Defining A Command Architecture Enabling Proactive Simulations On A Complex Manufacturing System

International audienceProactive simulation is a new tool, which can be especially useful for driving complex manufacturing facilities. Indeed, the data collected after such simulations can be very useful to be able to take the best decision in the shortest time as the facility is currently running. This paper provides an insight into the different concepts of proactive simulation. Special emphasis is placed on the place of simulation in the control loop, and especially its relationship with the decisional center. The facility supporting this architecture is also briefly presented

Myopia of service-oriented holonic manufacturing systems: the contribution of an observer

Volume 402Service orientation paradigm is particularly well adapted to distributed manu-facturing systems. The difficulty of such systems' production activity control deals with the knowledge management. Indeed, the knowledge is distributed among each entity, which is able to create, modify or communicate them with oth-er entities. As a matter of fact, any entity cannot have a full up-to-date access to all the data of the system. On the shop floor level, a convenient way to implement service oriented manufacturing systems is to rely on the paradigm of Holonic Manufacturing Systems. This paper introduces the possibility of specializing a re-source holon with the objectives to gather the data from the whole holarchy and make these data available to any holon for a decision making. This holon is thus playing the role of a discrete-event observer. After positioning the service-oriented architectures, the HMS reference architecture PROSA is described, especially in terms of decision making. After the decisions were defined, the problematic of on-line decision making in a HMS is described, and a solution of implementation of the observer and of forecasting tools in the architecture is exposed. Finally, two applications are presented, based on an industrial job-shop

Utilisation de la simulation proactive: une aide au pilotage des systèmes de production

International audienceLa simulation est un outil puissant utilisé depuis longtemps comme aide à la conception des systèmes de production. La simulation proactive est une nouvelle approche qui permet une aide précieuse à la conduite de ces systèmes. Dans cet article, nous présentons une architecture de commande permettant l'utilisation de cet outil, ce qui permet d'expliciter les obstacles restant à surmonter avant un développement optimal

Using online simulation in Holonic Manufacturing Systems

Journal homepage: www.elsevier.com/locate/engappaiInternational audienceThis paper deals with the use of online simulation on Holonic Manufacturing Systems. Concepts needed for the use of online simulation in a classical hierarchical system were already defined, the observer being the central one. The behavior's differences between both classes of systems are studied to determine the best way to adapt these concepts to this new environment. In the PROSA reference architecture, staff holons were chosen to welcome the simulation models and the observer. An application on an industrial sized Holonic Manufacturing System is described to demonstrate the validity of the approach

A study of the robustness of the group scheduling method using an emulation of a complex FMS

International audienceIn the field of predictive-reactive scheduling methods, group sequencing is reputed to be robust (in terms of uncertainties absorption) due to the flexibility it adds with regard to the sequence of operations. However, this assumption has been established on experiments made on simple theoretical examples. The aim of this paper is to carry out experimentation on a complex flexible manufacturing system in order to determine whether or not the flexibility of the group scheduling method can in fact absorb uncertainties. In the study, transportation times of parts between machines are considered as uncertain. Simulation studies have been designed in order to evaluate the relationship between flexibility and the ability to absorb uncertainties. Comparisons are made between schedules generated using the group sequencing method with different flexibility levels and a schedule with no flexibility. A last schedule takes into account uncertainties whereas schedules generated using the group sequencing method do not. As it is the best possible schedule, it provides a lower bound and enables to calculate the degradation of performance of calculated schedules. The results show that group sequencing perform very well, enabling the quality of the schedule to be improved, especially when the level of uncertainty of the problem increases. The results also show that flexibility is the key factor for robustness. The rise in the level of flexibility increases the robustness of the schedule towards the uncertainties

Proposal of an Approach to Automate the Generation of a Transitic System's Observer and Decision Support using MDE

International audienceShort term decision support for manufacturing systems is generally difficult because of the initial data needed by the calculations. Previous works suggest the use of a discrete event observer in order to retrieve these data from a virtual copy of the workshop, as up to date as possible at any time. This proposal offered many perspectives, but suffers from the difficulties to generate a decision support tool combining decision calculations and observation. Meanwhile, interesting developments were made in literature about automatic generation of logic control programs for those same manufacturing systems, especially using the Model Driven Engineering. This paper suggests the use of MDE to generate logic control programs, the observer and the decision support tool at the same time, based on the same data collected by the designer of the system. Thus, the last section presents the evolution needed in the initial data structure, as well as the conception flow suggested to automatize the generatio

Effect of the Nd content on the structural and photoluminescence properties of silicon-rich silicon dioxide thin films

In this article, the microstructure and photoluminescence (PL) properties of Nd-doped silicon-rich silicon oxide (SRSO) are reported as a function of the annealing temperature and the Nd concentration. The thin films, which were grown on Si substrates by reactive magnetron co-sputtering, contain the same Si excess as determined by Rutherford backscattering spectrometry. Fourier transform infrared (FTIR) spectra show that a phase separation occurs during the annealing because of the condensation of the Si excess resulting in the formation of silicon nanoparticles (Si-np) as detected by high-resolution transmission electron microscopy and X-ray diffraction (XRD) measurements. Under non-resonant excitation at 488 nm, our Nd-doped SRSO films simultaneously exhibited PL from Si-np and Nd3+ demonstrating the efficient energy transfer between Si-np and Nd3+ and the sensitizing effect of Si-np. Upon increasing the Nd concentration from 0.08 to 4.9 at.%, our samples revealed a progressive quenching of the Nd3+ PL which can be correlated with the concomitant increase of disorder within the host matrix as shown by FTIR experiments. Moreover, the presence of Nd-oxide nanocrystals in the highest Nd-doped sample was established by XRD. It is, therefore, suggested that the Nd clustering, as well as disorder, are responsible for the concentration quenching of the PL of Nd3+

Data processing from manufacturing systems to decision support systems: propositions of alternative design approaches

International audienceWith the increase of flexibility and production rates, the complexity of manufacturing systems reached a point where the operator in charge of the production activity control of the system is not able to forecast efficiently the impact of his decisions on the global performances. As a matter of fact, more and more Decision Support Systems (DSS) are developed, as much in literature or industrial applications. DSS have one common point: the initialization of their forecasting functionality is based on data coming from the manufacturing system. Furthermore, this feature is fundamental, as it has a direct impact on the accuracy of the forecasts. Considering the variety of input and output data, a data processing is necessary to adapt those coming from the manufacturing system. The aim of this paper is to present several design approaches enabling the integrator of a new manufacturing system to speed up the implementation, with the idea of automate and systematize the maximum design phases thanks the model driven engineering

APPLICATION DU PARADIGME HOLONIQUE A UN SYSTEME DE RESERVOIRS

Colloque avec actes et comité de lecture. internationale.International audienceLe paradigme holonique a été largement étudié dans le cadre de la production manufacturière. Ces productions sont de type discrètes, car les opérations incluses dans les gammes ne mettent pas en jeu de variables à évolution continue. Une classe différente de systèmes est étudiée ici, les systèmes hybrides, qui englobe l’ensemble des systèmes ayant une évolution continue par morceaux, et dont les changements sont liés à l’évolution de variables discrètes. Dans ce cas, une reconfiguration du système est généralement nécessaire, et le paradigme holonique est une réponse pertinente au besoin de flexibilité en découlant. Ce papier propose l’adaptation d’une architecture de référence connue de la littérature discrète au cas des systèmes hybrides. Le modèle proposé est composé de l’union du modèle hybride et du modèle holonique, où le contrôleur proposé est représenté par l’holon Produit et l’holon Ordre, l'interface est représentée par la partie logique du holon Ressources et le système de production est représenté par la partie physique du holon ressource. La spécification d’holon produit utilisée est orientée services, et la spécification d’holon ressource est une abstraction de la partie physique de la ressource contenant tous les modèles de conversion d’état discret vers l’état continu et vice-versa. Un cas d’étude s’appuyant sur un système de commutations d’arrivées a été choisi