Controle hierárquico de circuitos de componentes de processos industriais modelados por abstrações sucessivas de sistemas a eventos discretos

Abstract

This paper develops a multilevel modeling strategy by successive abstractions of discrete event systems (DES) for the control of circuit components of industrial processes. The strategy aims to reduce the complexity of modeling circuit components and supervisor synthesis by exploring the multilevel hierarchical supervisory control of DES. In each hierarchical level, the components are associated successively in series or in parallel and the abstractions are obtained in intermediate equivalent models with an isomorphic structure to that of a single component. In a previous work, the modeling strategy was used in a circuit containing only on-off valves. The present paper extends the strategy to other types of componentes, including control valves subject to failures. As an example, an equivalent valve to a circuit formed by a control valve and an on-off valve is obtained and the requirements to guarantee nonblocking in the hierarchical structure are analyzed. Finally, based on the example and considering the abstract model of the equivalent control valve, a proposal of conditions is discussed that weakes the observer property to ensure nonblocking hierarchical supervisory control of the system.