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

Claim 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 V Ri , 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 P Ri ; calculating the braking forces F Bi from the wheel brake pressures P Ri according the equation ##EQU29## where θR is the amount of inertia of the wheel, C Pi is the braking ratio, and R is the radius of the wheel; determining the longitudinal vehicle speed V L from the wheel speeds V Ri and from the deceleration of the vehicle; estimating the vehicle transverse speed V q 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 V q of said vehicle transverse speed V q , according to the relationships ##EQU30## where V and H indicate the front and rear, respectively, and where l 1 and l 2 are the respective lengths of the vehicle axles from the vehicle center of gravity; and determining the respective elastic steering angle values δE i from the calculated braking forces F Bi ; determining the slip angles α i , using said estimated attitude angle values β V and β H and said respective elastic steering angle values δE i , according to the relationships α.sub. =δ-β.sub. V -δ.sub.E1 α.sub.2 =δ-β.sub.V -δ.sub.E2 α.sub.3 =β.sub.H -δ.sub.E3 α.sub.4 =β.sub.H -δ.sub.E4 and, 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.

Claim 2

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 V Ri , 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 P Ri ; calculating the braking forces F Bi from the wheel brake pressures P Ri according the equation ##EQU29## where θR is the amount of inertia of the wheel, C Pi is the braking ratio, and R is the radius of the wheel; determining the longitudinal vehicle speed V L from the wheel speeds V Ri and from the deceleration of the vehicle; estimating the vehicle transverse speed V q 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 V q of said vehicle transverse speed V q , according to the relationships ##EQU30## where V and H indicate the front and rear, respectively, and where l 1 and l 2 are the respective lengths of the vehicle axles from the vehicle center of gravity; and determining the respective elastic steering angle values δE i from the calculated braking forces F Bi ; determining the slip angles α i , using said estimated attitude angle values β V and β H and said respective elastic steering angle values δE i , according to the relationships α.sub. =δ-β.sub. V -δ.sub.E1 α.sub.2 =δ-β.sub.V -δ.sub.E2 α.sub.3 =β.sub.H -δ.sub.E3 α.sub.4 =β.sub.H -δ.sub.E4 and, 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.