METHOD AND SYSTEM FOR MEASURING ROTATION ANGLE AND TORSIONAL VIBRATION OF A ROTATING BODY BY WAY OF MODAL INTERFERENCE

摘要

The present disclosure relates to characterization of torque and torsional vibration in rotating bodies. More specifically, this invention enables high-fidelity, high-speed characterization of the rotary motion of a body without the requirement for surface modification. This invention relies on the inherent optical properties of the surface of the rotating body to determine the degree to which a rotating body vibrates, twists, or is otherwise translated. The system makes use of interference between propagation modes in a multi-mode optical fiber. A portion of the light reflected from the rotating body is captured by one or more multi-mode optical fiber(s) and guided to an optical detector. Rays entering the receiver fiber at different angles form different propagation modes in the fiber, and as such travel different distances. As the body rotates, the fraction of the reflected light that enters any given mode changes.