Abstract

This paper reported on an investigation to determine the spring and damper settings that ensured optimal ride comfort of vehicle in different speeds using design of experiment method (DOE). The extent to which the ride comfort optimal suspension settings vary for roads of different roughness and varying speeds and the levels of ride comfort that can be achieved, were addressed. Optimization was performed with the DOE method on a 7 DOF modeled in MATLAB software for speeds ranging from 60 to 90 km/h. Results indicated that optimization of suspension settings using the road and specified range of speed also improved the ride comfort on the same road at the different speeds. These settings also improved ride comfort for other roads at the optimization speed and other speeds, although not as much as when optimization has been done for the particular road. For improved ride comfort, damping generally has to be lower than the standard (compromised) setting, the rear spring as soft as possible and the front spring ranging from as soft as possible to stiffer depending on road and speed conditions. Ride comfort was most sensitive to a change in rear spring stiffness.

Key words: Ride comfort, optimization, design of experiment (DOE), suspension, road condition, spring and damper.