default accelerometer orientation differs from industry stan

Race Capture Pro hardware installation- power, wiring, physical installation, etc. See the dedicated forum for Sensor related topics

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GTIspirit
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default accelerometer orientation differs from industry stan

Post by GTIspirit »

Just wanted to raise everyone's awareness that the default accelerometer orientation of the RaceCapturePro differs from industry standard convention.

There is an SAE standard J670 on this topic, and automotive industry follows the convention:
+X to the front
Y is lateral

Z-down:
Image
or Z-up
Image

e.g. Z-Down orientation, figure directly from SAE J670
Image

Also referenced in this paper:
Vehicle Dynamics Modeling

brentp
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Post by brentp »

Thanks for the note. this has been a source of much discussion over the last few years. We went with the assumption on the cartesian coordinate system where X is left/right in relation to looking forward out of the car.

It would be a bit disruptive to make a change now, but might be worth doing in a major firmware and app release.
Brent Picasso
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JanVancura
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Post by JanVancura »

Hi Brent,
still thinking about the in app possibility of changing the coordinate system according to the SAE standard? If yes, can you add an option for ISO 8855 standard (X axis forward, Y left, Z up)? This is standard for all Europian countries (expect UK).

I know that I can make any axis configuration in Race Capture App, but if i change the orientation of Z axis from normal to inverted, calibration doesn't work correctly for this axis (it shows 3G after calibration). Can you please take a look at this bug?

It would be very nice to have in RC app two more buttons for SAE and ISO axis orientation (and maybe some switch between imperial (US) and SI units (metric)).

Apart from the above I'm very satisfied with RC/Pro.

Jan.

brentp
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Post by brentp »

Thanks. Logged the issue here. Tentative target is 2.9.0 firmware.
https://github.com/autosportlabs/RaceCa ... issues/360

brentp
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Post by brentp »

This update is definitely going into 2.9.0, coming soon!
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stieg
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Post by stieg »

Hey JanVancura,
I know that I can make any axis configuration in Race Capture App, but if i change the orientation of Z axis from normal to inverted, calibration doesn't work correctly for this axis (it shows 3G after calibration). Can you please take a look at this bug?
Filed https://github.com/autosportlabs/RaceCa ... issues/452 to track the issue. Lets see if we can get something resolved in 2.9.0. We don't have any intention of supporting multiple standards as that would add a lot of complication to our system, but we can try to make it so that you can configure your unit in this manner and have calibration work.
Andrew Stiegmann (Stieg)
Principal Engineer
Autosport Labs Inc.

brentp
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Post by brentp »

the IMU setup wizard feature coming in the app may address this calibration requirement as well, as it will automatically detect and calibrate for the installation orientation of the unit. https://github.com/autosportlabs/RaceCa ... issues/548
Brent Picasso
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csinasac
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Post by csinasac »

Brent, is this fully implemented and will the unit now auto detect and calibrate the appropriate x, y and z axis once in motion? If not, how do I properly calibrate it ... searched the docs and it isn't clear to me.

cheers,

Craig

brentp
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Post by brentp »

It is not implemented yet. When it is, you'll see the status of that github issue change to 'resolved'. For now, you will need to swap X/Y/Z axis as necessary based on device orientation.

Thanks for checking in on this!
Brent Picasso
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