| 摘要 |
PROBLEM TO BE SOLVED: To precisely calculate a wheel speed immediately before a wheel is stopped based on signals outputted every predetermined rotation angle of a wheel. SOLUTION: An outer peripheral length of a wheel corresponding to a predetermined rotation angle is subtracted in periods TP1, TP2 of signals outputted every predetermined rotation angle of a wheel, so as to calculate first wheel speeds VP1, VP2... and then the first wheel speeds VP1, PV2... are held till the next calculation. Meanwhile, times TC1, TC2... elapsed from the output of the signals are measured, and the outer peripheral length of a wheel corresponding to a predetermined rotation angle is divided by the elapsed times TC1, TC2..., so as to calculate second wheel speeds VC1, VC2... Then, any smaller one of the first wheel speeds VP1, VP2... and the second wheel speeds VC1, VC2... is selected, and outputted. Thereby, the held first wheel speeds VP1, VP2... are prevented from being continuously outputted after the wheel is stopped, preventing delay of judgment of stop of the wheel based on a threshold VS. COPYRIGHT: (C)2008,JPO&INPIT |
