Method and device for stabilizing a motor vehicle in order to prevent it from rolling over

• US 6,349,247 B1
• Filed: 10/13/2000
• Issued: 02/19/2002
• Est. Priority Date: 01/21/1998
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Jundt, Oliver, Hecker, Falk, Schramm, Herbert, Leimbach, Klaus-Dieter
• Primary Examiner(s): Beaulieu, Yonel
• Application Number:
  US09/600,683
• Time in Patent Office: 494 Days
• Field of Search: 701/1, 701/38, 701/72, 701/74, 701/82, 701/45, 280/271, 340/429
• US Class Current: 701/1
• 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

Abstract

A method for stabilizing a vehicle in particular to prevent overturning, in which a strategy is selected from at least two different strategies as a function of a quantity describing or corresponding to whether an overturn tendency about a vehicle axis oriented in the longitudinal direction of the vehicle exists, and which may be determined at least as a function of a quantity describing or corresponding to the wheel behavior of at least one wheel, and which may also be determined a function of a comparison which is carried out as a function of a quantity describing or corresponding to the lateral dynamics of the vehicle and of a characteristic value that is determined as a function of a quantity describing or corresponding to the instantaneous friction conditions.

Claims

1. A method for stabilizing a vehicle, the stabilizing including preventing the vehicle from overturning about a vehicle axis oriented in a longitudinal direction of the vehicle, the method comprising the steps of:

(a) performing at least one of the steps of;

(i) determining if an overturn tendency exists for the vehicle; and

(ii) making a comparison as a function of a quantity corresponding to lateral dynamics of the vehicle and of a characteristic value for the quantity corresponding to the lateral dynamics of the vehicle; and

(b) selecting a strategy for stabilizing the vehicle to prevent overturning from at least two different strategies as a function of at least one of the steps of determining and making; and

(c) performing at least one intervention for stabilizing the vehicle based on a selected one of the at least two different strategies, wherein one of the at least one intervention for one of the at least two different strategies is different than another of the at least one intervention for another of the at least two different strategies.

2. The method of claim 1, further comprising the step of performing another comparison as a function of the quantity corresponding to the lateral dynamics of the vehicle and of the characteristic value;

wherein the step of selecting a strategy includes the step of determining as a function of the another comparison whether to select one of the at least two strategies.

3. The method of claim 2, wherein:

the step of performing the another comparison includes the steps of;

determining a difference using the characteristic value and a magnitude of the quantity corresponding to the lateral dynamics of the vehicle; and

comparing the difference to a predefinable threshold value; and

the step of selecting a strategy is performed based on the step of comparing by selecting no strategy if the difference is greater than the predefinable threshold value, and by selecting one of the at least two strategies if the difference is not greater than the predefinable threshold value.

4. The method of claim 1, wherein a first strategy of the at least two strategies includes the step of performing at least one of an engine intervention and a brake intervention at at least one wheel having a large wheel load so that the at least one wheel is braked heavily.

5. The method of claim 1, further comprising the steps of:

performing at least one of the steps of;

making another comparison as a function of a difference determined from the characteristic value and a magnitude of the quantity corresponding to the lateral dynamics of the vehicle; and

making still another comparison as a function of the quantity corresponding to the lateral dynamics of the vehicle; and

determining whether to perform at least one of a brake intervention and an engine intervention of at least one of a first strategy and a second strategy as a function of at least one of the another comparison and the still another comparison.

6. The method of claim 1, wherein a second strategy of the at least two strategies includes the step of performing at least one of a brake intervention to uniformly brake all wheels of the vehicle and an engine intervention to reduce engine torque.

7. The method of claim 4, wherein:

the at least one of the brake intervention and the engine intervention is performed so that the quantity corresponding to the lateral dynamics of the vehicle approaches but does not exceed the characteristic value; and

the at least one of the brake intervention and the engine intervention at least depends on a difference determined using the characteristic value and the quantity corresponding to the lateral dynamics of the vehicle.

8. The method of claim 5, wherein for at least one of the steps of making the third comparison and making the fourth comparison:

the step of making the another comparison includes at least one of the steps of;

comparing the difference to a first threshold value; and

comparing a quantity corresponding to a time-related change of the difference to a second threshold value; and

the step of making the still another comparison includes the step of comparing a time-related change of the quantity corresponding to the lateral dynamics of the vehicle to a third threshold value;

wherein;

the at least one of the brake intervention and the engine intervention of the at least one of the first strategy and the second strategy is not performed if the difference is positive and the quantity corresponding to the time-related change of the difference is greater than the second threshold value;

the at least one of the brake intervention and the engine intervention of the first strategy is performed if;

in the an other comparison, at least one of the following is satisfied;

the difference is negative and the quantity corresponding to the time-related change of the difference is not greater than the second threshold value; and

in the still another comparison, the time-related change of the quantity corresponding to the lateral dynamics is not greater than the third threshold value; and

the at least one of the brake intervention and the engine intervention of the second strategy is performed if;

in the another comparison, at least one the following is satisfied;

the difference is negative and the quantity corresponding to the time-related change of the difference is not greater than the second threshold value; and

in the still another comparison, the quantity corresponding to the time-related change of the lateral dynamics is greater than the third threshold value.

9. The method of claim 1, wherein the characteristic value is determined at least as a function of a quantity corresponding to instantaneous friction conditions associated with a driving situation.

10. The method of claim 1, wherein the step of making the comparison includes the step of determining a difference using the characteristic value and a magnitude of the quantity corresponding to the lateral dynamics of the vehicle, a first strategy being selected if the difference is negative and a second strategy being selected if the difference is not negative.

11. The method of claim 10, further comprising the step of:

making another comparison as a function of a quantity corresponding to a timerelated change of the difference;

wherein;

the at least one of the brake intervention and the engine intervention of the second strategy is performed if the quantity corresponding to the time-related change of the difference is greater than a corresponding threshold value; and

the at least one of the brake intervention and the engine intervention of the first strategy is performed if the quantity corresponding to the time-related change is not greater than the corresponding threshold value.

12. The method of claim 1, wherein the step of determining if an overturn tendency exists includes the steps of:

determining an overturn quantity at least as a function of a quantity corresponding to a wheel behavior of at least one wheel; and

determining if the overturn tendency exists based on the overturn quantity.

13. The method of claim 10, wherein:

the step of determining if the overturn tendency exists includes the step of determining an overturn quantity at least as a function of a quantity corresponding to a wheel behavior of at least one wheel; and

in the step of selecting, the first strategy is selected if the overturn tendency exists and the second strategy is selected if the overturn tendency does not exist, the at least one intervention of the first strategy including at least one of a brake intervention and an engine intervention.

14. The method of claim 12, wherein:

the quantity corresponding to the wheel behavior at least depends on a wheel load associated with a specific wheel; and

the quantity corresponding to the wheel behavior corresponds to at least one of a wheel slip, a quantity corresponding to a wheel speed, a quantity corresponding to one of a wheel deceleration and a wheel acceleration, and an indication of an intervention by a slip controller to stabilize at least one wheel.

15. The method of claim 14, wherein:

at least one of a brake intervention and an engine intervention is performed at at least one wheel for a short time at least as a function of the quantity corresponding to the lateral dynamics of the vehicle; and

at least one of the quantity corresponding to the wheel behavior and a quantity corresponding to the indication of the intervention by the slip controller is determined for at least one of;

while at least one of a braking torque and a drive torque is at least one of generated and changed at the at least one wheel for the short time; and

subsequent to the at least one of the braking torque and the drive torque being at least one of generated and changed at the at least one wheel for the short time.

16. The method of claim 15, further comprising the step of determining a resulting change in the quantity corresponding to the wheel behavior;

wherein the overturn tendency exists for at least one of a magnitude of the resulting change being greater than a corresponding threshold value and the quantity corresponding to the indication of the intervention by the slip controller.

17. The method of claim 13, wherein:

the step of determining the quantity corresponding to the wheel behavior of the specific wheel includes the step of determining a quantity corresponding to one of a diameter and a radius of the specific wheel, at least as a function of a quantity corresponding to at least one of the wheel speed of the specific wheel, a quantity corresponding to a vehicle speed, the quantity corresponding to the lateral dynamics of the vehicle, and a quantity corresponding to a geometry of the vehicle; and

the overturn tendency of the vehicle exists if the quantity corresponding to the ore of the diameter and the radius is greater than a corresponding threshold value.

19. The method of claim 14, wherein the slip controller is a wheel-slip controller.

20. The method of claim 15, wherein the slip controller is a wheel-slip controller.

18. A device for stabilizing a vehicle, the stabilizing including preventing the vehicle from overturning about a vehicle axis oriented in a longitudinal direction of the vehicle, the device comprising:

an arrangement for performing at least one of determining if an overturn tendency exists for the vehicle and making a first comparison as a function of a quantity corresponding to lateral dynamics of the vehicle and of a characteristic value for the quantity corresponding to the lateral dynamics of the vehicle;

an arrangement for selecting a strategy for stabilizing the vehicle to prevent overturning from at least two different strategies as a function of a result provided by the arrangement for performing the at least one of determining if the overturn tendency exists and making the first comparison; and

an arrangement for performing at least one intervention for stabilizing the vehicle based on a selected one of the at least two different strategies.