Component-based hierarchical modeling of systems with continuous and discrete dynamics

This paper presents a component-based modeling technique for systems with continuous and discrete dynamics. It uses hierarchical composition to hide the implementation details of one component from other components, and keeps the components at the same level of hierarchy interacting under a well-defined model of computation. Continuous time, discrete event, and finite state machine models are considered. The signal conversions at the boundaries and the execution control among the components are studied. The modeling technique is implemented in Ptolemy II, a heterogeneous modeling and design environment. A hierarchical helicopter control system is modeled as an example.