Optimization of Storage Location Assignment in Tier-To-Tier Shuttle-Based Storage and Retrieval Systems Based on Mixed Storage

Table 4

Simulation results for different numbers of shuttle vehicles.

Number of shuttle vehicles	Optimum solution (s)	Elevator load rate (%)	Shuttle vehicle average load rate (%)	Optimal solution improvement rate (%)
1	1151743	25.08	100	—
2	698714	46.07	87.89	39.33
3	472597	61.83	81.56	32.36
4	386952	79.2	69.83	18.12
5	328175	87.34	49.93	15.19
6	289289	92.9	40.67	11.85
7	258173	96.41	41.26	10.76
8	235426	98.32	33.5	8.81