The principal concern in driving safety is the understanding and prevention of risky situations. A close examination of accident data reveals that losing the vehicle control is responsible for a huge proportion of car accidents. Preventing such kind of accidents using vehicle control systems, requires certain input data concerning vehicle dynamic parameters and vehicle road interaction. Unfortunately, some parameters, like the tyre-road contact forces that have a major impact on vehicle dynamics, are difficult to measure in a car. Therefore, this data must be estimated. In this context, this study presents an estimation process for load transfer and wheel-ground contact vertical forces. The proposed method is based on the dynamic response of a vehicle instrumented with cheap and currently available standard sensors. The estimation process is composed of two parts: the main role of the first part is to estimate the one-side lateral load transfer, while in the second part we propose and compare respectively the extended and unscented Kalman filter techniques for the estimation of vertical forces on the four wheels. Performances are tested using an experimental car in real driving situations. Experimental results demonstrate the ability of this approach to provide accurate estimations, and show its practical potential as a low-cost solution for vertical forces calculation. AQ1 Vehicle dynamics; state observers; tyre-road forces; rollover detection.
