A new artificial nervous system could one day give robots and prosthetic devices a sense of touch equivalent to, or better than, human skin, researchers report.
The new electronic skin system—called Asynchronous Coded Electronic Skin (ACES) —has ultra-high responsiveness and robustness to damage, and can pair with any kind of sensor skin layers to function effectively as an electronic skin.
“Humans use our sense of touch to accomplish almost every daily task, such as picking up a cup of coffee or making a handshake. Without it, we will even lose our sense of balance when walking, ” says Benjamin Tee, an assistant professor in the materials science & engineering department at the National University of Singapore.
“Similarly, robots need to have a sense of touch in order to interact better with humans, but robots today still cannot feel objects very well.”
A better electronic skin
Drawing inspiration from the human sensory nervous system, the researchers spent a year and a half developing a sensor system that could potentially perform better. While the ACES electronic nervous system detects signals like the human sensor nervous system, unlike the nerve bundles in the human skin, it is made up of a network of sensors connected via a single electrical conductor.
Further, it is unlike existing electronic skins that have interlinked wiring systems that can make them sensitive to damage and difficult to scale up.
“The human sensory nervous system is extremely efficient, and it works all the time to the extent that we often take it for granted. It is also very robust to damage. Our sense of touch, for example, does not get affected when we suffer a cut,” says Tee, who also holds appointments in the electrical and computer engineering department, the Institute for Health Innovation & Technology, N.1 Institute for Health, and the Hybrid Integrated Flexible Electronic Systems program.
“If we can mimic how our biological system works and make it even better, we can bring about tremendous advancements in the field of robotics where electronic skins are predominantly applied.”
10x faster than an eye blink
As reported in Science Robotics, ACES can detect touches more than 1,000 times faster than the human sensory nervous system. For example, it can differentiate physical contact between different sensors in less than 60 nanoseconds—the fastest ever achieved for an electronic skin technology—even with large numbers of sensors.
The high fidelity and capture speed of the ACES system allows the skin to accurately identify the shape, texture, and hardness of objects within 10 milliseconds, 10 times faster than the blink of an eye.
Researchers can also design the ACES platform to achieve high robustness to physical damage, an important property for electronic skins because they come into the frequent physical contact with the environment.
Unlike the current system used to interconnect sensors in existing electronic skins, all the sensors in ACES can be connected to a common electrical conductor with each sensor operating independently. This allows ACES-enabled electronic skins to continue functioning as long as there is one connection between the sensor and the conductor, making them less vulnerable to damage.
Easy scale-up
ACES has a simple wiring system and remarkable responsiveness even with increasing numbers of sensors. These key characteristics will facilitate the scale-up of intelligent electronic skins for artificial intelligence (AI) applications in robots, prosthetic devices, and other human machine interfaces.
“Scalability is a critical consideration as big pieces of high performing electronic skins are required to cover the relatively large surface areas of robots and prosthetic devices,” Tee says. “ACES can be easily paired with any kind of sensor skin layers, for example, those designed to sense temperatures and humidity, to create high performance ACES-enabled electronic skin with an exceptional sense of touch that can be used for a wide range of purposes.”
For instance, pairing ACES with the transparent, self-healing, and water-resistant sensor skin layer that Tee’s team recently developed, creates an electronic skin that can self-repair, like the human skin. This type of electronic skin could help to develop more realistic prosthetic limbs that will help disabled individuals restore their sense of touch.
Other potential applications include developing more intelligent robots that can perform disaster recovery tasks or take over mundane operations such as packing items in warehouses. The researchers are looking to further apply the ACES platform on advanced robots and prosthetic devices in the next phase of their research.
Source: National University of Singapore
