Exact and heuristic solutions based on dynamic programming for mixed model assembly line sequencing
Résumé
In this paper, the problem of sequencing mixed model assembly lines (MMAL) is considered. Usually MMAL consists of a number of workstations linked by a conveyor belt and each workstation has a work zone limited by upstream and downstream boundaries. We consider different models of products to be scheduled in the MMAL to meet the demand plan. In case of work overload, the operator has to rush or reinforcement workers assist him to finish the job on time. Our goal is to determine the sequence of products to minimize the work overload. This problem is known as the mixed model assembly line sequencing problem with work overload minimization (MMSP-W). This work is based on an industrial case study of a truck assembly line. We propose an exact method based on dynamic programming approach to solve the proposed problem. The limits of this optimal procedure are demonstrated with numerical tests. We then propose heuristics to solve the problem through extensions of the exact method. A comparison between the proposed heuristics and the exact method is studied. Numerical tests are carried out on academic instances from the literature and on industrial case study instances.