Assembly system design using interval-based customer demand

Abstract Uncertainty is a characteristic element in the early planning phase of assembly systems. Today, planning methods normally apply precise data and do not take uncertainty into account. In this context, customer demand is one of the most important planning parameters for the design of assembly systems, providing specifications for the quantity of products to be assembled. This parameter is essential for dimensioning assembly systems. However, in the early planning phase it is often based on forecasts and therefore subject to uncertainty. This paper proposes a new method for designing manual assembly systems. For that purpose, interval arithmetic is used to describe customer demand with intervals, which allows the uncertainty of this planning parameter to be taken into account. Results of the proposed method are compared with those of a scenario-based method by means of a practical application example of a self-balanced scooter production. It is shown that interval arithmetic provides additional information indicating robustness of system design.