Trajectory Reconstruction Algorithm based on Sensor Fusion between IMU and Strain Gauge for Stand-alone Digital Pen

摘要

We aim to realize a novel pen based interface system that provides various digital operations for both low-tech and high-tech people. In this paper, we propose a novel sensor fusion method between IMUs (Inertial Measurement Unit) and strain gauges embedded on a pen device. By using strain gauges for obtaining the correct direction of pen tip movement during writing, cumulative errors caused by the intrinsic noise/drift of IMU can be corrected. Therefore our proposed sensor fusion method can reconstruct longer handwritten trajectories such as multiple characters including multiple strokes that have not been achieved by conventional methods. This paper provides a pen tip direction estimation method using strain gauges attached on ink cylinder, trajectory reconstruction method using IMUs, and the sensor fusion method of both estimation streams. The algorithms are evaluated by writing experiments conducted by a robotic manipulator.