Yves Sallez

A stigmergic approach for dynamic routing of active products in FMS

This paper illustrates the capacity of a stigmergic routing control model to automatically find efficient routing paths for active products in flexible manufacturing systems (FMSs) undergoing perturbations. The proposed model is based upon a functional architecture with two levels: a virtual level in which virtual active products (VAPs) evolve stochastically in accelerated time, and a physical level in which physical active products (PAPs) evolve deterministically in real-time. The physical active products follow the best paths that have been detected on the virtual level, with a virtual level exploration being triggered when a perturbation is diagnosed in the transportation system. The data used for the simulation on the virtual level is then updated to reflect the real state of the transportation system. The models adaptive capabilities are illustrated with several simulation scenarios using NetLogo software, and an on-going real implementation is presented.

The lifecycle of active and intelligent products: The augmentation concept

This paper aims to demonstrate the consistency of extending the active or intelligent product concept to the whole product lifecycle. The first two sections describe the state of the art in the field of closed-loop PLM and the repercussions of introducing active products in the different phases of the product lifecycle: design, manufacturing, distribution, use and recycling. A functional generic model is then introduced. This model is based upon the ‘augmentation’ concept, which is available throughout the whole product lifecycle. To illustrate our proposal, we provide examples in the design and distribution phases. To validate our proposal, we focus on the manufacturing phase, describing a real implementation on a flexible assembly cell at Valenciennes AIP Primeca pole. Our ongoing research works to apply the ‘augmentation’ concept to the operating phase of a complex system in order to improve performance, especially in terms of availability.

Reactive and energy-aware scheduling of flexible manufacturing systems using potential fields

This paper presents a reactive scheduling approach for flexible manufacturing systems, which integrates the overall energy consumption of the production. This work is justified by the growing needs of manufacturers for energy-aware control, due to new important environmental criteria, which holds true in the context of high reactivity. It makes production hard to predict. The proposed reactive scheduling model is based on potential fields. In this model, resources that sense the intentions from products are able to switch to standby mode to avoid useless energy consumption and emit fields to attract products. Simulations are provided, featuring three indicators: makespan, overall energy consumption and the number of resource switches. Real experiments were carried out to illustrate the feasibility of the approach on a real system and validate the simulation results.

Ethernet-Based Car Control Network

The use of networks for communication between electronic control units has increased in car industry over the last two decades. Several types of networks were developed for this purpose. In this study, Ethernet at gigabit speed is tested as a network for such system. The use of Ethernet helps integrating real-time control functions and non-real-time entertainment functions. Two main scenarios were simulated using OPNET. The fist one simulates pure control networks on board of a moving vehicle. The second scenario is the same as the first one with an added video load to simulate on-board entertainment. Both simulations were successful, as the end-to-end delays were below the maximum round-trip delays required by the system

Embedded holonic fault diagnosis of complex transportation systems

The use of electronic equipment and embedded computing technologies in modern complex transportation systems continues to grow in a highly competitive market, in which product maintainability and availability is vital. These technological advances also make fault diagnosis and maintenance interventions much more challenging, since these operations require a deep understanding of the entire system. This paper proposes a holonic cooperative fault diagnosis approach, along with a generic architecture, to increase the embedded diagnosis capabilities of complex transportation systems. This concept is applied to the fault diagnosis of door systems of a railway transportation system.

Semi-heterarchical control of FMS: From theory to application

This paper presents both a model and a real implementation of a semi-heterarchical control system for flexible manufacturing systems (FMS). After presenting the concepts of heterarchical and semi-heterarchical control, a product-based control structure, composed of a dynamic allocation process (DAP) and a dynamic routing process (DRP), is proposed. Though the associated control processes (DAP and DRP) are hierarchically dependant, each is managed heterarchically, with no supervisor. The dynamic allocation algorithms are presented, and our highly distributed approach to routing control is then explained in detail. A real distributed application of the active entities and the control architecture was implemented in the AIP-PRIMECA pole at the University of Valenciennes, and this implementation is described in detail. A mixed-integer linear model of the FMS was used to compute lower bounds. The flexibility and robustness of our approach are highlighted through several real experiments.

Personal rapid transit in open control framework

Since last decade, the use of safe, comfortable and ecologic vehicles to operate in urban context as an alternative to private car has been required by authorities. Several projects have emerged on on-demand transport with new automated vehicles known as Cybercars or PRTs. In the context of intelligent transportation, where vehicles can be seen as autonomous and decisional entities composing a self-organized system to be controlled, this paper presents the open-control paradigm and gives an example of its instantiation with stigmergic scheme. The open-control concept, developed in our Lab (LAMIH), exhibits the classic explicit control, as well as an innovative type of control called implicit control. The implicit control allows system entities to be influenced via an Optimization Mechanism (OM). After introducing the open-control paradigm, we illustrate one possible implementation based upon a stigmergic approach and applied to a PRTs network. Implementation architecture and first experimental results are reported.

Role-based manufacturing control in a holonic multi-agent system

Multi-agent systems (MAS) are particularly adapted to deal with dynamic distributed environments and are typically used to manage business workflows or data flows in manufacturing systems. From a control perspective, holonic representation allows both the informational and the physical parts in such manufacturing systems to be modelled. In this article, we focus on the notion of role in holonic MAS (HoloMAS) and its contribution to the adaptive control of manufacturing systems. We validated our HoloMAS proposal using simulations and through a real implementation on a flexible assembly cell in our university lab. Our results clearly show that the notion of role helps to adapt and manage perturbations.

Semi-heterarchical Allocation and Routing Processes in FMS Control: A Stigmergic Approach

This paper deals with the production process control in flexible manufacturing systems (FMS), in which heterarchical relations exist between some decisional entities. After presenting a brief state-of-the art of the literature on the heterarchical concept we propose a semi-heterarchical control structure (composed of DAP: dynamic allocation process and of DRP: dynamic routing process), and explain the objective of our study. After presenting the concept of stigmergy, we focus in this paper on our innovative approach to routing in DRP including the active product concept. We then describe our two levels model and its main components (a virtual level VL in which virtual active products evolve stochastically in accelerated time, and a physical level PL in which physical active products evolve deterministically in real time). Our innovative approach exploits the capacity of a stigmergic routing control model to automatically find efficient routing paths for active products in FMS undergoing perturbations. After a brief presentation of the Netlogo simulation context, the qualitative and quantitative results are presented. The results illustrate the advantages of our routing approach and its capacity to surmount perturbations. The integration and implementation of our approach at the AIP-PRIMECA center in Valenciennes France is then detailed. Finally, we provide a brief overview of our future research concerning: firstly, a way to link our DRP model with the DAP distributed control system, secondly, the re-formulation of our model within the HMS (holonic manufacturing system) concept, and thirdly, the development of a new challenging and innovative concept of “hypervision”.

Product-based and resource-based heterarchical approaches for dynamic FMS scheduling

Abstract Two fundamental approaches can be adopted for heterarchical scheduling of flexible manufacturing systems: resource-based scheduling or product-based scheduling. The first part of this paper defines the basic concepts of these two methods (modeling, structure design methodology, communication protocols). The second describes the specific advantages and drawbacks of these two approaches using the results provided to illustrate the discussion. The final section considers a real implementation of the product-based heterarchical philosophy.