Unknown aero-engine data driving smooth switching control method based on switching model

Abstract

The invention provides an unknown aero-engine data driving smooth switching control method based on a switching model. The method comprises the steps that the situation that an aero-engine system is influenced by disturbance is considered, an aero-engine switching model is established based on the aero-engine system, and a controller with unknown dynamics is designed; obtaining a closed-loop aero-engine switching model based on the aero-engine switching model and a designed controller with unknown dynamics; designing a data-driven smooth control scheme based on the closed-loop aero-engine switching model; and verifying the stability and smooth switching performance of the data-driven smooth control scheme. The method comprises the following steps: establishing an aero-engine switching model based on an aero-engine system by considering the condition of disturbance influence and unknown dynamics, and designing a controller with unknown dynamics; according to the data-driven smooth switching control method provided by the invention, accidents possibly occurring when the aero-engine is in different working modes are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine control, and in particular to a data-driven smooth switching control method for an unknown aero-engine based on a switching model. Background Art

[0002] Aircraft engine systems are highly complex and precision-critical thermomechanical systems. They typically have multiple operating modes, each with distinct operating characteristics, necessitating the application of switching system approaches. Switching systems consist of a finite number of continuous or discrete submodels and switching laws. Accurately modeling self-excited vibrations in industrial systems is extremely challenging. Existing research on adaptive control design has focused on adaptive control systems with known models. Furthermore, the vast majority of research on data-driven control of aircraft engine control systems has focused on steady-state characteristics while ignoring transient performance. As a result, existing aircraft engines can experience engine stall, surge, and even serious accidents when operating in different modes. Summary of the Invention

[0003] In response to the technical problems raised above, the present invention provides a data-driven smooth switching control method for an unknown aircraft engine based on a switching model, so that the typical steady-state performance requirements, stability, unique transient performance requirements, and fuel jump suppression of existing aircraft engines under the influence of disturbances are forced to be met at the same time, so as to solve technical problems such as aircraft engine stalling and surge.

[0004] The technical means adopted in the present invention are as follows:

[0005] A data-driven smooth switching control method for an unknown aircraft engine based on a switching model comprises the following steps:

[0006] S1: Considering the situation where the aircraft engine system is affected by disturbances, an aircraft engine switching model is established based on the aircraft engine system, and a controller with unknown dynamics is designed;

[0007] S2: Based on the aircraft engine switching model and the designed controller with unknown dynamics, a closed-loop aircraft engine switching model is obtained;

[0008] S3: Design of a data-driven smoothing control scheme based on a closed-loop aircraft engine switching model;

[0009] S4: Verify the stability and smooth switching performance of the data-driven smooth control scheme.

[0010] Furthermore, in S1, the controller with unknown dynamics is designed as:

[0011] u(t)=K η(t) x(t)

[0012] Where η(t) represents a finite set of switching signals, Indicates the system status, K η(t) represents the controller gain matrix.

[0013] Furthermore, in S1, the controller designed with unknown dynamics can stabilize the matrix set Any matrix pair To satisfy the requirement that the aero-engine system based on the aero-engine model with unknown dynamics is stable,

[0014] in,

[0015]

[0016] X i :=[x i (h)x i (2h)…x i (nh)],

[0017] D i :=[d i (h)d i (2h)…d i (nh)],

[0018] U i :=[u i (h)u i (2h)…u i (nh)],

[0019]

[0020] X i , D i , U i They are all different sub-models, collecting state signal measurements {x i (kh)} k＝1,2,…,n and the input signal measurement value {u i (kh)} k＝1,2,…,n The data matrix formed;

[0021] Where n represents the amount of data collected, h>0 represents the sampling period, represents the unknown noise measurement value that affects the accuracy of the collected data, and k is a given parameter;

[0022] for There is an unknown noise sequence D i To apply:

[0023]

[0024] in, and is a known matrix; the unknown system matrix A i and B i Also satisfies the unknown noise sequence D i Condition, I represents the identity matrix.

[0025] Furthermore, the collected data are obtained during the execution of different sub-models, the data are collected offline, and the data collected by each sub-model does not contain information about other sub-models.

[0026] Furthermore, in S2, by substituting the controller model into the aero-engine system based on the aero-engine model with unknown dynamics, a closed-loop aero-engine switching model is obtained as follows:

[0027]

[0028] in,;

[0029] When the closed-loop aero engine switching model is switched, the sub-controller and sub-model will change. This change occurs instantaneously and may cause Undesirable and unexpected jumps may occur at certain locations; these jumps may degrade system performance or even cause instability. Therefore, smooth switching is adopted.

[0030] For the closed-loop aero-engine switching model, at the switching instant If there exists a specified constant α ≥ 0 that ensures the relationship:

[0031]

[0032] This shows that the closed-loop aircraft engine switching model has smooth switching performance.

[0033] in, represents the right limit value of the switching point controller, represents the left limit value of the switching point controller, and α represents a given constant that represents smooth switching performance.

[0034] Furthermore, in S3, the data-driven smooth switching control strategy consists of the switching law η(t) and the controller u(t) to ensure the stability and smooth switching performance of the closed-loop aircraft engine switching model.

[0035] Among them, the switching law η(t) is

[0036] Among them, P i represents the positive definite Lyapunov function matrix.

[0037] Furthermore, in S4, the stability of the system is verified by constructing the Lyapunov function.

[0038] Furthermore, in S4, the smooth switching performance of the closed-loop aircraft engine switching model is also verified.

[0039] Assume that the switching occurs at t = t q , replace the i-th sub-model with the j-th sub-model to become the current active sub-model,

[0040] according to get:

[0041]

[0042] The closed-loop aero-engine switching model satisfies the smooth switching performance.

[0043] Furthermore, after step S4, the method further includes step S5, considering a practical aircraft engine model with unknown dynamics,

[0044] For an aero-engine system based on a closed-loop aero-engine switching model, given a constant θ, if there exists a matrix K i ,P i > 0, for i∈S there exists a constant g ij ≤0,m ij ≥0,α i ≥0,β>0 drive:

[0045]

[0046] in,

[0047]

[0048] Compared with the prior art, the present invention has the following advantages:

[0049] The present invention considers the situation of being affected by disturbances and having unknown dynamics, establishes an aircraft engine switching model based on the aircraft engine system, and designs a controller with unknown dynamics; obtains a closed-loop aircraft engine switching model based on the aircraft engine switching model and the designed controller with unknown dynamics; verifies the steady-state characteristics and transient characteristics of the data-driven smooth switching control method in this embodiment; considers a more practical aircraft engine model with unknown dynamics, and verifies the effectiveness of the proposed data-driven smooth switching control method. The data-driven smooth switching control method proposed in the present invention ensures that the system output of the aircraft engine switching model converges to zero asymptotically under the conditions of being affected by disturbances and having unknown dynamics, thereby avoiding engine stall, surge and serious accidents that may occur when the aircraft engine is in different working modes, and ensuring safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0051] Figure 1 This is a flow chart of a data-driven smooth switching control method for an unknown aircraft engine based on a switching model in the present invention;

[0052] Figure 2 A comparison diagram of switching signals when the proposed data-driven smooth switching control method is used and when the data-driven smooth switching control method is not considered during numerical simulation verification in an embodiment of the present invention;

[0053] Figure 3 A comparison diagram of fan speed evolution when the proposed data-driven smooth switching control method is used and when the data-driven smooth switching control method is not considered during numerical simulation verification in an embodiment of the present invention;

[0054] Figure 4 A comparison diagram of the core speed evolution when the proposed data-driven smooth switching control method is selected and when the data-driven smooth switching control method is not considered during numerical simulation verification in an embodiment of the present invention;

[0055] Figure 5 This is a comparison diagram of fuel flow rates when the proposed data-driven smooth switching control method is selected and when the data-driven smooth switching control method is not considered during numerical simulation verification in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0057] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0058] This embodiment provides a data-driven smooth switching control method for unknown aircraft engines based on a switching model. Figure 1 As shown, the specific steps include:

[0059] S1: Considering the situation where the aircraft engine system is affected by disturbances, an aircraft engine switching model is established based on the aircraft engine system, and a controller with unknown dynamics is designed. It is shown that the aircraft engine system with unknown dynamics based on the aircraft engine switching model is stable.

[0060] In a specific embodiment, in S1, the turbofan engine switching model is:

[0061]

[0062] in, N h (t) represents the actual high-pressure rotor speed, represents the high-pressure rotor speed at the equilibrium point, N l (t) represents the actual low-pressure rotor speed, represents the low-pressure rotor speed at the equilibrium point, W f (t) represents the actual fuel flow rate, represents the fuel flow at the equilibrium point, A and B represent the system matrix, represents the time series of the switching instant, and η(t) represents the switching signal of a finite set.

[0063] make And u(t)=ΔW f (t), then the aero-engine model with unknown dynamics based on the turbofan engine switching model can be expressed as:

[0064]

[0065] in, Indicates the system status, Represents the input signal, for S is a set of non-negative integers, the system matrix A i and B i is unknown.

[0066] For different sub-models, collect state signal measurements {x i (kh)} k＝1,2,…,n and the input signal measurement value {u i (kh)} k＝1,2,…,n To form the following data matrix:

[0067] X i :=[x i (h)x i (2h)…x i (nh)],

[0068] D i :=[d i (h)d i (2h)…d i (nh)],

[0069] U i :=[u i (h)u i (2h)…u i (nh)],

[0070]

[0071] Where n represents the amount of data collected, h>0 represents the sampling period, represents the unknown noise measurement that affects the accuracy of the collected data and satisfies the following assumptions.

[0072] Specifically, the sub-models represent different stages, such as sub-model one represents the cruising stage, and sub-model two represents the acceleration stage.

[0073] Assumption 1. For There is an unknown noise sequence D i To apply:

[0074]

[0075] in, and is a known matrix. T represents the transpose of the matrix.

[0076] In addition, based on the collected data, it is possible to meet:

[0077]

[0078] It should be noted that the collected data is obtained during the execution of different sub-models. The data is collected offline, and the data collected by each sub-model does not contain information about other sub-models.

[0079] Will Bring in For an unknown set of noise sequences, we can deduce:

[0080]

[0081] in,

[0082] Matrix π i Depends only on the known data matrix X i , U i , and D i The unknown truth

[0083] System matrix A i and B i Meet the conditions However, it should be noted that more than one matrix pair This condition may be met, so the matrix set

[0084]

[0085] To represent all matrix pairs that satisfy this condition This means that if there exists a controller that stabilizes Any matrix pair Then the aero-engine system based on the aero-engine model with unknown dynamics is also stable.

[0086] Then the controller model of the active control system based on the aircraft engine model with unknown dynamics is constructed as:

[0087] u(t)=K η(t) x(t)

[0088] S2: Based on the aircraft engine switching model and the designed controller with unknown dynamics, a closed-loop aircraft engine switching model is obtained, which shows that the closed-loop aircraft engine switching model has smooth switching transient performance;

[0089] In a specific embodiment, in S2, a closed-loop aircraft engine switching model is obtained by substituting the controller model into an aircraft engine system based on an aircraft engine model with unknown dynamics, as shown below:

[0090]

[0091] When the closed-loop aero engine switching model is switched, the sub-controller and sub-model will change. This change occurs instantaneously and may cause Undesirable and undesirable jumps occur at certain locations. These jumps may degrade system performance or even cause instability. To address this challenge, smooth switching is employed, which is defined as follows.

[0092] Definition 1. For the closed-loop aero-engine switching model, at the switching instant If there exists a specified constant α ≥ 0 that ensures the relationship:

[0093]

[0094] This shows that the closed-loop aero-engine switching model has smooth switching performance.

[0095] S3: A data-driven smoothing control scheme is designed based on a closed-loop aircraft engine switching model to verify the stability and smooth switching performance of this method.

[0096] In a specific embodiment, in S3, the process of designing a data-driven smoothing control scheme based on a closed-loop aircraft engine switching model is as follows:

[0097] S31: Design a data-driven smooth switching solution for a closed-loop aircraft engine switching model:

[0098] Lemma 1. For a symmetric matrix M 11 ∈R k×k ,M 22 ∈R n×n ,N 11 ∈R k×k ,N 22 ∈R n×n , matrix M 12 ∈R k×n ,N 12 ∈R k×n If M 22 ≤0, N 22 ≤0 and Then, there exists a matrix satisfy:

[0099]

[0100] Therefore, the following statements are equivalent:

[0101] (1) There exist α≥0 and β>0 such that:

[0102]

[0103] (2) The following inequality:

[0104]

[0105] and

[0106]

[0107] holds true, where β is a given constant.

[0108] The data-driven smooth switching control strategy consists of a switching law η(t) and a controller u(t) to ensure the stability and smooth switching performance of the closed-loop aero-engine switching model.

[0109] Theorem 1. Based on the closed-loop aircraft engine switching model, if there is K i ,P i >0, constant g ij ≤0,m ij ≤0,α i ≥0,β>0, for drive:

[0110]

[0111] Among them, K i , K j , P j They represent the controller gain matrix of sub-model i, the controller gain matrix of sub-model j and the Lyapunov function matrix respectively.

[0112]

[0113] Then the data driven smooth switching problem is solved based on the data matrix, controller and switching signal.

[0114]

[0115] S32: Verify the stability of a closed-loop aero-engine switching model. In model-based control of switching systems, the following Lyapunov function is usually constructed:

[0116] V i (t) = x T (t)P i x(t)

[0117] To achieve:

[0118]

[0119] To verify that the system is stable. Therefore, if there is a feedback gain K i and the matrix P i Can satisfy the inequality conditions:

[0120]

[0121] in, Then it can be said that the closed-loop aero-engine switching model is stable.

[0122] Construct feedback gain K based on data matrix i and the matrix P i To satisfy the above inequality conditions. By defining Γ(t)=[IA i B i ], and multiply both sides of the above conditions by P i -1 , we can get:

[0123]

[0124] Therefore, if we can prove that Γ(t) T M i Γ(t)>0, then the above inequality condition holds.

[0125] In addition, for It can be deduced that:

[0126]

[0127] Due to π 22i is non-singular, then:

[0128]

[0129] So we can get:

[0130]

[0131] Combine and It can be concluded that Γ(t) T M i Γ(t)>0, which proves that the closed-loop aero-engine switching model is stable.

[0132] S33: Verify the smooth switching performance of the closed-loop aero-engine switching model, assuming the switching occurs at t = t q , the jth sub-model replaces the i-th sub-model to become the current active sub-model. You can get:

[0133]

[0134] Therefore, the closed-loop aero-engine switching model satisfies the smooth switching performance.

[0135] In a specific embodiment, a standard for solving the data-driven smooth switching control problem of a closed-loop aircraft engine switching model is formed based on Theorem 1. Different from the smooth switching problem of a conventional aircraft engine switching model, this method considers a more practical aircraft engine model with unknown dynamics.

[0136] For an aero-engine system based on a closed-loop aero-engine switching model, if there is a matrix K i ,P i > 0, for i∈S there exists a constant g ij ≤0,m ij ≥0,α i ≥0,β>0 drive:

[0137]

[0138] in,

[0139]

[0140] Then, the data matrix, controller and switching signal together constitute the data driven smooth switching technology. In addition, the gain can be respectively i =P i -1 , L i =K i P i -1 to confirm.

[0141] The matrix π 11i , Π 12i , Π 21i , Π 22i , M 11i , M 12i , M 21i Substitution It can be deduced that:

[0142]

[0143] in,

[0144]

[0145] Definition i =P i -1 , L i =K i P i -1 , and Using Shure's method, you can get Right now Equivalent to Get the certificate.

[0146] Specifically, in order to verify the effect of the data-driven smooth switching control method proposed in this embodiment, a simulation verification was carried out using the aircraft engine hardware-in-the-loop simulation platform as an example. The model simulator uses a National Instruments industrial personal computer (NI IPC) and is equipped with a PharLap real-time operating system. It simulates a turbofan engine and is connected to the host computer through TCP / IP communication, realizing efficient human-computer interaction. At the same time, using a laptop computer connected to the STM32H743 microcontroller through ST-link, the online debugging function was successfully implemented, and a fully functional controller was built. At the same time, the STM32H743 microcontroller was connected to the laptop computer through ST-link, and the online debugging function was successfully implemented, and a fully functional controller was built. Through serial communication, the microcontroller and NIIPC achieve a good connection, which makes it possible to control the aircraft engine model, and together constitute an aircraft engine hardware-in-the-loop simulation platform, such as Figure 3 As shown in the figure, the flow chart of aircraft engine hardware-in-the-loop simulation is as follows Figure 4 shown.

[0147] The parameters of the given aircraft engine switching model are as follows:

[0148]

[0149] The effectiveness of the proposed data-driven smooth switching control technique is demonstrated by comparing the smooth switching case with the non-smooth switching case.

[0150] In the case of smooth switching, by solving and Get m 12 =m 21 =-0.7, g 12 =g 21 =-1, α1=α2=0.21, β1=β2=1, n=55, h=0.1,

[0151]

[0152] In the case of non-smooth switching, by solving the same formula above, we can get m 12 =m 21 =-0.1, g 12 =g 21 =-1, α1=α2=1, β1=β2=1, n=55, h=0.1,

[0153]

[0154] In order to verify the superiority of the proposed data-driven smooth switching control method, the experiments were divided into two groups according to the control method: the data-driven smooth switching control method proposed in this embodiment and the control method without considering data-driven smooth switching. Figure 2-5 The switching signal is as shown. Figure 2 shown. Figure 3 and Figure 4 The evolution of fan speed and core speed are described separately. It can be seen that in the case of smooth switching, the system state is more stable and eventually reaches zero. Figure 5 The fuel flow increment is shown. It is clear that there is no large sudden jump in the fuel flow increment under the smooth switching method. Therefore, the results show that the proposed data-driven smooth switching control method is effective.

[0155] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0156] In the above embodiments of the present invention, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0157] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only exemplary. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0158] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0159] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0160] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk, etc. Various media that can store program codes.

[0161] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A data-driven smooth switching control method for unknown aircraft engines based on a switching model, characterized in that: The steps include: S1: Considering the situation where the aircraft engine system is affected by disturbances, an aircraft engine switching model is established based on the aircraft engine system, and a controller with unknown dynamics is designed; S2: Based on the aircraft engine switching model and the designed controller with unknown dynamics, a closed-loop aircraft engine switching model is obtained; S3: Design of a data-driven smoothing control scheme based on a closed-loop aircraft engine switching model; S4: Verify the stability and smooth switching performance of the data-driven smooth control scheme.

2. The method according to claim 1, characterized in that In S1, the designed controller with unknown dynamics is: in, represents a switching signal that takes a finite set, Indicates the system status, represents the controller gain matrix.

3. The method according to claim 1, characterized in that In S1, the controller designed with unknown dynamics can stabilize the matrix set Any matrix pair , to satisfy the requirement that the aero-engine system based on the aero-engine model with unknown dynamics is stable, in, X i , D i , U i Each is a different sub-model, collecting state signal measurements and input signal measurement values The data matrix formed; in, Indicates the amount of data collected, represents the sampling period, represents unknown noise measurements that affect the accuracy of the collected data, k For the given parameters; for , there is an unknown noise sequence To apply: in, , and is a known matrix; the unknown system matrix and Also satisfies the unknown noise sequence Condition, I represents the identity matrix.

4. The method according to claim 3, characterized in that The collected data are obtained during the execution of different sub-models. The data are collected offline, and the data collected by each sub-model does not contain information about other sub-models.

5. The method according to claim 1, wherein In S2, by substituting the controller model into the aero-engine system based on the aero-engine model with unknown dynamics, a closed-loop aero-engine switching model is obtained as follows: in,; When the closed-loop aero engine switching model is switched, the sub-controller and sub-model will change. This change occurs instantaneously and may cause Undesirable and unexpected jumps may occur at certain locations; these jumps may degrade system performance or even cause instability. Therefore, smooth switching is adopted. For the closed-loop aero-engine switching model, at the switching instant , if there is a specified constant Ensure the relationship: This shows that the closed-loop aircraft engine switching model has smooth switching performance. in, represents the right limit value of the switching point controller, represents the left limit value of the switching point controller, Indicates a given constant indicating smooth switching performance.

6. The method according to claim 1, characterized in that In S3, the data-driven smooth switching control strategy is composed of the switching law and controller composition to ensure the stability and smooth switching performance of the closed-loop aero-engine switching model, Among them, the switching law for ; in, represents the positive definite Lyapunov function matrix.

7. The method according to claim 1, characterized in that In S4, the stability of the system is verified by constructing the Lyapunov function.

8. The method according to claim 1, characterized in that In S4, the smooth switching performance of the closed-loop aero-engine switching model was also verified. Assume that the switch occurs , will The sub-model replaces the The sub-model becomes the current active sub-model, according to get: The closed-loop aero-engine switching model satisfies the smooth switching performance.

9. The method according to claim 1, characterized in that After step S4, the method further includes step S5, considering a practical aircraft engine model with unknown dynamics, For an aero-engine system based on a closed-loop aero-engine switching model, if there is a matrix ,for Existence constant drive: in, 。

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