This work proposes a synchronization controller for a class of networked finite and infinite dimensional systems. The leader, or reference model is assumed known and networked controllers are proposed to ensure that each networked system follows the leader and synchronize with each other. An attack, which takes the form of severing a link or reversing the sign of a synchronization gain, is assumed to occur at an unknown time, and its goal is to either desynchronize or destabilize the networked systems. Adaptive detection observers are designed to monitor the systems and at the onset of an attack, declare the presence of an attack and subsequently engage in an attack accommodation via an appropriate control reconfiguration. To enhance robustness against false alarms and minimize the detection time, time varying thresholds are introduced. When any of the residuals exceed the time varying thresholds, an attack in the networked systems is declared. Migrating to the infinite dimensional case requires additional assumptions and the corresponding stability and convergence results are not trivially extendable. A numerical example of four networked diffusion PDEs is included in order to provide an insight on the effects of a fixed threshold in detecting the presence of an attack and on the effects of accommodation in aiding the systems to recover by resynchronizing.
['Michael A. Demetriou']
Desynchronization and resynchronization of interconnected finite and infinite dimensional systems: interpretation of attack and accommodation using FDI framework