Multi-objective optimization based on improved non-dominated sorting genetic algorithm II for tolerance allocation of auto-body parts

Abstract

The auto-body is usually composed of compliant sheet metals. The assembly variation is inevitable in the process of auto-body assembly. A reasonable tolerance allocation method for compliant sheet metal body parts is an important means to control assembly variation and improve the quality of automotive assembly. In this article, on the basis of tolerance-deviation model and tolerance-cost model, a multi-objective optimization model for tolerance allocation of auto-body is established. Part tolerance and manufacturing cost are regarded as design variables in the model. Then, orthogonal design and cumulative sorting strategy are proposed to modify the non-dominated sorting genetic algorithm II. Finally, the process of tolerance allocation is demonstrated through an example of the rear lamp bracket assembly. The results show that the improved non-dominated sorting genetic algorithm II algorithm has obvious optimization effect.