| 摘要 |
PROBLEM TO BE SOLVED: To correct the zero point of a G sensor according to the condition of a road surface, by computing the zero point of the G sensor from the output value of the G sensor and the acceleration or deceleration of a wheel in a predetermined time, and computing a present zero point on the basis of a zero point computed a specified time before. SOLUTION: A wheel speed V from time ta to time te is detected by a wheel speed sensor, and average accelerations or decelerationsαa -ad are computed from the changes of wheel speeds Va -Ve in a specified short timeΔt. And average output values GZa -GZd in the short timeΔt are measured by a G sensor. Next, a zero point (G0) of the G sensor is computed from the average acceleration or decelerationαof the wheel, the average output value GZ of the G sensor and an already-known grade coefficient K (which changes with the characteristic and the filled condition of the G sensor, but does not change by the running condition of a car once it is found). And a present zero point of the G sensor is found from the last-time zero point and the before-last- time zero point, for example. By using this present zero point, it becomes possible to compute the acceleration or deceleration of the car precisely from the output values of the G sensor, and to perform precise brake control.
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