Abstract
Classical causality assignment procedures are efficient methods to obtain an ODE representation of a causal bond graph. In many cases of electronic applications it is useful to simulate a system containing some components represented by State Space Models. This is the case of the SPICE models for semiconductor devices. The Algebraic Causality Analysis extends the bond graph analysis to such systems. However in the case of causality faults or indeterminate causalities, the published algorithms appear to be incomplete and heuristic. So we propose the Formal Causality Analysis that enables a systematic causality analysis of bond graphs. The systematic nature of the algorithm is obtained by the formal algebraic treatment of the system constraints in the case of causality faults and indeterminate causalities. Some typical examples are given to illustrate the algorithm. Obviously the interest of the algorithm is that it should be used in a bond graph simulator.