Abstract:

 To shorten the length of the virtual window and reduce the order picking time, the picking device was improved and a compressible dynamic virtual window algorithm was proposed. A gravity buffer and a flashboard were added to each dispenser. The items were launched to the gravity buffer in which the gap between each other was at fiost compressed, and then merged to the conveyor from the gravity buffer. Therefore the items were close to each other on the conveyor and the length of the virtual window was shortened. A model of the compressible dynamic virtual window algorithm was built based on the sequential picking strategy. The simulation with 3 sets of data collected from a tobacco distribution center showed that the picking time could be reduced by 87.45％～87.77％, and the picking time was decreased when the launching time of the dispenser and the merging time of the gravity buffer increased.

Key words: virtual window, compressible dynamic virtual window algorithm, sequential picking, automated picking, picking time