Performance improvement in perturbation-based extremum seeking control for Hammerstein plants

This paper is aimed at improving the transient performance of extremum seeking systems by addressing the problem of transient misdirection. Transient misdirection describes the transient behaviour of an extremum seeking system being regulated away from its optimal operating condition. This phenomenon not only reduces the control efficiency but is also undesirable in many practical applications. Based on a preliminary analysis for transient misdirection, an adaptive high-pass filter with a time-varying cut-off frequency that is high during transients and low during steady states is proposed. The adaptive high-pass filter-based extremum seeking scheme is applied to Hammerstein plants, and non-local stability of the obtained system is proven using Lyapunov analysis. The proposed scheme can achieve a transient time nearly one-tenth of that of the compared scheme without adding tuning complexity or sensitivity to noise, as illustrated through simulation examples, demonstrating its effectiveness, practical prospect, and advantage over state-of-the-art schemes.