Abstract
In this paper, two kinds of methods are proposed to decrease the effects of disturbances in the identification of process dynamics of an adaptive control system using the m-sequence signal.
In order to eliminate the effects of low frequency disturbances, such as drift, added to the system output, a new digital correlator is presented based on the calculating principle of the cross-correlation function φxy(τ)=x(t)y(t+τ).
To minimize the effects of wide bandwidth disturbances, exp (πζ/√1-ζ2) is used as a performance index for adaptive control and is calculated from the ratio of the first plus area and the first minus area of the impulse response of the control system to be identified.
This method has also the following merits.
(1) The method is less affected by the bias error of cross-correlation function.
(2) The time required for identification is reduced.
(3) The number of integrators of the correlator is reduced.
Moreover, it is reported that the error of estimation of the index performance can be reduced by correcting the bias error of crosscorrelation function.
