Researchers have developed an electronic skin (e-skin) that can detect sensations similar to the ones human feel when they are experiencing pain, paving the way for more life-like prosthetic devices and humanoid robots.

Professor Jae Eun Jang (left) in the Department of Information and Communication Engineering at Daegu Gyeongbuk Institute of Science and Technology (GIST) and Combined M.S.-Ph.D. program student Minkyung Shim (right). The two were part of a team that developed a new e-skin that can detect pain and temperature. (Image source: DGIST)

A team from the Daegu Gyeongbuk Institute of Science and Technology (DGIST) in South Korea developed the technology, which can detect “prick” and “hot” pain sensations similarly to how humans do, said Minkyug Shim, one of the institute researchers on the project.

While other research to develop e-skin for robotics and prosthetics has generally been focused on “enhancing performance such as the sensitivity, detecting range, and stability,” Shim said, the DGIST team took a different approach.

“We thought that pain feeling is very important to avoid the destruction by dangerous situation or materials,” he told Design News.

While enabling this type of detection in e-skins is a “complicated” problem to solve, Shim said, the team achieved its goal using a design based on zinc oxide nanowire technology.

Researchers applied the nanowire as a self-power tactile sensor that uses the piezoelectric effect, to generate electrical signals by detecting pressure, he said. At the same time, the team applied a temperature sensor using the nanowire so one sensor, in effect, performs the job of two, Shim said.

“Pressure and temperature were detected by single sensor structure, because these were carried out by only the zinc nanowire,” he told us.

One Nanowire, Two Tasks

To develop the e-skin, the team arranged electrodes on a polyimide flexible substrate and grew the nanowire, measuring the piezoelectric effect by pressure and the Seebeck effect by temperature change at the same time, researchers said. They also developed a signal processing technique that gauges the generation of pain signals considering the pressure level, stimulated area, and temperature, Shim said.

“If our system recognized the factor related to pain feeling by high pressure or temperature, the system generates the artificial pain signal (electrical),” he told Design News.

Researchers published a paper on their work in the Journal of Soft Robotics.

In the development of robots and prosthetics, the ability to sense pain using the e-skin the team developed can add a human-like sensation to a machine or artificial appendage, causing different reactions to stimuli, Shim said.

“The robot detecting the artificial pain signal can avoid a dangerous situation,” he told Design News. “In the case of prosthetics, the disabled people can feel real pain sensation if the technology transferring the generated pain signal by artificial prosthetic to the human central nervous system is developed.” 

Shim also presented a futuristic scenario in which artificial intelligence (AI) systems learn the feeling of pain so they can sympathize with humans, avoiding any potentially dangerous scenarios or even an attack by a potentially killer robot, he said.

“Many people are worrying about attack of developed AI robots,” Shim told Design News. “The solution is that the AI robots can sympathize with the pain of human by [using] our tactile system. If the AI robots learn the pain feeling by an external situation or attack and know that the situation is dangerous, the attack of AI robots on the human can be prevented in advance.”

Researchers aim to continue their work to add different sensations to the e-skin, such as the ability to sense when an object or material has a rough surface or texture, Shim said.

Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco and New York City. In her free time she enjoys surfing, traveling, music, yoga and cooking. She currently resides in a village on the southwest coast of Portugal.