How can i read this Bode plot?

In summary, the conversation is discussing a graph that measures the x-axis frequency response for nominal and payload values. The first peak of the graph is believed to represent a resonance frequency, but the meaning of the other peaks is unknown. It is suggested to stay below the first peak for good closed loop control, and the other peaks may be caused by other system modes. More information is needed to determine if the peaks are real or just measurement noise.
  • #1
skyhj105
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0
I think that first peak of the graph represent a resonance frequeny but i don`t know some peaks which are located after first peak.
Is it a just noise? or some other?
 

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  • #2
The measurement is what it is regardless of the names you assign to the peaks, so I'm not sure what you're really asking.

To determine if the plots are real or just measurement noise, one needs much more detail than you provided.
 
  • #3
anorlunda said:
To determine if the plots are real or just measurement noise, one needs much more detail than you provided.

Thank you for your answer.
I `ll tell you more detail. The value what this plot measure is x-axis frequency response for nominal and payload.(I don`t konw meanig of nominal load and payload exactly... what is this?)
x-axis is one axis of nanopositioning system.
 
  • #4
Sorry, that is still not enough information to answer your question.
 
  • #5
skyhj105 said:
I `ll tell you more detail. The value what this plot measure is x-axis frequency response for nominal and payload.
The graph text suggests nominal response when unloaded, compared to response with a maximum load.
Payload is not mentioned. I would expect it to be somewhere between the two.

It appears that when the load is increased to the maximum, the frequency of the first peak is lower, which is what is expected from a loaded resonant system. The fact that the phase cleanly changes by 180° degrees at that frequency confirms that it is a resonance.

Can you give a reference for the scanned figure.
 
  • #6
skyhj105 said:
I think that first peak of the graph represent a resonance frequeny but i don`t know some peaks which are located after first peak.
Is it a just noise? or some other?
The simple answer is that you should stay well below the first peak if you want good closed loop control.

The other peaks are other system modes probably, transverse modes etc...
 
  • #7
MRFMengineer said:
The simple answer is that you should stay well below the first peak if you want good closed loop control.

The other peaks are other system modes probably, transverse modes etc...

You are looking at the open loop response of the system, how are you planning to use it? Closed loop?
 

1. What is a Bode plot?

A Bode plot is a graphical representation of a system's frequency response. It shows how the magnitude and phase of a system's output vary with frequency.

2. How do I interpret a Bode plot?

To interpret a Bode plot, you need to understand the two axes. The horizontal axis represents frequency, usually in logarithmic scale. The vertical axis represents either the magnitude or phase of the system's output, depending on which plot you are looking at. The plot will show how these values change with frequency, allowing you to identify the system's frequency response characteristics.

3. What information can I get from a Bode plot?

A Bode plot can provide information about a system's gain, phase shift, bandwidth, and stability. It can also help identify frequency domains where the system is most sensitive or least sensitive to input signals.

4. How can I use a Bode plot in my research?

Bode plots are commonly used in fields such as control systems, signal processing, and electrical engineering. They can help you analyze and design systems, identify system parameters, and compare different systems or components.

5. How do I create a Bode plot?

To create a Bode plot, you need to have the transfer function or frequency response data of the system. You can then plot the magnitude and phase values at different frequencies using software such as MATLAB or by hand. Alternatively, you can use a frequency analyzer to measure the system's frequency response and plot the data on a Bode plot.

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