The automated symbolic derivation of state equations for dynamic systems

A system which is capable of generating symbolic state equations for dynamic systems is described. The underlying object-oriented knowledge representation structure is based on the bond graph modeling methodology which abstracts a complex system into a network of simple relations that describe the behavior of the system. Constraint propagation techniques provide a method for determining the causal relationships that must exist between system variables in a state-determined system, thereby identifying a set of state variables for the system. The relation network and the state variables are manipulated by MACSYMA to define the state equations for the physical system dynamics. The availability of state equations in symbolic form allows the engineer to assess the influence of component parameters on the overall function of the physical system without having to resort to simulation iterations. This representation establishes the foundation for a model-based reasoning system currently under development