Upgrade of a computer-writing tool with MEMS inertial sensors

Abstract

This paper presents an improvement to gesture reconstruction with a computer-writing tool based on an inertial principle. The computer-writing tool is modified with a complete, miniaturized, six degrees-of-freedom inertial measurement unit in order to reduce the error in the tool’s orientation with respect to the reference coordinate system and, consequently, to reduce the error in the tool’s tip position on the paper. The improvement is achieved by calibrating the inertial measurement unit using advanced modeling of the nonlinear voltage output of a triple-axis low-g MEMS accelerometer. The nonlinear accelerometer’s model considers an interacting influence between the measuring axes of the arbitrarily oriented writing tool. With a combination of the attitude compensation and the zero-velocity compensation techniques the positional error of the tool’s tip on the paper is reduced.