Virtual sensors design in vehicle sideslip angle and velocity of the centre of gravity estimation

The aim of an observer (virtual sensor) is to estimate a special variable from available information and a system model. The vehicle sideslip angle and velocity of the centre of gravity (V_g) are the important parameters in the vehicle stability control system. Extended Luenberger observer, extended Kalman filter and sliding-mode observer (SMO) are the widely used to observe the two parameters. Chattering is usually caused by a sign function in the SMO, so a hyperbolic tangent switching function is used instead of the sign function to overcome the chattering problem in this paper. The SMO with the hyperbolic tangent switching function is used to estimate the tire-road forces, and then the sideslip angle and V_g are calculated using the single-track model. The accuracy and robustness of the proposed observer are proved by the results of the simulator ve-DYNA under different conditions.