Fabrício Junqueira

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

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.

A New Method for the Hierarchical Modelling of Productive Systems

Industry reorganization and the increase in the automation level of productive processes results in the augmentation of complexity of the interactions among enterprise subsystems related to monitoring and control. Analysis techniques are used to deal with the complexity, design of new productive systems, and improve the performance of existing systems. In this context there is currently a special focus in distributed simulation. It deals with the execution of simulation in physically dispersed computers connected through a network. In order to explore the potential of distributed simulations, this paper proposes a new method for the hierarchical modeling of productive systems proper for distributed environment. The application of the method is illustrated through an example. This method has been successfully applied to a number of case studies in order to confirm its effectiveness.

A platform for distributed modeling and simulation of productive systems based on Petri nets and object-oriented paradigm

The increasing complexity of productive systems associated with the geographical dispersion of industries motivates new demands and the adoption of new design tools. In this context the purpose of this work is to introduce a new platform for distributed modeling and analyses 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

Open distributed supervisory system design using Petri nets

The design of supervisory system for automated environments can be seen as a task involving techniques and methods of two main areas: software and control engineering. In this context, the purpose of this work is to introduce a new approach for open distributed supervisory system design based on the merging of traditional techniques of software engineering (such as object-oriented concepts) with formal models of discrete events dynamic systems- (such as Petri nets). In this first level of abstraction, the reference model of open distributed processing (RM-ODP) is used as a standard architectural framework for the construction of open distributed system. Based on the RM-ODP, the unified modeling language (UML) diagrams are built as a second level of abstraction. Finally, the Petri nets (the third level of abstraction) are used throughout the process in order to guarantee the coherence among the UML models from requirement analysis to implementation, and to provide formal models of the system.

An architecture based on IoT and CPS to organize and locate services

The fourth Industrial Revolution, also called Industry 4.0 (I4.0), has been increasing the expectation around productive systems. It is a new concept that has been changing the view and the value chain of enterprises. The I4.0 comprise the smart factory, bringing the emerging concepts of Internet of Things (IoT) and cyber-physical system (CPS) into manufacturing processes in a way to enable the design and creation of smart products, procedures and processes. Although, this scenario needs more investigation by the research and development fields, especially for architectures to guide the I4.0 implementation, mainly because it is in an initial stage and requires a comprehensive understanding to become a consolidated environment. The overall aim of this research is the presentation of an architecture based on IoT and CPS focused on I4.0. The proposal is centered on a hierarchical organization of services to contribute to the communication between machines and products so that products can be automatically guided in the manufacturing processes.

Modeling of Mechanisms for Reconfigurable and Distributed Manufacturing Control System

This paper presents the modeling of fault diagnosis mechanisms extending a method to design reconfigurable and distributed manufacturing control system. The method combines different techniques: service-oriented architecture, holonic and multi-agent system, production flow schema and input-output place-transition Petri net. An application example demonstrates advantages of the proposal, such as at cloud-based engineering, reuse, implementation and reconfiguration flexibility.

A method to design a manufacturing control system considering flexible reconfiguration

The manufacturing control system must immediately react to a variation in product, process specification, fault occurrence, changes in the resources functional capabilities, and other operational factors. Besides, to gain competitive advantage, distributed productive systems must work in cooperation with each other. To effectively integrate these heterogeneous envi-ronments, this paper proposes a method to combine holonic control system, service-oriented architecture and Petri net (PN) techniques. The PN models represent the workflow of the design method itself, the structure and the dynamic of the control system. To demonstrate the advantages of the proposal, an application example of the manufacturing system is described.

A Service-Oriented and Holonic Control Architecture to the Reconfiguration of Dispersed Manufacturing Systems

Manufacturing control systems must quickly react to variations of product, process specifications, fault occurrence, changes in the resources functional capabilities, and other operational demands. Besides, to gain competitive advantages, dispersed manufacturing systems must cooperate with each other. The combination of holonic control system and service-oriented architecture techniques can be effective to integrate these heterogeneous environments since the agents must also cooperate to achieve their services. Therefore, this paper introduces a service-oriented and holonic control architecture using Petri net to represent the workflow of design method itself, structure and dynamic of the entities. The modeling of an example is presented to demonstrate application at self-organization and adaptation, fault treatment, degeneration, and relatively shorter implementing time.

Safety in Supervisory Control for Critical Systems

Recent studies show the designs of automated systems are becoming increasingly complex to meet the global competitive market. Additionally, organizations have focused on policies to achieve people’s safety and health, environmental management system, and controlling of risks, based on standards. In this context, any industrial system in the event of a fault that is not diagnosed and treated correctly could be considered to pose a serious risk to people’s health, to the environment and to the industrial equipment. According to experts, the concept of Safety Instrumented Systems (SIS) is a practical solution to these types of issues. They strongly recommend layers for risk reduction based on control systems organized hierarchically in order to manage risks, preventing or mitigating faults, or to bringing the process to a safe state. Additionally, the concept of Risk and Hazard Control can be applied to accomplish the required functionalities. It is based on problem solving components and considers a cooperative way to find a control solution. In this context, the software architecture can be based on a service-oriented architecture (SOA) approach. This paper initially proposes a new architecture for design of safety control systems for critical systems, based on Safety Supervisory Control Architecture, in accordance with standards IEC 61508 and IEC 61511. Furthermore, a method is also proposed for design the control layer of risk prevention within Safety Supervisory Control Architecture.

A Procedure for Modeling of Holonic Control Systems for Intelligent Building (HCS-IB)

Faults occurrence is inevitable in real world and a practical alternative approach is the reduction of fault consequences. Despite of this, the majority of buildings control systems do not have such mechanisms. Thus, this work proposes a procedure for the modeling of control systems for intelligent buildings which considers their functional specifications in normal operation, and in case of faults occurrence. The procedure adopts the concepts of discrete event system, holon, and Petri net and its extensions. It is presented some models derived from case studies, and mechanisms to fault-diagnosis, decision and reconfiguration.