Tire-road friction coefficient estimation with vehicle steering

Lateral tire deflection enables the estimation of the tire-road friction coefficient. Vehicle steering, such as driving on a curved highway, can influence the friction coefficient estimation. This paper demonstrates an algorithm to estimate the tire-road friction coefficient when a vehicle is steering. The relationship between the friction coefficient and the vehicle steering is derived through a tire brush model. The change of lateral velocity inside the tire-road contact patch is used in the algorithm along with the lateral deflection. The models for the lateral deflection and the change of lateral velocity are derived with the tire brush model, a simple tire model, and a parabolic lateral deflection model. Approximated tire slip angles are fed to the estimation algorithm to capture the change of the steering angle. This algorithm is evaluated in experiments with the steering of a test vehicle.