Describing function analysis of second-order sliding mode observers
The second- order sliding mode observer dynamics are analyzed in the frequency domain. The so- called super- twisting algorithm is utilized for generating the second- order sliding mode in the observer dynamical system. The frequency response of the observer dynamics is obtained and used as a characteristic of the observer. The analysis proposed is based on the describing function method and the concept of the equivalent gains of nonlinear functions of the super- twisting algorithm.
describing function sliding mode observers frequency-domain methods