Method for controlling vehicle dynamics

• US 5,275,475 A
• Filed: 04/13/1992
• Issued: 01/04/1994
• Est. Priority Date: 08/23/1990
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Ehret, Thomas, Hartmann, Uwe, Van Zanten, Anton, Kost, Friedrich
• Primary Examiner(s): Oberleitner, Robert J.
• Assistant Examiner(s): Muratori, Alfred
• Application Number:
  US07/847,107
• Time in Patent Office: 631 Days
• Field of Search: 303/100, 303/103, 303/110, 303/111, 303/113.4, 303/24.1, 364/426.01-426.03
• US Class Current: 303/146
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60T 8/246 Change of direction

Abstract

Using a model calculation, desired changes in the yaw rate Δφ and the transverse acceleration Δy are determined from a small change actually made in the steering angle and are compared to measured quantities Δφ_F and Δy_F determined on the vehicle. The deviations of the actual values of yaw rate and transverse acceleration from the calculated values are weighted using predetermined weighting factors for the relative importance of yaw rate and transverse acceleration and supplied with factors dependent on the individual wheel; finally, the values relating to the same wheel are added. They represent desired changes in the brake slip values and a controller finally converts these into brake slip value changes.

Claims

1. A method of controlling brake slip at each of n tires of a vehicle during braking to control driving dynamics, said method comprising the steps of:

a) making a small change Δ

δ

in steering angle of the vehicle;

b) performing a model calculation to obtain a calculated yaw rate Δ

φ and

a calculated transverse acceleration Δ

y using the following model differential equations;

space="preserve" listing-type="equation">Δ

φ

+k.sub.1 Δ

φ

+k.sub.2 Δ

φ

=k.sub.5 ·

Δ

δ

(I)

space="preserve" listing-type="equation">Δ

y+k.sub.3 Δ

y+k.sub.4 Δ

y=k.sub.6 ·

Δ

δ

(II)

wherein k₁ to k₄ are constants and k₅ and k₆ are quantities dependent on vehicle speed;

c) measuring an actual yaw rate Δ

φ

_F and an actual transverse acceleration Δ

y_F ;

d) comparing the actual yaw rate and calculated yaw rate and determining a deviation of the calculated yaw rate from the actual yaw rate Δ

φ

-Δ

φ

_F ;

e) comparing the actual transverse acceleration and the calculated transverse acceleration and determining a deviation of the calculated transverse acceleration from the actual transverse acceleration Δ

y-Δ

y_F ;

f) calculating changes in brake slip, Δ

λ

_i, at each of the n tires of the vehicle from quantities P.sub.φ

i and P_yi dependent on braking forces B_i and cornering forces S_i and the steering angle δ

, and from the deviation of the calculated yaw rate from the actual yaw rate determined in step d) and the deviation of the calculated transverse acceleration from the actual transverse acceleration determined in step e) using the following equation;

space="preserve" listing-type="equation">Δ

λ

.sub.i =C.sub.1 P.sub.yi (Δ

Y-Δ

Y.sub.F)+C.sub.2 P.sub.φ

i (Δ

φ

-Δ

φ

.sub.F) (III)

wherein c₁ and c₂ are predetermined weighting factors for changes in the transverse acceleration and the yaw rate, wherein i designates one of the n tires; and

g) changing brake pressures at each tire according to the brake slip changes calculated in step f).

2. A method according to claim 1, wherein in step f) the calculated brake slip has differential (PD) and integral components (PI,PID).

3. A method for controlling braking forces at each of n tires of a vehicle during braking to control driving dynamics, said method comprising the steps of:

a) making a small change Δ

δ

in steering angle of the vehicle;

b) performing a model calculation to obtain a calculated yaw rate Δ

φ and

a calculated transverse acceleration Δ

y using the following model differential equations;

space="preserve" listing-type="equation">Δ

φ

+k.sub.1 Δ

φ

+k.sub.2 Δ

φ

=k.sub.5 ·

Δ

δ

(I)

space="preserve" listing-type="equation">Δ

y+k.sub.3 Δ

y+k.sub.4 Δ

y=k.sub.6 ·

Δ

δ

(II)

wherein k₁ to k₄ are constants and k₅ and k₆ are quantities dependent on vehicle speed;

c) measuring an actual yaw rate Δ

φ

_F and an actual transverse acceleration Δ

Y_F ;

d) comparing the actual yaw rate and calculated yaw rate and determining a deviation of the calculated yaw rate from the actual yaw rate Δ

φ

-Δ

φ

;

e) comparing the actual transverse acceleration and the calculated transverse acceleration and determining a deviation of the calculated transverse acceleration from the actual transverse acceleration Δ

y--Δ

y_F ;

f) calculating changes in braking forces, Δ

B_i, at each of the n tires of the vehicle from quantities P.sub.φ

i '"'"' and P_yi '"'"' dependent on braking forces B_i and cornering forces S_i and the steering angle δ

, and from the deviation of the calculated yaw rate from the actual yaw rate determined in step d) and the deviation of the calculated transverse acceleration from the actual transverse acceleration determined in step e) using the following equation;

space="preserve" listing-type="equation">Δ

B.sub.i =C.sub.2 P.sub.yi '"'"' (Δ

Y-Δ

Y.sub.F)+C.sub.2 P.sub.φ

i '"'"'(Δ

φ

-Δ

φ

.sub.F) (IV)

wherein i designates one of the n tires; and

wherein c₁ and c₂ are predetermined weighting factors for changes in the transverse acceleration and the yaw rate,

g) changing brake pressures at each tire according to the braking force changes calculated in step f).

4. A method according to claim 3, wherein in step f) the braking forces have differential (PD) and integral components (PI,PID).