中频段 L( y=90°-g2+g19-g2-g2 -20dB/dec 3 -40dB/dec -20dB/dec *g4-g1丝>0° 0 0 -40dB/dec -60dB/dee 60 50 广mx(o)=tg1√h-g厉=gh/ 2√万 30 h=@ 20 02 3 0 2 4 68101214161820 0mx=V0203= =0h School of Mechanical Engineering ME369-lecture 8.1 Shanghai Jiao Tong University Fall 2015 中频段 K G(sH(s)= s(0.2s+1)(0.02s+1) K=40.=3.3/sy=52.6 -20dB/dec K=10 0.=6.2/s y=31.7 -40dB/dec K=30 o=11.6/s y=10.3 -40dB/dec K=60o.=16.5/s y=-1.4 -40dB/dec K=12000=61.3/sy=-46.1 -60dB/dec -60dB/dec 背定不稳定 -40dB/dec 可能稳定，但稳定裕量较小 -20dB/dec 一般稳定，且稳定裕量大 School of Mechanical Engineering ME369-lecture 8.1 Shanghai Jiao Tong University Fall 2015 66 ME369-lecture 8.1 Fall 2015 School of Mechanical Engineering Shanghai Jiao Tong University 1 1 1 1 1 2 3 4 1 1 2 3 90 0 c c c c c c tg tg tg tg tg tg                              中频段 3 cmax 2 3 2 h h         h h tg h c tg h tg 2 1 1 ( ) 1 1 1 max          3 2 h    ME369-lecture 8.1 Fall 2015 School of Mechanical Engineering Shanghai Jiao Tong University –60dB/dec 肯定不稳定 –40dB/dec 可能稳定，但稳定裕量较小 –20dB/dec 一般稳定，且稳定裕量大 ( ) ( ) (0.2 1)(0.02 1) K G s H s s s s    K  4 3.3/ c   s   52.6 20 / dB dec K 10 6.2/ c   s   31.7 40 / dB dec K  30 11.6/ c   s  10.3 40 / dB dec K  60 16.5/ c   s   1.4 40 / dB dec K 1200 61.3/ c   s   46.1 60 / dB dec 中频段