Method for adapting the control strategy of a slip-control system of a vehicle in a μ-split-situation

Patent metadata

Field	Value
Publication number	US-10315634-B2
Application number	US-201715433605-A
Country	US
Kind code	B2
Filing date	Feb 15, 2017
Priority date	Aug 15, 2014
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

The disclosure relates to a method for adapting a control strategy of a slip-control system of a brake system of a vehicle in a μ-split situation, in which different wheel-specific brake pressures, are set at opposite wheels of a vehicle axle. The resulting brake pressure difference is limited. In some examples, to generate a brake pressure request, a maximum pressure difference value deviating from a reference pressure difference with a predefined tolerance value is determined on a wheel-specific basis for the wheels lying opposite one another. The reference pressure difference corresponds to the value of the current low-pass-filtered brake pressure difference, and the brake pressure request for each wheel is determined as a minimum of the wheel-specific brake pressure determined from the control strategy of the slip-control system, and from the sum of the average brake pressure of the wheel lying opposite and the wheel-specific maximum pressure difference value.

First claim

What is claimed is:

1. A method for adapting a control strategy of a slip control system of a brake system of a vehicle in a μ-split situation, in which wheel-specific brake pressures (P req, wdc, i+1, 0 ,P req, wdc, i+1, 1 ) that are defined differently from the control strategy of the slip control system are set at opposite vehicle wheels (LM-wheel 0, HM-wheel 1) of a vehicle axle, and in doing so a resulting brake pressure difference is limited, wherein:
determining a maximum wheel-specific pressure difference value (p diff, i+1, 0 , p diff, i+1, 1 ) for producing a brake pressure demand (P req, i+1, 0, P req, i+1, 1 ) for the opposite vehicle wheels (LM-wheel 0, HM-wheel 1), where the maximum wheel-specific pressure difference value (p diff, i+1, 0, p diff, i+1, 1 ) deviates with a predetermined tolerance value (P tol ) from a reference pressure difference (p 01 ), the reference pressure difference corresponds to a value of a current low-pass filtered brake pressure difference (p filt, diff, i ), and
determining the brake pressure demand for each of the vehicle wheels (LM-wheel 0, HM-wheel 1), which includes a minimum of the wheel-specific brake pressure that is determined from the control strategy of the slip control system, and a sum of:
the wheel-specific brake pressure for the opposite vehicle wheel that is determined from the control strategy of the slip control systems, and
the maximum wheel-specific pressure difference value (p diff, i+1, 0, p diff, i+1, 1 ), where the maximum wheel-specific pressure difference value (p diff, i+1, 0, p diff, i+1, 1 ) deviates from the value of the current low-pass filtered brake pressure difference (p filt, diff i ) by the predetermined tolerance value (p tol ).

2. The method of claim 1 , wherein, identical tolerance values are used for the determination of the maximum wheel-specific pressure difference value for the opposite vehicle wheels.

3. The method of claim 1 , wherein different tolerance values are used for the determination of the maximum wheel-specific pressure difference value for the opposite vehicle wheels.

4. The method of claim 1 , wherein the brake pressure difference is modified depending on a difference of accelerations of two mutually opposite vehicle wheels and is then low-pass filtered.

5. A method for adapting a control strategy of a slip control system of a brake system of a vehicle in a μ-split situation, in which wheel-specific brake pressures (P req, wdc, 1+1, 0, P req, wdc, i+1, 1 ) that are defined differently from the control strategy of the slip control system are set at opposite vehicle wheels (LM-wheel 0, HM-wheel 1) of a vehicle axle, and in doing so a resulting brake pressure difference is limited, wherein:
determining a maximum wheel-specific pressure difference value (p diff, i+1, 0, p diff, i+1, 1 ) for producing a brake pressure demand (P req, i+1, 0, P req, i+1, 1 ) for the opposite vehicle wheels (LM-wheel 0, HM-wheel 1), where the maximum wheel-specific pressure difference value (p diff, i+1, 0, p diff, i+1, 1 ) deviates with a predetermined tolerance value (p tol ) from a reference pressure difference (p 01 ), the reference pressure difference corresponds to a value of a current low-pass filtered brake pressure difference (p filt, diff, i ), and
determining the brake pressure demand for each of the vehicle wheels (LM-wheel 0, HM-wheel 1), which includes a minimum of the wheel-specific brake pressure that is determined from the control strategy of the slip control system, and a sum of:
an average brake pressure of the opposite vehicle wheel, and
the maximum wheel-specific pressure difference value (p diff, i+1, 0, p diff, i+1, 1 ), where the maximum wheel-specific pressure difference value (p diff, i+1, 0, p diff, i+1, 1 ) deviates from the value of the current low-pass filtered brake pressure difference (p filt, diff i ) by the predetermined tolerance value (p tol ).

6. The method of claim 5 , wherein for the determination of the brake pressure demand, the average brake pressure of the opposite vehicle wheel is modified depending on an average acceleration thereof.

7. The method of claim 6 , wherein, identical tolerance values are used for the determination of the maximum wheel-specific pressure difference value for the opposite vehicle wheels.

8. The method of claim 5 , wherein different tolerance values are used for the determination of the maximum wheel-specific pressure difference value for the opposite vehicle wheels.

9. The method of claim 5 , wherein the brake pressure difference is modified depending on a difference of accelerations of two mutually opposite vehicle wheels and is then low-pass filtered.

Assignees

• Continental Teves Ag & Co Ohg

Inventors

• Kerber Henning
• Roszyk Mario
• Müller Jochen
• Cornils Arne
• Burkhard Dieter

Classifications

• B60T8/1764 Primary

  Regulation during travel on surface with different coefficients of friction, e.g. between left and right sides, mu-split {or between front and rear} · CPC title

• B60T8/1763

  responsive to the coefficient of friction between the wheels and the ground surface (B60T8/1764 takes precedence) · CPC title

• B60T2210/124

  Roads with different friction levels · CPC title

• B60T8/171

  Detecting parameters used in the regulation; Measuring values used in the regulation · CPC title

• B60T8/1761

  responsive to wheel or brake dynamics, e.g. wheel slip, wheel acceleration or rate of change of brake fluid pressure · CPC title