Sequencing picking operations and travel time models for man-on-board storage and retrieval warehousing system

This paper deals with the order sequencing problem in a man-on-board storage and retrieval warehousing system which is suitable for storing items of small size and light weight. Considering the operating characteristics of the man-on-board system, a heuristic procedure is presented for the problem of sequencing a given set of retrieval requests. The validity of the procedure is investigated through the computer simulation. The results show that the procedure performs better than those from previous studies. The authors also develop the expected travel time models based on the probabilistic analysis for single and dual commands assuming randomized storage assignment policy.