Modeling and Simulation of Digital Controllers for Hybrid Dynamic Structure Systems

Authors

Abstract

Complex systems exhibiting structural changes can be better represented by models that can mimic these transformations. The Heterogeneous Flow System Specification (HFSS) is a comprehensive formalism that can represent a large variety of models using a unifying representation. The HFSS formalism represents models in a hierarchical and modular form. The explicit representation of structure makes possible to alter it dynamically. Among hybrid models, the most important include digital controllers and hybrid integrators. The HFSS ability to provide a common ground to represent all these elements permits to model complex systems in a simple framework. We present a detailed model of a PID controller and we show how this digital controller can be merged with other types of components. To illustrate formalism application we use a dynamic structure network of hybrid components to model a 2-stage rocket system, whose velocity is set by a PI digital controller. Simulation results for the rocket system are presented.