شاخص هایی برای اندازه گیری عملکرد ریخت شناسی و سیستم های انتقال مواد در سیستم های تولید انعطاف پذیر

The aim of this paper is to present some existing and several new indicators of performances useful to help the designer to find a good solution for morphology and choice of material handling systems in flexible manufacturing systems. Our purpose here is to focus on the evaluation of the pair morphology–material handling systems, studied concurrently due to their strong interdependence. As a result of a survey of literature in this area, we present in this paper the indicators we have retained as suited to this purpose and easily implemented. New indicators related to the performances of these systems, such as the flexibility, are also suggested. A classification of indicators is introduced: (1) the operational indicators, which characterise the dynamic behaviour of the studied FMS such as the mean flow-time of jobs or the utilisation rates of machines; (2) the strategic indicators which measure the capacity of the system to evolve toward manufacturing new products such as the flexibility on which the emphasis is put; (3) the economic indicators such as the purchasing cost, the functioning cost or the maintenance cost. To better introduce the role, the usefulness of each indicator and their practical use, an illustrative example is presented.

Nowadays manufacturing systems have become more and more complex. The design or the reorganisation of manufacturing systems is a very difficult activity. That is why it is essential that decision makers possess decision tools and assistances necessary to manage this activity. For these reasons, we are interested in the evaluation of the performances of physical part of the flexible manufacturing system (FMS). It is widely known that the material handling systems (MHSs) now represent a major part of the total manufacturing cost [1], [2] and [3]. This fact highlights the necessity to choose adequately the MHSs when a manufacturing system is designed. Indeed this choice greatly affects the performances and is complex for several reasons [4] and [5]. Firstly, there are considerable interactions between machines and MHSs; secondly the workshop morphology exerts a major influence over it [6]; thirdly many various MHSs are available. The design of an FMS is also a very difficult activity because existing methods only evaluate specific aspects of the solutions proposed by designers [7]. In order to help the designer and/or the decision makers in their work, it would be very useful to have indicators which could measure the performance of the various solutions. A few useful indicators have been suggested in the literature related to FMS design [8], [9], [10] and [11]. Our purpose here is to focus on the evaluation of the morphology and the MHS, studied concurrently due to their strong interdependence. As a result of a survey of literature in this area, we present in this paper the indicators we have retained as suited to this purpose and easily implemented. New indicators related to the performances of these systems, such as the flexibility, are also suggested. This paper is organised as follows. First, the main features of morphology and MHSs are introduced. The choice of MHSs and the interactions between the morphology and the MHSs are pointed out. Then, we use the classification proposed by [12] to describe in detail each new indicator that we propose. To better explain the benefits of indicators, we present a simple application example, in which the application of each indicator allows its role and its usefulness to be more precisely understood.

The purpose of this paper was to focus on the evaluation of morphology and MHS, studied together due to their strong interdependence. As the result of a survey of the literature related to FMS design, we have presented the indicators suited to this purpose. New indicators have also been suggested, especially to evaluate the flexibility, the quickness and the economical cost of the pair morphology–material handling systems. We have described them in detail and given an illustrative example of their practical use. Indicators represent a major issue in the evaluation of the performance of morphology and material handling systems in flexible manufacturing system. Indicators evaluating the pair morphology–material handling systems may be either directly used by decision makers or incorporated in decision support systems. We are now interested in improving these indicators and in designing new ones to evaluate others additional aspects.