Transfer Function-Based Road Classification for Vehicles with Nonlinear Semi-Active Suspension

Abstract

Ride comfort and handling are two important criteria regarding vehicle vibration control. For solving the inconsistency between ride comfort and handling, a semi-active suspension system equipped with a road classification system can be a suitable solution. Because the road condition varies during driving, the control gain of the semi-active suspension system should be adaptively changed according to the road level. In this paper, accelerometer data and a transfer function scheme will be used for road classification, and there is no need to measure the road directly with difficult and often expensive methods. In this approach, a transfer function that makes relevant the Power Spectral Density (PSD) of the road surface and the PSD of car acceleration is used. Road classification is investigated for a vehicle with a nonlinear, semi-active suspension system equipped with Continuous Damping Control (CDC) and nonlinear springs. To show the applicability of the proposed method in scenarios close to real situations, robustness analysis is done by considering vehicle model uncertainties and sensor noise. The simulation results show that the proposed method is robust against typical uncertainties and accelerometer noise and can classify the road level, which is used to tune the parameters of the nonlinear, semi-active suspension system.