Relative velocity estimation for semi-active suspension with disturbance-decoupled Kalman filtering using production vehicle sensors

This paper presents a method for estimating the relative velocity of a semi-active suspension using in-vehicle sensors. To overcome the challenges of unobservability of the full vehicle model and the inaccuracies inherent in 1/4 and 1/2 vehicle models, a disturbance-decoupled observer is adapted, incorporating model compensation. An augmented Kalman filter is employed to enable relative velocity estimation without needing prior knowledge of the sprung mass. Additionally, road height is estimated using the front suspension’s relative velocity, eliminating the need for the wheelbase preview assumption. In addition, roll motion compensation improves the accuracy of the estimation using in-vehicle 3D-IMU sensors. The proposed method is validated through both simulations and vehicle experiments. The results demonstrate that this approach effectively reduces the substantial estimation errors found in previous studies, especially during severe pitch and roll motions.