METHOD AND ARRANGEMENT FOR TIRE TO ROAD FRICTION ESTIMATION

The present disclosure relates to a method and arrangement for estimating a friction coefficient (µ i ) between tires of a wheeled two-axis two-track road vehicle (1) and the ground. If the longitudinal velocity v x of the vehicle (1) is above a first threshold v xthres and the wheel angle ´ f and/or the yaw rate © z is below a second threshold ´ thres /© zthres , a positive torque is applied to both wheels on a first axle and an and opposite, negative torque, to both wheels on a second axle while following driver requested longitudinal vehicle (1) acceleration ( a x ). Wheel speeds É i are measured and tire forces ( f i ) estimated. The friction coefficient (µ i ) between the tires and the ground are estimated from the measured wheel speeds É i and the estimated tire forces ( f i ). The estimated friction coefficient (µ i ) is made available to other vehicle (1) systems.