A system regulation and control method triggered by network attacks

Abstract

This invention relates to an event-triggered system regulation and control method in a network control system. This method ensures the safe operation of the network control system even when it is subjected to a DoS attack, achieving actual trajectory tracking and disturbance suppression. Specifically, this invention ensures that the network control system can achieve actual trajectory tracking and disturbance suppression even under DoS attacks; that is, the system's tracking error can be arbitrarily reduced by adjusting the event triggering mechanism parameters. This invention has excellent practicality and accuracy and can be applied to various practical network control systems, such as vehicle networking control systems and networked motor control systems.

Description

Technical Field

[0001] This invention relates to an event-triggered system regulation and control method in a network control system, specifically an elastic event-triggered system regulation and control method for a general linear network control system under a denial-of-service (DoS) attack. Background Technology

[0002] In recent years, with the rapid development of information technology, network control systems have become increasingly important in modern digital control platforms. This is because network control systems can connect controllers and controlled objects via networks, greatly enhancing the convenience of control system deployment. However, practical network control systems are not entirely secure and reliable, and are susceptible to network attacks at any time. Furthermore, data in network control systems is transmitted in packet form, making continuous controllers unsuitable for direct application. This makes the development of resilient event-triggered system regulation and control methods for general linear network control systems under network attacks of significant research importance. Existing system regulation and control methods are designed under the assumption that network control systems are secure, without considering the possibility of DoS network attacks.

[0003] Therefore, designing a resilient event-triggered system adjustment and control method that can still ensure the normal operation of the system under DoS network attacks, and avoiding the failure of the network control system to work properly due to DoS attacks, and realizing the secure control of the network control system, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of existing technologies and propose an event-triggered system regulation and control method under network attacks. This method proposes a flexible event-triggered control method for general linear network control systems under DoS network attacks. This paper studies the output regulation problem of general linear network control systems under DoS network attacks, namely the trajectory tracking and disturbance suppression problem. This method can still guarantee the required closed-loop system performance when the network is subjected to a DoS attack. This invention can ensure that the network control system achieves actual trajectory tracking and disturbance suppression under DoS network attacks; that is, the tracking error of the system can be arbitrarily reduced by adjusting the event triggering mechanism parameters. This invention has good practicality and accuracy and can be applied to various practical network control systems, such as vehicle networking control systems and networked motor control systems.

[0005] The technical solution of this invention is:

[0006] A system regulation and control method triggered by a network attack, comprising the following steps:

[0007] Step S1: Establish a linear system model. The established linear system model is as follows:

[0008]

[0009] e = Cx + Du + Fw

[0010] in, Represents the state of a linear system. This represents the control input of a linear system. This represents the tracking error of a linear system. Let A, B, E, C, D, F represent the set of real numbers, be constant matrices, and w represent the external system model. This indicates the reference signal to be tracked and the interference signal to be suppressed;

[0011]

[0012] in It is a constant matrix;

[0013] Step S2: Establish a DoS network attack model. The established DoS network attack model is as follows:

[0014] H n ={h n}∪[h n ,h n +τ n )

[0015] in, This indicates the start time of the DoS attack, where h0 ≥ 0. Represents the set of non-negative integers. Indicates the duration of a DoS attack, H n This represents the model of the nth network attack, where n = 1, 2, 3…N, and N is the number of network attacks; when τ n When = 0, this nth network attack occurs at h. n Considering a pulse at time t, and a time interval [τ, t] where t ≥ τ, the time intervals during which the network control system is subjected to a DoS attack and during which it can communicate normally are defined as follows:

[0016]

[0017] Θ(τ,t)=[τ,t]\Ξ(τ,t)

[0018] The frequency and duration of DoS network attacks are subject to the following constraints, where the attack frequency satisfies:

[0019]

[0020] Where n(τ,t) represents the attack frequency within the time period [τ,t], and η and τ D It is a non-negative positive integer, and the duration of the DoS attack satisfies:

[0021]

[0022] Where |Ξ(τ,t)| represents the total attack duration within the time period [τ,t], and κ and T are non-negative positive constants;

[0023] Step S3: Establish the regulator equation and solve the established regulator equation based on the linear system model and external system model established in step S1.

[0024] The established regulator equation is as follows

[0025] XA σ =AX+BU+E

[0026] 0 = CX + DU + F

[0027] Where (X,U) represents the solution to the regulator equation. To ensure that the above regulator equation has a solution under any matrices E and F, the following transfer zero conditions must be satisfied:

[0028]

[0029] in, Representing matrix A σ The spectrum;

[0030] Step S4: Construct an event-triggered observer based on the solution of the regulator equation in step S3, and control the controlled object based on the error output information. The constructed event-triggered observer is as follows:

[0031]

[0032] in

[0033]

[0034]

[0035] K = [K x K v ]

[0036] K v =UK x X

[0037] K x A+BK is a constant matrix. x It is Hurwitz's, where L is a constant matrix such that It's by Hurwitz, tk Indicates the time when the event is triggered and is generated by the event triggering mechanism, t k The initial time is t0, t0≥0, because the network control system is not secure and is subject to DoS network attacks, then e(t k The model is as follows:

[0038]

[0039] That is, at the next trigger time t k+1 During the normal communication period Θ(t0,t), e(t) k+1 Then it can be received normally by the controller, and the controller updates normally; at the next trigger time t k+1 When in the DoS network attack interval Ξ(t0,t), e(t) k+1 If ) cannot be received normally by the controller, then e(t) k+1 ) is still equal to e(t) k That is, the controller still uses the previous trigger time t. k Error output information e(t) k );

[0040] Step S5: Construct the event triggering mechanism and determine the event triggering time in step S4 based on the constructed event triggering mechanism;

[0041] The constructed event triggering mechanism is as follows:

[0042]

[0043] Where inf{·} represents taking the minimum value that satisfies the constraint condition. Represents some positive constants. Next trigger time t k+1 During the normal communication period Θ(t0,t), the event trigger condition is used. Determine the next trigger time t k+1 ; at the next trigger time t k+1 When the network is in the DoS attack range Ξ(t0,t), the event triggering conditions cannot be applied. At this time, [the following is used]: Determine the next trigger time t k+1 ;

[0044] Step S6: Construct an event-triggered controller for a linear system model under a DoS network attack.

[0045] The event trigger controller is created as follows:

[0046] u(t)=Kz(t)

[0047]

[0048] Step S7: Control the linear system according to the event trigger controller obtained in step S6, so that the linear system can still maintain normal operation under DoS network attack.

[0049] The beneficial effects of this invention are:

[0050] This invention proposes an event-triggered system regulation and control method for a general linear network control system under DoS network attacks. This method can still ensure the safe operation of the network control system when it is subjected to DoS network attacks, and achieve actual trajectory tracking and disturbance suppression, providing a new approach for network control systems to resist DoS network attacks.

[0051] This invention proposes a resilient event-triggered control method for general linear network control systems under DoS attacks. This method can still guarantee the required closed-loop system performance even when the network is subjected to a DoS attack. Therefore, designing a suitable algorithm is crucial for ensuring the safe operation of the network control system. This invention ensures that the network control system can achieve actual trajectory tracking and disturbance suppression under DoS attacks; that is, the tracking error can be arbitrarily minimized by adjusting the event triggering mechanism parameters. This invention has good practicality and accuracy and can be applied to various practical network control systems, such as vehicle networking control systems and networked motor control systems. Attached Figure Description

[0052] Figure 1 This is a block diagram of a closed-loop system under a DoS network attack, representing a specific example of the present invention.

[0053] Figure 2 This is a timing diagram of a DoS network attack in a specific example of the present invention;

[0054] Figure 3 This is an event triggering condition diagram for a specific example of the present invention;

[0055] Figure 4 This is a system tracking error diagram for a specific example of the present invention. Detailed Implementation

[0056] This section, in conjunction with the accompanying drawings, provides a more detailed description of the invention through various embodiments. In this embodiment, Matlab 2020a software is used to simulate and verify the effectiveness of the controller.

[0057] A system regulation and control method triggered by a network attack, comprising the following steps:

[0058] Step S1: Consider the following general linear system:

[0059]

[0060]

[0061] The external systems are as follows:

[0062]

[0063] Initial system state and external system parameters: x(0) = [3.0 2.0] T w(0) = [0 1.0] T .

[0064] Step S2, the closed-loop system control block diagram under a DoS network attack is as follows: Figure 1 As shown, ETM represents the designed event triggering mechanism, and ACK represents the event triggered when the controller receives the latest e(t). k When a DoS attack is detected, a signal indicating receipt is sent back to the ETM. The DoS attack model is described as follows: Figure 2 As shown. Let t0 = 0, and consider 15 DoS network attacks occurring within the time period t ∈ [0, 80], with each attack lasting less than or equal to 0.5 seconds.

[0065] Step S3: First, verify the following transmission null conditions:

[0066]

[0067] If the above conditions are met, solve the following regulator equation:

[0068] XS = A σ X+BU+E

[0069] 0 = CX + F

[0070] The solution (X,U) to the regulator equation is obtained:

[0071]

[0072] U = [-0.1 0.4]

[0073] Step S4: Construct the following event-triggered observer:

[0074]

[0075] in

[0076]

[0077] F2=L=[8.0000 20.9360 11.0000 0.1000] T

[0078] Initial observer state parameters: z(0) = [3.0 7.0 -0.5 0.4] T .

[0079] Step S5: Construct the following event triggering mechanism:

[0080]

[0081] Step S6: Design the controller as follows:

[0082] u(t)=KZ(t)

[0083]

[0084] Where K = [-0.5500 9.1250 -5.5750 3.5000], and the definitions of F1 and F2 have been given in step S4.

[0085] Simulation results are as follows Figure 3 and Figure 4 As shown. Among them Figure 3 This indicates the event triggering conditions in the designed event triggering mechanism. Figure 4 This represents the system tracking error. (By...) Figure 4 It can be seen that the system tracking error asymptotically approaches a minimum value near a zero point. This minimum value can be adjusted to any small value by adjusting the event triggering mechanism parameter δ to meet the needs of practical applications.

[0086] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A system regulation and control method triggered by an event under a network attack, characterized in that... The specific steps are as follows: Step S1: Establish the linear system model and the external system model; Step S2: Establish a DoS network attack model; Step S3: Establish the regulator equation and solve the established regulator equation based on the linear system model and external system model established in step S1. Step S4: Construct an event-triggered observer based on the solution of the regulator equation obtained in step S3; Step S5: Construct the event triggering mechanism and determine the event triggering time in step S4 based on the constructed event triggering mechanism; Step S6: Construct an event-triggered controller for a linear system model under a DoS network attack; Step S7: Control the linear system using the event-triggered controller obtained in step S6; In step S1, the established linear system model is as follows: in, Represents the state of a linear system. This represents the control input of a linear system. This represents the tracking error of a linear system. Represents the set of real numbers. is a positive integer, It is a constant matrix. For external system model, This indicates the reference signal to be tracked and the interference signal to be suppressed; in, It is a constant matrix. is a positive integer; In step S2, the established DoS network attack model is as follows: in, Indicates the start time of the DoS attack, where , Represents the set of non-negative integers. Indicates the duration of the DoS attack. Indicates the first Secondary network attack model; In step S3, the regulator equation is established as follows: The method for solving the regulator equations based on the linear system model and the external system model is as follows: The solution to the regulator equation is given by the following relationship: The regulator equation in any matrix The solution is below; in, Representation matrix The spectrum; In step S4, the constructed event-triggered observer is: in It is a constant matrix such that It's by Hurwitz. It is a constant matrix such that It's by Hurwitz. Indicates the moment when the event is triggered and is generated by the event triggering mechanism. The initial time is , It is a non-negative integer. The model is as follows: That is, the next triggering time During normal communication periods Inside, The controller receives the data normally and updates it normally; the next trigger time... Within the range of DoS network attacks hour, Then it cannot be received normally by the controller. Still equal to That is, the controller still uses the previous trigger time. Error output information at time ; In step S5, the constructed event triggering mechanism is as follows: in, This indicates taking the minimum value that satisfies the constraints. Represents a positive constant. The next trigger time During normal communication periods Internally, through event triggering conditions To determine the next trigger time ; at the next trigger time Within the range of DoS network attacks When the event triggering conditions cannot be applied, use To determine the next trigger time .

2. The system regulation and control method for event triggering under network attack as described in claim 1, characterized in that: In step S6, the event triggering controller established is: 。

Images