Performability-based fleet sizing in a material handling system

This research examines the problem of determining the optimal fleet size for fixed-path material handling systems on the bases of performance and reliability, simultaneously. In this paper, a regression model is developed to study the relationships among various material handling system design characteristics (fleet size, guide path layout, and number of P/D stations, vehicle speed and failure rates, guide path intersection failure rates, and P/D station failure rates) and performability, measured as the average number of material moves between failures (MBF). The regression model highlights the important relationships between the selected factors and performability, and may be used to determine the performability-based optima for the controllable design characteristics.