| 摘要 |
PROBLEM TO BE SOLVED: To accurately estimate the hydraulic pressure of a pressure chamber in a master cylinder device including a pressure piston and an input piston.SOLUTION: The stroke Xmc of a pressure piston is estimated on the basis of servo pressure (S22), the stroke Xs of an input piston is estimated on the basis of the stroke of a brake pedal (S23), a gap Gap between the pressure piston and the input piston is obtained on the basis of these estimates (S24), and whether the gap Gap is equal to or less than an abutment determination threshold value Xth (S25). When the gap Gap is larger than the abutment determination threshold value Xth, a separated state is determined, the hydraulic pressure of a pressure chamber is estimated equal to the servo pressure (S26), and when the gap Gap is smaller than the abutment determination threshold value Xth, an abutted state is estimated, and estimated to be a value obtained by multiplying the servo pressure by a coefficient α larger than 1.SELECTED DRAWING: Figure 7 |
