Patent ID: 8306712

Claim:
A method of determining an adhesive condition of a surface of a vehicle road using a statistical pattern recognition technique, the method comprising the steps of: (a) providing a plurality of probability distribution functions for a plurality of road surfaces which represent respective adhesive effects between the vehicle tire of a driven vehicle and the vehicle road; (b) obtaining a steering wheel angle, a vehicle speed, and a yaw rate of the driven vehicle; (c) calculating an index which represents a vehicle understeer characteristic for a vehicle traveling on a current road that is a function of the steering wheel angle input, the vehicle speed, and the yaw rate; (d) applying a probability analysis for each of the road surface adhesive conditions as a function of the index; (e) recursively updating the probability analysis for each respective road surface adhesive condition; (f) determining a likelihood factor for each road surface adhesive condition as a function of each respective recursively updated probability analysis, each respective road surface adhesive condition having a respective likelihood factor that identifies the likelihood of the road surface having the respective adhesive condition as a function of the index; (g) selecting the respective road surface adhesive condition having a highest likelihood factor among each of the determined likelihood factors; and (h) a vehicle control system adjusting control operations as a function of the selected road surface adhesive condition for enhancing vehicle stability of the vehicle.