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.

不确定性是装配系统早期规划阶段的一个特征元素。今天，规划方法通常应用精确的数据，不考虑不确定性。在这种情况下，客户需求是装配系统设计最重要的规划参数之一，为要装配的产品数量提供规范。此参数对于标注装配系统至关重要。然而，在早期规划阶段，它通常基于预测，因此受到不确定性的影响。本文提出了一种设计手动装配系统的新方法。为此，使用区间算法以区间来描述客户需求，这允许考虑该计划参数的不确定性。通过自平衡滑板车生产的实际应用示例，将所提出方法的结果与基于场景的方法的结果进行比较。结果表明，区间算术提供了指示系统设计稳健性的附加信息。