Assembly automated guided vehicle conflict-free path planning in flexible assembly workshop

The assembly automated guided vehicle (AGV) in flexible assembly workshop carries the workpiece through a series of stations based on process requirements to achieve mobile assembly. Its conflict-free path planning is a multi-source path planning problem and crucial for ensuring product safe assembly. In order to plan a secure and conflict-free path for assembly AGV, a conflict-free path planning method was proposed. Firstly, an improved D* algorithm for multi-source path planning was designed by embedding the Floyd algorithm into D* algorithm to enhance its initial path searching stage. This enhancement provides shortest path information between any two nodes while allowing recall of parent node, reducing re-planning time when start and destination change, thus improving the efficiency of assembly AGV's path planning. Then, the improved D* algorithm combined with time window to develop a conflict resolution strategy for multiple AGVs. Priorities were assigned to conflicting AGVs based on task completion time, path length to destination, and arrival time at the conflict node; subsequently selecting an appropriate conflict resolution scheme according to specific situation. Experimental result shows that this conflict-free path planning method can effectively and efficiently plan an optimal path for assembly AGV when it encounters the destination changes or potential conflict.