Patent ID: 10234344

Abstract:
A multi-axis force sensor is compact in that it comprises a single strand of optical fiber and a single, movable reflecting element having a reflecting surface separated from a fiber end-face by a gap, and yet is capable of measuring axially and/or laterally applied forces with high sensitivity. The force to be measured causes the reflecting surface to tilt, translate or deform. The single strand of fiber is configured to have multiple cores that carry multiple optical interrogation signals through an end-face of the fiber to incidence on the reflecting surface. The cores are configured so that the propagation vectors of the interrogation signals, as the signals emanate from the fiber end-face, make non-perpendicular angles with that end-face. Furthermore, the cores are configured to capture a portion of the interrogation signals back-reflected from the reflecting surface. The amount of power coupled back into each core is a function of the position of the reflecting surface, which in turn is a function of the magnitude and direction of the applied force. A deformable casing to which the force is applied may surround the reflecting element, the gap and the fiber end-face.