題組內容

4. Consider a negative feedback control system with loop transfer function GH(s) = 2(T2s +1)/s2(Tis + 1), where T1 and T2 are positive, their related Nyquist plots of GH(s) are given below,

62a0606f80dee.jpg62a0608c9d0fd.jpg

(a). For Figure (a), what's the relation of T1 and T2? Also, determine the stability of this negative feedback control system by applying Nyquist stability criterion. (10%)