1. 自動控制與實驗 Bode Plots

2. Advantage of Working with Frequency Response in terms of Bode Plots zBode plots of systems in series (or tandem) simply add which is quite convenient. zBode’s important phase-gain relationship is given in terms of logarithms of phase and gain.

3. Advantage of Working with Frequency Response in terms of Bode Plots zA much wider range of system behavior (from low to high frequency behavior) can be displayed on a single plot. zBode plots can be determined experimentally. zDynamic compensator design can be based entirely on Bode plots.

4. Bode Form of the Transfer Function zBode form ： all one zK 0 is transfer function magnitude at very low frequencies.

5. Classes of terms of transfer functions z(1) z(2) z(3)

6. Class1:singularities at the origin

7. Class2: first-order term za) For zb) For zwe call the break point zbelow: magnitude is approximately constant 1 zabove: magnitude is like class 1

8. Exp:

9. phase za) For zb) For zc) For

10. Exp:

11. Class3:second order term zBreak point zPeak amplitude zmagnitude change slop +40dB or -40dB zphase change +180 0 or -180 0

12. Matlab’s Bode Plots zbode(num,den)

13. Example: G(s) U 0 sinωtY(t) U 0 ω/(s 2 + ω 2) Ĺ 1/(s 2 +s+3)

14. Result: (response of G(s)=1/(s 2 +s+3) to sint )

15. Example: zKG 1 =10/s(s 2 +0.4s+4) zKG 2 =0.01*(s 2 +0.01s+1)/s 2 [(s 2 /4)+0.02(s/2)+1] numG=0.01*[1 0.01 1] denG=[0.25 0.01 1 0 0] bode(numG,denG) numG=10 denG=[1 0.4 4 0] bode(numG,denG)