Upper limb position tracking system using inertial and magnetic sensors

Recently, extensive research has been carried out to investigate human motion in daily life using micro-electro-mechanical system (MEMS) inertial sensors. This study proposes an upper limb position tracking system that uses inertial and magnetic sensors. Two sensor units were attached to an upper arm and a forearm. The sensor unit has a three-axis accelerometer, a three-axis gyroscope, and a three-axis magnetometer. The magnetometer was not used for the forearm to optimize cost and space, which is one of the most important contributions of this study. Each sensor unit fused the sensor signals with a Kalman filter to provide a drift-free and stable orientation. The orientations of the upper arm and the forearm were applied to a joint-link model. The positioning accuracy was evaluated through comparison with a standard motion capture system. The proposed system provided a stable upper limb position. The upper limb position tracking system proposed herein could be applied to various fields, including clinical diagnosis, telerehabilitation, and virtual reality.