Techniken zur Bestimmung von Parametern für die elektrische Personenwarnung

Abstract

Methods for the determination of parameters for the electrical warning of persons Objectives: The aims of this publication are to present the main findings of research into the development of a wearable system for electrical warning, identify the current challenges and introduce the next research objectives. Methods: A basic study (n = 81) with self-adhesive electrodes on the right upper arm was used to investigate the influence of pulse width, electrode size and electrode position on perceived thresholds as well as qualitative and spatial perception. Varying textile cuff types were developed and tested. The suitability of varying support materials and textile electrodes was investigated with regard to adaptability, comfort, electrical conductivity, DC resistance and traction elastic behaviour. The textile and self-adhesive electrodes were compared with regard to thresholds as well as qualitative and spatial perceptions (n = 30). Results: Practical parameter sets of the thresholds (perception, attention, intolerance) were determined for various pulse widths, electrode sizes and positions. The dominant qualitative perceptions were “Knocking” (perception and attention threshold) and “Muscle twitch” (intolerance threshold). The spatial perception was located at the stimulation area. The resulting textile cuff contains a knitted fabric with electrically conductive surfaces and a layer of an electrically conductive silicone compound. The comparison between textile and self-adhesive electrodes showed no differences regarding thresholds and qualitative and spatial perceptions. The impedance of the textile electrodes was (1.5 to 3 times) higher than that of the self-adhesive electrodes. Conclusions: Future studies will investigate the influences of working conditions, climatic conditions, age, gender and skin properties. The further development of the textile cuffs is focused on the improvement of the contact between electrode and skin to optimise the transition impedance. Keywords: electric stimulation – electrode – TENS – smart textile – wearable