Dynamic Allocation of Buffer Capacity in Discrete Event Systems

ABSTRACT

In this article, the problem of dynamic allocation of buffer capacity in a discrete event system is studied, and a solution is proposed. This problem is of interest, among others, in Kanban manufacturing systems, where the buffer capacities are equal to the number of Kanbans in each working centre.

The contribution of the article consists of an on-line control strategy, using estimates of the system performance for the dynamic allocation of buffer capacity in order to increase the performance of the system, despite unknown disturbances entering the system. The system performance estimation procedure is based on a simple adaptation of already known finite perturbation analysis rules. The proposed control strategy has been tested by means of simulation on a multi part-type Kanban system. In this case, the control action specializes in the dynamic allocation of Kanbans to each part-type in order to counteract the effects of unknown changes in the product-mix on the system throughput. Several simulation tests have been performed in order to verify the behavior of the proposed control strategy under different frequencies of the control action and under different types of variation of the product mix.

Key Words:

• path estimation techniques
• discrete event systems
• dynamic control
• Kanban systems
• perturbation analysis