AnsweredAssumed Answered

different behavior between roll and pitch

Question asked by Remi Beges Employee on Aug 11, 2015
Latest reply on Aug 11, 2015 by Mike Stanley

Hello all,

 

I am running the sensor fusion toolbox with a KL26Z and the latest Freedom FXS-MULT2B sensor shield.

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=FRDM-FXS-MULT2-B

 

While going through the demo, I noticed some strange behavior between pitch and roll. Indeed, while physically rotating the board around its X axis (the axis going from the usb connectors to the bluetooth module), the roll never goes beyond 90 degrees, even if the board is rotated well beyond 90 degrees.

Past physically rotating above 90 degrees, the value goes down. Also, the pitch value should stay close to 0, but changes a lot and seems directly proportional to the compass (yaw) value that changes a lot as well.

 

On the other hand, when rotating around Y axis, pitch does exactly what I expected, going above 90 degrees when the board is rotated beyond perpendicular. And roll and compass stay almost still this time, which is also expected.

 

 

So in clear :

->pitch-only rotation : ok, only pitch affected

->roll-only rotation : not ok, roll, pitch and yaw are all affected

 

Did someone else noticed this behavior ? I'm using the default Android coordinates system, can this be the reason ?

 

PS : If i'm not clear enough please let me know, I'll try to take pictures.

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