Multi-objective order planning model and algorithm for integrated steel production

A multi-objective order planning optimization model is formulated for the integrated steelmaking-continuous casting-hot rolling (SM-CC-HR) production process. The objectives include maximizing hot charge ratio, minimizing earliness/tardiness ratio and minimizing open order ratio. Production capacities, steel grade and slab dimension are synthetically taken into consideration in the model constraints. NSGA-II (fast elitist non-dominated sorting genetic algorithm) basing on fast-non-dominated-sort and crowding-distance is one of the better elitist multi-objective evolutionary algorithms. It doesnpsilat limit the elitist extent, which will result in prematurely converging to local Pareto-optimal front. An improved NSGA-II algorithm is proposed, adding new individuals on every generation. Simulation results on three examples in different size show that the proposed algorithm is able to find more solutions with better spread and higher coverage.