A Coiled Carbon Nanotube Yarn-Integrated Surface Electromyography System To Monitor Isotonic and Isometric Movements

Abstract

A surface electromyogram (sEMG) electrode collects electrical currents generated by neuromuscular activity by a noninvasive technique on the skin. It is particularly attractive for wearable systems for various human activities and health care monitoring. However, it remains challenging to discriminate EMG signals from isotonic (concentric/eccentric) and isometric movements. By applying nanotechnology, we provide a coiled carbon nanotube (CNT) yarn-integrated sEMG device to overcome sEMG-based motion recognition. When the arm was contracted at different angles, the sEMG-derived root mean square amplitude signals were constant regardless of the angle of the moving arm. However, the coiled CNT yarn-derived open circuit voltage (OCV) signals proportionally increased when the arm’s angle increased, and presented negative and positive values depending on the moving direction of the arm. Moreover, isometric contraction is characterized by the onset of EMG signals without an OCV signal, and isotonic contraction is determined by both EMG signals and OCV signals. Taken together, the integration of EMG and coiled CNT yarn electrodes provides complementary information, including the strength, direction, and degree of muscle movement. Therefore, we suggest that our system has high potential as a wearable system to monitor human motions in industrial and human system applications.

Skin‐Inspired Ultrafast Self‐Healing Wearable Patch with Hybrid Cooling for Comfortable and Durable Electromyographic Monitoring

“…The SiO 2 (x)@PDMS(y)/PVA provides high solar reflectance thanks to the wide band gaps (≈9 eV) of SiO 2 particles [33] and the strong visible scattering of porous PDMS. [31] In addition, high mid-infrared thermal emittance can be achieved because of the strong phonon polariton resonances of SiO 2 particles at 9.6 μm, [24,29] which means perfect absorption can be achieved in the resonance region. Additionally, PDMS and PVA hydrogel [25,31] also have high infrared absorption in the atmospheric window.…”

“…EMG signals contain abundant information about force production, muscle activation patterns, and fatigue and are widely used in clinical and research settings and humanmachine interfaces. [22][23][24] To capture the EMG signals, three patches of the same size (20 × 10 × 2 mm) adhered to the forearm and then were connected to a sensor board (SICHIRAY) and a microcontroller (Arduino Uno) (Figure 6a). The amplitude of the generated EMG signal is determined by gripping a hand grip (Mizuno) with different strengths.…”

“…Therefore, the EMG wearable electrode patches must provide wearers with good comfortability as well as durability during long-term use in muscle rehabilitation, human-machine interaction (HMI), and robotic applications. [22][23][24] This arouses increased attention toward mimicking natural skin with selfhealing capabilities for good durability and a rational design for heat dissipation.…”

Recent Advances in Carbon Nanotube‐Based Energy Harvesting Technologies

“…Twistrons have been deployed for harvesting mechanical energy from nature and human motion. [137] For example, Kim et al demonstrated the use of coiled twistrons for harvesting ocean wave energy (Figure 8a). More specifically, a 10-cm-long coiled twistron harvester generated an output power of 1.66 W kg −1 when operated at a typical ocean temperature (13 °C) using wave frequencies ranging from 0.9 to 1.2 Hz.…”