Investigation of motion artifacts for biopotential measurement in wearable devices

The goal of this study is to investigate the two major reasons of motion artifacts, impedance variation and triboelectric charge accumulation. A theoretical model is established to analyze and estimate the dominant factor in different scenarios. This model also quantitatively explains how the major factors influence signal quality. A wearable device as small as a button was developed and used for experiment validation. The results showed that the body triboelectricity was the dominant factor to two-electrode settings where caused little influence on three-electrode settings. Also the impedance variation due to motion resulted in ECG baseline fluctuating whereas the surface charge accumulation might cause failure of ECG acquisition. This study aims to provide fundamental understanding of motion artifacts and new evidence for technical improvement for wearable ExG systems.