Calibration of multi-axis MEMS force sensors using the shape from motion method

Abstract

This paper presents a new design of a two-axis MEMS (microelectromechanical systems) capacitive force sensor with strict linearity and a new sensor calibration method for micro-sensors. Precise calibration of multi-axis micro force sensors is difficult for several reasons, including the need to apply many known force vectors at precise orientations at the micro force scale, and the risk of damaging the small, fragile MEMS device. In this paper the shape from motion method is introduced for micro force sensors resulting in a rapid and effective calibration technique. Structural-electrostatic coupled field simulations are conducted in order to optimize the sensor design, which is calibrated with the shape from motion method as well as the least squares method for comparison purposes. Calibration results demonstrate that the shape from motion method is an effective, practical, and accurate method for calibrating multiaxis micro force sensors.