An effective evolutionary algorithm for steelmaking and continuous casting scheduling

Steelmaking-continuous casting (SCC) problem is the most important problem in steelmaking industry, which directly determines the quality and delivery time of products. Due to the complex production process with loopback in some operations, the production scheduling is very difficult. Manual scheduling method is inefficient and prones to long waiting time. In this paper, a mathematical model is proposed to describe the problem of SCC with reentrant operations. And an evolutionary algorithm with improved search strategy is designed to make the solution escape from the local optimum and enhance the search quality. The heuristic decoding method can make the solutions meet the constraints and balance the objectives of waiting time and makespan. Finally, the effectiveness of the optimization model and the algorithm is testified by computational experiments and comparing with the heuristic algorithm in simulated problem instances of different scales.