  With the rapid growth of the express industry, intelligent warehouses that
employ autonomous robots for carrying parcels have been widely used to handle
the vast express volume. For such warehouses, the warehouse layout design plays
a key role in improving the transportation efficiency. However, this work is
still done by human experts, which is expensive and leads to suboptimal
results. In this paper, we aim to automate the warehouse layout designing
process. We propose a two-layer evolutionary algorithm to efficiently explore
the warehouse layout space, where an auxiliary objective fitness approximation
model is introduced to predict the outcome of the designed warehouse layout and
a two-layer population structure is proposed to incorporate the approximation
model into the ordinary evolution framework. Empirical experiments show that
our method can efficiently design effective warehouse layouts that outperform
both heuristic-designed and vanilla evolution-designed warehouse layouts.
