Seongmin Lee 0003 Hungsun Son Three Degree-of-Freedom Orientation Measurement for Spherical Wheel Motion Platform using Optical Sensors. 1462-1466 2019 AIM https://doi.org/10.1109/AIM.2019.8868850 conf/aimech/2019 db/conf/aimech/aim2019.html#LeeS19