The scheduler function involves planning how to produce the current volume of orders in the FMS, considering the current status of machine tools, work-in-process, tooling, fixtures, and so on. [91 The scheduling can be done automatically or... The scheduler function involves planning how to produce the current volume of orders in the FMS, considering the current status of machine tools, work-in-process, tooling, fixtures, and so on. [91 The scheduling can be done automatically or can be assisted by an operator. Most FMS control systems combine automatic and manual scheduling; the system generates an initial schedule that can be changed manually by the operator. The dispatcher function involves carrying out the schedule and coordinating the activities on the shop floor, that is, deciding when and where to transport a pallet, when to start a process on a machining center, and so on.
The monitor function is concerned with monitoring work progress, machine status, alarm messages, and so on, and providing input to the scheduler and dispatcher as well as generating various production reports and alarm messages. A transport control module manages the transportation of parts and palettes within the system. Having an AGV system with multiple vehicles, the routing control logic can become rather sophisticated and become a critical part of the FMS control software. A load/unload module with a terminal at the loading area shows the operators which parts to introduce to the system and enables him or her to update the status of the control system when parts are3. Materials Handling System
The automated materials handling system is a fundamental component that helps mold a group of independent CNC machines into a comprehensive FMS. The system must be capable of accepting workpieces mounted on pallets and moving them from workstation to workstation as needed. It must also be able to place workpieces on hold as they wait to be processed at a given workstation.
The materials handling system must be able to unload a workpiece at one station and load another for transport to the next station. It must accommodate computer control and be completely compatible with other components in the flexible manufacturing system. Finally, the materials handling system for an FMS must be able to withstand the rigors of a shop environment. Some FMSes are configured with automated guided vehicles (AGVs) as a principal means of materials handling. 展开