Compositional Model~basedDesign of Physical systems

Model-based design constructs physical systems in two stages. First, a causal relation network (CRN) of quantities that entails the desired behavior is constructed from a domain model. Second, a physical system is designed by assembling components such that all the causal relations specified by the CRN are imposed. The Compositional Model-based Design method, CMD, simplifies the design of complex physical systems by decomposing the specified behavior into logical portions, building CRNs for each portion, and incrementafly composing the CRNs until the entire desired behavior is achieved. Importantly, the method detects potential interactions between individual CRNs that may nullify the portions of behavior already designed for by detecting violations of the closure assumptions under which each CRN was formed. 1~heCRN is revised using operators derived from axioms that specify the conditions for a change to hold in the presence of such interference. While this paper illustrates the method in the context of a boiler control system, the approach applies to regulatory physical systems with multiple operating regions.