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Unformatted text preview: 8/09 MECH466 : Automatic Control -1 10 0 10 1 10 MECH466 : Automatic Control 2 10 22 Remarks on Bode diagram
Bode diagram shows amplification and phase
shift of a system output for sinusoidal inputs with
It is very useful and important in analysis and
design of control systems.
The shape of Bode plot contains information of
stability, time responses, and much more!
It can also be used for system identification.
(Given FRF experimental data, obtain a transfer
function that matches the data.) 23 2008/09 MECH466 : Automatic Control 24 6 System identification Summary and exercises Sweep frequencies of sinusoidal signals and
obtain FRF data (i.e., gain and phase).
Select G(s) so that G(jω) fits the FRF data.
Select G(s) Frequency response
Steady state response to a sinusoidal input
For a linear system, sinusoidal input generates
sinusoidal output with same frequency but different
amplitude and phase.
phase. Agilent Technologies: FFT Dynamic Signal Analyzer
Generate sin signals
Sweep frequencies Bode plot is a graphical representation of
frequency response function. (“bode.m”)
Exercises Collect FRF data
G(s) Read Section 10.1.
Solve Problem 10.1.
2008/09 MECH466 : Automatic Control 25 2008/09 MECH466 : Automatic Control 26 Derivation of frequency response Another example of FRF
Second order system
Second Term having denominator of G(s)
G(s) Im 0 as t goes to infinity. Re
2008/09 MECH466 : Automatic Control 27 2008/09 MECH466 : Automatic Control 28 7...
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This document was uploaded on 03/05/2014 for the course MECH 466 at University of British Columbia.
- Fall '08