Vehicle stabilization device and method

• US 9,187,121 B2
• Filed: 09/07/2012
• Issued: 11/17/2015
• Est. Priority Date: 12/09/2011
• Status: Active Grant

• Current Assignee: Wabco GmbH (Wabco Holdings Incorporated)
• Original Assignee: Wabco GmbH (Wabco Holdings Incorporated)
• Inventors: Gerecke, Marc, Kopper, Heiko, Michaelsen, Arne
• Primary Examiner(s): Cheung, Mary
• Assistant Examiner(s): WONG, YUEN H
• Application Number:
  US14/362,769
• Publication Number:
  US 20140365078A1
• Time in Patent Office: 1,166 Days
• US Class Current: 1/1
• CPC Class Codes: B60T 2260/02 Active Steering, Steer-by-Wire
• 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: B62D 6/003 in order to control vehicle yaw movement, i.e. around a vertical axis B62D6/007 takes precedence
• CPC Class Codes: B62D 6/04 responsive only to forces disturbing the intended course of the vehicle, e.g. forces acting transversely to the direction of vehicle travel
• CPC Class Codes: B62D 7/159 characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition

Abstract

For stabilizing a vehicle, a steering angle of at least one steered front axle and/or additional axle is changed by automatic forced steering Additional drive stabilization is achievable by initiating an adjustment of a changed steering angle of the steered front axle and/or additional axle in response to a tilting tendency of the vehicle recognized via a tilt-stability control device as above a tilt limit, in addition to initiating a vehicle delay for reducing this tilting tendency. This counteracts an understeering or oversteering influence of the vehicle delay Additionally or alternatively, additional drive stabilization is achievable by determining the direction of movement in the wheel contact point of an additional axle wheel on the steered additional axle relative to the vehicle'"'"'s longitudinal axis and adjusting the steering angle of the steered additional axle based thereon to reduce the drift angle of the additional axle wheel relative to its direction of movement.

Claims

1. A vehicle stabilization method, in which at least one of a steering angle of at least one steerable front axle of a vehicle and a steering angle of at least one steerable additional axle of the vehicle is changed relative to a longitudinal axis of the vehicle by automatic forced steering of the at least one steerable front axle and the at least one steerable additional axle, the method comprising:

a) when a tilt tendency of the vehicle is detected by a tilt stability control device as being greater than a tilt limit angle, decelerating the vehicle to reduce the tilt tendency, and using a track keeping device to adjust at least one of (i) a changed steering angle of the at least one steerable front axle and (ii) a changed steering angle of the at least one steerable additional axle to counteract one of understeering and oversteering of the vehicle resulting from decelerating the vehicle; and

b) determining a direction of motion at a wheel contact point of at least one additional axle wheel disposed on the at least one steerable additional axle relative to the longitudinal axis of the vehicle, adjusting the steering angle of the at least one steerable additional axle based on the direction of motion to reduce a drift angle of the at least one additional axle wheel relative to the direction of motion, determining whether there is one of understeering of the vehicle in excess of a preselected understeer limit value, and oversteering of the vehicle in excess of a preselected oversteer limit value, and effecting at least one braking intervention on the at least one additional axle wheel of the at least one steerable additional axle when one of understeering of the vehicle in excess of the understeer limit value and oversteering of the vehicle in excess of the oversteer limit value is determined.

2. The stabilization method as claimed in claim 1, wherein a track radius of the vehicle about a point of rotation corresponds to a steering angle demand by a steering wheel of the vehicle even during decelerating of the vehicle and adjusting of at least one of the changed steering angle of the at least one steerable front axle and the changed steering angle of the at least one steerable additional axle.

3. The stabilization method as claimed in claim 1, wherein decelerating the vehicle includes operating at least one wheel brake of the vehicle.

4. The stabilization method as claimed in claim 1, wherein adjusting the steering angle of the at least one steerable additional axle is effected only when one of understeering of the vehicle in excess of the understeer limit value and oversteering of the vehicle in excess of the oversteer limit value is determined.

5. A vehicle stabilization device for stabilizing a vehicle by changing at least one of a steering angle of at least one steerable front axle of the vehicle and a steering angle of at least one steerable additional axle of the vehicle relative to a longitudinal axis of the vehicle by automatic forced steering of the at least one steerable front axle and the at least one steerable additional axle, the device comprising:

a) a track keeping device configured to adjust at least one of (i) a changed steering angle of the at least one steerable front axle and (ii) a changed steering angle of the at least one steerable additional axle to counteract one of understeering and oversteering of the vehicle resulting from decelerating the vehicle to reduce a tilt tendency of the vehicle detected by a tilt stability control device as being greater than a tilt limit angle; and

b) an estimation device configured to determine a direction of motion at a wheel contact point of at least one additional axle wheel disposed on the at least one steerable additional axle relative to the longitudinal axis of the vehicle, a drift angle reduction device configured to adjust the steering angle of the at least one steerable additional axle based on the direction of motion to reduce a drift angle of the at least one additional axle wheel relative to the direction of motion, a direction of travel deviation detector configured to detect understeering of the vehicle greater than a preselected understeer limit value and oversteering of the vehicle greater than a preselected oversteer limit value, and a braking intervention device configured to activate at least one braking intervention on the at least one additional axle wheel of the at least one steerable additional axle when there is one of understeering of the vehicle greater than the understeer limit value and oversteering of the vehicle greater than the oversteer limit value.

6. The stabilization device as claimed in claim 5, wherein the track keeping device is configured such that a track radius of the vehicle about a point of rotation corresponds to a steering angle demand by a steering wheel of the vehicle even during deceleration of the vehicle and adjustment of at least one of the changed steering angle of the at least one steerable front axle and the changed steering angle of the at least one steerable additional angle.

7. The stabilization device as claimed in claim 5, further comprising a brake operating device configured to operate at least one wheel brake of the vehicle to decelerate the vehicle.

8. The stabilization device as claimed in claim 5, wherein the drift angle reduction device is configured such that the steering angle of the at least one steerable additional axle is adjusted only when there is one of understeering of the vehicle greater than the understeer limit value and oversteering of the vehicle greater than the oversteer limit value.

9. A vehicle stabilization device configured to effect a vehicle stabilization method in which at least one of a steering angle of at least one steerable front axle of a vehicle and a steering angle of at least one steerable additional axle of the vehicle relative to a longitudinal axis of the vehicle is changed by automatic forced steering of the at least one steerable front axle and the at least one steerable additional axle, the method comprising:

a) when a tilt tendency of the vehicle is detected by a tilt stability control device as being greater than a tilt limit angle, decelerating the vehicle to reduce the tilt tendency, and adjusting at least one of (i) a changed steering angle of the at least one steerable front axle and (ii) a changed steering angle of the at least one steerable additional axle to counteract one of understeering and oversteering of the vehicle resulting from decelerating the vehicle; and

b) determining a direction of motion at a wheel contact point of at least one additional axle wheel disposed on the at least one steerable additional axle relative to the longitudinal axis of the vehicle, adjusting the steering angle of the at least one steerable additional axle based on the direction of motion to reduce a drift angle of the at least one additional axle wheel relative to the direction of motion, determining whether there is one of understeering of the vehicle in excess of a preselected understeer limit value and oversteering of the vehicle in excess of a preselected oversteer limit value, and effecting at least one braking intervention on the at least one additional axle wheel of the at least one steerable additional axle when one of understeering of the vehicle in excess of the understeer limit value and oversteering of the vehicle in excess of the oversteer limit value is determined.

10. A vehicle, comprising at least one steerable front axle;

at least one steerable additional axle; and

a vehicle stabilization device for stabilizing the vehicle by changing at least one of a steering angle of the at least one steerable front axle and a steering angle of the at least one steerable additional axle of the vehicle relative to a longitudinal axis of the vehicle by automatic forced steering of the at least one steerable front axle and the at least one steerable additional axle, the device comprising;

a track keeping device configured to adjust at least one of (i) a changed steering angle of the at least one steerable front axle and (ii) a changed steering angle of the at least one steerable additional axle to counteract one of understeering and oversteering of the vehicle resulting from decelerating the vehicle to reduce a tilt tendency of the vehicle detected by a tilt stability control device as being greater than a tilt limit angle;

an estimation device configured to determine a direction of motion at a wheel contact point of at least one additional axle wheel disposed on the at least one steerable additional axle relative to the longitudinal axis of the vehicle;

a drift angle reduction device configured to adjust the steering angle of the at least one steerable additional axle based on the direction of motion to reduce a drift angle of the at least one additional axle wheel relative to the direction of motion;

a direction of travel deviation detector configured to detect understeering of the vehicle greater than a preselected understeer limit value and oversteering of the vehicle greater than a preselected oversteer limit value; and

a braking intervention device configured to activate at least one braking intervention on the at least one additional axle wheel of the at least one steerable additional axle when there is one of understeering of the vehicle greater than the understeer limit value and oversteering of the vehicle greater than the oversteer limit value.