Eddy-Current Sensing Principle in Inertial Sensors

Abstract

The eddy-current displacement sensing principle is, to the best of our knowledge, not yet used in inertial sensors. The main reasons for this are the important performance limitations of the existing eddy-current sensor solutions, such as: low sensitivity, poor stability, high power consumption and bulkiness. Our novel high-frequency Eddy-Current Displacement Sensor (ECDS), however, has significantly improved performance with respect to these limitations and allows the use of planar, stable coils, making it a viable candidate for use in inertial sensors. An implementation example of an ECDS-based inertial sensor with a bandwidth of 370 Hz and a noise floor of 13 um/Hz^0.5 is proposed. Although not yet competitive with state-of-the-art inertial sensors, it performs better than other types of inductive accelerometers and offers the inherent advantages of ECDSs, such as insensitivity to the environment.