Yeroglu C.Tan N.2024-08-042024-08-04201097839026618691474-6670https://doi.org/10.3182/20100826-3-tr-4016.00029https://hdl.handle.net/11616/91682International Federation of Automatic Control (IFAC)IFAC International Workshop on Periodic Control Systems, PSYCO 2010 -- 26 August 2010 through 28 August 2010 -- Antalya -- 105495This paper deals with limit cycle prediction for nonlinear systems which have fractional order transfer functions. Describing function method is used for the analysis of fractional order nonlinear systems. It is observed that the limit cycle frequencies obtained from the simulation of the fractional order nonlinear systems, agree with the theoretical values of the limit cycle frequencies obtained from Nyquist plots of the fractional order plant and complex plot of the negative inverse of describing function. The critical gain of the system is estimated from Nyquist plot. The fractional order nonlinear system becomes stable for the gain smaller than the critical gain value. System starts to oscillate for the gain bigger than the critical gain value. © 2010 IFAC.eninfo:eu-repo/semantics/closedAccessDescribing functionFractional order systemsLimit cycleNonlinear systemsNyquist plotConference Object4PART 114414910.3182/20100826-3-tr-4016.000292-s2.0-84901945656N/A