Method and device for stabilizing a vehicle

• US 6,494,281 B1
• Filed: 03/06/2000
• Issued: 12/17/2002
• Est. Priority Date: 04/07/1998
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Faye, Ian, Wetzel, Gabriel, Leimbach, Klaus-Dieter
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): Klebe, G. B.
• Application Number:
  US09/445,521
• Time in Patent Office: 1,016 Days
• Field of Search: 180/282, 180/197, 180/271, 180/170, 701/69, 701/70, 701/71, 701/82, 364/426.02, 364/426.03, 303/7, 303/140, 303/146, 303/125
• US Class Current: 180/197
• CPC Class Codes: B60K 31/00 Vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator fittings acting on two or more sub-units B60W30/14; speedometers G01P; systems or devices for controlling speed in general G05D13/00 ; in traffic anti-collision system for road vehicles G08G1/16
• CPC Class Codes: B60T 2230/03 Overturn, rollover
• CPC Class Codes: B60T 2270/313 with less than three sensors (yaw rate, steering angle, lateral acceleration)
• CPC Class Codes: B60T 8/17554 specially adapted for enhancing stability around the vehicles longitudinal axle, i.e. roll-over prevention road vehicle drive control systems for roll-over prevention otherwise than by controlling a particular sub-unit B60W30/04
• CPC Class Codes: B60T 8/243 for roll-over protection
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 30/18145 Cornering

Abstract

A method of stabilizing a motor vehicle, preferably to prevent a vehicle from rolling over about a vehicle axis oriented in a longitudinal direction of the vehicle. To do so, a quantity describing the transverse dynamics of the vehicle is determined. This quantity is compared with at least one characteristic value, in particular a threshold value, for this quantity. For the case when the quantity describing the transverse dynamics of the vehicle is greater than or equal to the characteristic value, a speed of the vehicle is reduced to or maintained at a preselectable speed value at least by braking measures on at least one wheel and/or by engine measures and/or by retarder measures (SR).

Claims

1. A method of stabilizing a vehicle to prevent the vehicle from rolling over about a vehicle axis oriented in a longitudinal direction of the vehicle, comprising the steps of:

determining a first quantity describing transverse dynamics of the vehicle, the first quantity being determined at least as a function of a speed of the vehicle and a yaw rate of the vehicle, the first quantity not being determined as a function of the output of a transverse acceleration sensor;

comparing the first quantity with at least one characteristic value for the first quantity; and

when the first quantity is at least equal to the at least one characteristic value, performing one of the steps of reducing a speed of the vehicle to and keeping the speed at a preselectable speed value by performing at least one of the steps of;

implementing brake measures on at least one wheel of the vehicle,

implementing engine measures, and

implementing retarder measures.

2. The method according to claim 1, wherein the at least one characteristic value corresponds to a threshold value.

3. The method according to claim 2, wherein the first quantity corresponds to a quantity describing a transverse acceleration of the vehicle.

4. The method according to claim 2, wherein the yaw rate of the vehicle is determined as a function of the speed of the vehicle and a steering angle of the vehicle.

5. The method according to claim 1, wherein at least one of the following conditions occurs:

the at least one characteristic value corresponds to one of a fixedly predetermined value and a value determined for a respective driving condition of the vehicle, and

a value of the first quantity allowed for the vehicle without the vehicle becoming unstable on attaining the value of the first quantity is used as the at least one characteristic value.

6. The method according to claim 1, further comprising the step of:

determining the at least one characteristic value at least as a function of a wheel load of at least one wheel of the vehicle.

7. The method according to claim 6, wherein the wheel load is determined as a function of a contact force of a respective one of the at least one wheel.

8. The method according to claim 6, further comprising the steps of:

performing one of the steps of;

determining the at least one characteristic value as a function of a wheel load of at least one inside wheel during a turning operation, and

determining a mass of the vehicle as a function of the wheel load of the at least one inside wheel, the at least one characteristic value being outputted from an engine characteristics map as a function of the mass of the vehicle.

9. The method according to claim 1, wherein the preselectable speed value is one of fixedly predetermined, determined at least as a function of at least one of the at least one characteristic value and the yaw rate of the vehicle, and determined using an engine characteristics map.

10. The method according to claim 1, further comprising the step of:

implementing at least one of the braking measures, the engine measures, and the retarder measures as long as the preselectable speed value is lower than the speed of the vehicle.

11. The method according to claim 1, further comprising the step of:

performing one of the steps of;

uniformly braking all wheels of the vehicle via appropriate braking measures, and

braking all of the wheels of the vehicle via appropriate braking measures, involving at least one of the steps of;

braking at least a rear inside wheel during a turning operation less than the other wheels of the vehicle,

not braking the rear inside wheel during the turning operation, and

reducing a moment delivered by an engine via appropriate engine measures.

12. The method according to claim 1, further comprising the steps of:

reducing the at least one characteristic value by a small value;

comparing the first quantity with the reduced at least one characteristic value;

when the first quantity is greater than the reduced at least one characteristic value, reducing the speed of the vehicle to the preselectable speed value by performing at least one of the brake measures on at least one wheel of the vehicle, the engine measures, and the retarder measures.

13. A device for stabilizing a vehicle to prevent the vehicle from rolling over about a vehicle axis oriented in a longitudinal direction of the vehicle, the device comprising:

a comparing device for determining a quantity describing a transverse dynamic of the vehicle and comparing the quantity to at least one characteristic value for the quantity;

the quantity being determined at least as a function of a speed of the vehicle and a yaw rate of the vehicle, the quantity not being determined as a function of the output of a transverse acceleration sensor; and

a braking system for performing, when the quantity is at least equal to the at least one characteristic value, one of reduction of a speed of the vehicle to a preselectable speed value and a maintenance of the speed of the vehicle at the preselectable speed by at least one of braking measures on at least one wheel of the vehicle, engine measures, and retarder measures.

14. The device according to claim 13, wherein the at least one characteristic value corresponds to a threshold value.

15. The device according to claim 13, wherein the quantity describing the transverse dynamic of the vehicle corresponds to a quantity describing a transverse acceleration of the vehicle.

16. The device according to claim 13, wherein the yaw rate of the vehicle is determined as a function of the speed of the vehicle and a steering angle of the vehicle.