یک روش پارامتریک منطق فازی به بخش مسیریابی پویا تحت انعطاف پذیری مسیریابی کامل

Manufacturing flexibility is a competitive weapon for surviving today’s highly variable and volatile markets. It is critical therefore, to select the appropriate type of flexibility for a given manufacturing system, and to design effective strategies for using this flexibility in a way to improve the system performance. This study focuses on full routing flexibility which includes not only alternative machines for operations but also alternative sequences of operations for producing the same work piece. Upon completion of an operation, an on-line dispatching decision called part routing is required to choose one of the alternatives as the next step. This study introduces three new approaches, including a fuzzy logic approach, for dynamic part routing. The fuzzy part routing system adapts itself to the characteristics of a given flexible manufacturing system (FMS) installation by setting the key parameters of the membership functions as well as its Takagi-Sugeno type rule base, in such a way to capture the bottlenecks in the environment. Thus, the model does not require a search or training for the parameter set. The proposed approaches are tested against several crisp and fuzzy routing algorithms taken from the literature, by means of extensive simulation experiments in hypothetical FMS environments under variable system configurations. The results show that the proposed fuzzy approach remains robust across different system configurations and flexibility levels, and performs favourably compared to the other algorithms. The results also reveal important characteristic behaviour regarding routing flexibility.

Today’s competitive market conditions are characterized by a high degree of variability and volatility. Variable demand, shorter product life cycles, higher customization, lead-time based pressure and multi-product portfolios describe the nature of the environment in which many manufacturing organizations have to compete. In this context, flexibility refers to the ability of a manufacturing system to respond cost effectively and rapidly to changing production needs and requirements, and should be seen as a competitive weapon. The challenge is, however, to select the appropriate type and level of flexibility for a given manufacturing system, and to design effective strategies for using this flexibility in a way to improve the system performance.

This paper focuses on full routing flexibility and introduces dynamic routing tools that work in a robust manner not only in cases where it is possible to perform operations on alternative machines (operation flexibility), but also in cases where alternative sequences of operations can be used to produce a part (processing flexibility). Nearly all of the previous work that study the dynamic routing problem focus only on operation flexibility. An important remark, however, is that while operation flexibility can be accomplished by machine investment, either by duplicating machines or by acquiring machines with high flexibility, processing flexibility is mainly a design characteristic and deserves attention as an economical way of incorporating routing flexibility in a manufacturing system. The results presented in this work have great importance in this respect.