917 research outputs found
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
Online Optimization of LTI Systems Under Persistent Attacks: Stability, Tracking, and Robustness
We study the stability properties of the interconnection of an LTI dynamical
plant and a feedback controller that generates control signals that are
compromised by a malicious attacker. We consider two classes of controllers: a
static output-feedback controller, and a dynamical gradient-flow controller
that seeks to steer the output of the plant towards the solution of a convex
optimization problem. We analyze the stability of the closed-loop system under
a class of switching attacks that persistently modify the control inputs
generated by the controllers. The stability analysis leverages the framework of
hybrid dynamical systems, Lyapunov-based arguments for switching systems with
unstable modes, and singular perturbation theory. Our results reveal that under
a suitable time-scale separation, the stability of the interconnected system
can be preserved when the attack occurs with "sufficiently low frequency" in
any bounded time interval. We present simulation results in a power-grid
example that corroborate the technical findings
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