Calibration of Multi-Axis MEMS Force Sensors Using the Shape-From-Motion Method

Precise calibration of multi-axis microelectromechanical systems (MEMS) force sensors is difficult for several reasons, including the need to apply many known force vectors at precise orientations at the micro- and nanoNewton (nN) force scales, and the risk of damaging the small, fragile microdevices. To tackle these challenges, this paper introduces the shape-from-motion calibration method. A new design of a two-axis MEMS capacitive force sensor with high linearity and nN resolutions is presented. Structural-electrostatic coupled-field simulations are conducted in order to optimize the sensor design. The designed sensor is calibrated with the shape-from-motion method, the least-squares method as well as the gravity-based method for comparison purposes. Calibration results demonstrate that the shape-from-motion method provides a rapid, practical, and accurate technique for calibrating multi-axis MEMS sensors