Device for calculating estimated vehicle acceleration and speed
First Claim
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1. A device for calculating estimated vehicle acceleration and speed of a vehicle having a gravity-type accelerometer, comprising:
- means for detecting a wheel speed of at least one wheel of the vehicle at each calculation cycle;
means for calculating a representative speed Vr based on said wheel speed;
means for detecting a gravitationally detected acceleration Am by said gravity-type accelerometer;
means for correcting the gravitationally detected acceleration Am to produce a substiute acceleration as;
means for calculating an estimated vehicle acceleration Av and an estimated vehicle speed Vv based on said representative speed Vr;
means for calculating a subservient acceleration Az which constitutes a part of the equations for calculating said estimated vehicle acceleration and speed, Av and Vv;
means for selecting either one of said subservient acceleration Az and said substitute acceleration As based on a comparison between said subservient acceleration Az and said substitute acceleration As and for outputting said selected one of said subservient acceleration Az and said substitute acceleration As to be used in place of said part of the equations for calculating Av and Vv in said calculating means.
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Abstract
A device for calculating estimated vehicle acceleration and speed for use in estimating vehicle speed Vv and vehicle acceleration Av, such that a subservient acceleration Az based on the wheel speed is used when As>Az during acceleration or when As<Az during deceleration, while the substitute acceleration As based on the gravity-type accelerometer is used in place of Az when As<Az during acceleration or when As>Az during deceleration.
15 Citations
22 Claims
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1. A device for calculating estimated vehicle acceleration and speed of a vehicle having a gravity-type accelerometer, comprising:
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means for detecting a wheel speed of at least one wheel of the vehicle at each calculation cycle; means for calculating a representative speed Vr based on said wheel speed; means for detecting a gravitationally detected acceleration Am by said gravity-type accelerometer; means for correcting the gravitationally detected acceleration Am to produce a substiute acceleration as; means for calculating an estimated vehicle acceleration Av and an estimated vehicle speed Vv based on said representative speed Vr; means for calculating a subservient acceleration Az which constitutes a part of the equations for calculating said estimated vehicle acceleration and speed, Av and Vv; means for selecting either one of said subservient acceleration Az and said substitute acceleration As based on a comparison between said subservient acceleration Az and said substitute acceleration As and for outputting said selected one of said subservient acceleration Az and said substitute acceleration As to be used in place of said part of the equations for calculating Av and Vv in said calculating means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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20. A device according to claim 18, wherein said uncertainty Ax is calculated as a relatively small value when an absolute value of a difference between the substitute acceleration As and the subservient acceleration Az is relatively large.
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21. A device according to claim 18, wherein said uncertainty Ax is calculated as a gradually increasing value when said selecting means continues to select said substitute acceleration As.
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22. A device according to claim 18, wherein said uncertainty Ax is calculated as a relatively large value when said corrected gravitationally detected acceleration Ac is relatively large.
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Specification