A stacker is a floor-borne vehicle (industrial truck), i.e. a means of transport moving goods from A to B, a resource just as conveyors or an AS/RS. Our stacker control system takes this philosophy as orientation basis and uses these devices accordingly. By comparison, a zone-to-zone picking system features an i-point and single zones/stations. At the end or at an outward transfer point of the loop there is a target or destination such as e.g. packaging stations. Sources and sinks are defined, get assigned names; routes connect these points with each other. During this process it is saved how these routes are used, e.g. by a forklift truck. A stacker control system thus organizes transports between points which are connected to each other through routes of certain lengths. This is completed by route optimization. The route system of our material flow plan is supplemented by tour definitions which make a route to become a route section of a tour. This way, a defined cross-linking is ensured. A stacker / forklift truck may either drive a tour or serve only individual places.
Stacker control system integrated into DC21
The stacker control system is integrated into DC21. This means that the warehouse and transport management system generates orders for collecting goods from or supplying goods to zones/stations. In addition, it is possible to dispatch manual orders and special jobs such as e.g. "unloading lorry at gate 3". See our application at TRW. We are also able to dispatch orders from external systems. A master control station allows identifying/visualizing the current position of a stacker, its current tour, the jobs it performs right now and which still needs to be performed, time and place. Forklift truck terminals or PDA guide the driver via RF. The driver uses these devices to return information about where and in which quality his orders were accomplished. Example: collecting goods of one type in a certain quantity on a number of load carriers at a zone/station or equipping with empties for the production. This way, the resource capacity is known and the stacker is able to receive and take over additional jobs on its way.