Method of determining rotary speed of a rotating element in a braking effort regulation system
First Claim
1. In a system for preventing slippage of at least one wheel of a vehicle, a method of regulating wheel braking effort as a function of rotary speed of a vehicle wheel subject to wide speed variations and of providing control output signals representative of wheel speed even under slow wheel operating conditions, said slippage-preventing system havinga transducer (1) which provides a transduced output signal (uS) having a frequency representative of the speed of the wheel and an evaluation circuit (2-9) which processes said transducer output signal (uS) and provides the control output signal (nR) which has a characteristic value which is representative of and proportional to the speed of the wheel,comprising the steps ofdigitizing the transducer output signal (uS) to derive a digital signal (uS2);
- calculating (7) the inverse function of the digital signal to derive an essentially triangular-wave-shaped signal (y2);
determining (8) the degree of slope of the essentially linear portions of the triangular-wave-shaped signal (y2) to derive a differentiated signal (y3), which differentiated signal is representative of the speed of the wheel;
obtaining said control output signal (nR) from the differentiated signal (yR); and
regulating braking effort in said slippage-preventing system as a function of said control output signal (nR).
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Accused Products
Abstract
A braking effort regulation system is improved by providing a rotary speed signal, which is accurate even under slow rotation conditions.
To obtain an accurate analog value of the rotary speed of a rotating object, typically the wheel of an automotive vehicle, from a transducer (1) having at least approximately sinusoidal output voltage, the transducer output voltage (uS, uS1) is converted into a digital signal (uS2), preferably filtered to obtain a filtered signal (uS3). The inverse function (y2 =arc sin (Ao sin ωt)=c(εR 7ωt), y2 =arc sin (Ao sin ωt) is then calculated. By differentiation and determination of the differential value of the signal y2, a signal (yR, y3) is then obtained which, after an additional preferably filtering step, will result in the desired speed-representative output signal (nR).
15 Citations
11 Claims
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1. In a system for preventing slippage of at least one wheel of a vehicle, a method of regulating wheel braking effort as a function of rotary speed of a vehicle wheel subject to wide speed variations and of providing control output signals representative of wheel speed even under slow wheel operating conditions, said slippage-preventing system having
a transducer (1) which provides a transduced output signal (uS) having a frequency representative of the speed of the wheel and an evaluation circuit (2-9) which processes said transducer output signal (uS) and provides the control output signal (nR) which has a characteristic value which is representative of and proportional to the speed of the wheel, comprising the steps of digitizing the transducer output signal (uS) to derive a digital signal (uS2); -
calculating (7) the inverse function of the digital signal to derive an essentially triangular-wave-shaped signal (y2); determining (8) the degree of slope of the essentially linear portions of the triangular-wave-shaped signal (y2) to derive a differentiated signal (y3), which differentiated signal is representative of the speed of the wheel; obtaining said control output signal (nR) from the differentiated signal (yR); and regulating braking effort in said slippage-preventing system as a function of said control output signal (nR). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification