Patent ID: 7605586

Claim:
A method for determining the absolute angular position θ of the steering wheel of a motor vehicle with respect to the chassis of said vehicle, said method comprising using a system including: a device for incremental measurement of the relative angular position δ of the steering wheel, including: an encoder positioned to rotate together with the steering wheel, said encoder including a main multipolar track; a fixed sensor arranged with respect to and at a gap distance from the encoder, including at least two sensitive elements positioned with respect to the main track so as to deliver two periodic electrical signals S 1 , S 2 , in quadrature, the sensor including a suitable electronic circuit, so as to deliver the relative angular position δ of the steering wheel based on the signals S 1 , S 2 ; a device for measuring differential speed ΔV/V of vehicle wheels on a same axle; a processing device sampling, in a period t, the angular positions δ(t i ) and the differential speeds ΔV/V(t i ), said device including calculation means for determining, at every t n instant, an estimate θ*(t n ) of the absolute angular position θ(t n ) according to the differential speed ΔV/V(t n ), the average offset(t n ) difference between the angular positions θ*(t i ) and δ(t i ), where i varies from 0 to n; and the absolute angular position θ(t n ); said method further including the following repeated steps: measuring the angular position δ(t i ) and the differential speed ΔV/V(t i ); determining an estimate θ*(t n ) of the absolute angular position θ(t n ) according to the differential speed ΔV/V(t n ); determining the difference in the average of the vectors {circumflex over (θ)}*(t n )=[θ*(t 0 ), . . . , θ*(t n )] and {circumflex over (δ)}*(t n )=[(t 0 ), . . . , δ(t n )] so as to obtain the average offset(t n ) difference; determining the absolute angular position θ(t n ) by adding the average offset(t n ) difference and the angular position δ(t n ).