Why doesn't OCS2 choose to use quaternions to describe the pose of floating base？

[HuNingHe]

I'm sorry to post an issue here. It would be more convenient if the discussion was opened.

• In FactoryFunctions.cpp, I can find that ocs2 build the floating base robot by adding Translation and SphericalZYX joints, instead of using freeflyer joint in pinocchio.

• I would like to ask why this was chosen, as I thought it would be better to use quaternions to describe the floating base pose.