Planification de la production et de la maintenance des systèmes de production : approche hiérarchisée

Formulation du problème et conditions d'optimalité -- Commande hiérarchisée -- Expérimentation de l'approche de commande hiérarchisée

MODELING THE INTEGRATION OF OCCUPATIONAL HEALTH AND SAFETY RISKS WITH OPERATIONAL RISKS ASSOCIATED WITH AUTONOMOUS AND MULTI-SKILLED WORK PERFORMED IN UNCERTAIN ENVIRONMENTS

ABSTRACT Sharing information poses a significant challenge in attempting to integrate and manage occupational health and safety in response to operational risks where autonomous and multiskilled work is performed in uncertain environments. Managers and workers stand to benefit from a model developed as a prototype for an information system that is based on data flow technique, skills characteristic of autonomous and multi-skilled workers, and which rests on systemic analysis of the technological sub-system prevalent within a firm. Our knowledge of econometrics leads us to endorse training and exchanges aimed at promoting awareness of risks and upgrading job know-how among workers. Once the regulated risks and the risks unanimously recognized by health and safety experts have been controlled, we offer here a guide in reaching a preliminary decision that integrates parameters commonly associated with commercial efficiency and diligence in the pursuit of workplace health and safety. Lastly, findings have been validated through a case study carried out among firms engaged in the moving industry. RÉSUMÉ L'intégration de la santé et de la sécurité du travail aux risques opérationnels dans le travail autonome et polyvalent en environnements incertains comporte un défi important en ce qui concerne le partage de l'information sur les risques et la gestion de ces risques en incertitude. Pour soutenir les gestionnaires et les travailleurs, un modèle prototype de système d'information a été conçu à partir de la technique des flux de données, les connaissances caractérisant les travailleurs autonomes et polyvalents en environnements incertains, les comportements stratégiques des acteurs principaux et repose sur l'analyse systémique du sous-système technologique d'une entreprise. Ensuite, à partir de connaissances en économétrie, il a été recommandé de favoriser la formation et l'échange sur les risques et les savoirs de métiers des travailleurs. Une aide à la décision préliminaire, intégrant les paramètres prépondérants d'efficacité commerciale et de diligence en santé et en sécurité du travail, a été proposée. Finalement, une validation par l'étude du cas de l'industrie des transporteurs neufs et usagés a été faite

An Alternative Nonlinear Lyapunov Redesign Velocity Controller for an Electrohydraulic Drive

This research aims at developing control law strategies that improve the performances and the robustness of electrohydraulic servosystems (EHSS) operation while considering easy implementation. To address the strongly nonlinear nature of the EHSS, a number of control algorithms based on backstepping approach is intensively used in the literature. The main contribution of this paper is to consider an alternative approach to synthetize a Lyapunov redesign nonlinear EHSS velocity controller. The proposed control law design is based on an appropriate choice of the control lyapunov function (clf), the extension of the Sontag formula and the construction of a nonlinear observer. The clf includes all the three system variable states in a positive define function. The Sontag formula is used in the time derivative of our clf in order to ensure an asymptotic stabilizing controller for regulating and tracking objectives. A nonlinear observer is developed in order to bring to the proposed controller the estimated values of the first and the second time output derivatives. The design, the tuning implementation and the performances of the proposed controller are compared to those of its equivalent backstepping controller. It is shown that the proposed controller is easier to design with simple implementation tuning while the backstepping controller has several complex design steps and implementation tuning issue. Moreover, the best performances especially under disturbance in the viscous damping are achieved with the proposed controller

An APS software selection methodology integrating experts and decisions-maker’s opinions on selection criteria: A case study

With important advancements achieved in information technology, wide varieties of advanced planning and scheduling (APS) software has emerged in recent decades. Each of those APS software uses their own techniques, algorithms and logic to plan and schedule operations, which makes the task of evaluating them very difficult. However, choosing the right APS software is critical for companies because of significant resources engaged and risk of disturbing operations. Presently, a clear, structured and rational approach is lacking in the literature for APS software selection. The main contribution of this paper is to fill this gap by developing an APS software selection methodology. The methodology is based on fuzzy quality function deployment (QFD) and two well-known multiple criteria decision-making (MCDM) techniques, analytic hierarchy process (AHP) and VIKOR. This work considers both company needs and APS selection criteria to build a hybrid hierarchical decision structure. House of quality helps in translating the relevance of the company needs in the evaluation of criteria. Triangular fuzzy numbers are also used to reduce uncertainties in the process. An application of the proposed methodology to an aero-derivative gas turbine case company is carried out to demonstrate the useful and easy implementation of the proposed methodology

On sustainable design and manufacturing for the footwear industry – Towards circular manufacturing

The global fashion industry is facing carbon footprint issues, but technological innovations are helping to improve its performance and environmental efficiency in terms of footwear manufacturing. This paper explores how Design for Additive Manufacturing (DfAM), Design for Assembly (DfA), and Design for Disassembly (DfD) strategies, along with Additive Manufacturing's (AM) capability to produce intricate parts, can contribute to the fashion industry's shift towards a Circular Manufacturing model. The focus is on footwear manufacturing and its carbon footprint issues. The proposed additively manufactured shoe design utilizes Polyamide 12 and Thermoplastic polyurethane as feedstock, featuring a glueless mechanical assembly system based on a snapfit. Notably, the upper part of the shoe incorporates a variable lattice structure to ensure flexibility in different areas. Finite Element Analysis (FEA) demonstrates that the snapfit assembly exceeds the industry standard's minimum disassembly force requirement. Additionally, an optimization algorithm for the variable lattice structure results in a 34% mass reduction while maintaining the desired Young's modulus in each shoe zone. This design approach aligns with the footwear industry's sustainability goals, aiming to reduce environmental impact and enhance product durability. The study successfully developed a strategy to implement AM for sustainable shoe fabrication

Lockout/tagout and operational risks in the production control of manufacturing systems with passive redundancy

This paper addresses problems associated with production control and occupational safety in a manufacturing system prone to failure involving two machines working in passive redundancy. Machines turning out one part experience two modes of failure and repair: firstly, where failure occurs when a machine remains in fair condition; and, secondly, where such failure results in outright breakdown. Accordingly, we examine both modes of failure for their impact on a flexible manufacturing system (FMS) with respect to production control in terms of costs associated with lockout/tagout procedures and corrective maintenance. This study seeks to identify optimal costs related to backlogs, inventories and maintenance over an infinite planning horizon, along with levels of occupational risk where production control includes efficient planning of lockouts/tagouts. Our study offers numerical methods which may be employed to achieve optimal conditions in setting control policies. A numerical example and sensitivity analysis support this approach.Flexible manufacturing systems Passive redundancy Corrective maintenance Lockout/tagout