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Method for electrically actuated braking of a motor vehicle and electrically actuated brake system

  • US 6,079,801 A
  • Filed: 10/26/1998
  • Issued: 06/27/2000
  • Est. Priority Date: 10/24/1997
  • Status: Expired due to Term
First Claim
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1. A method of operating an electrically actuated braking system of a motor vehicle, which comprises the following steps:

  • measuring wheel speeds of individual wheels of a motor vehicle with wheel sensors;

    individually controlling electrical, continuously acting wheel brake actuators such that an independent brake pressure is applied to each wheel of the motor vehicle;

    carrying out the following calculation and control procedures in a control unit;

    calculating a wheel slip and a wheel acceleration for each wheel;

    storing a respective actual value of the brake pressure in case of an upward transgression of a predefined first threshold value for one of the wheel slip and the wheel acceleration;

    forming a quotient of the stored actual value and a pressure value that is characteristic of the motor vehicle at a coefficient of friction μ

    =1 for the respective wheel, and estimating a first coefficient of friction;

    carrying out a brake-pressure closed-loop control operation to prevent locking at the individual wheels with reference to the estimated coefficient of friction in accordance with a predefined algorithm;

    clearing the first coefficient of friction in case of a downward transgression of a second threshold value for one of the wheel slip and the wheel acceleration, and replacing the first coefficient of friction with a new estimated coefficient of friction that can be increased up to a value for a dry underlying surface; and

    using the stored brake pressure as a setpoint value for a brake-pressure closed-loop control operation to prevent locking.

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