Advanced vehicle routing in AHMS

Vehicle based overhead transportation systems are a widely used Automated Material Handling System (AMHS) solution applied in factories for 300mm and 200mm front-end wafer manufacturing. The track layout of modern AMHS shows the characteristics of a large transportation network. The stable delivery performance and the avoidance for these systems. The vehicle routing algorithms applied in the material control system or the transportation controller directly impact the delivery performance and the avoidance of congestions. Here we present apart from the standard shortest path routing algorithm, also a minimum cost routing algorithm, a look-ahead congestion avoidance routing algorithm and a shortest time routing algorithm. The impact of these vehicle routing algorithms on factory performance is tested with an example wafer fab model built with the simulation tool AutoMod