Patent ID: 6931912

Claim:
A method for estimating friction coefficient of a road surface, comprising calculating, in a tire/wheel assembly having an axle hub, a tire, and a wheel attached to the axial hub to support the tire, tangential and vertical components of a force acting between a section of a transmission path between the axle hub and the tire and the other section of the transmission path based on measurement values of relative displacements in the tangential and vertical directions, respectively, between the sections of the transmission path, the sections of the transmission path being bounded by an elastic body arranged within the transmission path; and in order to calculate the friction coefficient between the tire/wheel assembly and the road surface based on the acting force of these components, measuring an angular rate of the tire/wheel assembly along with measurements of each component of the acting force, and calculating the friction coefficient μ between the tire/wheel assembly and the road surface from the equation μ=(Fb+(I 0 /R)dω/dt)/N, with the measured tangential force Fb, vertical force N and angular rate co as well as the known moment of inertia I 0 and known effective radius R of the tire/wheel assembly.