Cyber-physical Systems

7The Three Layers of Cyber‐Physical Systems

This chapter introduces the three layers that constitute every cyber‐physical system (CPS). Our aim is to articulate the concepts that were presented in the first part of this book in order to construct a scientific theory of CPSs that are systematically characterized by physical, data, and decision layers, as well as the necessary processes that define cross‐layer relations. One important remark before we start: there are several layered architectures to analyze and develop specific CPSs, such as industrial production systems [1, 2] and power grids [3], but our proposal is very different. Those existing layered models focus on practical questions of particular cases, offering flexibility and a unified lexicon to assess and deploy such CPSs. In this book, our objective is to characterize what constitutes CPSs as such, not restricting our study to specific cases. In fact, different CPSs will be analyzed in Part III as realizations of the general theory proposed here. The approach taken here extends the ideas introduced in [4–7].

7.1 Introduction

In the first chapter, we provided a broad definition of CPSs, which was put forth by the standardization organization NIST. This chapter will finally state our proposed definition of CPSs. The idea is to characterize a typical CPS following the concept of “system” as defined in Chapter 2, indicating that, to be a CPS, it must be composed of a physical system from where data are collected ...