Vehicle travel direction estimating device
First Claim
1. A vehicle travel direction estimating device for repeatedly estimating a travel direction of a vehicle, comprising:
- wheel speed calculation means for measuring a rotational velocity of a wheel of said vehicle and for producing an absolute value of said rotational velocity as a wheel speed of said wheel during each repeated estimating;
estimated vehicle acceleration calculation means for calculating an estimated vehicle acceleration Aw as a function of said wheel speed;
gravity-type accelerometer for producing a gravitationally detected acceleration Am;
first differentiating means for differentiating said gravitationally detected acceleration Am and for producing a first differential value Dam;
second differentiating means for differentiating said estimated vehicle acceleration Aw and for producing a second differential value Daw;
detection means for detecting said travel direction of said vehicle based on said first and second differential values Dam and Daw; and
means for controlling a braking of said vehicle in response to said detected travel direction of said vehicle.
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Accused Products
Abstract
A vehicle travel direction estimating device is provided which has a wheel speed calculating device for calculating the speed and acceleration Aw of a vehicle. In addition, a gravity-type accelerometer is provided for producing a gravitationally detected acceleration Am. When both Aw and Am increase or decrease simultaneously, it is determined that the vehicle is travelling forward, and when one of Aw and Am increases while the other decreases, it is determined that the vehicle is travelling in reverse. To detect this feature, a calculating system is provided to form differential values Daw and Dam from accelerations Aw and Am. The vehicle travel direction is estimated using the differential values Daw and Dam.
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Citations
35 Claims
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1. A vehicle travel direction estimating device for repeatedly estimating a travel direction of a vehicle, comprising:
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wheel speed calculation means for measuring a rotational velocity of a wheel of said vehicle and for producing an absolute value of said rotational velocity as a wheel speed of said wheel during each repeated estimating; estimated vehicle acceleration calculation means for calculating an estimated vehicle acceleration Aw as a function of said wheel speed; gravity-type accelerometer for producing a gravitationally detected acceleration Am; first differentiating means for differentiating said gravitationally detected acceleration Am and for producing a first differential value Dam; second differentiating means for differentiating said estimated vehicle acceleration Aw and for producing a second differential value Daw; detection means for detecting said travel direction of said vehicle based on said first and second differential values Dam and Daw; and means for controlling a braking of said vehicle in response to said detected travel direction of said vehicle. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A vehicle travel direction estimating device for repeatedly estimating a travel direction of a vehicle, comprising:
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wheel speed calculation means for measuring a rotational velocity of a wheel of said vehicle and for producing an absolute value of said rotational velocity as a wheel speed of said wheel during each repeated estimation of said vehicle travel direction; estimated vehicle acceleration calculation means for calculating an estimated vehicle acceleration Aw as a function of said wheel speed; gravity-type accelerometer for producing a gravitationally detected acceleration Am; first differentiating means for differentiating said gravitationally detected acceleration Am and for producing a first differential value Dam; second differentiating means for differentiating said estimated vehicle acceleration Aw and for producing a second differential value Daw; and detection means for detecting said travel direction of said vehicle based on said first and second differential values Dam and Daw, said detection means further comprising; means for fixing said detected vehicle travel direction until said vehicle stops moving, when a level of certainty of detection reaches a predetermined level; and means for clearing said fixed detected vehicle travel direction when said vehicle restarts moving after being stopped and for resuming said detection from a cleared state.
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8. A system having an apparatus for estimating a travel direction of a vehicle having a plurality of wheels, said apparatus comprising:
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means for determining an estimated acceleration signal representative of an acceleration of said vehicle as a function of a rotational speed of at least one wheel of said vehicle; means for producing an independent acceleration signal which is representative of said acceleration of said vehicle, and for determining said independent acceleration signal independently of the speeds of said plurality of wheels of said vehicle; first means for differentiating said independent acceleration signal and for producing a first differential value; second means for differentiating said estimated acceleration signal and for producing a second differential value; detection means for detecting said vehicle travel direction base on said first and second differential values; and means for controlling a braking of said vehicle in response to said detected vehicle travel direction. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A system having an apparatus for estimating a travel direction of a vehicle having a plurality of wheels, said apparatus comprising:
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means for determining an estimated acceleration signal representative of an acceleration of said vehicle as a function of a rotational speed of at least one wheel of said vehicle, said determining means comprising; means for measuring the speed of the vehicle as a function of the rotational speed of said at least one wheel of said vehicle; and means for estimating the acceleration of the vehicle as a function of the measured speed and for producing said estimated acceleration signal; means for producing an independent acceleration signal which is representative of said acceleration of said vehicle, and for determining said independent acceleration signal independently of the speeds of said plurality of wheels of said vehicle; first means for differentiating said independent acceleration signal and for producing a first differential value; second means for differentiating said estimated acceleration signal and for producing a second differential value; detection means for detecting said vehicle travel direction based on said first and second differential values, wherein an antilock brake control device utilizes said travel direction estimating apparatus to operate a plurality of brake actuating devices to control an amount of braking pressure to a wheel of said vehicle.
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22. A process having a method for estimating a travel direction of a vehicle which having a plurality of wheels, the method comprising:
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determining an estimated acceleration signal representative of an acceleration of the vehicle as a function of a rotational speed of at least one wheel of the vehicle; producing an independent acceleration signal which is representative of the acceleration of the vehicle, by determining the independent acceleration signal independently of the speed of the at least one wheel of the vehicle; differentiating the independent acceleration signal and producing a first differential value; differentiating the estimated acceleration signal and producing a second differential value; detecting the direction of vehicle travel based on the first and second differential values; and controlling a braking of the vehicle in response to the detected vehicle direction. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method for estimating a travel direction of a vehicle having a plurality of wheels, said method comprising:
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determining an estimated acceleration signal representative of an acceleration of the vehicle as a function of a rotational speed of at least one wheel of the vehicle, the determining step comprising; measuring a speed of the vehicle as a function of the rotational speed of the at least one wheel of the vehicle; and estimating the acceleration of the vehicle as a function of the measured speed and producing the estimated acceleration signal; producing an independent acceleration signal which is representative of the acceleration of the vehicle, by determining the independent acceleration signal independently of the speed of the at least one wheel of the vehicle; differentiating the independent acceleration signal and producing a first differential value; differentiating the estimated acceleration signal and producing a second differential value; detecting the direction of vehicle travel based on the first and second differential values; and controlling an amount of brake pressure to each wheel of the vehicle in accordance with the estimated acceleration of the vehicle to perform an antilock brake control on the vehicle.
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Specification