Damper sensors usefulness

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Belatti
Belatti
33
Joined: 10 Jul 2007, 21:48
Location: Argentina

Re: Damper sensors usefulness

Post

A new question here. It may be related to this thread, too:
viewtopic.php?f=6&t=7710

What kind of filters do you have to pass damper sensors data through when you want to use them in:
a) post rigs
b) computing simulations
c) statistical graphs like FFT, histograms, etc..

I admit Im having a problem in recognizing what is noise and what is not.
Also I have my doubts when it comes to sample rate selection.
My system can record at 200Hz max and thats what I use in damper sensors.

To add something else to the discussion, I plot these 2 graphs:

Image

Here you can see 1 second of the same data recorded at 200Hz (WHITE) and exported to a 100Hz (RED) file. In blue I have pointed out the noticeable differences.


Image

Here we have the same data as in the previous image but with a moving average filter applied (0,1 sec). The curves are smoother, there are no noticeable differences between both.

I doubt but I wonder if this curves are closer to the real suspension movement than the unfiltered ones.
"You need great passion, because everything you do with great pleasure, you do well." -Juan Manuel Fangio

"I have no idols. I admire work, dedication and competence." -Ayrton Senna

Belatti
Belatti
33
Joined: 10 Jul 2007, 21:48
Location: Argentina

Re: Damper sensors usefulness

Post

Another thig I did to see if I can sort it out was to use the band pass filter to decompose the signal in frequency bands:

Image

There are barely noticeable amplitudes above 10Hz...
"You need great passion, because everything you do with great pleasure, you do well." -Juan Manuel Fangio

"I have no idols. I admire work, dedication and competence." -Ayrton Senna

Jersey Tom
Jersey Tom
166
Joined: 29 May 2006, 20:49
Location: Huntersville, NC

Re: Damper sensors usefulness

Post

FFT and/or spectrogram would probably be much easier to visualize that. But yes.. generally as frequency goes up, content amplitude diminishes quickly.

Majority of frequency content should likely come from low-frequency (handling range) behavior.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

speedsense
speedsense
13
Joined: 31 May 2009, 19:11
Location: California, USA

Re: Damper sensors usefulness

Post

Belatti wrote:A new question here. It may be related to this thread, too:
viewtopic.php?f=6&t=7710

What kind of filters do you have to pass damper sensors data through when you want to use them in:
a) post rigs
b) computing simulations
c) statistical graphs like FFT, histograms, etc..

I admit Im having a problem in recognizing what is noise and what is not.
Also I have my doubts when it comes to sample rate selection.
My system can record at 200Hz max and thats what I use in damper sensors.

To add something else to the discussion, I plot these 2 graphs:

Image

Here you can see 1 second of the same data recorded at 200Hz (WHITE) and exported to a 100Hz (RED) file. In blue I have pointed out the noticeable differences.


Image

Here we have the same data as in the previous image but with a moving average filter applied (0,1 sec). The curves are smoother, there are no noticeable differences between both.

I doubt but I wonder if this curves are closer to the real suspension movement than the unfiltered ones.
I don't recognize the system software, what type is it?

One quick way to determine if it's noise would be to graph a second,third and even a fourth, lap on top (over plot) and check for consistency. Secondly, if you suspect noise, one of the "common" areas of noises are pot mounts that aren't secure. As most pots are able to read down to .002 of an inch, if the mounting has even the slightest vibration, it will appear in the data.

To me the durations of movement are too long to be noise,especially as they still appear when smoothed by half.
"Driving a car as fast as possible (in a race) is all about maintaining the highest possible acceleration level in the appropriate direction." Peter Wright,Techical Director, Team Lotus

Belatti
Belatti
33
Joined: 10 Jul 2007, 21:48
Location: Argentina

Re: Damper sensors usefulness

Post

speedsense wrote: I don't recognize the system software, what type is it?.
Pi Toolbox (club level dongle :cry: )

I´ll try your advice and also check what the sensor reads with the engine running even if the car is standing still, too.
"You need great passion, because everything you do with great pleasure, you do well." -Juan Manuel Fangio

"I have no idols. I admire work, dedication and competence." -Ayrton Senna

Caito
Caito
13
Joined: 16 Jun 2009, 05:30
Location: Switzerland

Re: Damper sensors usefulness

Post

Can't you check post rig programmed movement vs your detected movement. The difference would be your "noise". Although that would consider no tire deflection.
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