Tyre–road friction coefficient estimation based on the discrete-time extended Kalman filter

This paper presents a new algorithm for estimation of the instantaneous value and the maximum value of the tyre–road friction coefficient (the adhesion coefficient) depending on the quality of the road surface. The algorithm applies the discrete-time extended Kalman filter for state estimation. The underlying discrete-time non-linear state-space model was based on a two-wheel longitudinal vehicle dynamics model extended to include the scale factor parameter of the ‘magic formula’ for the longitudinal tyre force introduced by Pacejka. To verify the Kalman-filter-based algorithm, a validated real-time hardware-in-the-loop simulation environment was utilized, and the results were in agreement with the expectations.