هماهنگی فرصت طلبانه عملیات در ساخت تولید کارگاهی

The starting point of this article is production planning and control (PPC) in job shop production, i.e., processing units in a job shop are investigated executing different operations on part types. In this context, the problem is to allocate the single operations of production orders to processing units with respect to the underlying objectives. PPC systems, however, fail to incorporate the knowledge of production-related theory and tend to be based on relatively simple heuristics (see Steven, 1999, p. 319). This means that the inherent flexibility of a production system will largely be ignored. Existing PPC systems, thus, show a clear theoretical deficit. Given this background, the article aims at • integrating production-related theory more strongly into the world of PPC, and • exploiting developments in the area of distributed problem solving.

The concept of multi-agent systems was adopted as a solution approach with a consequential differentiation between inter-agent and intra-agent levels. Whilst the cooperation of agents (order, processing and coordination agents) is the focus for problem solving on the inter-agent level, the intra-agent level concentrates on the problem-related decision-making behaviour of the agents. In this article, the modelling of process coordination results from a consideration of findings from production theory. In comparative simulation studies (see Gössinger, 2000, p. 165) on the performance of this approach with priority rules (e.g. First Come First Served, Shortest Processing Time, Smallest Slack, Most Work Remaining, Greatest Number of Operations Remaining, Smallest Slack-Shortest Processing Time) profitability could be shown with regard to the objectives • total flow time, • mean flow time, • number of tardy jobs, • utilisation of processing units and • utilisation of intermediate storage. On the other hand, a better result was achieved in the case of “mean due date deviation” with the priority rule “Smallest Slack-Shortest Processing Time”. Increased transport intensity proved to be disadvantageous. Thus, opportunistic coordination can be considered a suitable approach to production planning and control in job shop production.