Solving Transient Scheduling Problems with Constraint Programming

Abstract

We are interested in Discrete Event Dynamic Systems and especially in Flexible Manufacturing Systems (FMS) and their production management. In order to master the combinatorial complexity, we adopt steady, repetitive and deterministic schedule. We have already determined an approach to compute this cyclic schedule (which corresponds to the steady state) while optimizing quantitative and qualitative performance criteria: cycle time (throughput), Work In Process, simplicity of the schedule. In order to apply this schedule we consider and compute the transient periods to start and end the production. In a previous paper [9], we gave a preliminary study ofthe transient states. We computed upper and lower bounds for the transient state, the steady state and the makespan then we established a method to optimize the makespan. In this paper, we recall some necessary assumptions and definitions for the study of the transient states then we give a heuristic for the computation and optimization of the makespan.