公开(公告)号：JP2003261016A

公开(公告)日：2003-09-16

申请号：JP2002063490

申请日：2002-03-08

Applicant: TOYOTA CENTRAL RES & DEV ,  TOYOTA MOTOR CORP

Inventor： UMENO KOJI ,  SUGAI MASARU ,  MIZOGUCHI YOJI ,  HORINOUCHI KATSUTOSHI

IPC: G01N19/02 ,  B60R16/02 ,  B60T8/172 ,  B60T8/1763 ,  B60T8/58

Abstract: PROBLEM TO BE SOLVED: To estimate the maximum road surface coefficient of friction with excellent accuracy before the tire grip reaches the limit when a car makes a turn. SOLUTION: A μ gradient operation unit 21 operates the μ gradient which is the gradient of the road surface coefficient of friction μ to the slip ratio or the slip speed based on the wheel speed signal, and supplies the operated μgradient to a threshold determination unit 22. The threshold determination unit 22 compares the μ gradient supplied from the μ gradient operation unit 21 with the threshold (which is 70% of the μ gradient in the straight drive), and raises a first determination flag to promote the estimation of the maximum road surface coefficient of friction μmax when the μ gradient is below the threshold. A μmax estimation unit 26 estimates the maximum road surface coefficient of friction μmax by multiplying the transverse acceleration Gy [G] detected by a transverse acceleration sensor by 1.4 when the threshold determination unit 22 detects the raise of the first determination flag. COPYRIGHT: (C)2003,JPO