Research About Path Planning Of Multiple Mobile Robots In Intelligent Warehouse System

Mature industry will move to a recession and can't meet the needs of society. Robots will inevitably take the place of humans. Intelligent warehouse system creates a new paradigm for pick-pack-and-ship warehouses that significantly improves the worker productivity. This dissertation focuses on the path-planning problem of intelligent warehouse mobile multi-robots. Multiple mobile robots path planning is to find out optimal and collisionless path that connects the start point with goal point for each mobile robot in the same work space. Previous studies only focused on the single mobile robot or decomposed the multiple robots path planning to single ones. But these methods can not make sure validity and optimality.This thesis mainly includes two aspects: multi-robots'cooperation and the method of abstracting map. For the cooperation of multi-robots, cooperative A* is presented by expanding two dimensional spatial map to three dimensional space-time map and using the reservation table. Robots can get collisionless and optimal paths by cooperative A*. For improving the searching efficiency, hierarchical methods are presented to abstract map. Robots can firstly plan paths on the high level map, and then get the actual path by refining abstracted paths.In this thesis, it is presented the exact description of multiple mobile robots path planning. For researching convenience, a path planning simulation program is prepared to verify the validity and optimality. According to the environment of intelligent warehouse, this thesis presents a cooperative A* algorithm and tests its validity. Inspired from the idea of hierarchy, this thesis also realizes a hierarchical path-planning A* algorithm and tests its validity.