Introduction to System Science with MATLAB, 2nd Edition

6System Modeling

In this chapter, we undertake the important task of identifying and quantitatively modeling systems. Frequently, a very valuable aid in the initial identification of the inputs and outputs and various subsystems of a given system is to model graphically the overall system, including explicit designation of all subsystems and internal inputs and outputs. The powerful influence of visual and spatial conception and recognition of the model in a graphical format can be very revealing and productive for both model synthesis and analysis. We will examine block diagrams, signal flow graphs, and organizational diagrams as graphical modeling tools in this chapter.

Several major specific system identification and modeling techniques are examined. The basic single‐input, single‐output model is examined and justified as an excellent beginning model for many systems. Then the modeling techniques for physical and nonphysical science‐based systems are examined, and the modeling differences are identified. The use of experimental methods for system modeling and verification is given, including the valuable aids provided by dimensional analysis and least‐squares methods. A method called weighted input; output modeling provides a rational means for ranking and weighting inputs and outputs based on their contribution to the system’s behavior. Stochastic system modeling is briefly addressed, and some of the essential features of this important field are assessed. Finally, some ...