1 Introduction
Automated vehicle storage and retrieval systems (AVSRSs), also known as shuttle systems, represent a scalable and powerful way to store small unit loads and to supply picking or manufacturing areas on the basis of goods-to-person principle. This warehouse technology leverages the separation of horizontal and vertical transportation of units such as containers, boxes or trays in order to achieve high throughput capaci ties. Hence, vehicles are restricted to a single tier or lifting system to execute transport tasks in horizontal and vertical direction, respectively (FEM 2017).