Process for improving the regulating behavior of an anti-lock systems

• US 6,012,010 A
• Filed: 05/04/1998
• Issued: 01/04/2000
• Est. Priority Date: 06/22/1995
• Status: Expired due to Term

• Current Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Original Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Inventors: Buttner, Hans-Joachim, Fennel, Helmut, Batistic, Ivica
• Primary Examiner(s): Louis-Jacques, Jacques H.
• Assistant Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US08/981,165
• Time in Patent Office: 610 Days
• Field of Search: 701/70, 701/71, 701/72, 701/74, 701/78, 701/83, 701/89, 701/91, 303/163, 303/165, 303/186, 303/189, 303/901, 180/197, 340/444
• US Class Current: 701/72
• CPC Class Codes: B60T 2201/16 Curve braking control, e.g. turn control within ABS control algorithm
• 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: Y10S 303/901 ABS check valve detail

Abstract

To improve the control behavior of an anti-lock control system or brake slip control system, more particularly, to improve the steerability of a vehicle and its drivability when braking during cornering is performed, criteria for cornering identification and for determining the direction of cornering are derived from the wheel slip of the individual wheels. When cornering is identified, the normal control mode which is intended for straight travel and is configured for an individual control of all wheels or an individual control of the front wheels in conjunction with a select-low control of the rear wheels is changed to a cornering control mode. In the cornering control mode, the average pressure level of the curve-inward front wheel is decreased by a predetermined value and the average pressure level of the curve-outward front wheel is increased by a predetermined value. A corresponding variation of the average pressure level on the rear wheels is also possible in vehicles having a select-low control and valve pairs on the individual wheels.

Claims

1. A method of improving the control behavior of an anti-lock control system for a four-wheeled vehicle during cornering, wherein the rotational behavior of the vehicle wheels is measured and evaluated to determine a vehicle reference speed which is used as a reference value for ascertaining a wheel slip as well as for braking pressure modulation, and wherein criteria for cornering identification and for identification of the direction of cornering are derived from the wheel slip of the individual wheels, wherein, when cornering is identified, a normal control mode--which is intended for straight travel and is configured for an individual control of multiple wheels--is changed to a cornering control mode, wherein in comparison to the normal control mode, an average braking pressure level of the curve-inward front wheel is decreased by a predetermined value and an average braking pressure level of the curve-outward front wheel is increased by a predetermined value wherein, in a vehicle with a select-low control on the rear wheels, the average pressure level is decreased on the curve-inward rear wheel and increased on the curve-outward rear wheel in the cornering control mode.

2. The method as claimed in claim 1,

wherein the amount of variation of at least one of the average braking pressure levels is a function of the rotational speed difference of the rear wheels.

3. The method as claimed in claim 1 wherein, when programmed circuitries and filters with a low-pass characteristic are used, the filtered wheel slip signals are produced according to the relation

4. The method as claimed in claim 3, wherein the time constant ranges in the order between 50 and 100 msec.

5. A method of improving the control behavior of an anti-lock control system for a four-wheeled vehicle during cornering, wherein the rotational behavior of the vehicle wheels is measured and evaluated to determine a vehicle reference speed which is used as a reference value for ascertaining a wheel slip as well as for braking pressure modulation, and wherein criteria for cornering identification and for identification of the direction of cornering are derived from the wheel slip of the individual wheels, wherein, when cornering is identified, a normal control mode--which is intended for straight travel and is configured for an individual control of multiple wheels--is changed to a cornering control mode, wherein in comparison to the normal control mode, an average braking pressure level of the curve-inward front wheel is decreased by a predetermined value and an average braking pressure level of the curve-outward front wheel is increased by a predetermined value wherein, for cornering identification, the wheel slip values of the individual wheels are filtered and the filtered values are compared, and wherein switch-over to the cornering control mode is effected when simultaneously the filtered wheel slip on the two front wheels is in excess of a predetermined front-wheel-related maximum slip value that is responsive to a vehicle reference speed, the filtered wheel slip of one rear wheel is above a predetermined rear-wheel-related maximum slip value that is responsive to the vehicle reference speed, and the filtered wheel slip of the other rear wheel is below a predetermined rear-wheel-related minimum slip value that is responsive to the vehicle reference speed, and wherein the rear wheel having the higher speed is assessed as the curve-outward rear wheel to determine the direction of cornering.

6. The method as claimed in claim 5, wherein a value in the order between 3 and 10% of the vehicle reference speed is predetermined for the front-wheel-related maximum slip value, a value in the order between 2 and 5% of the vehicle reference speed is predetermined for the rear-wheel-related maximum slip value, and a value in the order between 0.5 and 2% of the vehicle reference speed is predetermined for the rear-wheel-related minimum slip value.

7. A method of improving the control behavior of an anti-lock control system for a four-wheeled vehicle during cornering, wherein the rotational behavior of the vehicle wheels is measured and evaluated to determine a vehicle reference speed which is used as a reference value for ascertaining a wheel slip as well as for braking pressure modulation, and wherein criteria for cornering identification and for identification of the direction of cornering are derived from the wheel slip of the individual wheels, wherein, when cornering is identified, a normal control mode--which is intended for straight travel and is configured for an individual control of multiple wheels--is changed to a cornering control mode, wherein in comparison to the normal control mode, an average braking pressure level of the curve-inward front wheel is decreased by a predetermined value and an average braking pressure level of the curve-outward front wheel is increased by a predetermined value wherein a difference of filtered slip values of the rear wheels is determined in the cornering control mode, and a control threshold on the curve-inward front wheel, which defines an average pressure level, is increase according to the relation

View Dependent Claims (8)

8. The method as claimed in claim 7, wherein, during brake operations without anti-lock control, the constants k₁ k₂ adopt different predetermined values versus brake operations with anti-lock control.