Hoist scheduling problem: an approach based on constraint logic programming

Scheduling the movements of a hoist in printed circuit board electroplating is known is the hoist scheduling problem (HSP). The objective of the HSP is to find an optimal cyclic sequence of moves for hoists. Results are already available for this problem, using classical operational research tools. They are briefly presented. Most of the proposed solutions are limited to the very specific initial model and are consequently difficult to apply in industrial problems. The constraint logic programming (CLP) approach to the problem is presented. A CLP model of the problem that allows modeling and solving more realistic cases is presented, and the results and the analysis of the solutions are outlined