A state-space approach to adaptive rejection of harmonic sensor disturbances in discrete-time systems

This paper considers the problem of rejecting harmonic disturbances given by a finite sum of unbiased sinusoidal signals with unknown amplitude, phase and frequencies, in the particular case in which they act additively on the sensor input. The problem is addressed using a state-space formulation in the discrete-time domain. The proposed approach is based on the use of a self-tuning external model which is able to provide an online estimate of the disturbance. Two adaptive algorithms that provide the disturbance parameters estimates are presented, the first one based on RWLS algorithm and the second one based on the Kalman filter. The self-tuning external model performance is shown through a simulation example