Multi-objective Optimization And Control Strategy Design Of Hybrid Powertrain

With the rapid development of economy,the popularity of automobile is getting higher and higher.At the same time,the problem of environmental deterioration and economy are becoming more and more important.With the development of new energy vehicles,such researches are more and more,but the comprehensive study on the vehicle dynamics and stability is less.Through the theoretical analysis,it is found that the common factors that affect the power and fuel economy,powertrain parameters,also affect the stability of the vehicle,therefore,this paper aims to improve vehicle dynamics and stability,and use Matlab/Simulink simulation software,combined with non-dominated sorting based multi-objective optimization algorithm with elite strategy(NSGA-Ⅱ)to study the parameter optimization of vehicle powertrain.In this paper,the multi-objective genetic algorithm and computer simulation are introduced into the optimization of transmission parameters,and the optimal transmission parameters are obtained by theoretical calculation and simulation verification.The main research work of this paper include the below sides:(1)On the basis of the specific parameters of the selected vehicle model and research requires,building the automobile model,engine model,electric machinery model,tyre model,powertrain model,steering model and other models using Matlab/Simulink simulation software.(2)According to the knowledge of automobile theory,the mathematical model of multi-objective optimization of transmission system is established.The mathematical model is based on the gear ratio of the derailleur and the gear ratio of the main retarder as the decision variables,take the acceleration time and yaw rate deviation as the objective function,the vehicle dynamic constraints and speed ratio constraints as constraints,then formulating the torque distribution strategy for the follow-up multi-objective optimization simulation.(3)According to the established multi-objective optimization mathematical model,using NSGA-Ⅱ to optimize the powertrain parameters,and get a group of distributed Pareto optimal solution,and select one for the analysis and verification.(4)The simulation of the powertrain parameters before and after optimization are carried out by Matlab/Simulink simulation model.The dynamic and stability performances are compared before and after optimization,and the accuracy and practicability of the selected algorithm and optimization results are verified.Compared with the simulation results before and after optimization,the results are satisfactory,which indicates that the research content of this paper has a certain theoretical significance and practical application value.