• 0

# Integrating accelerometer data in DasyLab using DT9837

## Question

Hello,

I have tried to collect acceleration, velocity, and displacement data from accelerometer raw signals. I lose lots of data in the process. Even if i input a sin wave from a signal generator, the integration chops the aplitude down by orders of magnitude each time. What am I doing wrong? I am also having troubles with the integrated signals drifting very fast - the 'restart calculation' integration option works o.k; is there anything else I can do to obtain accurate signals? Or am i better off post processing the raw acceleration data in MATALB or something with more robust solvers?

Thank you

## Recommended Posts

• 1

I've used DASYLab to collect displacement data, but instead of integrating the raw data, I performed the integration with the FFT module. Here's a simple worksheet (attachment). First, it injects a 50Hz sine wave fed into the Data Window module, which is necessary for a good FFT. You can find internet windowing information by using the search phrase "fft windowing types." After the Data Window, the FFT generates an amplitude-optimized FFT and does a double integration for displacement. The next step is to transform the acceleration data to mils (A mil is a thousandth of an inch — .001 inch) by multiplying it by 386,000 ft/s/s. It then extracts the maximum value and the position of that value to produce results of 3.91 mils at 50Hz. Years ago, I could do the math to show that a 1-volt p-p 50Hz sine wave has a displacement of 50Hz but not today. I'll leave that up to you.

##### Share on other sites

• 1

According to DASYLab Help, Integration is finding the area under the curve using the following formula:

Dist = (1 / sample rate), which explains the small amplitude.

##### Share on other sites

• 0

Hello @Generic Goat.

Please reply with your DASYLab worksheet and screen captures of the displays in DASYLab showing the issue(s).

Regards,

Fausto

##### Share on other sites

• 0

on the signal generator, I am inputting a 1hz sine wave with 1v amplitude. I am expecting a -cos waveform with similar amplitude. However, I am getting an amplitude that is much smaller than what I was expecting. There is also some detrending needed. What do you recommend?

• 0

##### Share on other sites

• 0

Integrate block 1 and 2 are the same.

##### Share on other sites

• 0

This works great. integrating twice...

386,000∫∫1 sin(2*pi*50 t)dt

yields 3.9mils at 50hz according to Wolfram!

Thank you.

## Create an account

Register a new account