Engineering Tomography Laboratory (ETL), Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY, UK.
Sensors (Basel). 2022 Jul 4;22(13):5040. doi: 10.3390/s22135040.
Electrical impedance tomography (EIT) is a promising technique for large area tactile sensing for robotic skin. This study presents a novel EIT-based force and touch sensor that features a latex membrane acting as soft skin and an ionic liquid domain. The sensor works based on fringing field EIT where the touch or force leads to a deformation in the latex membrane causing detectable changes in EIT data. This article analyses the performance of this electronic skin in terms of its dynamical behaviour, position accuracy and quantitative force sensing. Investigation into the sensor's performance showed it to be hypersensitive, in that it can reliably detect forces as small as 64 mN. Furthermore, multi-touch discrimination and annular force sensing is displayed. The hysteresis in force sensing is investigated showing a very negligible hysteresis. This is a direct result of the latex membrane and the ionic liquid-based domain design compared to more traditional fabric-based touch sensors due to the reduction in electromechanical coupling. A novel test is devised that displayed the dynamic performance of the sensor by showing its ability to record a 1 Hz frequency, which was applied to the membrane in a tapping fashion. Overall, the results show a considerable progress in ionic liquid EIT-based sensors. These findings place the EIT-based sensors that comprise a liquid domain, at the forefront of research into tactile robotic skin.
电阻抗断层成像（EIT）是一种很有前途的机器人皮肤大面积触觉传感技术。本研究提出了一种基于 EIT 的新型力和触觉传感器，其特点是采用乳胶膜作为柔软的皮肤和离子液体域。该传感器基于边缘场 EIT 工作，触觉或力导致乳胶膜变形，从而导致 EIT 数据的可检测变化。本文分析了这种电子皮肤在动态行为、位置精度和定量力感测方面的性能。对传感器性能的研究表明，它具有超灵敏性，能够可靠地检测小至 64 mN 的力。此外，还展示了多点触控识别和环形力感测。研究了力感测中的滞后现象，结果表明滞后非常小。这是由于乳胶膜和基于离子液体的域设计与更传统的基于织物的触摸传感器相比，由于减少了机电耦合，从而导致滞后现象减少。设计了一种新的测试，通过显示其记录 1 Hz 频率的能力来显示传感器的动态性能，该频率以敲击方式施加到膜上。总的来说，结果表明在基于离子液体的 EIT 传感器方面取得了相当大的进展。这些发现将包含液体域的 EIT 基传感器置于触觉机器人皮肤研究的前沿。
