Scheduling of production with alternative process plans

Abstract

This chapter deals with a scheduling problem with alternative process plans that was motivated by a production of wire harnesses where certain parts can be processed manually or automatically by different types of machines. Only a subset of all the given activities will form the solution, so the decision whether the activity will appear in the final schedule has to be made during the scheduling process. The problem considered is an extension of the resource constrained project scheduling problem with positive and negative time-lags and sequence dependent setup times. We extend the classic RCPSP problem by a definition of alternative branchings and for this representation of the problem, an mixed integer linear programming model is formulated. Furthermore, a heuristic algorithm based on priority schedule construction with an unscheduling step is proposed for the considered problem and it is used to solve the large instances of the considered problem.