Bond Graph Primer Controllab Products Bond graphs The starting point of modeling a physical system is mostly an Ideal Physical model. To perform simulations, this Ideal Physical model must first be transformed into mathemacical descriptions, either using block diagrams or equation descriptions. Often this is a laborious procedure. Especially when the Ideal Physical model is adapted, the complete derivation of the mathematical description has to be repeated.
Bond graphs are a unique way of describing dynamic models.
A bond graph is a drawing in which the physical structure as well as the nature of subsystems are shown and can be directly derived from the Ideal Physical Model. When the Ideal Physical Model is partially changed, only the correspong part of a bond graph has to be changed. Power ports specify both an effort variable and a flow varible. Signal ports specify only one variable, which can either be a flow, an effort or a mathematical variable. Two type of knots are described in bond graphs, zero junctions and one junctions.