An Evaluation Method of Electromagnetic Interference on Bio-Sensor Used for Wearable Robot Control

Applications of wearable bio-sensors are rapidly increasing for health care and medical purposes, but various sinusoidal and impulse electromagnetic interferences can have a significant influence on their performance. In this paper, we focus on the electromagnetic interference evaluation of bio-sensors used for control of wearable robots, such as a myoelectric artificial hand. We proposed a method for measuring the common-mode voltage between the human body with a bio-sensor and the ground plane, which is generated by external sinusoidal or impulse electromagnetic fields. First, using sinusoidal electromagnetic interference, we clarified that the mechanism of generation of interference voltage in wearable bio-sensor is due to unbalance of contact resistances between pair of bio-signal detection electrodes. Next, as an example of impulse electromagnetic interference, we evaluated the interference voltage generated in the bio-sensor by combining the proposed measurement method with electric circuit simulation under the IEC-prescribed indirect electrostatic discharge test environment. This method provides a powerful means for evaluating the interference characteristics in the wearable robot design stage.