Schneider, William P.2023-01-172023-01-17197030679068https://hdl.handle.net/10657/13624To investigate the nature of sustained oscillations in a fourth order control system with an Amplitude sensitive nonlinearity. The basic assumption is that the open loop linear transfer function of the system is stable. The graphical technique for solving this problem is by substituting the nonlinearity by its equivalent describing function and then applying Nyquist stability criterion. An analytical method to solve the problem is developed. Expressions for amplitude and frequency of sustained oscillations are derived. Regions of stability and instability are indicated. Expressions for amplitude and frequency of sustained oscillations are derived. Regions of stability and instability are indicated. Expressions for amplitude and frequency of sustained oscillations are reduced to Third and Second order control system by reducing the order of the system. An example is presented and the results are verified.application/pdfenThis item is protected by copyright but is made available here under a claim of fair use (17 U.S.C. Section 107) for non-profit research and educational purposes. Users of this work assume the responsibility for determining copyright status prior to reusing, publishing, or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires express permission of the copyright holder.Thesisreformatted digital