Aji Resindra

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9 years, 8 months ago.

Pitch and Roll never exceed 90 degree

hello sir. I have just tested your example code (freeIMU_Demo) and played with my gy-86 when i suddenly realized that the value of pitch and roll never exceed 90 degree. When i tilted my gy, the pitch would rise to 90 and if i continue to tilt it, the value would start decreasing. Can you help me with that? Thank you

Question relating to:

Last updated: 29 Mar 2018
FreeIMU demo program for mbed

1 Answer

Yifei Teng
9 years, 8 months ago.

Hi thanks for your question. There was minimal modification made to the FreeIMU ARHS algorithm after it was ported to mbed, so the cause of the problem probably lies somewhere else. You can try updating the FreeIMU library in the demo program, since it does not automatically fetch the newest version. Calibrating the magnetometer may also fix the issue. I will take a deeper look at the problem as soon as possible.

Accepted Answer

Hi sir. Thanks for your respond I have just tried to update the library but the problem still there. I have also tried DMP but the problem still persist. The only algorithm that work is DCM. so i guess the problem lies in conversion from quaternion to YPR. I don't really understand quaternion yet so that is just my guess. Thank you sir.

posted by Aji Resindra 24 Aug 2014

Hello again sir. today i managed to get the full rotation of roll and pitch axis using the getEuler function. Actually I didn't really know the difference between euler angle and YPR but some reference said the are the same so i think the problem is solved from now. Thank you.

posted by Aji Resindra 27 Aug 2014

I think its because of gimbal lock http://en.wikipedia.org/wiki/Gimbal_lock

posted by Joseph Roberts 18 Sep 2014