Parametric optimization of an off-road car suspension system aiming for a compromise between comfort and safety

Resumo

This work addresses the the parametric optimization of an off-road car suspension system. The aim is

to find a compromise between comfort and safety while respecting functional constraints such as maximum de-
flections for the suspension and the tires, as well as the tendency of oversteering on cornering. The vertical vehicle

dynamic is used to evaluate both the comfort and safety criteria for different operational conditions: uniform recti-
linear movement; braking; curves; and longitudinal acceleration. Tires were subjected to base excitation, obtained

from the Power Spectral Density (PSD) of the road profile. The tendency to oversteer on cornering was measured
by comparing the frontal and rear torsional stiffness. The Finite Element Method (FEM) was implemented to solve

the transient equilibrium problem needed to evaluate the comfort and safety criteria as well as the functional con-
straints. The design variables considered in the parametric optimization were the springs and tires stiffness, and

dampers damping. The optimization algorithm used was a modified version of the Particle Swarm Optimization
(PSO). Results show that it is possible to obtain a feasible final configuration minimizing the objective function,
thus improving both safety and comfort criteria.