Hybrid Dynamical Approach Makes FMS Scheduling More Effective

Abstract

In the present paper a general job-shop type scheduling problem for FMS is considered. About ten years ago by paper Perkins, Kumar [3] a new direction, the use of hybrid dynamical approach to the solution of manufacturing scheduling problems arose. Recently, Matveev, Savkin [5] developed a qualitative theory for the investigation of these and similar problems. In the present paper an attempt is made to show the place and way of use of this approach in the solution of industrial problems. The formulation of the tasks involves complex problem obtained by CAPP and PPS subsystems interaction of CIM systems. The effect of the use of hybrid dynamical approach is in the opportunity of overlapping production, which may result in a significant increase of efficiency of equipment utilization. A proposal is given to determine the so called demand rates which are ideal inputs of servers (machines) realizing production according to the orders of higher hierarchical levels of PPS. The use of hybrid dynamical approach can be well investigated for single- machine (server) processing of multiple flows. But, at an ideal flow at the input of the machines (servers) the outputs differ from the ideal input for the next machines in order. This gives difficulties for job-shop type processing. A proposal is given in the paper to overcome this difficulty by the use of controlled buffers proposed. As far as we know, this is the first publication in Hungary dealing with the use of hybrid dynamical approach to FMS scheduling.