Constrained Multi-objective Optimization Research And Its Application In Rolling Schedule

With the rapid development of modern industry,people demand for the quality and output of sheet products are increasing.It is obvious that the traditional experience methods can not meet the needs of actual production.The optimization of rolling schedule is directly related to the quality and energy consumption of sheet products.It is of great practical significance to formulate reasonable rolling schedule to take full advantage to the production capacity of rolling mill,reduce the total energy consumption and improve the quality of products.The optimization of rolling schedule for tandem cold rolling can be simplified as a constrained multi-objective optimization problem.The main work of this paper is as follows:Aiming at the problem that traditional multi-objective optimization algorithm can not judge the search direction and make effectively use of individual information when dealing with constrained multi-objective optimization problems,a constrained multi-objective optimization algorithm based on constrained allowable relaxation dominant selection strategy(CARDOA)is proposed.In order to solve the problem of searching direction,we adopt the selection strategy of constrained allowable relaxation dominant,which makes the algorithms evolve to the feasible Pareto front,while retaining more excellent infeasible solutions,so as to improve the diversity of the population.To solve the problem of individual information utilization,we adopt the technology of constraints processing of double populations,using excellent infeasible solutions and feasible solutions,to produce new individuals together and accelerate the convergence speed of the algorithm.Experiments on classical test functions show that CARDOA algorithm outperforms the contrast algorithms in overall performance,and the Pareto solution set obtained is better in convergence and distribution.Taking a five-stand tandem cold rolling mill as the research object,this paper analyzes the relevant mathematical models of the cold rolling schedule,and gives the calculation process of the rolling schedule.The optimization model with the objective function of equal power margin,good shape of the final stand and prevention of skidding is established,and the constraints are determined.The constrained multi-objective optimization algorithm proposed in this paper is used to optimize the established rolling schedule optimal model.The simulation results show that the results obtained by this algorithm are better than the original schedule,which has a certain guiding significance for the optimization of rolling schedule in the future.