Method for compensating variations of a wheel speed sensor

Method of compensating inaccuracies in a wheel speed sensor, wherein signal-forming elements are arranged on a sensor wheel and wherein a determined angle is associated with a given number of signal-forming elements to determine a wheel speed, and wherein the wheel speed is determined by evaluating the time during which the wheel rotates around the angle, wherein a correction factor which is included in the determination of the wheel speed is memorized with respect to each element to compensate for variations of the signal-forming elements and/or the positioning of the elements, and the correction factors are updated during the driving operation, wherein updating is performed so that the non-corrected wheel speed measured by the sensor is compared with a reference value of the wheel speed established by means of a calculating model, and the correction factor is updated in dependence on this comparison, comprising the steps of:

• establishing the reference value by way of a calculating model wherein a compensation relationship curve is defined through the measured wheel speed variation and a membership function is associated with each signal-forming element,
• defining a regression relationship through the measurement data for each membership function, and
• establishing the reference value of the wheel speed by superposition of the regression relationship which is weighted with the membership functions, and
• adjusting the membership functions, in dependence on the wheel speed, so that a defined frequency range of the wheel speed can be measured.