Algorithms for real-time scheduling of jobs on mixed model assembly lines

The problem of how to sequence jobs with options on a mixed model assembly line without work-in-process storage has been well addressed in the literature. In almost all of the previously developed models, the common goal has been to generate schedules that would maximize the utilization of station capacities. However, the problem of setups and utility work, which is the uncompleted work on a job leaving the station, has not been studied in detail. In this paper, a generalized formulation of the sequencing problem is presented. A Branch and Bound procedure and two heuristic algorithms are developed to determine a sequence which minimizes total setup and utility work costs simultaneously. The Branch and Bound algorithm is restricted to small size problems, while the heuristics can be used to obtain a solution for any realistic problem within a very small amount of computation time. The algorithms are tested on real data and shown to be applicable to real-time scheduling of jobs on mixed model assembly lines.