Optimal design of vehicle suspension system using multi-objective differential algorithm

In this paper, a multi-objective differential evolution with fuzzified mutation factor using the combination of non-dominated sorting and crowding distance criterion (MODE-FM) is used for Pareto optimization (in bi- and 7-objectve spaces) of a 5-degree of freedom active and linear suspension vehicle model considering the seven conflicting functions simultaneously, under stationary random road profile. The significant conflicting objective functions that have been utilized here for assessing the applicability of the aforesaid suspension system reaching the compromise between ride comfort and road holding capability are, namely, vertical seat acceleration, vertical forward tire velocity, vertical rear tire velocity, relative displacement between sprung mass and forward tire, relative displacement between sprung mass and rear tire, forward control and rear control force. Further, the design variables include the coefficients of springs and dampers of suspension system and seat and coefficients of control force along with the seat position in relation to the center of mass of sprung mass in which the suggested design can be achieved. It should be noted that the road roughness used here is in class C based on the ISO 8608 standard. Comparison of the attained results of this work with those in the literature has proved the superiority of the results of this work.