Initial Calibration Method of Human Upper Limb Frame in Inertial Motion Capture System

The precision of the inertial motion capture system is mainly affected by the error of the Miniature Inertial Measurement Unit (MIMU) sensor and the deviation between the human body frames and the sensor installation frame. Therefore, it is necessary to calibrate the sensors' error and the frames' deviation before operating the system. This paper introduces a method to calibrate the deviation of the frames. This method has low requirements on the inertial sensor's installation manner and the experimental personnel's calibration actions. Collecting $1\sim 2s$ of data can satisfy the calibration requirements and quickly complete the calibration. The static error of the relative attitude angle of the human body after calibration and compensation is within $10^{\circ}$, and the error is reduced by 41.0% on average. In the case of uniaxial motion around the joint, the attitude angle of the non-motion axes fluctuates within $14^{\circ}$, proving that this method can effectively improve the system's accuracy.