Analysis of gain margins and phase margins of a nonlinear reactor control system

By using the gain-phase margin tester, the parameter-plane method for the nonlinear control system is extended to frequency-domain related to gain margin and phase margin. The stability and self-excited oscillation are investigated with respect to the adjustable parameters. The useful information concerning the effects of adjustable parameters can be obtained, after the describing function curves and the boundaries of constant gain margin and constant phase margin are plotted in the parameter plane. Some interesting consequences are offered by employing the practical control system of a material testing reactor