Should I keep my rotations as quaternions to modify and combine them?

Using Arduino Programming Questions
1

Hello,

I am using several Bosch BNO055 IMUs.

First I need to apply simple, static rotations (π or π/2 radians) to the quaternions provided by the sensors. Then I need to combine the orientations with fixed-lengths vectors to calculate positions in a 3D space.

Should I keep the orientation data as quaternions for these operations or should I rather convert them into rotation matrices or another form first (with the idea of still being able to avoid the gimbal lock) ? I guess that for the combination of the orientations with 3D vectors, final conversion to Euler angles will be the best form?

Thank you in advance.

2

(with the idea of still being able to avoid the gimbal lock)

You can't. 3D angular transformations cannot be uniquely defined.

Rotations using quaternions are straightforward, if a bit more complicated than using 3x3 matrices derived from angles.