Method for measuring the rotation speed of a vehicle wheel
First Claim
1. A method for measuring the rotation speed of a vehicle wheel with a noise reduced system having a magnetic tachometer, an electronic management module (10), a processor-based analogue-to-digital converter (11), a computational module (12), and a frequency analyzing module (13), the method comprising:
- acquiring in real time by the computer-based electronic management module (10) an analogue measurement signal (Sma) generated by the magnetic tachometer and containing a useful signal the frequency of which is representative of the rotation speed of the wheel;
digitizing by the processor-based analogue to digital converter (11) in real-time the analogue measurement signal (Sma) in order to obtain a time-dependent digital measurement signal (Smnt);
calculating by the processor-based computational module (12) a Fourier transform of the time-dependent digital measurement signal (Smnt) in an observation window in order to obtain a frequency-dependent digital measurement signal (Smnf); and
carrying out a frequency analysis by the frequency analyzing module (13) on the frequency-dependent digital measurement signal so as to identify by a search for peaks a useful spectral line (15;
16) and to determine the frequency of the useful spectral line in order to obtain the frequency of the useful signal, which corresponds to the rotation speed of the wheel,wherein the frequency analysis by the frequency analyzing module includes implementing adaptive filtering,wherein the adaptive filtering consists in adapting the position of a spectral analysis window (Fas) in which the useful spectral line (15;
16) is assumed to be found depending on a prediction of the frequency of the useful spectral line (15;
16), andwherein the width of the spectral analysis window (Fas) is adapted depending on the level of perturbations present in the frequency-dependent digital measurement signal (Smnf),whereby an accurate rotation speed of the wheel is obtained without an undesirable effect of noise resulting from perturbations of electrical, electromagnetic or mechanical origin to which at least the tachometer and the electronic measurement module (10) are subjected.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for measuring the rotation speed of a wheel including the steps of: acquiring an analog measurement signal (Sma) generated by a magnetic tachometer and containing a useful signal the frequency of which is representative of the rotation speed of the wheel; digitizing in real-time the analog measurement signal (Sma) in order to obtain a time-dependent digital measurement signal (Smnt); calculating a Fourier transform of the time-dependent digital measurement signal (Smnt) in order to obtain a frequency-dependent digital measurement signal (Smnf); and carrying out a frequency analysis in order to identify by a search for peaks a useful spectral line (16) so as to obtain the frequency of the useful signal and therefore the rotation speed of the wheel.
-
Citations
9 Claims
-
1. A method for measuring the rotation speed of a vehicle wheel with a noise reduced system having a magnetic tachometer, an electronic management module (10), a processor-based analogue-to-digital converter (11), a computational module (12), and a frequency analyzing module (13), the method comprising:
-
acquiring in real time by the computer-based electronic management module (10) an analogue measurement signal (Sma) generated by the magnetic tachometer and containing a useful signal the frequency of which is representative of the rotation speed of the wheel; digitizing by the processor-based analogue to digital converter (11) in real-time the analogue measurement signal (Sma) in order to obtain a time-dependent digital measurement signal (Smnt); calculating by the processor-based computational module (12) a Fourier transform of the time-dependent digital measurement signal (Smnt) in an observation window in order to obtain a frequency-dependent digital measurement signal (Smnf); and carrying out a frequency analysis by the frequency analyzing module (13) on the frequency-dependent digital measurement signal so as to identify by a search for peaks a useful spectral line (15;
16) and to determine the frequency of the useful spectral line in order to obtain the frequency of the useful signal, which corresponds to the rotation speed of the wheel,wherein the frequency analysis by the frequency analyzing module includes implementing adaptive filtering, wherein the adaptive filtering consists in adapting the position of a spectral analysis window (Fas) in which the useful spectral line (15;
16) is assumed to be found depending on a prediction of the frequency of the useful spectral line (15;
16), andwherein the width of the spectral analysis window (Fas) is adapted depending on the level of perturbations present in the frequency-dependent digital measurement signal (Smnf), whereby an accurate rotation speed of the wheel is obtained without an undesirable effect of noise resulting from perturbations of electrical, electromagnetic or mechanical origin to which at least the tachometer and the electronic measurement module (10) are subjected. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
Specification