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    BNO055 Z-Axis Output values changing but they shouldn't

    BNO055 Z-Axis Output values changing but they shouldn't

    New Poster

    Hi Community,

    i have a problem regarding BNO055's euler angle output values.

    I am using the BNO055 in combination with an Microchip-Atmel SAMD21 MCU and Bosch's standard C Library.

    I configured the BNOs axis-remap-sign register to match the orientation on my board. According to the App-Note BST-BNO055-DS000-17 (Page 17), i figured out i need to put it in mode "P3". Operation mode is NDOF, because i need the fused data to match accuracy and distortion robustness requirements.

    Now to the application:

    I have to measure the rotation of an object only on the z-axis. The BNO could be mounted horizontally or vertically, but i only need the rotation angle for the z-axis. (heading, z-axis, yaw...)

    x -and y-axis can be completely ignored in my application. I dont want to use the Quaternion output because i think its not necessary for my application (correct me if i HAVE TO use it).

    The Problem:

    The BNO is not only considering the rotation on the z-axis on its euler output value (the value for the yaw, heading) but also, depending on its orientation, the x-axis. So the euler output value for the z-axis is changing while there is no rotation arround the z-axis. But if i turn my board a 90 dgrees, the bno suddenly considers a rotation on the x-axis as a rotation on the z-axis. And i dont mean that the euler value given by the bno is changing only by a few degrees, its changing like it would normally. It doesnt jump arround or so. Thats also the case for quaternion output format. I hope you can follow my explanation. I am confident that i know what im doing and im sure i configured all the registers i have to configure.

    I have read that, depending on its orientation in space, depending in which direction the gravity force from earth is taking effect, the BNO switches its reference axis on its own. But that shouldn't be the case when im configuring the axis-remap-registers, am i right?

    So im very thankful for any answers regarding this / my "problem". Im sure i am getting some basic stuff wrong or didn't find the right part in the app note.

    1 REPLY 1

    Community Moderator
    Community Moderator

    Hello VD_2222,

    Could you confirm if your axis remapping was correct that your sensor placement matched your coordinate system?