Pull control for Job Shop: Holonic Manufacturing System approach using multicriteria decision-making

International audienceFaced with international competition, industrial production increasingly requires implementation conditions which, in some cases, lead to seek new techniques for workshop control. This is the case when it is asked to establish Just in Time management in a Job Shop having the characteristics of working with small series. A new approach for the organization of the ‘control’ function in such a context is presented here. This approach relies on the use of the holonic paradigm on an isoarchic architecture and on a decision-making capacity based on a multicriteria analysis. The various concepts of this approach are addressed first. Then, the multicriteria decision mechanisms that are used are detailed, as well as the implementation and instrumentation phases. The first results that were obtained are presented

Control by quality: proposition of a typology

International audienceThe application of Quality tools and methods in industrial management has always had a fundamental impact on the control of production. It influences the behavior of the actors concerned, while introducing the necessary notions and formalizations, especially for production systems with little or no automation, which constitute a large part of the industrial activity. Several quality approaches are applied in the workshop and are implemented at the level of the control. In this paper, the authors present a typology of the various approaches that have successively influenced control, such as statistical process control, quality assurance, and continuous improvement. First the authors present a parallel between production control and quality organizational structure. They note the duality between control, which is aimed at increasing productivity, and quality, which aims to satisfy the needs of the customer. They also note the hierarchical organizational structure of these two systems of management with, at each level, the notion of a feedback loop. This notion is fundamental to any kind of decision making. The paper is organized around the operational, tactical, and strategic levels, by describing for each level the main methods and tools for control by quality. The overview of these tools and methods starts at the operational level, with the Statistical Process Control, the Taguchi technique, and the "six sigma" approach. On the tactical level, we find a quality system approach, with a documented description of the procedures introduced in the firm. The management system can refer here to Quality Assurance, Total Productive Maintenance, or Management by Total Quality. The formalization through procedures of the rules of decision governing the process control enhances the validity of these rules. This leads to the enhancement of their reliability and to their consolidation. All this counterbalances the human, intrinsically fluctuating, behavior of the control operators. Strategic control by quality is then detailed, and the two main approaches, the continuous improvement approach and the proactive improvement approach, are introduced. Finally, the authors observe that at each of the three levels, the continuous process improvement, which is a component of Total Quality, becomes an essential preoccupation for the control. Ultimately, the recursive utilization of the Deming cycle remains the best practice for the control by quality

Supplier evaluation process within a self-organized logistical network

International audienceOver the past years the relationships between industrial companies have dramatically evolved, the objective being the improvement of the internal management of each of the partner companies and of their global performance in meeting the requirements of the customers. The control of the relationship between partner companies concerns all the actions they develop together to achieve their common objectives and to react at the right time to any failure of one of the partners. A negotiation between the partners is thus required, and this approach involves the management and organization of each partner’s production. The client companies will have to optimize at the same time both their production and their relationships with their suppliers. The suppliers will have to position themselves in reply to the calls for proposals emitted by client companies and demonstrate their capacity to support these companies while using their own assets. This paper aims at improving the control of the customer - supplier relationship by proposing an organization of all the partners called "self organized logistic network". In this network, each supplier can evaluate his performance using a multicriteria decision aid method. The objective of the suppliers evaluation process is threefold to select the reliable supplier who delivers low-cost products or services that meet the customers’ requirements, to ensure that the suppliers with whom the company operates are reliable and satisfy the needs of the client company in terms of quality, quantity, delivery times, etc, and also to dynamically monitor the relationship between the supplier and the customer

A self organized holonic control for mechatronics complex systems: application to a robotized car park

International audienceIn this paper, we describe the two conditions so that a complex system, composed of several mechatronics machines, may be qualified as a mechatronics system. The first condition reflects the aptitude of these machines to work together without the intervention of a central decision system of higher hierarchical level. The second reflects their aptitude to manage their own behavior and to generate the tasks to be carried out in the context of their execution. A self organized holonic control accomplishes these conditions. An example of implementation of this approach is presented with the application to a robotized car park

Formal DEVS modelling and simulation of a Flow-Shop relocation method without interrupting the production

International audienceThis paper presents an organisational method to keep the production going during the removal of a flow-shop. Assume a flow-shop system is to be moved on a new site and its production has to continue, our method can be applied to follow requests for the removal period. The method works as follows: we segment the removals in groups of machines and move them ones after the others. This method can be successfully executed provided that a prime condition is met: envisaging sufficient stocks’ plug between each group. The role of the latter stocks is to ensure operations’ production continuity between the old and the new site, when the non-operational group is being removed. Removal is then renewed until the whole line is moved and is operational on the new site. To validate this approach, we have used simulation and developed a model of the flow-shop according to coupled DEVS formalism. Our model enables to segment a production line. As a consequence, we can simulate the sequential displacement of machines’ groups towards the new site. Among the solutions suggested, those starting with the final group (finished products) and while finishing with the first group are much more effective. In this paper, we present and discuss some simulation results of an industrial case study. The results demonstrate the compared effectiveness of various strategies of removal, and make possible for the industrialist to envisage a good estimated project management

PROSIS: An isoarchic structure for HMS control

International audienceThis paper presents a holonic and isoarchic approach to the Flexible Manufacturing System (FMS) control. This approach is based on a flat holonic form, where each holon is a model for each entity of the FMS, with a unifying level of communication between holons. After description of this model, called PROSIS, the interaction protocol and decision rules are presented. The objective is to increase the FMS productivity and flexibility, particularly on responsiveness aspects. This responsiveness is achieved through decentralized generation of the production tasks. The reactive behaviour of the FMS control is illustrated by the example of a flexible turning cell, upon occurrence of a failure or of an urgent batch order, and the resulting Gantt charts are shown

Experimental assessment of the productivity improvement when using U-shaped production cells with variable takt time

International audiencePurpose – The aims of this research is to discuss the benefits of U layout for production cell operating in variable takt time. Different experiments were conducted using benchmarks, in order to highlight the performance gap between a straight cell and a U-cell. Design/methodology/approach – The implementation of the production cell, in U-shaped or in straight line, is optimized through linear programming based on the number of operators. The two corresponding programs, in Mosel language, use the same approach, in order to not introduce defects in the comparison of results. The study used our own datasets and well known academic benchmarks. Findings – A comparison between the obtained takt times, with equivalent operating conditions, in U-cell and straight cell was conducted. A significant increase of the production rate was observed. This increase has often exceeded 10 per cent to reach 32 per cent. All the experiments show that, with the same number of operators, a cell in a U layout is always at least as efficient, in terms of reachable production rates, than an equivalent cell in a linear layout. 96 per cent give an improvement of production rate. Moreover, the dispersion of the U-cell results is weaker, which suggests that the U-layout gives, in more robust manner, better performances.Research limitations/implications – The results were obtained through a study of various academic benchmarks. The results must be validated on industrial situations.Practical implications – This paper will be very useful for researchers and practitioners in order to understand lean implementations and its derived benefits. This paper will allow them evaluating and analysing the expected benefits of the implementation of the production cell in U-shaped (operating in variable takt time).Originality/value – U-Cells constitute an appropriate solution for a layout of any kind of production cells with variable structure. When facing a significant variation in the demand, the response consists in modulating the number of operators assigned to the cell. This study addresses jointly the problem of U-cells layout and the operation in variable takt time

Integration of a Flat Holonic Form in an HLA Environment

International audienceManagers need to create and sustain internal systems and controls to ensure that their customer focused strategies are being implemented. Companies are currently in a spiral of permanent optimization. Accordingly, many companies turn to their core activity. In this framework, one notices the development of the concept of “industrial partnership”. In this context and to control the customer–supplier relationships (CSR), we proposed a self-organized control model in which all partner entities (customers/suppliers) negotiate to guarantee good quality connections between customers and suppliers. This means meeting customer expectations as closely as possible and respecting supplier capacities. In this proposal, self-organized control is characterized more precisely by an organizational architecture of the flat holonic form type. This flat holonic form is based on the concept of autonomous control entity (ACE). The holonic architecture, the behaviour of an ACE, the interaction mechanisms between ACEs and the self-evaluation supplier process are presented, and then the modelling of ACEs using discrete event system specification (DEVS) is described. An implementation of the simulation of such a system was done via a distributed simulation environment high level architecture (HLA). A case study illustrating the proposed approach is presented

Environnement G-DEVS/HLA pour la simulation distribuée de systèmes de production multiprocessus

International audienceThis paper presents a simulation environment for manufacturing systems integrating control processes and operational processes. From the operational processes specification according to the JIS Z 8206 norm and from the control processes as Workflows standards, distributed G-DEVS models are generated. At first, the transformation of a process in G-DEVS models is described. Then, the implementation of a global simulation of the set of these models via an HLA architecture allowing interconnection and interoperability between the model components is presented. An illustration of the use of this environment is given in the microelectronic field. We conclude by the application of this approach to the study of the synchronizations between production lines and to the implementation of coupling between simulation and reality