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Method for determining the slip angles and/or the cornering forces of a braked vehicle

  • US 5,371,677 A
  • Filed: 05/27/1992
  • Issued: 12/06/1994
  • Est. Priority Date: 09/28/1990
  • Status: Expired due to Term
First Claim
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1. A method for increasing the controllability of a wheeled vehicle having a dynamic drive control system for controlling at least the brake pressure applied to the wheels, said method including the steps of:

  • determining the respective the wheel speeds VRi, where i=1, . . . 4 and indicates the respective vehicle wheel, the steering angle δ

    , the yaw rate ρ and

    the respective wheel brake cylinder pressures PRi ;

    calculating the braking forces FBi from the wheel brake pressures PRi according the equation ##EQU29## where θ

    R is the amount of inertia of the wheel, CPi is the braking ratio, and R is the radius of the wheel;

    determining the longitudinal vehicle speed VL from the wheel speeds VRi and from the deceleration of the vehicle;

    estimating the vehicle transverse speed Vq from the determined values for δ and

    ρ

    using a Kalman Filter;

    estimating the attitude angles β

    v and β

    v from the estimated value Vq of said vehicle transverse speed Vq, according to the relationships ##EQU30## where V and H indicate the front and rear, respectively, and where l1 and l2 are the respective lengths of the vehicle axles from the vehicle center of gravity; and

    determining the respective elastic steering angle values δ

    Ei from the calculated braking forces FBi ;

    determining the slip angles α

    i, using said estimated attitude angle values β

    V and β

    H and said respective elastic steering angle values δ

    Ei, according to the relationships
    
    
    space="preserve" listing-type="equation">α

    .sub. =δ



    .sub. V -δ

    .sub.E1
    
    
    space="preserve" listing-type="equation">α

    .sub.2 =δ



    .sub.V -δ

    .sub.E2
    
    
    space="preserve" listing-type="equation">α

    .sub.3 =β

    .sub.H -δ

    .sub.E3
    
    
    space="preserve" listing-type="equation">α

    .sub.4 =β

    .sub.H -δ

    .sub.E4and, applying the determined slip angles α

    i to the dynamic drive control system and utilizing the values α

    i for controlling the brake pressure applied to the wheels.

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