522开环幅相曲线的绘制52.152.3 (1+r;S) bos+bs n …+bm-1S+bn G(S)=K (1+T;s) s"+a,s"-+…+a.,s+ 0 n j=1 lim G(io)=lim k 20O<-V'? K 元 Go) m→0 lim G(io)=lim 00a0(i)"-maan0""< =im n-n →0 2 y=3 y=3 [G] 对控制系统而言 y=2 n>m,故limG(jo) 0 0→ 元 0∠-(n-m) 2 y=I 1  − = = + + =    n j j m i i s T s s G s K 1 1 (1 ) (1 ) ( ) n n n n m m m m a s a s a s a b s b s b s b + + + + + + + + = − − − − 1 1 0 1 1 1 0 1   2 lim ( ) lim ( ) lim 0 0 0           = =  −  → → → K j K G j 2 0 ( ) , lim ( ) ,    n m n m G j =  − −  → 故 对控制系统而言 5.2.2 开环幅相曲线的绘制 2 lim ( ) ( ) lim ( ) lim 0 0 0 0        = =  − −  − → − → → n m a b a j b G j n m n m 5.2.1 5.2.3