Evaluation of Smartwatch Inertia Measurement Unit (IMU) for Studying Human Movements
This study aims to evaluate the temporal and spatial accuracy of the inertia measurement unit (IMU) data from a wearable smartwatch using a controlled movement and comparisons with the optical tracking measured data during gait. The Sony Watch 3 was used for two tests. First, a rotational test was performed in which the watch was attached to a rotating shaft that rotated at a constant speed. Second, a subject test was performed in which the watches were attached to shin and foot. The IMU outputs were analyzed to obtain the gait motion, and results were compared with measurement from the optical tracking system. For the rotational test, the IMU data showed moderate temporal accuracy (sampling interval: 0.012 ms ± 0.005 ms), and high spatial accuracy (error of trajectory: 0.03 m ± 0.03 m). For the subject test, the error between two measurements was 1.2° ± 1.9°.
KeywordsIMU Motion tracking Smart watch
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