This study researches the storage assignment problems in Robotic Mobile Fulfillment System. The thesis mainly discusses which items should put in the same rack to minimize the total frequency of rack movement in picking process. In order to find the optimal solutions, items often ordered together should be assigned to the same rack.
An optimization model is built for finding the optimal solutions in small examples. Based on historical examples, some properties are found to optimize the assignment of items in racks, so theorems and corollaries are discovered to develop algorithms. Two algorithms are presented in the thesis based on theorems and corollaries. Algorithm 1 is verified, then compared to the algorithm in previous literature and the optimal solutions. Algorithm 2 has not been verified. The results show that which algorithm can find a better solution.

This study researches the storage assignment problems in Robotic Mobile Fulfillment System. The thesis mainly discusses which items should put in the same rack to minimize the total frequency of rack movement in picking process. In order to find the optimal solutions, items often ordered together should be assigned to the same rack.
An optimization model is built for finding the optimal solutions in small examples. Based on historical examples, some properties are found to optimize the assignment of items in racks, so theorems and corollaries are discovered to develop algorithms. Two algorithms are presented in the thesis based on theorems and corollaries. Algorithm 1 is verified, then compared to the algorithm in previous literature and the optimal solutions. Algorithm 2 has not been verified. The results show that which algorithm can find a better solution.

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