Supervision and control of heterarchical discrete event systems

Abstract

This paper presents a method for distributing centralized control models of discrete events systems (DES). The contribution of our approach is to offer a systematic way to decompose centralised models in order to obtain a modular representation of the production process. We observe as an advantage of this method that the main model properties are preserved and that the knowledge acquired during the modelling process is still valuable for the new structure. We emphasise that redundant information can be introduced to the system to increase local autonomy and to help the local fault detection and identification functions. Another important aspect is that the distributed models (sub-models) can be modified in order to increase their flexibility and to reach a more realistic behaviour representation. A set of terminologies and definitions related to the Control and Supervision domain are introduced in this paper to assist the understanding of our work.<br>Este artigo apresenta uma metodologia de distribuição de modelos de controle e de supervisão de sistemas a eventos discretos (SED). A contribuição da nossa proposta é de propiciar uma forma sistemática de decomposição de modelos centralizados com a finalidade de obter uma representação modular da produção, preservando suas principais propriedades assim como o conhecimento adquirido durante a fase de concepção do modelo. Uma das características da nossa proposta é a possibilidade de introduzir informações redundantes nos sub-modelos afim de aumentar a autonomia local e auxiliar as funções de tratamento de falhas. Ressaltamos também que a distribuição do modelo centralizado permite adaptações locais que aumentam sua flexibilidade e precisam seu comportament, aproximando-o do sistema físico considerado. Neste artigo, nos apresentamos também alguns termos e definições relativos à área de Controle e Supervisão de SED que serviram de base aos nossos trabalhos

Evaluating Centralized and Heterarchical Control of Smart Manufacturing Systems in the Era of Industry 4.0

“…A reconfigurable manufacturing system is a system designed so as to allow for rapid changes in structure, both hardware and software, in order to rapidly adjust the production capacity and functionality of a part family in response to sudden changes in market or in regulatory requirements [15]. These new manufacturing system characteristics led to significant changes in production control systems supervising systems different activities (e.g., a control action can be applied on the sequence of products that have to be manufactured, on the tuning operations of a production system or on operations aimed at restoring the proper functionality of the process) [16]. From the manufacturing point of view, a control system is used to control the manufacturing process, to set the run-mode to meet market requirements or to set the sequence of tasks that a processing unit has to perform, to optimize the production process [17].…”

“…From the manufacturing point of view, a control system is used to control the manufacturing process, to set the run-mode to meet market requirements or to set the sequence of tasks that a processing unit has to perform, to optimize the production process [17]. Therefore, the final aim of a control system is coordinating and directing all the production activities [8] and monitoring the production system to prevent undesired functioning [16].…”

Aportes Metodológicos para el Diseño de Sistemas de Supervisión de Procesos Continuos

“…Determina el estado actual del sistema controlado y hace inferencias necesarias para producir datos adicionales como históricos o diagnóstico. El monitoreo se limita a la captura de datos del proceso y no tiene acciones directas en los modelos o en la evolución del estado (Da Silveira y Combacau, 2006;Lambert, et al, 1999;Isermann, 1997Isermann, , 1998Suárez, et al, 2003). Funciones asociadas a las acciones sobre controladores locales determinadas por usuarios o sistemas de niveles superiores, entre las que se encuentran: los procedimientos de arranque y parada y la selección de modos de operación.…”

Implementación de Supervisores en una Arquitectura de Referencia Basadas en Sistemas de Manufactura Holónicos

“…Una vía para lograr esto es tener procesos flexibles, y se logra con nuevas tecnologías, y estructuras organizacionales que permitan adaptarse a los cambios que exige el mercado. En este sentido existen distintos enfoques como los holónicos (Wyns, 1999), los heteráquicos (Silveira and Combacau, 2003;Saad et al, 1995) y los jerárquicos (Li, 1994;ISA, 1995). Dentro de los enfoques holónicos se encuentra la Arquitectura de Integración para la Automatización de Complejos de Producción (Chacón et al, 2002), en ella se basará nuestra propuesta.…”