Abstract for: Block Diagrams of Generic System Dynamics Models
In system dynamics methodology, a formal mathematical model of a dynamic system consists of a stock-flow diagram and a set of equations. It is possible to simplify and express a system dynamics model as a set of differential equations, which can then be used to obtain the corresponding block diagram for that system dynamics model. In the paper, we obtain simplified differential equations for two system dynamics models and based on the differential equations, we construct two block diagrams. Differential equations serve as a bridge between the two systems modeling perspectives, system dynamics and control theory. In addition, we also show other mathematical forms that can be used to express a dynamic model such as approximate integral equations, difference equations, and integral equations. In Appendix A, a summary of Laplace transforms, transfer functions, and block diagrams are provided as a quick reference. In Appendix B, 18 generic system dynamics models, their simplified differential equations, and their corresponding block diagrams are presented. We carefully formulated SD models and their corresponding block diagrams and verified their behavior by simulating them and by observing the same exact behavior from the SD model and its block diagram. Similar to “differential equations”, this paper aims to construct a bridge between control theory and system dynamics.