PHYSICAL QUANTITY ESTIMATING DEVICE, ROAD SURFACE FRICTION CONDITION ESTIMATING DEVICE, STEERING ANGLE NEUTRAL POINT ESTIMATING DEVICE AND PNEUMATIC PRESSURE DROP ESTIMATING DEVICE

摘要

PROBLEM TO BE SOLVED: To accurately estimate the friction condition of a road surface without the need for additional steering angles. SOLUTION: A slipping angle estimating means 34 estimates the slipping angle of a front wheel in accordance with a steering angle and a vehicle speed, an SAT estimating means 36 estimates SAT in accordance with steering torque and assisting torque, and a slipping angle reference value computing means 38 computes a slipping angle reference value for an estimated value for the SAT. An friction condition estimating means 40 estimates a gripping condition by utilizing the fact that the degraded gripping condition causes the slipping angle to be larger as compared with the slipping angle reference value. A steering angle neutral point and the pneumatic pressure drop of a tire are also estimated.