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Road gradient estimating system

  • US 20090024354A1
  • Filed: 07/18/2008
  • Published: 01/22/2009
  • Est. Priority Date: 07/18/2007
  • Status: Active Grant
First Claim
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1. A road gradient estimating system comprising:

  • a first portion for calculating a first physical amount “

    Ggrad0”

    corresponding to an estimated gradient value of a road on which a vehicle is currently traveling, based on a difference between an acceleration “

    A”

    detected by an acceleration sensor for detecting acceleration of the vehicle in a vehicle longitudinal direction and an acceleration “

    A′



    of the vehicle with respect to the road;

    a second portion for storing data for relation between vehicle speed and a second physical amount corresponding to a limiting value for rate-of-change of road gradient;

    a third portion, to which information of vehicle speed is inputted, for calculating a third physical amount (α

    up, α

    down) corresponding to the limiting value for rate-of-change of road gradient at the inputted vehicle speed, based on the relation between the vehicle speed and the second physical amount stored in the second portion; and

    a fourth portion for comparing rate-of-change of the first physical amount “

    Ggrad0”

    corresponding to the estimated gradient value with the third physical amount (α

    up, α

    down) corresponding to the limiting value for the rate-of-change of road gradient calculated at the third portion,wherein the fourth portion corrects the first physical amount “

    Ggrad0”

    corresponding to the estimated gradient value, in such a manner that the first physical amount “

    Ggrad0”

    corresponding to the estimated gradient value is limited to the limiting value for the rate-of-change of road gradient calculated at the third portion, when the rate-of-change of the first physical amount “

    Ggrad0”

    corresponding to the estimated gradient value is larger than the third physical amount (α

    up, α

    down) corresponding to the limiting value for the rate-of-change of road gradient calculated at the third portion.

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