VEHICLE WHEEL SLIP CONTROL SYSTEM USING PREDICTIVE MODEL TO ESTIMATE FRICTION COEFFICIENT

A vehicle slip control system for controlling a wheel slip based on a friction coefficient of a road surface measures an engine torque T.sub.E by applying an intake pipe negative pressure Pm and a number of engine revolutions Ne to an engine model. A drive torque T is measured by applying the engine torque T.sub.E to an A/T model, and a driving wheel acceleration d.omega. is obtained by finding a difference of a detected driving wheel speed .omega.. By filtering this driving wheel acceleration d.omega., a post-filter driving wheel acceleration d.omega..sub.0 is calculated. A squat force Ws is calculated from the drive-torque T and the post-filter driving wheel acceleration d.omega., and a friction coefficient .mu. of the road surface is estimated from the squat force Ws. The estimated friction coefficient .mu. is used to control a wheel slip.