Heuristic-Tabu Algorithm for Hybrid Flowshop Scheduling with Limited Waiting Time

This paper deals with the hybrid flowshop scheduling problem with limited waiting time constraint. The problem is to determine a schedule that minimizes the makespan for a given set of jobs over a finite planning horizon respecting the constraint that for each job the waiting time between two consecutive stages cannot be greater than a given upper bound. To solve the problem, a constructive backtracking heuristic algorithm is developed to construct a schedule for the overall problem. The proposed algorithm operates on the technique of so-called recursive backtracking which constructs a schedule from sequenced job the first to the last, and for each job from the first stage to the last, while respecting the limited waiting time constraint. A simple tabu search algorithm is then used to improve the solution. Computational results are presented to evaluate the performance of the proposed algorithms.