Performance evaluation of a double shuttle automated storage and retrieval system

A Double Shuttle Automated Storage/Retrieval operating on a Four Command Cycle is studied in this paper. A retrieval sequencing heuristic along with an approximation for the expected command cycle time is presented in the system. A lower bound is also developed for the mean four command cycle times for various retrieval block sizes and a number of open locations. The throughput of a double shuttle automated storage/retrievalsystem(AS/RS)working on the four command cycles under the heuristic is compared with the that of a single