Slip-Based Estimation of Tire-Road Friction

An approach to estimate the tire road friction during normal drive using only the wheel slip, that is, the relative difference in wheel velocities, is presented. The driver can be informed about the maximal friction force and be alarmed for sudden changes. Friction related parameters are estimated using only signals from standard sensors in a modern car, and the physical relation between these parameters and the maximal friction force is determined from extensive field trials using a Volvo 850 GLT as a test car.