Impact of Electrostatic Discharge on Wearable Robotic Hand and Improvement of Immunity Performance by Wireless Control

Myoelectric artificial hand is a typical wearable robotic hand operated by motors based on detected myoelectric signals. A wired connection between the myoelectric signal detector and motor controller is currently the mainstream, but the wireless control is expected for convenience. In this study, focusing on a myoelectric artificial hand, we performed electrostatic dischargeimmunity tests based on IEC61000-4-2 to clarify the mechanism of malfunction with respect to electrostatic discharge noise. Using an optical electric field sensor, we investigated the correlation between the peak level, time duration, and energy of electric field generated by electrostatic discharge and the malfunction rate of myoelectric artificial hand. The measurement results showed that the malfunction of myoelectric artificial hand was strongly correlated with the peak electric field level, and the primary coupling location of electrostatic discharge noise on the myoelectric artificial hand was the wires between the myoelectric signal detector and the motor controller. Based on these findings, we developed a wireless myoelectric artificial hand to remove the above-mentioned wires and to increase the convenience. As a result, compared to the wired control, the wireless myoelectric artificial hand exhibited a much higher immunity level for the electrostatic discharge noise. This is because the wires that were experimentally identified to pick up noise were replaced by a wireless link where a wideband modulation scheme resistant to electrostatic discharge type impulse noise was adopted.