Hello everybody

I am developing roundness measurement system. Eccentricity of the job introduces error into the roundness measurement. To remove this FFT
technique is used. 1st harmonics represent eccentricity error. If it is removed then accentricity error can be removed from the measurement.

My problem is how to remove the harmonic from the FFT spectrum.

Please Help.

Vikas Meshram
Senior Scientist,
Centre For Advanced Technology,
Indore,MP,India.

 

To remove 1st harmonic from fft spectrrum, you should control the system which gives round shape to the object.
You can use feedforward control for this controlling task.

regards,

A.K.D.

 

Amit

Tnanks for the email. If FFT is used then you need not use feedforword control. If you do then you don't need FFT.

My question was how to filter it harmonic?

Regards

Vikas

 

Vikas,
we use FFT for analyzing the eccentricity. First harmonics present in FFT spectrum gives us the information about the change in eccentricity. Using this information we should take feedforward action to correct the change in Roundness. We will come to know about effect of Feedforward control by analyzing the FFT spectrum.

Please clarify which software you are using for FFT analysis? And also How it controls the roundness using only FFT? If you ask me, FFT Is an analysis tool, isn't it?


Regards,
Amit.

 

Amit
I am developing Roundness Measurement system. I don't want to control the roundness of the systen. As you know first harmonic gives you the information about the eccentricity; in my application I have to eliminate the error which is embedded into the roundness measurement data sample.

Vikas

 

Dear vikas,
We are also developing roundness measurement system. We can help each other once we understand each others aim ( commercial ). u can get in touch with us at "[email protected]", mailto:[email protected] . awaiting yr early reply

regards p.s.patil

 

Record the data to disk. Perform a forward Fourier transform on the data. Set the amplitude of the first harmonic to zero in the transformed data. Perform an inverse Fourier Transform to the previously transformed data.

 

sir,
i am a student of btech(E&C).i have given the project of measurement of eccentricity of a rotating cylinder through non contact method

pls, help us that how can we proceed in this way. your contribution prove to be a great worth for me. give your email id to me.

contact me at:
Ashish
Birla Institute, Bhimtal, India
[email protected]

 

For fast and cheap, look at a laser reflected from the surface onto a linear sensor array. Angle controls the span and sensor density controls the resolution. can be demoed with a cheap laser pointer and inexpensive phototransistors. Cheap is always popular with schools.

Regards

cww

> i am a student of btech(E&C).i have given the project of measurement of
> eccentricity of a rotating cylinder through non contact method
>
> pls, help us that how can we proceed in this way. your contribution prove
> to be a great worth for me. give your email id to me.

 

Hello everybody

I am developing roundness measurement system. Eccentricity of the job introduces error into the roundness measurement. To remove this FFT
technique is used. 1st harmonics represent eccentricity error. If it is removed then accentricity error can be removed from the measurement.

My problem is how to remove the harmonic from the FFT spectrum.

Please Help.

Vikas Meshram
Senior Scientist,
Centre For Advanced Technology,
Indore,MP,India.

Hello, is this problem has been fixed? and can you help me to know how to fix the eccentricity error, I have been confuseing about the problem for a long time? thank you very much!