| 摘要 |
PROBLEM TO BE SOLVED: To enhance the reliability of road surface state estimation by calculating an index unitarily showing a road surface state from parameters showing the irregular state of the road surface and the easiness of slippage of the road surface. SOLUTION: In steady traveling, an irregular state parameter arithmetic part 211 calculates the maximum amplitude of slip difference ratio in a fixed time from the difference in average speed between front and rear wheels or the difference in speed between front and rear wheels. An easiness-of-slippage parameter arithmetic part 212 calculates the average value from the frictional coefficient (hereinafter referred to asμ) judged value of a road surface. On both the parameters, a road surface index calculating means 220 calculate an index corresponding to each state of other parameter for unitarily showing the road state, or highμdegree, middleμdegree and lowμdegree by use of fuzzy inference. A road surface frictional efficient calculating means 230 continuously determines the index calculated by the means 220 and accumulatively evaluates it to calculate the road surface state in steady traveling, or road surfaceμ. Thus, the road surfaceμcan be precisely grasped to more precisely perform the traveling control.
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