Development of automated high-speed depalletizing system for complex stacking on roll box pallets

Abstract

The need for automated distribution systems has recently grown due to labor shortages and an increasing preference among consumers to shop online. The process of depalletizing roll box pallets (RBPs) requires skillful work in a limited space, but an automated RBP depalletizing system with a speed equal to or exceeding that of human workers has yet to be developed. We solved this issue using two technologies. One is a system design and the other is an algorithm for prioritizing the packages to be removed from the stack. We designed a high-speed depalletizing system that can be installed in a narrow space at the distribution site. Equipped with a compact linear actuator mechanism, the system utilizes an end effector that can handle multiple packages simultaneously. Moreover, by optimizing the process of transferring packages on the system, we increased the speed. Our algorithm for prioritizing packages allows the proper selection of packages held simultaneously for faster depalletizing. However, if the height of complexly stacked packages is not known, depalletizing is difficult. To solve this issue, we developed an algorithm with special rules. Finally, we conducted depalletizing trials with the latest prototype system using different arrangements of stacked packages, and achieved an average speed of 683 packages per hour.