Sujatha C., A.S.S. Siva Ram A.

This paper demonstrates the applicability of a multi objective genetic algorithm to analyze the effects of vibrations on the ride comfort and road holding capability of vehicles due to the variation of different parameters such as suspension stiffness and damping. The effect of driver’s seat position is also considered in the optimization. The maximum vertical acceleration of the seat, as well as the maximum roll acceleration of the sprung mass is minimized, keeping the working space of the suspension spring and damper constrained. An eight degrees of freedom (DOF) model of the vehicle is used for the present study. This model comprises the bounce modes of the sprung mass, wheels and driver’s seat. Besides, it also includes the pitch and roll modes of the sprung mass. The optimization is carried out using Non-Dominated Sorting Genetic Algorithm (NSGA- II) developed by Deb et al. Different suspension systems such as active, semi active and passive are investigated in the present study. Deterministic road input is applied to the vehicle model. A good pareto optimal solution is achieved in the optimization for different cases of suspension systems. The results also show that with the use of active suspensions, vertical acceleration of the driver and sprung mass pitch and roll accelerations are reduced by around 45% as compared to passive suspension system. The corresponding improvements with semi active suspension system are of the order of 15%, proving that active and semi-active suspension systems are beneficial compared to passive suspension system.