-time disturbance observer and the state feedback information of the aircraft engine, adjusts the control amount in real time based on the backstepping method and the dynamic inverse method, and combines the adaptive specified disturbance elimination method to generate adaptive control instructions through real-time estimation and feedback compensation of the lumped disturbance and output them to the aircraft engine and the fixed-time disturbance observer, so as to realize real-time tracking control of the aircraft engine speed and adaptive elimination of the specified disturbance; And among them: The aircraft engine is a single-shaft aircraft engine. For the single-shaft aircraft engine system, the input and output data thereof are used to meet the needs of control design and to obtain its affine nonlinear mathematical model with disturbance through the method of system identification: In the formula, x represents the shaft speed state vector of the aircraft engine and x =[ x 1 x 2] T , x 1 represents the increment of the aircraft engine shaft speed, x 2 represents the acceleration of the aircraft engine. They are x 1. x 2 Differentiation with respect to time and , d is the total interference of the system, f ( x ), g ( x ) are all about the state vector x A nonlinear function of y Represents the system output value of the aircraft engine, which is the increment of the aircraft engine shaft speed here x 1, u is the system input value of the aircraft engine, which is the output control quantity of the adaptive specified disturbance elimination composite controller; The command generator is used to generate a given dynamic command signal according to the overall control index requirements of the system, based on the known given reference command r d , through a transfer function G ( s ) to adjust and arrange the process and generate dynamic instructions that meet the requirements of preset control indicators x 1d , and find the differential of the instruction with respect to time To ensure that the dynamic response of the system under different working conditions can maintain good tracking performance; The fixed-time disturbance observer is based on the fixed-time extended state disturbance observation method. By extending the state observation method, the fixed-time disturbance observer realizes the observation and real-time estimation of the aggregated interference within a fixed time, and obtains the estimated value of the aggregated interference. , the fixed-time disturbance observer is designed as follows: in Corresponding to The observed value of represents the observation error, represents the coefficient of the nonlinear term, l represents the order of the observer, The coefficient representing the observer convergence speed, The specific matrix constructed satisfies the Hurwitz condition to ensure the stability of the system; The adaptive specified disturbance elimination composite controller adopts a two-step control law design strategy based on the backstepping method, and generates an output control quantity based on the input information of the command generator and the fixed-time disturbance observer. u And output to the aircraft engine and fixed-time disturbance observer to realize the adaptive specified disturbance elimination composite control of the aircraft engine. The control law design includes two steps: Firstly, the nonlinear backstepping method is used to design the virtual control quantity based on the system error feedback and the differential of the dynamic command signal. x Expected value of 2 x 2d , whose expression is: in K 1, K 2, K 3 is a positive gain parameter, which is used to control the response speed and stability of the system; u 1 and u 2 is the weight parameter and satisfies 0< u 1 <1, u 2 > 1. To achieve the convergence characteristics of the closed-loop system; e 1 =x 1 -x 1d , which represents the tracking error between the current state and the target state; at the same time, in order to improve the dynamic performance and anti-interference ability of the controller in practical applications, the following non-smooth command filter is designed to smooth the output of the control quantity: in, is the time constant and is used to control the response speed of the command filter. κ 1. κ 2. κ 3 are filter parameters and are all positive numbers. x 2c is the command filter output, by adjusting the parameters κ 1. κ 2. κ 3 to ensure the smoothness of the controlled quantity and the stability and smoothness of the output after filtering, and in the above two formulas, , α is the power exponent; Secondly, based on the dynamic inversion method and combined with the observed output of the fixed-time interferer, an adaptive specified disturbance elimination composite control law is designed to achieve closed-loop control of the aircraft engine system: in e 2 =x 2 -x 2c , represents the error between the current state and the expected state; K 4. K 5. K 6 is an appropriate positive number, which represents the control law gain parameter, which is used to adjust the feedback strength of the error and its nonlinear term to ensure the stability and rapid response capability of the system under different working conditions; exp(•) represents the power function with Euler number as the base, Output of the command filter x 2c Differentiation with respect to time, The adaptive parameters are given in advance and the composition weights of the interference compensation components in different tracking stages are adjusted.

2. An aircraft engine control method based on adaptive specified interference cancellation, based on the aircraft engine control system based on adaptive specified interference cancellation according to claim 1, characterized in that: The control method comprises at least the following steps when implemented: SS1. Control model establishment The aircraft engine is modeled systematically, and its input and output data are used to construct a nonlinear mathematical model with disturbance in the form of affine through system identification method in response to the needs of control design: In the formula, x represents the shaft speed state vector of the aircraft engine and x =[ x 1 x 2] T , x 1 represents the increment of the aircraft engine shaft speed, x 2 represents the acceleration of the aircraft engine. They are x 1. x 2 Differentiation with respect to time and , d is the aggregate interference in the system, f ( x ), g ( x ) are all about the state vector x A nonlinear function of y Represents the system output value of the aircraft engine, which is the increment of the aircraft engine shaft speed here x 1, u is the system input value of the aircraft engine, which is the output control quantity of the adaptive specified disturbance elimination composite controller; SS2. Trace instruction generation Based on given reference instructions r d , through a transfer function G ( s ) to adjust and arrange the process and generate dynamic instructions that meet the requirements of preset control indicators x 1d , and find the differential of the instruction with respect to time To ensure that the dynamic response of the system under different working conditions can maintain good tracking performance; SS3. Fixed-time interference observation Based on the fixed-time extended state disturbance observation method, the observation and real-time estimation of the aggregate interference within a fixed time are realized by extending the state observation method, and the estimated value of the aggregate interference is obtained. The fixed-time disturbance observer is designed as follows: in Corresponding to The observed value of represents the observation error, represents the coefficient of the nonlinear term, l represents the order of the observer, The coefficient representing the observer convergence speed, The specific matrix constructed satisfies the Hurwitz condition to ensure the stability of the system; SS4. Adaptive Specified Disturbance Cancellation Composite Control Calculation Firstly, the nonlinear backstepping method is used to design the virtual control quantity based on the system error feedback and the differential of the dynamic command signal. x Expected value of 2 x 2d , whose expression is: in K 1, K 2, K 3 is a positive gain parameter, which is used to control the response speed and stability of the system; u 1 and u 2 is the weight parameter and satisfies 0< u 1<1, u 2>1, to achieve the convergence characteristics of the closed-loop system; e 1 =x 1 -x 1d , which represents the tracking error between the current state and the target state; at the same time, in order to improve the dynamic performance and anti-interference ability of the controller in practical applications, the following non-smooth command filter is designed to smooth the output of the control quantity: in, is the time constant and is used to control the response speed of the command filter. κ 1. κ 2. κ 3 are filter parameters and are all positive numbers. x 2c is the command filter output, by adjusting the parameters κ 1. κ 2. κ 3 to ensure the smoothness of the controlled quantity and the stability and smoothness of the output after filtering, and in the above two formulas, , α is the power exponent; Secondly, based on the dynamic inversion method and combined with the observed output of the fixed-time interferer, an adaptive specified disturbance elimination composite control law is designed to achieve closed-loop control of the aircraft engine system: in e 2 =x 2 -x 2c , represents the error between the current state and the expected state; K 4. K 5. K 6 is an appropriate positive number, which represents the control law gain parameter, which is used to adjust the feedback strength of the error and its nonlinear term to ensure the stability and rapid response capability of the system under different working conditions; exp(•) represents the power function with Euler number as the base, Output of the command filter x 2c Differentiation with respect to time, The composition weights of the interference compensation components in different tracking stages are adjusted for the given adaptive parameters in advance; SS5. Closed-loop control judgment The system performs closed-loop control to determine whether an instruction to end control is received. If so, the control is ended. If not, the process jumps to step SS2 and executes the loop to continue tracking control and interference estimation to ensure that the engine maintains stable control performance under complex working conditions.

3. The method for controlling an aircraft engine based on adaptive specified interference elimination according to claim 2, characterized in that: In step SS1, x 1 is the increment of the aircraft engine shaft speed ΔN = N - N e ,in N is the actual speed of the current engine, N e The speed of the engine under static or reference conditions. This increment is used to reflect the change in the speed of the engine under different working conditions. u The output control quantity of the adaptive specified disturbance elimination compound controller is the increment of fuel flow. ∆W f =W f -W fe ,in W f is the current fuel flow of the engine, W fe is the base fuel flow.

4. The method for controlling an aircraft engine based on adaptive specified interference elimination according to claim 2, characterized in that: In the above step SS1, in order to improve the system modeling accuracy and the applicability of the model, the lumped interference d At least it includes the uncertainty effects caused by system parameter perturbations, unmodeled dynamics, external load fluctuations, and environmental factors; at the same time, f ( x )and g ( x ) all satisfy the local Lipschitz continuity condition, and the control gain function g ( x ) remains non-singular throughout the entire operating range.

5. The aircraft engine control method based on adaptive specified interference elimination according to claim 2, characterized in that: In the above step SS3, the order of the fixed time disturbance observer is l The selection must meet l ≥2, the design of the observer parameters needs to ensure that the system converges within a finite time, that is, there is a finite time T >0, so that for any t ≥ T At this moment, the observation error satisfies and , is the estimated value of the fixed-time disturbance observer output; at the same time, the nonlinear term coefficient ρ i and δ i The selection must satisfy 0< ρ i <1, δ i >1, i =1,2,…, l , to ensure that the observer has fixed-time convergence characteristics.

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