TIRE PARAMETER ESTIMATING DEVICE AND ROAD SURFACE DETERMINATION DEVICE

摘要

PROBLEM TO BE SOLVED: To estimate a tire parameter with high accuracy while suppressing cost and considering condition of a vehicle and road environment. SOLUTION: A grade detecting circuit 12 detects a grade based on a wheel speed detected by a wheel speed detecting circuit 11. A grade value comparison circuit 40 calculates a grade average r, which is an average of grades detected by the grade detecting circuit 12, and further calculates a rate of the grade average r to a grade initial value I; Rate (=r/I). A tire temperature estimating circuit 51 stores a table showing a relationship between the Rate and a tire temperature and estimates the tire temperature corresponding to the Rate calculated by the grade value comparison circuit 40 as a current tire temperature.