An object-oriented FMS real-time and feedback control model

Abstract

A new perspective for viewing a flexible manufacturing system (FMS) as a whole control system is proposed in this research, which develops a real-time feedback control model for the FMS. An integrated hierarchical control architecture is built to address the complexity of the FMS. Control commands in the format of production orders are spatially and temporally decomposed down the hierarchy. Feasible solutions are developed in a decentralized way and integrated by the common supermodule into feedback control. These solutions and the feedback of system performance are evaluated by a two-phase feedback evaluation strategy using feedback control laws. New planning for remaining processes might be generated to reduce the impact of unexpected current status under such a feedback strategy. The difficulty of integrating the database and control is effectively resolved by using object oriented information processing. A well-designed integrated generic hierarchical information processing structure is developed to implement a generic real-time and feedback control of FMS. The simulating result shows a significant improvement of the proposed approach in the overall FMS performance. The result also shows that, as the extent of the system disturbance increases, the improvement is more significant.