Method for controlling motor vehicle stability

• US 5,402,342 A
• Filed: 07/12/1993
• Issued: 03/28/1995
• Est. Priority Date: 09/04/1992
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Hartmann, Uwe, Ehret, Thomas
• Primary Examiner(s): Chin, Gary
• Application Number:
  US08/090,837
• Time in Patent Office: 624 Days
• Field of Search: 364/424.05, 364/426.02, 364/426.03, 180/197, 303/100, 303/106
• US Class Current: 701/1
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/206 Body oscillation speed; Body vibration frequency
• CPC Class Codes: B60G 2400/41 Steering angle
• CPC Class Codes: B60G 2500/40 Steering
• CPC Class Codes: B60G 2800/90 System Controller type
• CPC Class Codes: B60G 2800/92 ABS - Brake Control
• 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: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B62D 37/00 Stabilising vehicle bodies without controlling suspension arrangements

Abstract

A method for controlling vehicle stability comprises the steps of determining the rate of yaw and comparing it to a setpoint rate of yaw. The deviation is used to adjust a counter rate of yaw by means of a controller when the rate of yaw is too large. An optimal profile for a setpoint rate of yaw is determined, even when parameters such as the coefficient of friction of the road surface and the vehicle speed vary.

Claims

1. A method for controlling vehicle stability during curve travel, comprising the steps of:

determining a steering angle δ

, a rate of yaw ω

, a vehicle speed v_F, and a vehicle acceleration a;

determining a setpoint rate of yaw ω

_setpoint as a function of the steering angle δ and

the vehicle speed v_F, such that if the steering angle δ

falls within a lower range, the setpoint rate of yaw ω

_setpoint rises linearly with the steering angle δ

, and if the steering angle δ

falls within an upper range, the setpoint rate of yaw ω

_setpoint is constant, the lower and upper ranges being separated by a transition region;

comparing the determined rate of yaw ω

to a profile of the setpoint rate of yaw ω

_setpoint to determine a deviation Δ

ω

;

wherein the setpoint rate of yaw ω

_setpoint is determined in accordance with the relation

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

.sub.setpoint =x ω

.sub.setpoint.sup.0 +(1-x) ω

.sub.setpoint.sup.1

wherein ω

_setpoint⁰ is determined by the relation ##EQU2## wherein L represents a vehicle wheelbase and VCH represents a characteristic speed of the vehicle, wherein ω

_setpoint¹ is determined by the relation

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

.sub.setpoint.sup.1 =aq'"'"'/v.sub.F

wherein a second transversal acceleration aq'"'"' of the vehicle is as follows;

space="preserve" listing-type="equation">aq'"'"'=aq.sub.min for aq>

0 and aq<

aq.sub.min

space="preserve" listing-type="equation">aq'"'"'=aq.sub.min for aq<

0 and aq>

-aq.sub.min

space="preserve" listing-type="equation">aq'"'"'=aq otherwise

wherein aq represents a first transversal acceleration of the vehicle and aq_min represents a lowest value for aq on public streets during cornering travel of the vehicle in an extreme vehicle operating range, wherein x is determined by the relation

space="preserve" listing-type="equation">x=(ω

.sub.setpoint.sup.1 /ω

.sub.setpoint.sup.0 -k).sup.n /(1-k).sup.n

wherein k is a first constant between 0 and 1, n is a second constant greater than 0, and x is limited to values between and including 0 and 1; and

controlling the stability of a vehicle during said curve travel based upon the determined deviation Δ

ω

.

2. The method according to claim 1, wherein the first constant k is dependent upon the type of vehicle.

3. The method according to claim 1, wherein the second constant n is dependent upon the type of vehicle.

4. The method according to claim 1, wherein the first constant k is equal to 0.5.