Modeling and Analysis of a Wavelet Network Based Optical Sensor for Vibration Monitoring

Abstract

The main objective of this research is to present a wavelet network based optical lateral position sensor for vibration monitoring using a 2 2 photodetector array. In our approach, the power distribution of the light spot is measured taking into consideration the radial symmetry of the spot and its Gaussian intensity pro le. The proposed system uses a He-Ne laser source whose Gaussian beam impinges on the photodetector array. The normalized optical power for each photocell is obtained theoretically by deriving the optical power equations as the beam scans the plane of photodetectors. The position detection is based on nding a relationship between the power distribution of the photodetector array and the position of the beam center. An experimental setup of the system is developed to validate the theoretical results. Furthermore, a wavelet network function approximation technique is used to estimate the x{y position of the beam center corresponding to the measured optical powers.