Estimation delay compensation in high-gain observer-based parameter identification

In this paper, the properties of the disturbance estimation in a high gain observer are analyzed, and a time delay calculation method is proposed to improve the performance of parameter identification. This paper shows that the estimation delay depends on the observer gain, but has nothing to do with the parameter variation. Then, a novel algorithm is proposed to calculate the delay according to the phase response of disturbance estimation transfer function. Hence, in terms of system identification, this delay is compensated by lagging the state estimate by the same amount of delay. This technique, on one side, improves the performance of parameter identification accuracy, and, on the other side, gives a new insight into the high-gain observer design.