Browsing by Author "Adam, Emmanuel"
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- Behavioural validation of the ADACOR2 Self-organized holonic multi-agent manufacturing systemPublication . Barbosa, José; Leitão, Paulo; Adam, Emmanuel; Trentesaux, DamienGlobal economy is driving manufacturing companies into a paradigm revolution. Highly customizable products at lower prices and with higher quality are among the most imposed influence factors. To respond properly to these external and internal constraints, such as work absence and machine failures, companies must be in a constant adaptation phase. Several manufacturing control architectures have been proposed throughout the years displaying more or less success to adapt into different manufacturing situations. These architectures follow different design paradigms but recently the decentralization and distribution of the processing power into a set of cooperating and collaborative entities is becoming the trend. Despite of the effort spent, there is still the need to empower those architectures with evolutionary capabilities and self-organization mechanisms to enable the constant adaption to disturbances. This paper presents a behavioural mechanism embed in the ADACOR2 holons. A validation procedure for this mechanism is also presented and results extracted. This validation is achieved through the use of a benchmark and results are compared with classical hierarchical and heterarchical architectures as also with the ADACOR.
- Dynamic self-organization in holonic multi-agent manufacturing systems: The ADACOR evolutionPublication . Barbosa, José; Leitão, Paulo; Adam, Emmanuel; Trentesaux, DamienNowadays, systems are becoming increasingly complex, mainly due to an exponential increase in the number of entities and their interconnections. Examples of these complex systems can be found in manufacturing, smart-grids, traffic control, logistics, economics and biology, among others. Due to this complexity, particularly in manufacturing, a lack of responsiveness in coping with demand for higher quality products, the drastic reduction in product lifecycles and the increasing need for product customization are being observed. Traditional solutions, based on central monolithic control structures, are becoming obsolete as they are not suitable for reacting and adapting to these perturbations. The decentralization of the complexity problem through simple, intelligent and autonomous entities, such as those found in multi-agent systems, is seen as a suitable methodology for tackling this challenge in industrial scenarios. Additionally, the use of biologically inspired self-organization concepts has proved to be suitable for being embedded in these approaches enabling better performances to be achieved. According to these principals, several approaches have been proposed but none can be truly embedded and extract all the potential of self-organization mechanisms. This paper proposes an evolution to the ADACOR holonic control architecture inspired by biological and evolutionary theories. In particular, a two-dimension al self-organization mechanism was designed taking the behavioural and structural vectors into consideration, thus allowing truly evolutionary and reconfigurable systems to be achieved that can cope with emergent requirements. The approach proposed is validated with two simulation use cases.
- Enhancing ADACOR with biology insights towards reconfigurable manufacturing systemsPublication . Barbosa, José; Leitão, Paulo; Adam, Emmanuel; Trentesaux, DamienTraditional centralized manufacturing structures were found inadequate to face the challenging requirements of flexibility and re-configurability. Lately, several manufacturing paradigms were introduced to face this challenge, being unified in the objective of providing decentralized control over distributed entities. In spite of their potential benefits, some important questions are far from been answered, namely how control structures are dynamically formed and evolved and how to combine adaptation and optimization. This paper introduces the main principles for re-configurable manufacturing systems that answers to these questions, based on the ADACOR holonic architecture and incorporating mechanisms inspired in other areas of science, notably biology, nature, theory of complexity and artificial life.
- Holonic recursiveness with multi-agent system technologiesPublication . Suarez, Sonia; Leitão, Paulo; Adam, EmmanuelRecursive Systems are often needed or recommended for automatically deploy or build a software system composed of multiple entities on a large network, or on distributed locations, without a central control. We use the recursive definitions proposed in holonic systems, as the recursiveness is an elemental structural property of their structure. Holonic systems are used to be implemented using MAS technologies (platforms) on the basis of the shared functional properties of autonomy and cooperation of agents and holons. This paper discusses the adequacy of the actual MAS technologies for holonic recursiveness implementation. A comparison of MAS platforms is done through a framework that will guide the decisions of designers and developers.
- Improving the ADACOR2 supervisor holon scheduling mechanism with genetic algorithmsPublication . Barbosa, José; Leitão, Paulo; Adam, Emmanuel; Trentesaux, DamienManufacturing companies are being pushed to their limits due to an increase of production complexity guided by a growing standards demand by the costumers. To respond properly to this, manufacturing companies must adopt innovative control architectures that are able to handle better the occurrence of disturbances at shop-floor level (e.g. workstation breakdown, orders cancellation or modification). Additionally, the selection of a proper scheduling algorithms assumes a crucial point, in the sense that the increase of optimization levels depend on this. This paper presents a Genetic Algorithm (GA) based technique to be embedded into the supervisor entity present at the ADACOR2 aiming to improve the existing fast and non-optimal scheduling technique, improving the overall system processing execution. The main requirements of the GA is to be fast enough to be usable in demanding environments improving the optimization output. The proposed algorithm is tested using a Flexible Manufacturing System using different configurations of transportation and batch sizes. Results show that despite the presented GA technique increased the optimization calculation time it performs better considering the sum of this time with the gain in the optimization output.
- Nervousness in dynamic self-organized holonic multi-agent systemsPublication . Barbosa, José; Leitão, Paulo; Adam, Emmanuel; Trentesaux, DamienNew production control paradigms, such as holonic and multi-agent systems, allow the development of more flexible and adaptive factories. In these distributed approaches, autonomous entities possess a partial view of the environment, being the decisions taken from the cooperation among them. The introduction of self-organization mechanisms to enhance the system adaptation may cause the system instability when trying to constantly adapt their behaviours, which can drive the system to fall into a chaotic behaviour. This paper proposes a nervousness control mechanism based on the classical Proportional, Integral and Derivative feedback loop controllers to support the system self-organization. The validation of the proposed model is made through the simulation of a flexible manufacturing system.
- Self-adaptation for robustness and cooperation in holonic multi-agent systemsPublication . Leitão, Paulo; Valckenaers, Paul; Adam, EmmanuelThis paper reflects a discussion at the SARC workshop, held in Venice, October 2008. This workshop addresses robustness and cooperation in holonic multi-agent systems within a context of self-organizing and selfadaptive systems. The paper first presents the basic principles underlying holonic systems. The holonic system reveals itself as a ‘law of the artificial’: in a demanding and dynamic environment, all the larger systems will be holonic. Next, it addresses robustness in holonic systems, including its relationship to self-organization and self-adaptation. These self-* systems indeed are capable of delivering superior robustness. Third, it addresses cooperation in holons and holonic systems, including its relationship with the autonomy of the individual holons. Cooperation imposes constraints on a holon such that its chances of survival and success increase.
- Self-organized holonic manufacturing systems combining adaptation and performance optimizationPublication . Barbosa, José; Leitão, Paulo; Adam, Emmanuel; Trentesaux, DamienTraditional manufacturing solutions, based on centralized structures, are ineffective in unpredictable and volatile scenarios. Recent manufacturing paradigms, such as Holonic Manufacturing Systems, handle better these unpredictable situations but aren’t able to achieve the performance optimization levels displayed by the classical centralized solutions when the system runs without perturbations. This paper introduces a holonic manufacturing architecture that considers biological insights, namely emergence and self-organization, to achieve adaptation and responsiveness without degrading the performance optimization. For this purpose, self-organization and self-learning mechanisms embedded at micro and macro levels play an important role, as well the design of stabilizers to control the system nervousness in such dynamic and adaptive behaviour.
- Self-organized holonic multi-agent manufacturing system: the behavioural perspectivePublication . Barbosa, José; Leitão, Paulo; Adam, Emmanuel; Trentesaux, DamienNew manufacturing control architectures rely on the decentralization of the system entities to handle in a more effective way the current constraints imposed to the highly dynamic manufacturing world. Despite of their benefits, these architectures miss the performance levels of those achieved by traditional centralized systems running without failures. This paper proposes a holonic multi-agent system architecture, based on ADACOR foundations, which considers the self-organization concept to create a two vector solution embedded in micro and macro levels. The paper describes the self-organization mechanism embed at the micro level, named behavioural selforganization, being validated using the AIP-PRIMECA flexible manufacturing system.
- Structural self-organized holonic multi-agent manufacturing systemsPublication . Barbosa, José; Leitão, Paulo; Adam, Emmanuel; Trentesaux, DamienWorldwide systems are increasingly growing into unprecedented complexity levels. This increase of system complexity has to be tackled with new control approaches, where decentralization is playing an important role and particularly the Multi-Agent Systems and Holonic Systems. Despite the benefits of this distribution, new problems arise such as the need for entities coordination. This paper proposes an innovative holonic multi-agent system architecture, named ADACOR2, which sets foundation on the already proved ADACOR architecture. This new control architecture is empowered by a two vector self-organization, called behavioural and structural self-organization. This paper describes the structural self-organization vector, particularizing the need for embedding in it learning techniques and nervousness stabilizer. A futuristic test bed, inspired in a real flexible-manufacturing system, is used to demonstrate the benefits of this vector in the architecture.