Performance improvement and limitations in extremum seeking control

We propose the inclusion of a dynamic compensator in the extremum seeking a lgorithm which improves the stability and performance properties of the met hod. This compensator is added to the integrator used for adaptation to imp rove the overall relative degree and phase response of the extremum seeking loop. The compensator is potentially more effective in accounting for the plant dynamics than the often used phase shifting of the demodulation signa l. We present a detailed analysis of the extremum seeking system based on a veraging. This analysis provides two linear models, one for tracking refere nce changes and the other for sensitivity to noise, which offer insight int o how different parameters influence the performance. This analysis is less conservative than in previous cases and allows the use of faster adaptatio n for improved transients. We extend the extremum seeking method to problem s of tracking changes in the set point which are more general than step fun ctions. (C) 2000 published by Elsevier Science B.V. All rights reserved.