Optimal cyclic scheduling of a robotic processing line with two-product and time-window constraints

In this study, we develop effective optimization algorithms for solving the problem of cyclic scheduling of a multi-stage robotic processing line with two distinct parts and time window constraints. This problem in the literature is known as hoist scheduling problem. To our knowledge, most existing optimization algorithms for the hoist scheduling problem handle the case with identical parts. We present a formal analysis on the hoist scheduling problem with non-identical parts. The results are then used to develop new branching and bounding schemes to be used in the search process for optimal schedules. A proposed branch-and-bound algorithm is evaluated using both known benchmark problems as well as randomly generated test problems. A potential extension to the cases with arbitrary number of distinct parts is also discussed.