Method and device for detecting motor vehicle tilt

• US 6,272,420 B1
• Filed: 10/18/1999
• Issued: 08/07/2001
• Est. Priority Date: 11/22/1997
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schramm, Herbert, Wetzel, Gabriel, Leimbach, Klaus-Dieter, Dominke, Peter
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): PIPALA, EDWARD J
• Application Number:
  US09/355,133
• Time in Patent Office: 659 Days
• Field of Search: 701/1, 701/37, 701/38, 701/70-72, 701/91, 180/271, 180/272, 180/282, 280/5.502, 280/5.506, 280/5.507, 303/140, 303/146
• US Class Current: 701/72
• CPC Class Codes: B60R 16/0233 Vehicle tilting, overturning or roll over
• CPC Class Codes: B60T 2230/03 Overturn, rollover
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence

Abstract

A method and an apparatus relate to the detection of a tilt tendency of a vehicle about a vehicle axis oriented in the longitudinal direction of the vehicle. For this purpose, for at least one wheel, a variable describing the wheel rotation speed and at least one variable representing the transverse dynamics of the vehicle are ascertained. As a function of one of the variables representing the transverse dynamics of the vehicle, braking torques and/or drive torques are briefly generated and/or modified at at least one wheel. While the braking torques and/or drive torques at the at least one wheel are being briefly generated and/or modified, and/or after they have been briefly generated and/or modified, a variable which quantitatively describes the wheel behavior is determined for that at least one wheel, as a function of the variable describing the wheel rotation speed of that wheel. As a function of that variable quantitatively describing the wheel behavior of that wheel, a determination is made as to whether there is a tilt tendency of the vehicle about a vehicle axis oriented in the longitudinal direction of the vehicle.

Claims

1. A method for detecting a tilt tendency of a vehicle about a vehicle axis, the vehicle axis being oriented in a longitudinal direction of the vehicle, the method comprising the steps of:

(a) ascertaining, for at least one wheel, a variable describing a wheel rotation speed;

(b) ascertaining at least on variable representing transverse dynamics of the vehicle;

(c) at least one of generating and modifying at least one of a braking torque and drive torque at the least one wheel, the at least one of the generating and the modifying being a function of the at least one variable representing the transverse dynamics of the vehicle;

(d) determining a variable describing quantitatively a wheel behavior for the at least one wheel at least one of during and after step (c), the variable describing quantitatively the wheel behavior being a function of at least the variable describing the wheel rotation speed for the at lest one wheel; and

(e) determining whether the tilt tendency of the vehicle about the vehicle axis is present, the determining of whether the tilt tendency is present being a function of at least the variable describing quantitatively the wheel behavior for the at least one wheel.

2. The method according to claim 1, wherein the method is used for stabilizing the vehicle and the method further comprising the step of:

performing, in order to stabilize the vehicle, at least one of a braking intervention on the at least one wheel, an engine intervention and an intervention on chassis actuators when the tilt tendency is present.

3. The method according to claim 1, wherein the method is used for preventing a tipover of the vehicle and further comprising the step of:

performing, in order to prevent the vehicle from tipping over, at least one of a braking intervention on the at least one wheel, an engine intervention and an intervention on chassis actuators when the tilt tendency is present.

4. The method according to claim 2, wherein the performing of the braking intervention includes the step of performing a braking intervention at least on a front wheel on an outside of a curve so as to at least one of generate and increase a braking torque at the front wheel.

5. The method according to claim 3, wherein the performing of the braking intervention includes the step of performing a braking intervention at least on a front wheel on an outside of a curve so as to at least one of generate and increase a braking torque at the front wheel.

6. The method according to claim 1, wherein the determining of whether the tilt tendency is present includes the steps of:

comparing a magnitude of one of the at least one variable representing transverse dynamics of the vehicle to a threshold value; and

performing a detection of whether the tilt tendency is present if the magnitude is greater than the threshold value.

7. The method according to claim 6, wherein the at least one variable representing transverse dynamics of the vehicle includes a particular variable describing at least one of a transverse acceleration and a yaw rate of the vehicle, the particular variable being at least one of sensed by suitable measurement means and ascertained as a function of at least the variable describing the wheel rotation speed.

8. The method according to claim 1, wherein the determining of step (e) includes the steps of:

determining which of the at least one wheel is suitable for detecting the tilt tendency of the vehicle, the determining being a function of at least one of the at least one variable representing transverse dynamics of the vehicle; and

performing a detection of the tilt tendency of the vehicle by at least one of briefly generating and modifying at least one of a braking torque and a drive torque at the at least one wheel.

9. The method according to claim 8, wherein the step of determining which of the at least one wheel includes the steps of:

determining whether the vehicle is traveling through a curve, the determining whether the vehicle is traveling through the curve being a function of at least a variable ascertained from a variable describing at least one of a steering angle, a transverse acceleration of the vehicle and a yaw rate of the vehicle; and

selecting at least one wheel of wheels on an inside of the curve for detection of the tilt tendency of the vehicle.

10. The method according to claim 8, wherein the step of determining which of the at least one wheel includes taking into account a drive concept of the vehicle.

11. The method according to claim 1, wherein the at least one of the generating and the modifying at least one of the braking torque and the drive torque at the at least one wheel includes at least one of the following steps:

activating an actuator associated with a respective wheel so that at least one of a slight braking torque is built up and there is a slight change in a previously generated braking torque; and

activating a means associated with a vehicle engine and the actuator associated with the respective wheel so that at least one of a slight drive torque is generated and there is a slight change in a previously generated drive torque, the means associated with the vehicle engine influencing an engine torque delivered by the vehicle engine, the actuator associated with the respective wheel generating the braking torque at the respective wheel.

12. The method according to claim 1, wherein the step of ascertaining, for the at least one wheel, the variable describing the wheel rotation speed includes the step of:

ascertaining, for the at least one wheel, the variable describing quantitatively the wheel behavior from at least one of a variable describing a slip of a respective wheel, the variable describing the wheel rotation speed of the respective wheel, a variable describing a change over time in the wheel rotation speed of the respective wheel.

13. The method according to claim 12, wherein the step of ascertaining the variable describing quantitatively the wheel behavior includes the steps of:

ascertaining the variable describing the slip of the respective wheel as a function of at least one of the variable describing the wheel rotation speed of the respective wheel and a variable describing a vehicle speed; and

ascertaining the variable describing the vehicle speed as a function of at least one variable describing the wheel rotation speed.

14. The method according to claim 1, wherein the determining of step (e) includes the steps of:

ascertaining a resulting change in the variable describing quantitatively the wheel behavior for the at least one wheel at least one of during and after step (c), the ascertaining the resulting change in the variable describing quantitatively being used to detect the tilt tendency of the vehicle; and

comparing a magnitude of the resulting change in the variable describing quantitatively the wheel behavior to a corresponding threshold value such that if the magnitude is greater than the corresponding threshold value then the tilt tendency of the vehicle is present.

15. The method according to claim 1, wherein the at least one of generating and modifying of step (c) occurs simultaneously at all wheels of the vehicle.

16. An apparatus for detecting a tilt tendency of a vehicle about a vehicle axis, the vehicle axis being oriented in a longitudinal direction of the vehicle, comprising:

first means for ascertaining, for at least one wheel, a variable describing a wheel rotation speed;

second means for ascertaining at least one variable representing transverse dynamics of the vehicle;

third means for generating signals, the signals being a function of the at least one variable representing the transverse dynamics of the vehicle, the signals activating at least one of (A) an actuator associated with a respective wheel of the at least one wheel, the actuator at least one of briefly generating and modifying a braking torque at the respective wheel and (B) means for influencing a torque delivered by an engine and actuators associated with wheels of the vehicle, the influencing means and the actuators being activated such that a drive torque is at least one of briefly generated and modified at the respective wheel;

fourth means for determining a variable describing quantitatively a wheel behavior for the at least one wheel, the variable describing quantitatively the wheel behavior being a function of at least the variable ascertained by the first means for the at least one wheel, the fourth means determining the variable describing quantitatively the wheel behavior at least one of during and after at least one of briefly generating and modifying at least one of the braking torque and the drive torque at the at least one wheel; and

fifth means for determining the tilt tendency of the vehicle as a function of at least the variable determined by the fourth means for the at least one wheel.

17. The apparatus according to claim 16, wherein the apparatus is used for stabilizing the vehicle and wherein if the tilt tendency is present, then, for stabilizing the vehicle, at least at the at least one wheel, at least one of (a) the actuator associated with the at least one wheel generates a braking force, (b) the influencing means influences the engine torque and (c) chassis actuators are actuated.

18. The apparatus according to claim 17, wherein the at least one of (a), (b) and (c) includes the performance of a braking intervention at least on a front wheel on an outside of a curve, the braking intervention at least one of generating and increasing the braking torque at least at the front wheel.

19. The apparatus according to claim 16, wherein the stabilizing of the vehicle includes preventing tipover of the vehicle.