Optimization Research On A Single Service Queue Of Warehouse Robots With Determined Throughput

This thesis studies a new order fulfilling system featured by a number of robots transporting movables shelves to order pickers based on the environment of Kiva warehouse robots in Amazon Company. This warehouse uses the “goods-to-human” mode instead of the “human-to-goods” mode to improve productivity and flexibility simultaneously. The main contents are as follows:Firstly, we propose the mathematical model of the single service queue system with no-priority orders given the determined throughput based on the single service queue theory. We design the corresponding algorithm and verify it by numerical analysis. This model can help to optimize the number of robots and the velocity of robots. Secondly, we formulate and analyze the mathematical model of the single service queue system with priority orders given the determined throughput using the priority queue theory. This model will be helpful to optimize arrival rates of priority orders, assign robots, and design the velocity of robots. Thirdly, we simulate model for the single service queue system based on Arena 14.0 and use MATLAB.R2012 a to conduct numerical experiments, and apply results to the warehouse robots system. Results of numerical examples show the following conclusion:(a) Without considering paths blocking and technological costs, throughput time is more sensitive to the velocity of robots than the number of robots for the single service queue system with no-priority orders.(b) For the single service queue system with priority orders, the larger arrival rates of priority orders, the less throughput time. This study can provide the effective theory support for the operation management of warehouse robots.