Multi-objective Reliability Optimal Design Of Transmission Gear Train Based On NSGA-Ⅱ

Transmission is an important part of automobile powertrain. It has a direct effect on automobile quality of momentum and economy, controlling quality of reliability and portability as well as driving quality of placidity and efficiency. Automobile transmission gears are components with complex construction. To design a transmission that can work reliably during the time limit, and the parameters of gear are optimization, we must implement multi-objective reliability optimal design for automobile transmission gear train.The conventional methods, which have been used to solve the multi-objective problems, show several deficiency in some complicated multi-objective problems, so they are gradually replaced by multiple objective genetic algorithm. A fast elitist non-dominated sorting genetic algorithm (NSGA-II) can get the optimization results which distributed symmetrically, so this method has strong advantage in multi-objective optimization field. This paper introduces the concept and the theory of genetic algorithm, dissertates the basis of principle, flow of the algorithm and the essence of strategies for NSGA-â…¡.With the interference theory for distribution of stress-strength, reliability computation formula for gear is analyzed. This paper takes a certain microbus transmission as the research object. According to the determinate structure, the optimal gear ratio and the constraints of the reliability, the multi-objective reliability optimal mathematical model of transmission gear train is established with the objectives of the minimal volume of gear train, the minimal center distance and the maximal total contact ratio.Based on the theory, MATLAB is used as a tool to work out the program of NSGA-â…¡and multi-objective reliability optimal design for Automobile transmission gear train. This paper takes a certain microbus transmission as an example, utilizes NSGA-â…¡to optimize the multi-objective optimization problem and get its Pareto optimal solution set. In the end, MATLAB GUIDE is taken as the interface-exploiting tool to design a graphical user interface.