Thérèse Bonte

ORCA-FMS: a dynamic architecture for the optimized and reactive control of flexible manufacturing scheduling

Abstract Reactive and effective hybrid manufacturing control architectures, combining hierarchy and heterarchy adapted to the current constraints of the industrial market and its environment were created. In this article, a new generic hybrid control architecture called ORCA (dynamic Architecture for an Optimized and Reactive Control) is first proposed. This hybrid architecture is able to dynamically and partially switch between a hierarchical predictive architecture and a heterarchical reactive architecture, if an event forbidding the planned behavior to be followed occurs. In this article, this architecture was applied to a Flexible Manufacturing System (FMS) problem and denoted ORCA-FMS. ORCA-FMS was tested on an existing manufacturing cell with simulations and real experiments to prove the applicability and the effectiveness of this kind of hybrid architecture in an industrial environment.

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.

Reducing myopic behavior in FMS control: A semi-heterarchical simulation–optimization approach

Abstract Heterarchical FMS control architectures localize decisional capabilities in each entity, resulting in highly reactive, low complexity control architectures. Unfortunately, these architectures present myopic behavior since decisional entities have limited visibility of other decisional entities’ behavior and the alignment of an entity’s decision with the system’s global objective. In this paper, we propose a semi-heterarchical architecture in which a supervisor tackles different kinds of myopic decisions using simulation–optimization mechanisms and the current conditions of a flexible manufacturing system (FMS). The supervisor uses simulation results to calculate local and global performances and to evolve the solutions proposed by the optimization mechanisms. The approach proposed was configured to control a real assembly cell with highly heterarchical approaches. The completion time variance was used as the performance measure for myopic behavior reduction. The simulation results showed that the semi-heterarchical architecture can reduce myopic behavior whereby it strikes a balance between the ability to react to disturbances and maintaining low complexity, thus making it suitable for production control.

Arezzo-flexible manufacturing system: A generic flexible manufacturing system shop floor emulator approach for high-level control virtual commissioning

The benchmark of several high-level control strategies is required during the design of flexible manufacturing systems. Virtual commissioning is a popular approach to test and validate the behavior of the target control system based on a virtual model. It can actually simulate and help study the behavior of electro-mechanical shop floor components, characterized by a physical layer and low-level control functions but it fails to simulate the behavior of high-level control functions, such as dynamic resource allocation and product routing. Thus, virtual commissioning of the flexible manufacturing system can be a complex task because it requires to model the low- and high-level control functions in different software environments and to connect them through a specific interface. Switching from “virtual” to “real” remains a challenging issue since it requires to connect the high-level control functions to the real system through the real interface. This article introduces and details the Arezzo-flexible manufacturing system approach for supporting the virtual commissioning of the flexible manufacturing system, including the distinct but consistent modeling of their low- and high-level control functions. The Arezzo-flexible manufacturing system approach consists in gradually defining an emulator of the shop floor to which several candidate high-level control strategies can connect through a standard interface layer. The interface layer to the virtual shop floor emulates the real interface layer to the real shop floor, so that switching from the virtual to the real environment is straightforward. In this article, both the emulator design method and the involved generic components needed are described in turn. A real flexible cell is used as a case study to demonstrate the Arezzo-flexible manufacturing system approach and some illustrations are provided to emphasize the similarity between the shop floor emulator obtained (Arezzo-APV) and the real shop floor (Aip-Primeca flexible manufacturing system cell).

A multi-agent system based on reactive decision rules for solving the caregiver routing problem in home health care

Home Health Care (HHC) services are growing worldwide. HHC providers that employ their caregivers have to manage operational decisions such as assigning patients to caregivers and planning the caregivers’ routes. Centralized “off-line” approaches are generally used to deal with both these problems. In this paper, we solved the caregiver routing problem in a dynamic and distributed way using a Multi-agent system (MAS) to simulate caregiver behavior. Four decision rules were developed for the caregivers: NPR (Nearest Patient Rule), NRR (No-wait Route Rule), SRR (Shortest Route Rule), and BRR (Balanced Route Rule). These decision rules were implemented and tested on a multi-agent platform to assess their performances. We designed an experimental plan based on case studies that represent different sizes of HHC provider inspired from real-world examples. The results obtained show the relevance of using local decision rules to plan the caregivers route.

Routing Management in Physical Internet Crossdocking Hubs: Study of Grouping Strategies for Truck Loading

The aim of the innovative Physical Internet (PI) paradigm-shifting initiative is to reverse the unsustainability situation existing in current logistic systems. In the Physical Internet, the efficient management of crossdocking hubs is a key enabler of quick and synchronized transfer of containers across interconnected logistics networks. The paper focuses on the distributed control of truck loading protocols in a rail-road crossdocking hub. It proposes grouping strategies for truck loading based on the exploitation of active containers. The grouping approach, the simulation platform and the obtained results are successively detailed.

SYSTEMIC MODELING OF INTEGRATED SYSTEMS FOR DECISION MAKING EARLY ON IN THE DESIGN PROCESS

Integrated systems design has new possibilities due to the use of intelligent devices. However, these new technologies introduce new constraints for designing innovative architectures and assessing their dependability. This article presents the Safe-SADT formalism, an extension of the structured analysis and design technique (SADT), for dependability studies and a computer-aided design (CAD) tool/software for modeling and comparing several architecture design choices early on in the design process. Its originality is based on operational architecture composed of function entities executed by material entities. A Monte Carlo approach allows simulation of “possible life history” and points out designs weaknesses using sensitivity analysis. We illustrate the tool functionalities with a temperature system. Possibilities for future research in terms of software development and industrial applications are provided.

Control of Rail-Road PI-Hub: The ORCA Hybrid Control Architecture

In the innovative field of Physical Internet, the development of efficient PI-cross-docking hubs (denoted PI-hub) allowing quick, efficient and flexible transfer of containers is a cornerstone. The paper addresses the control of such facilities and focuses more particularly on a “rail-road” PI-hub. After a review of the related control issues, an instance of the ORCA hybrid control architecture is proposed. The focus is held on the PI-containers routing in a perturbed environment. More specifically, predictive and reactive routing strategies are presented. The simulation environment, protocol and results are then detailed.

Caregivers Routing Problem in Home Health Care: Literature Review

In France, Hospital-at-Home Services (HHS) providers that employ their caregivers have to define the assignment of patients to caregivers and the planning of the caregivers’ routes. In the literature, different approaches are proposed to deal with both these problems. Our aim in this paper is to present a literature review of such researches. The target is to show how operational research approaches and Multi-agent based methods can be combined and generate a “win-win” relationship between both approaches to solve HHS resources management in operational level.