This paper investigated the problem of H∞output tracking for a type of discrete network-based control systems subjected to quantization and data dropout. The state of controlled system and the reference model state were quantized before being communicated. The quantization error was treated as sector-bounded uncertainty. The effect of the random packet loss was modelled as a Bernoulli process. Later, a sufficient condition was proposed for the existence of H∞tracking controllers in terms of linear matrix inequalities(LMIs). The proposed controller could guarantee the output of the closed-loop networked control system tracks that of a given reference model well in the H∞sense.Finally, a numerical example was prensented to show the effectiveness and usfulness of the proposed H∞output tracking design.

Network-Based H_∞ Output Tracking Control for a Type of Discrete Time Systems

In recent years, the communication-protocol-based synthesis and analysis issues have gained substantial research interest owing mainly to their significance in networked systems. In this work, we s...

Communication-protocol-based analysis and synthesis of networked systems: progress, prospects and challenges

In this paper, we provide an overview of recent research efforts on networked control systems under denial-of-service attacks. Our goal is to discuss the utility of different attack modeling and analysis techniques proposed in the literature for addressing feedback control, state estimation, and multi-agent consensus problems in the face of jamming attacks in wireless channels and malicious packet drops in multi-hop networks. We discuss several modeling approaches that are employed for capturing the uncertainty in denial-of-service attack strategies. We give an outlook on deterministic constraint-based modeling ideas, game-theoretic and optimization-based techniques and probabilistic modeling approaches. A special emphasis is placed on tail-probability based failure models, which have been recently used for describing jamming attacks that affect signal to interference-plus-noise ratios of wireless channels as well as transmission failures on multi-hop networks due to packet-dropping attacks and non-malicious issues. We explain the use of attack models in the security analysis of networked systems. In addition to the modeling and analysis problems, a discussion is provided also on the recent developments concerning the design of attack-resilient control and communication protocols.

https://www.mdpi.com/1099-4300/21/2/210/pdf

An Overview on Denial-of-Service Attacks in Control Systems: Attack Models and Security Analyses.

This paper investigates the problem of event-based security control for state-dependent uncertain systems under hybrid-attacks. An event-triggered scheme is adopted to mitigate the communication burden, where the sampled data are delivered only when the predefined triggering condition is violated. Meanwhile, a new hybrid-attacks model, which contains denial-of-service attacks and replay attacks, is established to describe the randomly occurring cyber-attacks. By taking hybrid-attacks into account, a novel mathematical model for state-dependent uncertain systems with event-triggered scheme is established. Then, through employing Lyapunov–Krasocskii stability theory and linear matrix inequality techniques, sufficient conditions ensuring the state-dependent uncertain systems being exponentially mean-square stable are deduced. Based on the derived sufficient conditions, the desired output feedback controller gain is obtained. Finally, the feasibility of the proposed method is demonstrated by a numerical example, and the applicability of the developed theoretical results is also illustrated by the controller design for electronic circuits.

Event-Based Security Control for State-Dependent Uncertain Systems Under Hybrid-Attacks and Its Application to Electronic Circuits

Optimal Denial-of-Service attack energy management against state estimation over an SINR-based network

This brief is concerned with the secure control problem of cyber-physical systems under denial-of-service (DoS) attacks. Considering the energy constraints of the attackers, it is reasonable to assume that the maximum number of consecutive DoS attacks is bounded. According to the packet-based transmission scheme, a novel packet-based control method is proposed to resist DoS attacks. By constructing a nested switching model, several stability conditions are derived, which are dependent on the number of consecutive attacks. Furthermore, a controller design method is developed based on the linear matrix inequalities. Finally, a smart gird example is employed to show the effectiveness of the proposed method.

Packet-Based State Feedback Control Under DoS Attacks in Cyber-Physical Systems

An active security control approach is developed in this article for cyber-physical systems (CPSs) under denial-of-service (DoS) attacks, where DoS attacks exist in both the sensor-to-controller (S–C) channel and the controller-to-actuator (C–A) channel. Due to the cost constraints of attacks, it is reasonable to consider that the number of maximum continuous DoS attacks in both the S–C and the C–A channels is bounded. Then, to defend the two-channel DoS attacks, an active security control strategy that makes full use of the unattacked intervals is designed to ensure that the control inputs are updated timely in each period. Meanwhile, a security controller that contains both the current and future control inputs is designed. Under the active security control strategy and the security controller, the addressed CPS under two-channel DoS attacks can be asymptotically stable without losing the control performance. Finally, both the simulations and experiments are given to demonstrate the effectiveness of the proposed active security control approach.

Active Security Control Approach Against DoS Attacks in Cyber-Physical Systems

An improved switched system approach is proposed for the stability and stabilization of networked control systems with time-varying delays. The approach features a mode-dependent state feedback controller guaranteeing the exponential stability of the closed-loop system, which is implemented within the packet-based control framework. The effectiveness of the proposed approach is finally demonstrated experimentally by a networked inverted pendulum control system.

Improved Switched System Approach to Networked Control Systems With Time-Varying Delays

This paper investigates the modeling and stabilization problem for cyber-physical systems (CPSs) under time-delay attacks. First of all, the attack-induced delays are divided into multiple equilong subintervals and each subinterval is separated into a nominal part and an uncertain part. Then, the system is considered to dwell in different subsystems when the attack-induced delays fall into different subintervals. In this way, the CPS is modeled as a discrete-time switched system with norm-bounded uncertainties. Moreover, the mode-dependent controller is designed to defend the time-delay attacks and guarantee the exponential stability of the closed-loop CPS, which is switched according to the attack-induced delays and implemented combined with the packet-based control strategy. Finally, the experiments of a networked inverted pendulum control system are given to demonstrate the effectiveness of the proposed method.

A Switched System Approach Against Time-Delay Attacks in Cyber- Physical Systems

Disclosed is a generalized expansion state observer-based networked large-correlation motion system position synchronous control method. Firstly, the system uncertain dynamic state and each sub-systemcoupling part caused by time-varying delay are processed as the total disturbance of the system; a generalized expansion state observer is designed, and the system sum disturbance is observed while the system state is observed, and then a large-correlation motion system position servo decoupling controller based on disturbance compensation is designed. Then, a networked large-correlation motion system position synchronous coupling error model is established, a synchronous controller is designed, and the networked large-correlation motion system position synchronous control is realized. By virtue of the method, the influence of mutual coupling and time delay between the subsystems can be treated, so that it is ensured that the system has high anti-interference performance and robustness, and high position synchronous control performance is achieved while the system achieves high position servo decoupling control performance.

Tongxiang Li

Papers

Packet-Based State Feedback Control Under DoS Attacks in Cyber-Physical Systems

Active Security Control Approach Against DoS Attacks in Cyber-Physical Systems

Improved Switched System Approach to Networked Control Systems With Time-Varying Delays

A Switched System Approach Against Time-Delay Attacks in Cyber- Physical Systems

Generalized expansion state observer-based networked large-correlation motion system position synchronous control method