Towards the Maintenance Principles of Cyber-Physical Systems

Cyber-physical systems (CPSs) are rapidly proliferating in different applications. Their system features significantly differ from those of linear complex systems (LCSs). Consequently, they pose novel challenges with regard to ensuring the dependability of system operation. Maintenance of CPSs raises new theoretical and practical issues. To guarantee a high level of dependability, new and efficient system maintenance principles should be explored and operationalized in various contexts. This paper reports on the first results of the authors’ work in this direction. A comprehensive literature review has been conducted with the objective of identifying the specific features of LCSs and CPSs. We analysed the major maintenance principles and approaches currently applied to complex systems to see how they can be applied to CPSs. We found that the existing maintenance principles have various relationships with CPSs: (i) some of them cannot be considered in the context of CPSs due to incongruent system features, (ii) some of them can be adapted due to certain partial congruencies, and (iii) some of them can be applied directly due to the congruency of some system features of LCSs with CPSs. It was also found and demonstrated through a number of practical examples that many specific maintenance principles need to be developed for CPSs. We assert that the system features of CPSs without parallel in LCSs primarily reveal what sort of new maintenance principles and approaches are needed. The ultimate goal of our on-going research is to define and test these new maintenance principles. In this paper, we identify and define these principles, starting from the unique system features of CPSs and aiming to develop a maintenance advisory system.