FEM 9.860 - Guideline: Cycle time calculation for automated vehicle storage and retrieval systems

FEM 9.860-EN

The term automated vehicle storage and retrieval systems is used for storage systems for storing transportation units (TUs) such as containers, boxes or trays. The technology is characterized by horizontal transport and vertical transport being largely separated from each other. Usually, the shuttle vehicles perform horizontal transport functions as well as picking up and discharging loads while the vertical transport is realised using lifts.

A calculation of performance data as per VDI 3561 or FEM 9.851 is ineffectual since diagonal travel is impossible in automated vehicle storage and retrieval systems due to their operating principle.

VDI 3646 covers cycle times of conveying means in the continuous conveyor technology of automated storage systems. It is therefore not suited for discontinuous components such as the lift and shuttle vehicle. Therefore, only VDI 4480 can be taken into consideration as a generally accepted basis of calculation. However, the scope of VDI 4480 is the calculation of throughput in automatic warehouses. In part 1, page 1 it states “In order to take account of various technologies, movement sequences and the sequence of approaches to the various reference storage locations are not prescribed.” Therefore, VDI 4480 does not include a detailed calculation approach for cycle time and is not suitable for the calculations described here.