稳定性充要条件（续） Iff condition The poles of characteristic equation have negative real part 系统特征方程的根全部具有负实部 D(s)=a(s-p,)s-(G,+j0,s-(o,-jo,】=0 →闭环系统的极点全部在s平面左半部 x平面 0 (稳定) (不稳定) →稳定性与零点无关 School of Mechanical Engineering ME369-lecture 6.2 Shanghai Jiao Tong University Fal12015 [例1]稳定性充要条件 K 单位反馈系统 G(s)= (K>0,T>0) 求K的取值范围 s(Ts+1) School of Mechanical Engineering ME369-lecture 6.2 Shanghai Jiao Tong University Fall 2015 55 ME369-lecture 6.2 Fall 2015 School of Mechanical Engineering Shanghai Jiao Tong University Iff condition : The poles of characteristic equation have negative real part 系统特征方程的根全部具有负实部 0 1 1 ( ) ( ) [ ( )][ ( )] 0 K r i j j j j i j D s a s p s j s j                稳定性与零点无关 闭环系统的极点全部在s平面左半部 稳定性充要条件（续） ME369-lecture 6.2 Fall 2015 School of Mechanical Engineering Shanghai Jiao Tong University ( ) ( 1) K G s s Ts   单位反馈系统 [例1]稳定性充要条件 ( 0, 0) K T   求K的取值范围