Integration of capacitive and piezoelectric accelerometers using a digital approach

This study is to obtain an acceleration signal with a nice quality and apply it to a linear motion stage. The accelerometers used in this paper are piezoelectric and capacitive accelerometers. Since a piezoelectric accelerometer cannot measure low-frequency acceleration, its application to servo systems is limited. On the contrary, a capacitive accelerometer is able to measure low-frequency acceleration. However, its output noise is significant, and its dynamic bandwidth is small compared with the piezoelectric accelerometer. This paper proposes a high-performance accelerometer, which digitally integrates the salient features of both capacitive and piezoelectric accelerometers. The proposed accelerometer can measure both low- and high- frequency acceleration. It is also applied to compensating for load disturbance in a linear drive for performance improvement.