Variable structure robust state and parameter estimator (Q2722624)

This paper is based on some results of \textit{G. Ciccarella, M. Dalla Mora} and \textit{A. Germani} [Int. J. Control 57, 537-556 (1993; Zbl 0772.93018)] and \textit{S. A. Bortoff} and \textit{M. W. Spong} [Proceedings of 29th Conference on Decision and Control, Honolulu, Hawaii, December 1990, 772-777 (1990)]. A variable structure robust state and parameter estimator for a class of SISO nonlinear systems is designed, and an upper bound for the corresponding estimate error functional is derived. It turns out to be a linear combination of external and internal uncertainties levels. In the absence of any uncertainties and noise perturbations, the global asymptotic error stability directly follows from the main theorem. Three simulation examples (two simple mechanical systems and a van der Pol oscillator) are considered to illustrate the effectiveness of the suggested approach.