Thermally insensitive open-loop hung mass accelerometer with differential eddy current sensing

Abstract

A thermally insensitive open-loop hung mass accelerometer utilizes a transverse geometry to attach the body/flexures/proof mass so that thermal expansion effects due to thermal gradients across the accelerometer or bulk temperatures changes of one flexure relative to the other cause minimal or no axial displacement of the proof mass. In this geometry, multiple flexures may be stacked to achieve the required stiffness, thus reducing manufacturing costs and any tolerancing issues, without affecting thermal sensitivity. The accelerometer is suitably designed to exhibit a radial symmetry. The accelerometer is suitably designed to use low CTE materials for at least the proof mass and body and a low thermal expansion differential Eddy current sensor head.