(c) The open loop transfer function of a unity feedback system is given by G(s) 350 (s - 0.2) (s - 4)(s+d)(s2 - 4s+5)(52
Posted: Sun May 15, 2022 2:41 pm
(c) The open loop transfer function of a unity feedback system is given by G(s) 350 (s - 0.2) (s - 4)(s+d)(s2 - 4s+5)(52 +28 - 3) where the constant d is a real number. Find all the poles of the open loop transfer function (s). () The Nyquist diagrams of G(s) for d = 0.75 and d = 2 are given in Figures 3.2 and 3.3, respectively. For each case, using the Nyquist stability criterion, determine the number of poles of the closed-loop system in the right-half plane. Hence, determine the stability of the closed-loop system when d = 0.75 and d = 2, respectively. [8 marks] Nyquist diagram for d=0.75 2 Imaginary Ads -2 3 -2 0 -15 -0.5 Real Axis Figure 3.2 Nyquist diagram for d-2 05 Imaginary Adis -0.5 -1 -1.6 -14 -12 -1 08 06-04-02 Real Axis 0 Figure 3.3