<title>Fiber optic vibration sensor and its application to structural control</title>

Abstract

Fiber optic interferometric sensors have been developed to provide real time measurement of structural vibrations. One immediate application is the measurement of vibrations on space structures. The detected vibration signals can be applied to a control system which activates appropriate actuators to dampen vibrations. In this work, optical fibers are arranged in a Michelson interferometer configuration in which one the interferometer arms is placed on the vibrating structure and other arm serves as the reference. As the structure vibrates, the fiber is strained and results in a change in phase of the light with respect to the reference arm. Necessary electronic circuits are developed to detect the induced phase changes. These circuits could be used for other kinds of fiber optic sensors such as pressure and temperature sensing, accurate positioning systems, and rotation sensing. The sensor is tested on a laboratory model of a space truss structure and an optical matrix-vector multiplier is used as the controller. In this paper the details of the sensor and experimental results will be presented.