Individual warning using electric signals

• Applicants: Professor Dr.-Ing. Jens Haueisen; Professorin Dr.-Ing. Sybille Krzywinski; Professor Dr.-Ing. Martin Schmauder
• Subject Area: Human Factors, Ergonomics, Human-Machine Systems
• Term: from 2016 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 317652676

Labor situations in potentially dangerous environments (e.g. railway tracks, road construction sites, in containers or during maintenance work in unclear facilities) require the reliable and individual warning of employees in case of danger so that they can get themselves into safety. State of the art are warning systems with optical (e.g. signal lamps), acoustic (e.g. sirens), or rarely, vibratory signals. Problematic situations arise when signal perception is impeded by distractions or various environmental influences. A new research approach involves electrical signals that can be applied reliably and easily to the skin surface using textiles.The overall goal is to establish a functioning, regulation-compliant warning system based on electrical stimulation that meets the requirements of the individual user. Thus, research into stimulation techniques is required, and stimulation thresholds must be determined to reliably detect electrical signals. In our work, we investigate the perceptibility of electrical stimulation, while simultaneously minimizing impairing functional effects. This innovative research approach complements already existing ones. However, there are no standards so that in a first step, a knowledge base must be developed exploratively.Based on 4 working hypotheses, in project phase 1, part 1, we were able to show that warning by means of electrical stimulation is possible under laboratory conditions. In extensive experiments with different signal forms, suitable signal types ensuring a reliable warning were established. A study was carried out based on 68 participants with adhesive electrodes in order to determine the basic perception thresholds, neglecting interfering influences such as climate, tools, working postures, or PSA. As a result, three threshold values could be defined: - Perception threshold- Attention threshold and- Intolerance threshold.In addition, concepts for textile functional models with different electrode designs have been developed.In project phase 1, part 2, the perceptual thresholds are to be investigated, i.e. signal perception under consideration of the above-mentioned influencing factors must be evaluated. Furthermore, the perception of spatial-temporal patterns on multiple electrodes will be investigated. For this purpose, the construction of a special laboratory space for the simulation of environmental influences (temperature, humidity, air movement) is planned. The study will initially be carried out with adhesive electrodes in accordance with project phase 1, part 1, in order to ensure comparability of the results. Based on functional samples (part 1), sleeves will be manufactured and examined by test persons. The threshold values are the basis for the future development of a warning system using electrical signals. Subsequently, i.e. in project phase 2, long-term and habituation effects will be investigated.

• DFG Programme: Research Grants