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Vehicle gradient analyzing apparatus

  • US 7,680,578 B2
  • Filed: 02/08/2005
  • Issued: 03/16/2010
  • Est. Priority Date: 11/05/2004
  • Status: Expired due to Fees
First Claim
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1. A system for determining a gradient of a road on which a vehicle drives, comprising:

  • a linearization unit;

    a sum unit; and

    a state space model and observer unit, whereinthe sum unit sums up wheel forces in a forward/backward direction, which are applied to respective wheels of the vehicle, to calculate a total sum wheel force, andthe linearization unit comprises;

    an air resistance calculation unit for calculating an air resistance force based on a velocity of the vehicle using a non-linear approximation equation;

    a rolling resistance calculation unit for calculating a rolling resistance force based on the velocity of the vehicle using the non-linear approximation equation; and

    a subtraction unit for subtracting the air resistance force and the rolling resistance force from the total sum wheel force to calculate a linearized total sum force, and whereinthe state space model and observer unit comprises;

    a state space model for applying a method of linear control theory to the total sum force; and

    an observer unit for calculating the gradient of the road based on a velocity difference between a modeled velocity of the vehicle calculated based on the linearized total sum force using the state space model, and an actually measured velocity of the vehicle.

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