Use of biased-relay feedback for system identification

The purpose of this work is to devise a relay feedback experiment that can identify two points on the Nyquist curve from a single test at the frequencies ω=0 and ω=ω u . An identification procedure is devised accordingly for this parameter identification. The theory of equivalent gain is described, the biased relay feedback system is analyzed, and the potential problems are explored. Parametric system identification is discussed followed by the conclusion