Offset For Vertical usage

ivancap

Hallo everyone. I need to use the sensor vertically. I've tested it horizontally and the moving one axis singularly the movement is in fact affecting only one angle. As soon as i put the sensor vertical, the movement in one axis is not stable and also affect other axis. Is there a way to set an offset to the sensor for working vertically. I implemented a manual offset on the angles but this does not help since the variation of the quaternion is clearly visible in 2 terms... See attached figure

https://www.dropbox.com/s/m9b410p7jx8sjb8/fig.pdf?dl=0

Eric

I'm not aware of any configuration for the sensor fusion algorithm.  What sensor fusion mode are you using?

ivancap

Actually NDoF, but i tried every mode.

ivancap

Ok, to other having same issue, i've used quaternion multiplication in order to rotate reference frame before getting the euler angles. And it works perfectly. Thanks.

patrice

Hello ivancap,

I opened two weeks ago a similar post as yours regarding issues with vertical usage and drift attitude between sensors after fast movements  : http://community.mbientlab.com/discussion/comment/4223#Comment_4223

I understand that you find a way to change the reference frame thanks to a quaternion multiplication but could you be more specific if you have time.

Did you finally : 

- choose to forget "sensorFusion!.eulerAngle" mode for "sensorFusion!.quaternion" mode, 

- in order then to re-calculate yourself all eulers angles from quaternion after an initial rotation of the frame reference ?

Did you succeed to automatically detect the vertical frame reference and adjust the quaternion rotation automatically ?

 Many thanks for your time and your support

ivancap

HI, yes, work on quaternion, then apply rotation, in my application i do not need to find out automatically the orientation.

The applied quaternion is a rotation quaternion that rotate the versor x to z. 

winston

Hello @ivancap, @patrice,

I wanted to inquire regarding the potential solution of the rotation quaternion so that the sensor could be used in a vertical position.

Is this just a matter of creating a new quaternion (new.w = old.w ; new.x = old.x; new.y= old.z ; new.z= -old.y) and then converting to Euler from there?

Thank you.