Three Degree-of-Freedom Orientation Measurement for Spherical Wheel Motion Platform using Optical Sensors

This paper presents the development of orientation sensing method using optical sensors for spherical wheel motion platform. Three degree-of-freedom (DOF) orientation of cockpit sphere is measured from optical sensors. Inertial measurement unit (IMU) has been widely utilized to estimate the orientation of objects, but is vulnerable to accumulation of integration error. Furthermore, magnetometer is sensitive to magnetic disturbance causing yaw drifting. The optical sensor with non-contact, cheap price, small size, high response and resolution, and high readable speed can be used to solve the yaw drifting problem. The kinematic equations have been developed to measure cockpit orientation which can be applied to closed loop control for spherical wheel motion platform. Finally, the experiments demonstrate that the cockpit orientation can be estimated from optical sensors.