ROAD SURFACE STATE ESTIMATING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a road surface state estimating device capable of estimating the allowance of a tire by estimating a road surface state without directly obtaining the maximum value of a road surfaceμ. SOLUTION: A wheel speed detection means 12 detects the speed of a wheel. A road surfaceμgradient estimating means 14 estimates a road surfaceμgradient based on the speed of the wheel. An acceleration and deceleration detection means 18 detects acceleration and deceleration levels by a variation in speed of the wheel and a manipulated variable of a brake and an accelerator. A steering angle detection means 20 detects the steered angle of a steering wheel of a vehicle. A stationary traveling judgment means 21 judges, based on the acceleration and deceleration levels and the steered angle, on whether a traveling state is a stationary traveling state or not by judging on whether a variation in speed of the vehicle and the steered angle come within specified ranges or not. A tire allowance calculation means 24 calculates the tire allowance from the road surfaceμgradient estimated in the state of slightly causing a slip angle during the stationary traveling.