Fault-tolerance as a key Requirement for the Control of Modern Systems

Networks of Embedded Systems are becoming ubiquitous today. The performance of these networks is measured in terms of the Quality of Service (QoS) delivered. This has been taken on board by the Computer Scientists, who have developed concepts like “Ubiquitous” and “Pervasive” Computing. In the world of Control, there has always been an “implicit” QoS, in that the quality or level of performance has been measured using a cost function, often the error between the reference signals and the system outputs. However, such “point-to-point” notions of QoS are fast becoming redundant in the networked, information-rich world. This paper outlines a new way of formulating the Control problem which is suitable for the networked world, enabling Fault Tolerance to become a natural consequence to ensure that the system performance is maintained under all eventualities. Thus Control has to become more ubiquitous, pervasive, and intelligent. To facilitate this outcome, this paper proposes a new research direction which could be termed “Embedded Cognitive Control”, bringing together the various fields of Cognitive Science, Embedded Systems, and Control.