Spray coated tactile sensor on a 3D surface for robotic skin

1 min read

A stretchable, pressure, insensitive, strain sensor has been developed by a KAIST research team, which uses an all solution-based process.

According to the researchers, the solution-based process is easily scalable to accommodate for large areas and can be coated as a thin-film on 3D irregularly shaped objects via spray coating. These conditions make their processing technique unique and highly suitable for robotic electronic skin or wearable electronic applications.

The making of electronic skin to mimic the tactile sensing properties of human skin is an active area of research for various applications such as wearable electronics, robotics, and prosthetics. One of the major challenges in electronic skin research is differentiating various external stimuli, particularly between strain and pressure. Another issue is uniformly depositing electrical skin on 3D irregularly shaped objects.

To overcome these issues, the research team, led by Professor Steve Park and Professor Jung Kim of KAIST, developed electronic skin that can be uniformly coated on 3D surfaces and distinguish mechanical stimuli. The new electronic skin can also distinguish mechanical stimuli analogous to human skin, the researchers add.

Detecting mechanical stimuli using electrical impedance tomography

The structure of the electronic skin was designed to respond differently under applied pressure and strain. Under applied strain, conducting pathways undergo significant conformational changes, considerably changing the resistance. On the other hand, under applied pressure, negligible conformational change in the conducting pathway occurs; e-skin is therefore non-responsive to pressure. The research team is currently working on strain insensitive pressure sensors to use with the developed strain sensors.

The research team also spatially mapped the local strain without the use of patterned electrode arrays utilising electrical impedance tomography (EIT). By using EIT, the researchers say it’s possible to minimise the number of electrodes, increase durability, and enable facile fabrication onto 3D surfaces.