Scheduling model and discrete particle swarm optimization algorithm for roller annealing

A two-stage no-wait hybrid flow shop scheduling problem is considered against the background of the scheduling problem of roller annealing operation in the cast steel plant of a roller corporation. An integer programming model is formulated, whose objective is to minimize the makespan. Both the discrete particle swarm optimization algorithm is proposed and the no-wait algorithm of grading is designed for solving the model. The last simulation experiment with the practical data demonstrates the feasibility and the effectiveness of the DPSO algorithm by comparisons and analyses. Furthermore, the equipment reformation strategies of the actual reference value are given which are beneficial for the policy-maker to arrange production reasonably.