Replenishment modeling for complex automatic picking system

The replenishment plan of complex automatic picking system(CAPS) determines the efficiency of picking and whether the picking can be operated smoothly, which is not only highly related to the pallet storage area and picking buffer but also the operation and operating efficiency of Horizontal Dispenser (HD) and Channel Dispenser(CD). The questions here can be summarized as when replenishment should be required and how many cartons of cigarettes should be dedicated to picking buffer. To answer these questions, we first present a comprehensive description for the general multi-tier, multi-model inventory system of CAPS and analyse the stocking and picking activities of HD and CD. Then we consider replenishment in two cases. One is single replenishing request from one picking flue, the other is multiple replenishing requests from more than one picking flues at the same time which is more complex. For the latter case, we solve the problem based-on optimal scheduling policy. Our mathematical model provides a viable solution to optimize replenishment operation for CAPS.