Dynamic Compensation of Ultra-Low-Range Pressure Sensors

Abstract

A technique has been developed to compensate pressure readings from arrays of highly sensitive membrane-type pressure sensors for deflections caused by acceleration normal to the plane of the membrane using a single inertial measurement unit. By normalizing the fourth-order unsteady Kirchoff-Love equation, it can be shown that inertial body pseudoforces and applied surface pressure elicit a similar and additive response from the sensors. Inertial effects arising from linear and angular acceleration as well as angular velocity may therefore be converted to ‘pseudopressures’ and eliminated by means of a simple linear compensation process which can be calibrated using only gravity. To demonstrate, signals from a conventional six-axis inertial measurement unit (including three orthogonal components each of angular velocity and linear acceleration) are used to provide an approximation of the acceleration of the sensing dies within a seven-channel distributed array of ultra-low pressure sensors. Applying the proposed correction reduces the maximum full-scale uncertainty of the measurements by as much as 50%.