A virtual actuator approach for the secure control of networked LPV systems under pulse-width modulated DoS attacks

In this paper, we formulate and analyze the problem of secure control in the context of networked linear parameter varying (LPV) systems. We consider an energy-constrained, pulse-width modulated (PWM) jammer, which corrupts the control communication channel by performing a denial-of-service (DoS) attack. In particular, the malicious attacker is able to erase the data sent to one or more actuators. In order to achieve secure control, we propose a virtual actuator technique under the assumption that the behavior of the attacker has been identified. The main advantage brought by this technique is that the existing components in the control system can be maintained without need of retuning them, since the virtual actuator will perform a reconfiguration of the plant, hiding the attack from the controller point of view. Using Lyapunov-based results that take into account the possible behavior of the attacker, design conditions for calculating the virtual actuators gains are obtained. A numerical example is used to illustrate the proposed secure control strategy.Peer ReviewedPostprint (author's final draft

Fault tolerant control for fixed set-point control nonlinear networked control systems

U radu se predlaže pristup za dobivanje algoritma regulatora koji tolerira grešku za vrstu umreženog upravljačkog sustava koji ima regulator s čvrstom zadanom točkom i nelinearno postrojenje. Najprije opisujemo nelinearni umreženi upravljački sustav te lineariziramo model postrojenja u radnoj točki, zatim konstruiramo spojeni model cijelog sustava koji uključuje sve faktore relevantne za naše istraživanje kao što su kašnjenje inducirano mrežom, gubitak podataka, greške senzora i aktuatora itd. Na temelju ovog modela postignuto je stanje stabilnosti u sustavu konstruiranjem Lyapunove funkcije. Zatim je iz stanja stabilnosti dobiven upravljački algoritam tolerancije greške. Konačno je na numeričkom primjeru dokazana validnost teorije.This paper proposes an approach for achieving fault tolerant control algorithm for a kind of networked control system which is fixed set-point control and with nonlinear plant. We firstly describe the nonlinear networked control system and linearize the model of the plant at the operating point, then construct a synthesis model of the whole system, which includes all relevant factors in our research such as network induced time delay, data packet loss, the faults of sensors and actuators etc. Based on this model, the stability condition in meaning square sense of the system is gained by constructing a Lyapunov function. Then the fault tolerant control algorithm is obtained from the stability condition. Lastly, a numerical example is used to prove the validity of the theory

H

This paper studies the H-infinity stochastic control problem for a class of networked control systems (NCSs) with time delays and packet dropouts. The state feedback closed-loop NCS is modeled as a Markovian jump linear system. Through using a Lyapunov function, a sufficient condition is obtained, under which the system is stochastically exponential stability with a desired H-infinity disturbance attenuation level. The designed H-infinity controller is obtained by solving a set of linear matrix inequalities with some inversion constraints. An numerical example is presented to demonstrate the effectiveness of the proposed method

Robust H

This paper investigates the problem of robust H∞ fault detection for networked Markov jump systems with random time-delay which is introduced by the network. The random time-delay is modeled as a Markov process, and the networked Markov jump systems are modeled as control systems containing two Markov chains. The delay-dependent fault detection filter is constructed. Furthermore, the sufficient and necessary conditions which make the closed-loop system stochastically stable and achieve prescribed H∞ performance are derived. The method of calculating controller, fault detection filter gain matrices, and the minimal H∞ attenuation level is also obtained. Finally, one numerical example is used to illustrate the effectiveness of the proposed method

Delay-Dependent Stability Analysis for Uncertain Switched Time-Delay Systems Using Average Dwell Time

We are concerned with the stability problem for linear discrete-time switched systems with time delays. The problem is solved by using multiple Lyapunov functions to develop constructive tools for the exponential stability analysis of the switched timedelay system. Furthermore, the uncertainties of the switched systems are also taken into consideration. Sufficient delay-dependent conditions are derived in terms of the average dwell time for the exponential stability based on linear matrix inequalities (LMIs). Finally, numerical examples are provided to illustrate the effectiveness of the proposed method

Guaranteed Cost Control for Multirate Networked Control Systems with Both Time-Delay and Packet-Dropout

Compared with traditional networked control systems, the sampling rates of the nodes are not the same in the multirate networked control systems (NCSs). This paper presents a new stabilization method for multirate NCSs. A multirate NCSs with simultaneous considering time-delay and packet-dropout is modeled as a time-varying sampling system with time-delay. The proposed Lyapunov function deceases at each input signal updating point, which is largely ignored in prior works. Sufficient condition for the stochastic mean-square stability of the multirate NCSs is given, and the cost function value is less than a bound. Numerical examples are presented to illustrate the effectiveness of the proposed control scheme

Modeling and Output Feedback Control of Networked Control Systems with Both Time Delays; and Packet Dropouts

This paper is concerned with the problem of modeling and output feedback controller design for a class of discrete-time networked control systems (NCSs) with time delays and packet dropouts. A Markovian jumping method is proposed to deal with random time delays and packet dropouts. Different from the previous studies on the issue, the characteristics of networked communication delays and packet dropouts can be truly reflected by the unified model; namely, both sensor-to-controller (S-C) and controller-to-actuator (C-A) time delays, and packet dropouts are modeled and their history behavior is described by multiple Markov chains. The resulting closed-loop system is described by a new Markovian jump linear system (MJLS) with Markov delays model. Based on Lyapunov stability theory and linear matrix inequality (LMI) method, sufficient conditions of the stochastic stability and output feedback controller design method for NCSs with random time delays and packet dropouts are presented. A numerical example is given to illustrate the effectiveness of the proposed method