Calibration of a Three-Axis Accelerometer Unit on a Centrifuge

Abstract

We focus on the problem of calibrating a three-axis accelerometer unit. If its sensors are intended to measure specific forces much stronger than Earth’s surface gravity, and if they also have significantly nonlinear characteristics, the sensors undergo a calibration procedure on a centrifuge capable of generating strong centripetal forces due to rapid rotation. The generated force measured by accelerometers then depends on the relative geometry of sensor proof masses and the axis of rotation. Since the rate of rotation is very high, the variations in coordinates of proof masses much smaller than their own size become significant. This implies one cannot measure them directly, and thus have to either estimate them along with all other parameters, or to exclude them from the equations. In addition, extra angular deformities that also cannot be measured directly arise under rapid rotations. This paper concerns the observability issues in the appropriate estimation problem.