Rotational speed estimation using the discrete Kalman filtering applied to a tacho signal

The paper deals with Kalman's filtering for the rotational speed time history of rotors, which is determined by the use of a tacho-signal that is composed of the string of pulses each of them is generated at least once per the complete rotor revolution. The accuracy of the estimation of the time interval length corresponding to the one complete revolution depends on the number of samples which corresponds to the mentioned time interval. The reciprocal value of the length of this interval determines the rotation frequency. If the rotation speed is multiply increased, the measurement error increases considerably as well. The Kalman filter is a suitable means for smoothing the rotational speed measurement by reducing the measurement error.