Scheduling and optimization for heating of steel soaking pits in a framework of hybrid system

A scheduling and optimization problem for heating of steel soaking pits, which includes the decision on the optimal number of soaking pits to be used, the optimal soaking time, and the optimal temperature setpoints of individual soaking pits for a soaking pit/rolling mill complex, is considered in a framework of hybrid dynamic system. This very complicated optimization problem is divided into three subproblems: determine the optimal number of soaking pits, determine the optimal soaking time and the most difficult one, i.e. determine the optimal temperature set-points for each soaking pits. In order to solve the third subproblem which is the most difficult one, an evolutionary programming algorithm, which has a rapid search speed and high accuracy, is designed. Finally, an example is given to demonstrate the validity of the algorithm