自控理论42极坐标图PPT课件

1、1表表4-1 24.惯性环节惯性环节g( (jw)w)g(s) = 0.5s+110.25 w w2+1a(w w)=1 j j(w)(w) = -tg-10.5w w 00.5124582001-14.500.97-26.600.89-4500.71-63.40-68.20 -760 -8400.450.370.240.05a a(w)(w)j j(w)(w)j01img(jw w)reg(jw w)35. 一阶微分环节一阶微分环节1)( tssgttgttjjgw ww ww ww w12)(11)( 01imre0 w w w w46.振荡环节振荡环节g(j)1212)(22222 ts

2、stsssgnnn w w w ww w22222222124)1(1)(w ww w w w w ww wttarctgttjg (0 1)o01)0 j (g o1800)j (g 221 w ww w nr2121)( w w rrma(00.707)00.707)9021)()(1 w wtnjgjg得得令令,0d)(da w ww w5振荡环节振荡环节g(j)曲线曲线（nyquist曲线曲线）0j1 w w21)( na2121)( w w raw wr60reim1aba:2r2nr12121 w ww w mb:onna90)(21)( w wj j w w2nn22n2)(w

3、w w ww w sssg振荡环节振荡环节 g( jw w )701imre7. 二阶微分环节二阶微分环节12)(22 tsstsg 221222212)2()1()(tttgttjgw w w w w ww ww w0 w w w w 288. 延迟环节延迟环节tsesg )(tjgw ww w 1)(01imre0 w ww w9 (1) liinmsgskststssskshsg111)()1()1()1()1()()( )1()1()()1()1()()(11 w ww ww wwwwww ww w nmtjtjjjjkjhjg10 0)90(00)90()(lim)0()0(00 w

4、 ww w w wkkjkjhjg )0( w w)1()1()()1()1()()(11 w ww ww wwwwww ww w nmtjtjjjjkjhjg11 0)90(00)0()0( kjhjg12nnnmmmajajbjbjbjhjg 11110)()()()()()(w ww ww ww ww ww w w w w ww ww ww ww ww ww ww wmnnmjbjjbjhjg)()()()()(00 mnmnmnb)90)(00013 mnmnmnbjhjg)90)(0)()(0014)1)(1)(1)(1()1)(1()()1)(1()(4321212211 stst

5、ststsssksgststsksg 31 mn imrewwww0g1(jw w)ww0imrewwg2(jw w)15 。中，即得与实轴的交点中，即得与实轴的交点代入代入求得求得令令曲线与实轴的交点：曲线与实轴的交点：)(j)(jr0)(j)(ji)(emw ww ww ww ww whghga 图图的的大大致致形形状状。，即即可可得得和和点点计计算算再再取取几几个个中中，即即得得与与虚虚轴轴的的交交点点代代入入求求得得令令曲曲线线与与虚虚轴轴的的交交点点：nyquist)()()(j)(ji0)(j)(jr)(mew wj jw ww ww ww ww ww ww wahghgb 16解

6、解 此系统此系统 = 0，n - m = 3, g(j 0)=1000 0 ； g(j)=0(n-m)(-900)= 0-270 0)5)(2)(1(1000)( ssssg)25)(4)(1()5)(2)(1(1000)5)(2)(1(1000)(222w ww ww ww ww ww ww ww ww ww w jjjjjjjg178)(r,100)(r17, 00)(i)25)(4)(1()17()810(1000)(2e1e21m22222 w ww ww ww ww ww ww ww ww ww ww ww wjgjgjgjjg与与实实轴轴交交点点：得得令令中中频频段段：8 .56)

7、(i2 . 10)(r2 . 1me w ww ww ww wjgjg与虚轴交点：与虚轴交点：得得令令w w=imrew0w0100-817 w w-j56.8w1.2w1.218 )05. 01)(2 . 01(10)()(w ww ww ww ww wjjjjhjg 19)05. 0(1)2 . 0(1 )01. 01(105 . 2)05. 0(1)2 . 0(1 )05. 01)(2 . 01)(10)()(22222w ww ww ww ww ww ww ww ww ww ww ww w jjjjjhjg)05. 01)(2 . 01(10)()(w ww ww ww ww wjjjjhjg 20图图4-6 例例4-4的频率特性的频率特性nyquist图图-110 w w-0.40w w w w6 w w5 w wreim21000102900)(0)0(180tg180)()(2) jgjgtstsksg) )( (1 1) )( (w ww wj j001001800)