Abstract
-
The tire-road friction coefficient is critical to
vehicle longitudinal, lateral and roll dynamics and control
because tire is the only contact part between the vehicle body
and the road. However, direct measurement of tire-road
friction coefficient is impossible in practice. This paper
presents a novel cost effective method for vehicle tire-road
friction coefficient estimation. This method only needs the
measurements of the wheel angular velocity, the traction/brake
torque and the longitudinal acceleration, which are all
available from the commonly installed sensors in ordinary
passenger vehicles, and can be used to estimate the individual
tire-road friction coefficient. There are three steps in the
proposed method. Firstly, the longitudinal slip ratio is
estimated by using a nonlinear filter with the measured wheel
angular velocity. Then the tire longitudinal force is estimated
by using a Kalman filter with the measured traction/brake
torque and longitudinal acceleration. At last, the friction
coefficient is estimated by using the recursive least squares
(RLS) method and the results obtained from the first two steps.
Numerical simulations are provided to validate the
effectiveness of the proposed method. It is shown by the
simulation results that the proposed method is effective in
estimating the tire-road friction coefficient.