Proactive Secure Control for CPSs

Abstract

Either the absence of an attack isolation algorithm or no available controllable pairs $$(A,\mathcal {B}_{l})$$ to alter can make the CPSs undergo attacks all the time. The system performance can be steadily deteriorated. To solve the problems, this chapter proposes attack detection, isolation and MTD control schemes for CPSs in a united framework. The physical process is described as a linear time-invariant discrete-time model [61, 73]. False data can be injected into the cyber layer to deteriorate the system performance [116]. The initial linear time-invariant discrete-time model is converted into a series of controllable sub-systems. An unpredictable switching sequence, which creates the MTD diagram, is given to activate the sub-system. A controller for each activated dynamics is designed. An observer-based attack detection scheme is designed to detect attacks. An attack isolation algorithm is proposed to accurately locate the attacked actuators by designing a series of parallel unknown input observer. After the attack detector reports an alarm, the attack isolation algorithm is invoked to locate and exclude the attacked actuators from the controllable pairs $$(A,\mathcal {B}_{l})$$ . A game-based defense controller is designed to deal with the case, in which there exist no available controllable pairs $$(A,\mathcal {B}_{l})$$ that can be used to make the MTD control diagram work.