A new approach of sensing low frequency vibration is discussed. Fiber optic gyro (FOG) is used as pendulum bob of a simple pendulum in this sensor system to sense angular vibration. The pendulum can be vibrated when the external force in one direction excites the whole system. The angular velocity must be measured firstly. The relationship between angular velocity and accelerated velocity can be given if known natural frequency of the simple pendulum, which can be obtained before measurement. Consequently vibration frequency can be derived. The result shows that this sensor system is sensitive to vibration frequency lower than 2Hz, but insensitive to higher frequency. The breakthrough lies on the different way to measure the vibration frequency. This approach is fit to the measurement of earthquake wave or other construction vibration.

Date Published: 9 September 2002
PDF: 3 pages
Proc. SPIE 4920, Advanced Sensor Systems and Applications, (9 September 2002); doi: 10.1117/12.482016

Published in SPIE Proceedings Vol. 4920:
Advanced Sensor Systems and Applications
Yun-Jiang Rao; Julian D. C. Jones; Hiroshi Naruse; Robert I. Chen, Editor(s)