Patent ID: 6895317

Claim:
An apparatus for estimating a grip factor of a vehicle wheel comprising: steering factor detection means for detecting at least one of steering factors including a steering torque and steering effort applied to a steering system extending from a steering wheel to a suspension of a vehicle; aligning torque estimation means for estimating an aligning torque produced on at least a wheel of said vehicle on the basis of the steering factor detected by said steering factor detection means; vehicle state variable detection means for detecting a state variable of said vehicle; wheel factor estimation means for estimating at least one of wheel factors including a side force and slip angle applied to said wheel on the basis of the state variable detected by said vehicle state variable detection means; and grip factor estimation means for estimating a grip factor of at least a tire of said wheel, which grip factor indicates a grip level of the tire in a lateral direction of the wheel, in accordance with a relationship between the aligning torque estimated by said aligning torque estimation means and the wheel factor estimated by said wheel factor estimation means.