Motion control with robust string stability of mobile-rack vehicles in autonomous logistics

Abstract

In order to reduce costs for a larger warehouse or expand the floor space of a small warehouse, it is impossible to implement this with a traditional warehouse, which is characterized as poorly utilized space. For the efficient storage and retrieval, the smart warehouse system with autonomous mobile-rack vehicles can optimize the space utilization by providing only a few open aisles at a time for accessing the racks with minimal intervention. This paper deals with designing the vehicle robust controller for maintaining safe spacing with collision avoidance in the fully automated warehouse. The compact vehicle dynamics are presented for the interconnected string of vehicles. Next, the string stability with safe working space of the mobile-rack vehicles has been described for guaranteeing complete autonomous logistics in smart warehouse. In addition, the controller order has been significantly reduced to a low-order system without performance degradation for real implementation. This control method can guarantee control stability as well as performances of mobile-rack vehicles against unavoidable uncertainties, disturbances, and noises for warehouse automation in the extremely cold environment without rail rack. Finally, the autonomous mobile-rack vehicle system is to become the promising vision of future smart warehouse technology in autonomous logistics.