车辆工程大三自动控制原理课件ch53ol fc plot

ThreeImportantAspectsforPlottingOLAP(NyquistStarting ）&endingpoint IntersectionwithrealFrequencyatcrossing

-------crossoverxx:Im[G(

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x

)H(x

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(k,T,T G( k G( CH5 Ex2：G(s)H

(k,T,T 1 1G(j0)H(j0)

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IntersectionwithRA:

I[G( )H(

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T njn T Discontinuous- CH5 RulesforOpen-loopamplitude-phaseStartingpoint：K, υ<0，originυ=0，realaxisatK：（K>0，υ>0，infinity：K>0，phaseangle:υ×(-K<0，phaseangle:υ×(-90°)- CH5 ending

1 K0

Forminimum-phaseG( )H( K G( )H( 0 ( ) CH5

foroscillatingelementswithG(s)H

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2

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2s

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plotasymptotesfromlowfrequencies(绘制低频段渐进线)Kω0 La 20lg 20

(db②

La 20lgK(db③ a ω

slope CH5 4.Open-loopLogarithmicFrequencyBodeEx6：G(s)H

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s(s

1

s

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CH5 DelayElements&DelayG(t 1( )r( G(s

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0 non-minimum-phase CH5 ExperimentalDeterminationof

(rad/[G(s)

s2

2 CH5 6.ExperimentalDeterminationof )G(s) s2

20

1

2

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1

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