Two-dimensional optical accelerometer based on commercial DVD pick-up head

摘要

This study develops a low-cost, highly sensitive two-dimensional optical accelerometer based on a commercially available DVD optical pick-up head. Vibrations of the structure of interest cause a change in the angle of the seismic mass within the accelerometer. The relative movement between the seismic mass and the base produces a change in the distribution of a focused light spot on the surface of a four-quadrant photodetector. The resulting change in the output of the voltage signals by the photodetector is then used to calculate the corresponding acceleration of the base. The experimental results indicate that the resonant frequencies of the accelerometer in the X-and Y-axis directions are 92.75 Hz and 92.87 Hz, respectively. Furthermore, the useful frequency range of the accelerometer is found to be approximately 20% of its resonant frequency. The sensitivities of the accelerometer in the X-and Y-axis directions are 22.9 V/g and 21.3 V/g, respectively. Finally, the noise equivalent acceleration (NEA) of the accelerometer is found to be less than 30 mu g Hz-1/2 over the frequency range 0.5 - 50 Hz.