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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...
Industrial control systems architectures have been evolving to the decentralization of control tasks. This evolution associated with the time-critical nature of these tasks, increases the dependability requirements for one of their most critical components: the communication system. Therefore, this is an important aspect on the control system design which must be properly evaluated. In this paper...
Global competition has given rise to logistic and production systems (LPSs), that are distributed manufacturing systems integrating international logistics and information technologies with production. This paper builds upon an LPS network design model previously proposed by some of the authors. The recalled technique formulates and solves a multi-criteria optimization problem to select the partners...
One of the most important factors in building high-performance, scalable industrial control applications is the ability to transfer process data from the server to the client machine in the most efficient and fast way. OPC DA is widely accepted and used as the standard in automation and network control systems. We present a system and method for caching process data in large industrial control systems...
In this paper we propose a system architecture that supports end-to-end scheduling of the distributed real-time thread abstraction. The real-time specification for Java (RTSJ) is used for the implementation of distributed real-time threads. By using simulations, we conclude that the proposed architecture is flexible enough to accommodate different scheduling algorithms
There are so many researches on Autonomous Distributed Manufacturing Systems (ADMSs), where cooperation among agents is used to solve problems, such as scheduling problem and routing problem. We target ADMSs where an ADMS consists of two sub-systems: a Production System (PS) and an Autonomous Transportation System (ATS). This paper discusses an on-line Tasks Assignment and Routing Problem (TARP) for...
This paper introduces query mechanisms that allow automotive control-systems (using a distributed real-time database management system (RTDBMS)) to be queried, monitored and stimulated during run-time without violating its temporal properties. The mechanisms are completely transparent to the control application since they are handled by the RTDBMS. The COMET RTDBMS is extended with ad hoc capabilities...
In this paper, we introduce a new model of urban traffic networks by using timed event graphs (TEG). Based on dioid algebra, the behavior of the system is described by (Max, +)-linear equations. This will allow to approach the traffic control problems which rise issues of cycle times and of synchronization. As a result, we show how we can solve a non-null initial marking problem inherent in dioid...
The DECOS integrated architecture divides the overall system into a set of nearly-independent distributed application subsystems, which share the node computers and the physical network of a single distributed computer system. This paper provides a solution to the controlled export and import of information between distributed application subsystems. We give the designer the ability to coordinate...
Network performance engineering can verify the design and dimensioning of large size control networks like CSMA based building automation networks. It combines performance analysis with diagnosis methods to evaluate the network utilization and detect design errors before installation and can therewith save the expenses of overdimensioning and redesign. This paper will develop a diagnosis model based...
Due to the widespread availability of the Internet, large scale distributed projects in manufacturing are becoming popular. Besides resource constraints, there exist precedence constraints among activities within each project. This paper presents a hybrid genetic algorithm to solve the resource-constrained multi-project scheduling problem (RCMPSP), which is well known NP-hard problem. Objectives described...
This paper introduces an adaptive feedback control strategy for (max,+)-linear systems. The feedback loop is tuned following to an estimation of the system transfer and in order to match a given reference model. An application of such an adaptive control strategy is possible for some manufacturing systems in which the feedback control corresponds to an adaptive resource allocation
This paper addresses the problem of vehicle positioning for automated transport in full-automated manufacturing systems. This study is motivated by the complexity of vehicle control found in semiconductor fabrication where the material handling network path is composed of multiple interconnected loops. We propose an integer linear program that minimizes the maximum time needed to serve a transport...
In many application fields, such as surveillance, monitoring, exploration, and rescuing, the use of multiple coordinated robot units seems to be the most convenient solution, in terms of costs, performance, and efficiency. In this paper we present a distributed real-time architecture for coordinating a set of mobile robot that have to operate according to a common objective. The interaction with the...
The approach presented in the paper deals with the analytical evaluation of the performance of predictive p-CSMA with no collision detection under saturation conditions, when all the nodes have always packets to send. Predictive p-CSMA employed in the MAC sublayer of LonTalk/EIA 709.1 protocol is the heart of communication capability of Lon Work's networks. It is displayed that the behavior of the...
This work pretends to develop a robot for vigilance tasks that are able to tolerate diverse kinds of attacks and be able to operate in environments with elevated electromagnetic noise, being even immune to sabotage provoked by means of high electromagnetic fields. A new CAN based communications system that interconnects the different devices that compose the mobile robot has been developed to achieve...
This paper presents the object-oriented platform-based design process for embedded real-time systems (SEEP). More specifically, it includes a case study to highlight the main design steps proposed by SEEP. Details regarding embedded system modeling and its transition to the programming level are presented. Moreover, it describes the embedded system generation and provides data obtained from the hardware...
This paper presents a design scheme for an intelligent fieldbus master with Ethernet interface based on Profibus. Significance of the design scheme was discussed, as there are many different kinds of fieldbuses coexisting. Architecture of Profibus protocol and its state machine was investigated. According to the state machine, an integrated communication process of the master was analyzed, and a design...
There are several (not only industrial) applications which can tolerate some losses. A concise way to distinguish between allowed and forbidden loss patterns are (m,k)-firm deadlines, which state that at most m out of k consecutive packets may get lost. An obstacle to the fulfillment of even the relaxed (m,k)-firm deadlines are channel errors. In this paper we consider the case where multiple periodic...
This paper describes a preliminary work carried on to assess the use of Bluetooth technology to transport MIDI data streams. The proposed approach is based on the well-known Bluetooth serial port profile. Although the music field motivated the work, the results are significant for the use of the profile in time critical applications such as industrial automation. In the paper a test-bed is described...
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