Tele-perception: artificial skin recognizes materials and objects at a distance

A research team from the Beijing Institute of Nanoenergy and Nanosystems and Tsinguha University has developed an artificial skin that can recognize materials at a distance of up to 150 mm. The multi-receptor skin reacts to pressure and uses electrostatic induction for tele-perception, the reception of sensory information from a distance.

Di Wei, professor and head of the Iontronics Laboratory at the Beijing Institute of Nanoenergy and Nanosystems, got the idea for an artificial skin for tele-perception from his daughter. She had seen a documentary about egg-laying platypuses and pointed out to her father that the animals are able to hunt in water without having to rely on their eyes. This aroused Wei's curiosity and he began to investigate the underlying sensory system in more detail.

He discovered that platypuses have a dual sensory system that allows them to detect mechanical stimuli and electrical changes in their environment. In contrast to other egg-laying aquatic animals, the platypus can recognize prey or potential threats without visual contact.

"We wanted to replicate the platypus's abilities in an artificial skin that combines both tactile and tele-perception functions," says Wei. "Our primary goal was to expand the perceptual range of artificial systems so that robots can recognize and interact with their environment without relying solely on physical contact. This could significantly improve the interaction and control of robots and overcome the limitations of conventional tactile sensors that rely on direct contact to function effectively."

The artificial skin, which the scientists describe in the study "Multi-receptor skin with highly sensitive tele-perception somatosensory", published in Science Advances, consists of a PTFE (polytetrafluoroethylene) and a PDMS (polydimethylsiloxane) thin film, a structurally doped elastomer in which inorganic, non-metallic nanoparticles are embedded. They improve the dielectric properties. A silver nanowire layer is also incorporated, which serves as an electrode. The PDMS-encapsulated substrate increases flexibility and protection.

The artificial skin can react to tactile stimuli via contact electrification. The researchers use the overlapping of the electron clouds of the two materials to facilitate the transfer of electrons, allowing triboelectricity to be generated and the stimulus to be evaluated.

Contactless detection

The situation is different with contactless perception, or tele-perception: For this, the skin uses electrostatic induction. The nanoparticles in the skin increase the dielectric polarization so that the skin can detect changes in electrical fields as soon as objects are in the vicinity. The skin can detect objects up to a maximum distance of 150 mm. The researchers use deep learning techniques to identify materials and recognize objects by evaluating the sensor data. According to the scientists, this was achieved with an accuracy of 99.56 percent.

But that is not enough for the researchers. They want to increase the accuracy even further and make the system more versatile so that it can be used more easily in practical applications. This is possible by integrating artificial intelligence (AI) even more and using new materials. This can improve the precision and range of detection, for example. The scientists also hope to increase the adaptability and robustness of the system, as well as real-time detection.

The dual-sensory skin could be used in robots and autonomous vehicles for better perception of the environment as well as in human-machine interfaces.

(olb)