A heuristic approach to determine bidirectional flow-path for AGV systems

Abstract

The rapid development of intelligent vehicles and free-ranging guide systems has increased the feasibility of practical applications for bidirectional AGV systems. This paper presents a heuristic approach for designing the flow-path layout of bidirectional automated guided vehicles. Assume that the block layout for the departments is predetermined, and that the pick-up/deposit (P/D) stations are located on the boundaries of the departments. Thus, the boundaries of the block layout can be transformed into a planar network where the nodes represent the P/D stations and the intersections of boundaries. The objective is to have a flow-path layout at minimal cost. The fixed cost of aisles and the travel cost of vehicles are considered simultaneously. There are three stages in the proposed heuristic approach: constructing an initial solution, improving the solution, and adjusting the solution. Several sample problems could be solved in less than one second using a pentium-166 PC, with less than 1% difference from the optimal solution on average. By adding some equipment for changing direction, this approach could also be applied to the material handling systems, which traverse on fixed-paths unidirectionally, such as conveyors, power-and-free, unidirectional automated guided vehicles and monorails. Significance: An effective and efficient heuristic approach is proposed for determining a bidirectional flow-path layout. The approach can be used effectively in many different divided-based configurations of AGV systems, such as tandem, segmented bidirectional single-loop (SBSL), segmented flow topology (SFT) and divided configuration.