Modelagem e simulação distribuída de sistema produtivo baseados em rede de Petri

Em função da capacidade computacional instalada e da estrutura dispersa de alguns sistemas produtivos, existe interesse em soluções de modelagem e simulação distribuída destes sistemas. Isso é considerado como um recurso fundamental para o projeto, implementação e melhoria de desempenho desses sistemas produtivos. A idéia é que por meio de simulações com o uso de computadores fisicamente dispersos, mas integrados através de uma rede de comunicação, pode-se avaliar o comportamento de sistemas em concepção e melhorar resultados de plantas existentes. Este trabalho propõe assim, um procedimento para a modelagem de sistemas produtivos em ambientes distribuídos. Esse procedimento foi aplicado com sucesso a alguns estudos de caso onde sua eficácia foi confirmada. Este trabalho envolve ainda a proposta de um algoritmo para o gerenciamento da simulação distribuída. Com o método de modelagem e o algoritmo de gerenciamento tem-se os principais elementos para a implementação prática de um simulador de sistemas produtivos dispersos.Based on the existing computational capability and disperse infrastructure of some productive systems, there are interest for distributed modeling and simulation of these systems. These techniques are considered fundamental for design, implementation and performance improvement of productive systems. The approach is the simulation through the use of computers physically dispersed but integrated via a communication network to evaluate the behavior of systems still in conception level and also to improve the performance of existing plants. This work proposes a procedure for modeling of productive systems in distributed environment. This procedure was applied to case studies to confirm it effectiveness. The work includes an algorithm for the management of the distributed simulation. With the modeling method and the management algorithm we have the main elements for the practical implementation of the disperse productive system simulator.CNPqCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)FAPES

Modelagem e simulação de rupturas de cadeias de suprimentos baseados em rede de Petri

Atualmente, as suas empresas precisam avaliar sua exposição aos riscos devido à crescente dependência dela com operações globais de fornecedores, clientes e outros parceiros e, por esse motivo, existe grande interesse no desenvolvimento de métodos de avaliação dos riscos operacionais e planos de continuidade de negócios. Neste contexto, o artigo introduz um método para modelagem e simulação das cadeias de suprimentos globais focado na análise de rupturas e práticas resilientes. O métodoconsidera as cadeias de suprimentos como sistemas a eventos discretos e a rede de Petri como técnica formal gráfica e matemática para modelagem e simulação da cadeia de suprimento. O artigo apresenta uma cadeia de suprimentos hipotética para explicar a aplicação do método e assume a negociação com fornecedores substitutos como prática resiliente.CNPQCAPESFAPES

Design of automatic control system based on unified timed hybrid Petri net

A practical problem in automation systems modeling is the choice between a fully hybrid approach and the fluidization of some parts conserving the general discrete event approach. This paper explores the approach based on specific hybrid parts into a discrete event system using a unified Petri nets environment called GHENeSys (General Hierarchical Enhanced Net System), which follows the ISO/IEC 15909 standard and includes extensions such as hierarchy and time concepts. Then, a design method based on GHENeSys Timed Hybrid Petri Net (GTHPN) technique is proposed to model these hybrid parts. GHENeSys subnets are associated with macro-places and help to control combinatorial explosion and has extended arcs to guarantee the GTHPN applicability to practical cases. All resulting models of the approach proposed could also benefit from an easier conversion to PLC programs in IEC 61131 representation. A case study is presented for producing constructive blocks showing the advantages of the current proposition.Un problema práctico en sistemas automatizados es la selección entre el enfoque totalmente híbrido o la fluidización de algunas partes conservando el enfoque general de eventos discretos. Este articulo trata el enfoque basado en partes hibridas en un modelo discreto usando el ambiente unificado de Redes de Petri llamado GHENeSys (Sistema de Red Extendida Jerárquica General), compatible con la norma ISO/IEC 15909 incluyendo los conceptos de jerarquía y tiempo. Por tanto, se propone un método de diseño y una técnica GTHPN (Redes de Petri Temporizadas Hibridas GHENeSys) para modelar estas partes híbridas. Las subredes en macro-lugares controlan la explosión de estados y controlar transiciones mediante arcos extendidos de GHENeSys garantiza la efectividad de GTHPN para casos prácticos. Además, todo modelo resultante permite una fácil conversión a programas de PLCs en lenguajes IEC61131. Se presenta un caso de estudio para producción de bloques de construcción demostrando estas ventajas mencionadas

Método para projeto de sistema de controle supervisório considerando flexibilidade de reconfiguração

Os atuais sistemas de controle supervisório da produção necessitam ter uma estrutura distribuída\ud implementando diferentes dominios com características de inteligência, agilidade, e tolerância a falhas, a fim de\ud considerar a flexibilidade de reconfiguração. A técnica de sistema de controle holônico (SCH) é adequada para\ud integrar as tecnologias heterogêneas desses domínios, pois propõe o desenvolvimento de entidades de controle\ud com autonomia, reatividade, proatividade, cooperação, interface social, recursos de aprendizagem e, além disso,\ud disponibiliza plataformas de sistema multi-agente para facilitar a implementação. No entanto, existe necessidade\ud de métodos formais para garantir que as especificações de projeto sejam efetivamente implementadas. Portanto,\ud este trabalho apresenta um método para projeto deste supervisório combinando as técnicas de SCH com rede\ud de Petri. Um estudo de caso de sistema de manufatura é considerado para mostrar a viabilidade da proposta e exemplificar a análise dos resultados alcançados.CNPQCAPESFAPES

A PETRI NET BASED PLATFORM FOR DISTRIBUTED MODELING AND SIMULATION OF PRODUCTIVE SYSTEMS

Abstract. Currently with the increasing complexity of productive systems associated with the geographical dispersion of industries there are new requiriments for design tools. In this context the purpose of this work is to introduce a new platform for distributed modeling and analysis of productive systems. The platform is based on Petri net as a modeling formalism and on the label-ring protocol for managing the distributed simulation. The focus of this paper is on the platform communication algorithm. An example is presented in order to illustrate the proposal. Keywords: Petri Net, Distributed Simulation, Productive Systems. 1

THE DEVELOPMENT OF A PLATFORM TO SIMULATE PRODUCTIVE SYSTEMS IN A DISTRIBUTED ENVIRONMENT

Abstract. Pushed by the need of enlarging productive systems, the use of open distributed automation concept is spreading in industry. In distributed systems, some activities, such as the network data transmission may be seen as a succession of discrete states and instantaneous events. In this case, Petri Nets may be used to model this kind of system because it is known as a powerful tool used to model and to analysis concurrent, distributed, asynchronous, and parallel systems and it has a useful graphic representation and mathematic formalism. This work proposes the development of a platform to model and simulate productive systems, in a distributed computers environment. The adoption of middleware systems in this platform guaranties more portability, interoperability, scalability, and interconnectivity, allowing a future integration of this platform with real machines/resources. To help on the design of this platform, both ODP (Open and Distributed Processing) and UML (Unified Modeling Language) diagrams are used

DEVELOPMENT OF AN OPEN DISTRIBUTED APPROACH FOR BUILDING AUTOMATION

Abstract. The demand for more efficient, reliable and safe systems has beneficed the development of new concepts for buildings automation. These features can be achieved through an effective building systems integration. However, considering that each building system has unique characteristics, the requirements specification, verification, validation and implementation of an integrated solution are complex tasks, possibly leading to an unreliable automation system. Thus, an adequate approach for treat these systems, is fundamental to manage them and to assure effectively its integration. On the other hand, treat the building system integration with characteristics of open distributed systems can provide solutions for many problems related to aspects such as flexibility, investment preservation, connectivity and interoperability. Then, in this paper Open Distributed Processing- ODP is introduced as a general framework upon which open distributed system can be modeled through the viewpoint concept and the use of an object oriented language (Unified Modeling Language UML). The Petri net (PN) is also considered because it could provide a effective model analysis. In this context, the purpose of this work is to introduce an open distributed approach for building automation based on the merging of ODP framework, UML and PN

Towards modular and coordinated manufacturing systems oriented to services

Nowadays, there is a trend for industry reorganization in geographically dispersed systems, carried out of their activities with autonomy. These systems must maintain coordinated relationship among themselves in order to assure an expected performance of the overall system. Thus, a manufacturing system is proposed, based on “web services” to assure an effective orchestration of services in order to produce final products. In addition, it considers special functions, such as teleoperation and remote monitoring, users’ online request, among others. Considering the proposed system as discrete event system (DES), techniques derived from Petri nets (PN), including the Production Flow Schema (PFS), can be used in a PFS/PN approach for modeling. The system is approached in different levels of abstraction: a conceptual model which is obtained by applying the PFS technique and a functional model which is obtained by applying PN. Finally, a particular example of the proposed system is presented

Towards modular and coordinated manufacturing systems oriented to services

Nowadays, there is a trend for industry reorganization in geographically dispersed systems, carried out of their activities with autonomy. These systems must maintain coordinated relationship among themselves in order to assure an expected performance of the overall system. Thus, a manufacturing system is proposed, based on “web services” to assure an effective orchestration of services in order to produce final products. In addition, it considers special functions, such as teleoperation and remote monitoring, users’ online request, among others. Considering the proposed system as discrete event system (DES), techniques derived from Petri nets (PN), including the Production Flow Schema (PFS), can be used in a PFS/PN approach for modeling. The system is approached in different levels of abstraction: a conceptual model which is obtained by applying the PFS technique and a functional model which is obtained by applying PN. Finally, a particular example of the proposed system is presentedActualmente, una tendencia es la reorganización industrial en sistemas geográficamente dispersos, en la ejecutando sus actividades con autonomía. Estos sistemas deben establecer relaciones coordinadas a fin de asegurar el funcionamiento general del sistema. Así, este trabajo propone un sistema de manufactura basado en “web service” para asegurar una efectiva orquestación de servicios para producir productos finales. Adicionalmente, es considerado funciones especiales, tales como teleoperación y el monitoreo remoto, solicitaciones online de usuarios, entre otras. Considerando el sistema propuesto como un sistema a eventos discretos (DES), técnicas derivadas de la rede de Petri (PN), incluyendo las de Production Flow Schema (PFS), pueden ser utilizadas en un abordaje PFS/PN para modelado. El sistema es abordado en diferentes niveles de abstracción: uno conceptual, el cual es obtenido aplicando técnicas PFS, y un modelo funcional, el cual es obtenido aplicando PN. Finalmente, el trabajo presenta un ejemplo del sistema propuest