Alternative shop floor control of a flexible manufacturing system - a temporal rescheduling approach

Utilizing alternative facilities to reduce the production loss owing to unexpected dynamic variations in the manufacturing environment, e.g. machine breakdown, tool failure, or unscheduled maintenance, is a conventional practice in a flexible manufacturing system (FMS). This paper presents a temporal approach (ALTEC) that contains an alternative dynamic controller with a manufacturing system capability database. An initial schedule is generated whenever an unexpected perturbation is identified from the shop floor. A real-time procedure with a conflict-resolution mechanism then drives the control engine for alternative machines. Simulation experiments are also performed to evaluate the temporal approach with four comparable models. Simulation results demonstrate significant improvement in both the mean flow time and makespan.