Читать книгу Cyber-physical Systems - Pedro H. J. Nardelli - Страница 28

A static system is the one dominantly composed of structural components so that its state does not change, or changes in a negligible way, in time and space. A dynamic system is related to frequent changes in state; they are usually related to operating and flow components. Dynamic systems can have several subclasses, such as (i) linear or nonlinear, (ii) discrete time or continuous time, (iii) periodic or event‐driven, (iv) deterministic or stochastic (or adaptive), (v) single input or multiple input, (vi) single output or multiple output, or (vii) stable or unstable (or chaotic). These characterizations are very important for any engineering system, either conceptual or material. The theory of dynamical systems – which is strongly mathematical – is at the core of most scientific and technological developments in the contemporary age [5]. New computer‐based approaches are also becoming more and more prominent [6, 7], introducing new methods in different sciences and also in technical activities. Note that these methods refer to theoretical practices applied to conceptual systems, but that are used to implement and operate material systems. We will return to this in upcoming chapters where we will discuss artificial intelligence, self‐organization, and agent‐based models.

Example 2.6 The wind turbine of Example 2.3 once again provides us a good illustration. The tower of the wind turbine is a structural component (a subsystem) that is classified as static since it is not expected to change its state in time and space. The turbine itself (the rotating machine; an operating component) is a dynamical system whose changes are coupled with the wind movement (a flow component) that will determine the electric energy conversion, which can be measured by current and voltage as a function of time. It can be classified as a nonlinear continuous stochastic system.