An approach to hybrid control problems based on approximating continuous plant dynamics by nondeterministic automata

This paper explains how the hybrid control problem of synthesizing a discrete control scheme for a continuous plant model can be solved by approximation continuous plant dynamics by nondeterministic finite automata and then applying standard methods from DES (discrete event systems) theory. A necessary condition is that the behaviour of the approximating automaton model contains the behaviour of the underlying continuous plant model. Then, any controller forcing the approximation to obey the specifications will also force the continuous plant model to satisfy the specifications. Approximating accuracy can be adjusted depending on the degree of complexity of the hybrid control problem to be solved. The method is illustrated by an application example from chemical process control, the synthesis of a discrete feedback strategy for the start-up procedure of a distillation column