Patent ID: 9242625
Filing Date: 2016-01-26
CPC Classification: B60T

Claim Text:
1. A road friction coefficient estimating unit, comprising: a sideslip angle calculation unit configured to calculate a tire sideslip angle β in each of a plurality of computation process cycles, the sideslip angle calculation unit being further configured to calculate a difference Δβ between a tire sideslip angle β calculated in a current computation process cycle and a tire sideslip angle β calculated in an immediately preceding computation process cycle; a cornering force calculation unit configured to calculate a cornering force CF in each of the plurality of computation process cycles, the cornering force calculation unit being further configured to calculate a difference ΔCF between a cornering force CF calculated in the current computation process cycle and a cornering force CF calculated in the immediately preceding computation process cycle; and a road friction coefficient calculating unit configured to calculate a road friction coefficient based on a ratio of the difference ΔCF to the difference Δβ, wherein the road friction coefficient calculating unit stores, in a memory, a table that shows a correlation between the ratio only at a fixed tire sideslip angle βd and the road friction coefficient, the fixed tire sideslip angle βd being a tire sideslip angle β calculated when the cornering force CF is at a boundary between a linear range and a saturated range, and the road friction coefficient calculating unit is further configured to calculate the road friction coefficient, while a vehicle having the road friction coefficient calculating unit is travelling, by applying the ratio to the table only when the tire sideslip angle β is the fixed tire sideslip angle βd.