PROBLEM TO BE SOLVED: To make precisely detectable a road-surface grade without delay, with respect to a change in an actual road grade. ;SOLUTION: A G sensor is arranged on the axle of a vehicle. The road- surface grade is detected, on the basis of the acceleration of the vehicle and on the basis of the output value of the G sensor. When the rate of change of the road-surface grade calculated by a road-surface-grade detection means is a value which cannot be an actual value, the calculated value of the road- surface grade prior to the change is continued to be output, until the calculated value of the road-surface grade returns to a value before the change. Even in a running state where the vehicle is subjected to disturbance from a road surface or the like and that the accuracy of the input value of the G sensor is lowered, an abnormal road-surface grade value which is generated by the disturbance is removed, without delays with reference to the change in the actual road grade, and the road-surface grade can be detected precisely.;COPYRIGHT: (C)2001,JPO
展开▼
