G meter discrepancy

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boggie1688
Posts: 138
Joined: Fri Apr 07, 2017 3:47 pm
Location: Oakland, CA

G meter discrepancy

Post by boggie1688 »

Some of you may have seen the video I posted from my recent Autox event. I was looking over the video and notice the g meter seems off. Particularly in the 180 turn towards the end if the run.

I've attached a raw datalog and was hoping someone could help. Is it the datalog? Meaning the RCP needs to be recalibrated? Or does it have something to do with how racerender is calculating the g?

https://drive.google.com/file/d/0B-Udn3 ... p=drivesdk

boggie1688
Posts: 138
Joined: Fri Apr 07, 2017 3:47 pm
Location: Oakland, CA

Post by boggie1688 »

I did a basic Pythagorean calculation on x and y; g= ( x^2+y^2 ) ^ (1/2). Created a column in the log, and loaded it into the app. The calculated G seem more in line with what is expected.

Anyone have the formula for calculating G with x,y,z with yaw, pitch, and roll??

I figure it would be best to calculate this, then compare with race render.

brentp
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Post by brentp »

How do you have the unit oriented during mounting? is it different than natural orientation (flat, upright, connector facing forward) ?

Also, did not see the video. Got a link?
Brent Picasso
CEO and Founder, Autosport Labs
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boggie1688
Posts: 138
Joined: Fri Apr 07, 2017 3:47 pm
Location: Oakland, CA

Post by boggie1688 »

Hey Brent,

Natural orientation. It is not on the center of rotation, but mounted under the driver seat. It has the 24 pin connector facing forward and the sd,led,usb connector facing the rear.

Here is a copy of the video:

https://drive.google.com/file/d/0B-Udn3 ... sp=sharing

brentp
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Post by brentp »

I watched the video, and the 180 degree section around 0:53. What were you expecting to see in the video? Looks like in the 180 degree section you had some consistent lateral G's.
Brent Picasso
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boggie1688
Posts: 138
Joined: Fri Apr 07, 2017 3:47 pm
Location: Oakland, CA

Post by boggie1688 »

The actual value seems low.

I admit, I'm red/green color blind. Given the size of the g meter, and the color, I'm having a hard time seeing the tenths place. But to my eyes, it says 0.0X mid turn.

Am I seeing this wrong?

brentp
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Post by brentp »

Did you check out the data in the app?

Looks like you were pulling about 1G in that turn-around.

Agree, RaceRender seems to be doing something with the actual g-force calculation.
Attachments
Run2.png
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boggie1688
Posts: 138
Joined: Fri Apr 07, 2017 3:47 pm
Location: Oakland, CA

Post by boggie1688 »

Thanks for confirming Brent.

I did check the data, but I wasn't 100% sure what I was looking at. The data log seemed correct, but I was trying to figure out where, if any, errors were being introduced.

I'll post on the racerender forum.

Your help is always appreciated.

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