Calculation of cycle times for multi-aisle automated storage and retrieval systems

The work presents an algebraic model for the computation of cycle times within an automatic warehouse featuring multi-aisle AS/RMs. The model considers the acceleration effects of the friction wheel-driven vehicles as well as the effects of strongly decreased horizontal velocities when driving along the curves. Assuming uniform distributed rack positions the computational model enables the calculation of the mean travel times for single and double command cycles of different types of multi-aisle layouts. Comprehensive numeric investigations show that for all examined cases the results of the mathematical models correlate with the results of different simulation methods. Based on the algebraic expressions it is possible to project an automated multi-aisle warehouse system depending on a few parameters and also optimize it.