Human velocity tracking and localization using 3 IMU sensors

In sports training and exercises, the velocity and position of the person is very important for motion evaluation. Despite of the development in motion capturing, a proper method for velocity monitoring for daily use is still not elaborated. In this work, a velocity tracking and localization method using only three IMU sensors is introduced. In the method, a reference root point on the pelvis is chosen to represent the velocity and location of the person. The three sensors are located at the right shank, right thigh and the pelvis to measure the kinematics of the lower limbs. Through proper acceleration error canceling algorithm, the acceleration data is refined to fuse with the root velocity calculated from lower limb kinematics. The drift-free and accurate 3D velocity result is achieved in this manner. The location of the person is tracked based on this velocity result and the limb kinematic subsequently. The benchmark study with the commercial optical reference shows that the accuracy in velocity tracking is within 3% of the moving velocity and localization accuracy is within 2% in both normal walking and jumping. For the utilize conveniences of the small-size wearable IMU sensors, this proposed velocity tracking and localization method is very useful in everyday applications both indoor and outdoor.