Active suppression of 5DOF vehicle via acceleration-difference-feedback and fuzzy-PID control strategy

This study investigates active control methods for vehicles aimed at reducing passenger motion sickness. A key challenge examined is the unwanted coupling between vertical and pitch dynamics in active suspension systems, which stems from traditional velocity-based feedback control in five-degree-of-freedom (5DOF) semi-vehicle models. To address this issue, a novel control scheme combining acceleration-difference-feedback (ADF) with fuzzy proportional-integral-derivative (PID) control, termed ADF-FuzzyPID control, is introduced. Through theoretical analysis, this strategy enables effective decoupling of the vertical and pitching motions of the vehicle body. By integrating ADF with fuzzy PID control, the proposed method achieves approximate independent control over vertical and pitch angular accelerations in the 5DOF system, leading to simultaneous attenuation of both response components. Simulation outcomes confirm that the approach significantly reduces vertical acceleration while markedly improving pitch angular acceleration performance under random disturbances on Class C road conditions. Compared with a passive suspension setup, the implementation of ADF-FuzzyPID control results in reductions of 63.5%, 22%, and 90.1% in the root-mean-squared (RMS) values of seat vertical acceleration, vehicle body vertical acceleration, and pitch angular acceleration, respectively.