Implementation and validation of a holonic manufacturing control system

Flexible manufacturing systems are complex, stochastic environments requiring the development of innovative, intelligent control architectures that support agility and re-configurability. ADACOR holonic control system addresses this challenge by introducing an adaptive production control approach supported by the presence of supervisor entities and the self-organization capabilities associated to each ADACOR holon. The validation of the concepts proposed by ADACOR control system requires their implementation and experimental testing, to analyze their correctness, applicability and merits. This paper describes the implementation of ADACOR concepts in a flexible manufacturing system, verifies their correctness and applicability, and evaluates the ADACOR control system performance, considering not only quantitative indicators directly related to production parameters, e.g. manufacturing lead time, but also qualitative indicators, such as the agility

Agent-based holonic production control

Indexado ISIThe manufacturing system environment is typically a complex system, involving many variables and constraints, being in certain cases a chaotic system. The introduction of new paradigms to face globalisation, distribution of activities and customer satisfaction requirements, increases the problem complexity. The new manufacturing control approaches should support the agile adaptation to volatile technological and economical environments and should react dynamically and quickly to disturbances. This paper intends to introduce an agent-based approach to the manufacturing problem, that uses holonic concepts, is focused on distributed manufacturing shop floor control for discrete batch production, considers the optimisation of set-up and maintenance operations, and develops mechanisms for agile and fast reaction to disturbances without compromising the global production optimisation

ADACOR: a holonic architecture for agile and adaptive manufacturing control

In the last decades significant changes in the manufacturing environment have been noticed: moving from a local economy towards a global economy, with markets asking for products with higher quality at lower costs, highly customised and with short life cycle. In these circumstances, the challenge is to develop manufacturing control systems with intelligence capabilities, fast adaptation to the environment changes and more robustness against the occurrence of disturbances. This paper presents an agile and adaptive manufacturing control architecture that addresses the need for the fast reaction to disturbances at the shop floor level, increasing the agility and flexibility of the enterprise, when it works in volatile environments. The proposed architecture introduces an adaptive control that balances dynamically between a more centralised structure and a more decentralised one, allowing combining the global production optimisation with agile reaction to unexpected disturbances

A framework for distributed manufacturing applications

The new organisational structures used in world wide manufacturing systems require the development of distributed applications, which present solutions to their requirements. The work research in the distributed manufacturing control leads to emergent paradigms, such as Holonic Manufacturing Systems (HMS) and Bionic Manufacturing Systems (BMS), which translates the concepts from social organisations and biological systems to the manufacturing world. This paper present a Framework for the development of distributed manufacturing applications, based in an agent-based architecture, which implements some Holonic and Bionic Manufacturing Systems concepts

Arquitecturas adaptativas e cooperativas para sistemas de fabrico distribuídos

A pressão competitiva actual, é ditada por um mercado aberto e global, e no qual as empresas são confrontadas com exigências cada vez mais fortes. A adopção de novos conceitos e paradigmas de fabrico, combinados com a implementação de novas tecnologias é a resposta a estes requisitos e a solução para o incremento da competitividade. Arquitecturas de controlo distribuídas, cooperativas, auto-organizativas e heterogéneas são prometedoras neste contexto. A arquitectura apresentada, pretende solucionar de forma eficaz os requisitos dos sistemas de fabrico emergentes, sendo baseada na tecnologia de multiagentes, e implementando alguns conceitos associados aos sistemas de fabrico holónico e biónico, suportando uma nova abordagem ao controlo, que inclui as fases operacional e de reengenharia do ciclo de vida de uma empresa.info:eu-repo/semantics/publishedVersio

Predictive disturbance management in manufacturing control systems

The manufacturing systems are dynamic, non-linear and often chaotic environments, subject to the occurrence of unexpected disturbances that leads to deviations from the initial plans and usually degrades the performance of the system. The treatment of exceptions and disturbances is one major requirement to the next generation of intelligent manufacturing control systems, that should be able to treat emergency as a normal situation. In this paper, a predictive disturbance management approach that transforms the traditional “fail and recover” practices into “predict and prevent” practices, improving the control system performance, will be presented. The predictive mechanism is based in the frequency analysis of each type of disturbance to find repetitive patterns in their occurrence

Towards autonomy, self-organisation and learning in holonic manufacturing

This paper intends to discuss self-organisation and learning capabilities in autonomous and cooperative holons that are part of a holonic manufacturing control system. These capabilities will support the dynamic adaptation of the manufacturing control to the manufacturing evolution and emergency, specially the agile reaction to unexpected disturbances

Experimental validation of ADACOR holonic control system

In the last years, several manufacturing control architectures using emergent paradigms and technologies, such as multi-agent and holonic manufacturing systems, have been proposed to address the challenge of developing control systems capable of handling certain types of disturbances at the factory level. One of these holonic architectures is ADACOR, which integrates a set of paradigms and technologies for distributed manufacturing systems complemented by formal modelling techniques, to achieve a flexible and adaptive holonic/collaborative control architecture. The results obtained in the first experiments using the ADACOR architecture are presented in this paper, and also compared to the results produced by other control architectures. For this purpose a set of quantitative and qualitative parameters were measured, to evaluate static and dynamic performance of the control architectures

Correction to: Northerly wind trends along the Portuguese marine coast since 1950

All figure captions are not accurate. Also, there is a repeated error in most figures because the vertical scales incorrectly show Wind Strenght instead of Wind Strength and in Fig. 4 (mid-panel) 2003 instead of 2004.info:eu-repo/semantics/publishedVersio

On the presence of the Ponto-Caspian hydrozoan Cordylophora caspia (Pallas, 1771) in an Iberian estuary: highlights on the introduction vectors and invasion routes

Several non-native invertebrate and vertebrate species have been detected in the Guadiana Estuary (SW-Iberian Peninsula, Europe) during the 21st century. In June 2015, the non-native hydroid Cordylophora caspia (Pallas, 1771) was detected for the first time in this estuary, which motivated an assessment of its distribution during late Spring and Summer 2016. The main goals of this paper were to: i) report the presence of Cordylophora caspia and its distribution in the Guadiana Estuary, ii) record the substrates colonized, salinity, and water temperatures at locations where the species was detected, iii) evaluate possible introduction vectors and invasion routes; and iv) discuss the potential impacts and management options. Cordylophora caspia occupied a 25-km stretch of the estuary with salinities between 0.2 and 13.8 and occupied a variety of human-made substrates. Shipping was the most likely introduction vector of C. caspia, which might have originated from populations in the Atlantic Ocean or the Mediterranean Sea. Currently, the potential ecological impacts are likely low since the population size is small due to an apparent shortage of suitable habitat. Economic effects are minimal at present because there are no major industries along the basin extracting water from the estuary. An integrated ecohydrological approach-i.e. freshets released from dams to control the populations of Cnidaria-was proposed to minimize or mitigate the potential negative effects of this species in the Guadiana Estuary.Delta Stewardship Council; Delta Science Program [1167]; Foundation for Science and Technology (FCT, Portugal) through the Jellyfisheries project [PTDC/MAR-BIO/0440/2014]; European Regional Development Fund (COMPETE program-Operational Competitiveness Programme); FCT [SFRH/BPD/108949/2015]; [UID/Multi/04326/2013]info:eu-repo/semantics/publishedVersio