Construction of upper body motion measurement model considering the position of human joints by inertial sensors

Abstract

It is important to measure and analyze the motion of human body in various fields. Recently, a new motion measurement method using an inertial sensor has been used. This method is suitable for real life conditions measurements because the measurement space is unrestricted, while the accuracy of the analysis depends on the configuration of the model. For these reasons, it is often applied to the lower limbs where relatively simple movements are performed. In addition, measurements involving complex shapes, such as the upper body, are considered to be difficult. Therefore, we propose a method to construct a detailed upper body model including back and waist from the output of inertial sensors. In other words, we aim to calculate the joint positions of the human upper body using only the output of inertial sensors, and to construct a detailed upper body motion measurement model by connecting them. As a result, the upper body model was constructed from the calculated joint positions, and the motion including bending and twisting was reproduced, which enabled more accurate motion measurement than the conventional method. In addition, in order to make the upper body model more detailed, the shape of the spine was estimated using the accurately estimated joint points on the spine, and the estimated spine had an anatomically correct shape. In conclusion, we have developed a more accurate and detailed upper body motion measurement model than the conventional one.