Howtosignalprocessing
- Can we draw Bode plot for unstable system?
- What makes a Bode plot unstable?
- What does a Bode plot tell you about a system?
- What is the importance of Bode plot in determining system stability?
Can we draw Bode plot for unstable system?
As we will see in an example, it is possible to draw a perfectly normal-looking Bode plot for a system that we know is unstable [2]. A Bode plot is actually comprised of two plots, the magnitude and phase plots.
What makes a Bode plot unstable?
If both the gain margin GM and the phase margin PM are equal to zero, then the control system is marginally stable. If the gain margin GM and / or the phase margin PM are/is negative, then the control system is unstable.
What does a Bode plot tell you about a system?
Bode plots show the frequency response, that is, the changes in magnitude and phase as a function of frequency. This is done on two semi-log scale plots. The top plot is typically magnitude or “gain” in dB. The bottom plot is phase, most commonly in degrees.
What is the importance of Bode plot in determining system stability?
The Bode plot provides the relative stability of the system in terms of the gain margin and phase margin. It can be drawn both for the closed loop system and open-loop system. It also provides us a method to improve the stability of the system.
