Engineers at Stanford University have created soft and sensitive electronic skin with multiple sensors that can measure applied pressure and its direction in real time. It has a three-dimensional hierarchical structure and mimics the principles of touch of human skin..
Robotics has existed for more than half a century, but it still has not entered our daily life due to limited perception. In particular, robots cannot manipulate objects as deftly as living organisms, because they cannot sense them. However, a team of researchers from Stanford was able to create a virtual electronic copy of biological skin, which allows robots to handle even delicate objects with care..
The microstructure of the presented coating consists of three flexible layers with carbon nanotubes embedded in a polyurethane matrix. The lower one includes many interconnected hills that are located on the border between the artificial epidermis and dermis. In the presence of external mechanical pressure, they create localized stress at their tops. On the inside of the upper part there are many capacitors (about 25 for each hill), each with an area of 0.09 mm2. These two layers are separated by an insulating dielectric to create a capacitive effect..
Electronic Skin Can Give Robots the Sense of Touch
Robot neat touches fresh raspberries.
Electronic skin has four types of receptors: two react to low-frequency static pressure and two quickly adaptable, reacting to high-frequency dynamic forces and vibrations. According to the developers, the three-dimensional structure and the ability of the top layer to deform anisotropically when a tilt force is applied is the key to obtaining information about the direction of pressure..
This is achieved due to the fact that capacitors located on the side of the hill and subject to greater pressure increase their capacitance more than those located on the opposite side. Electronic skin is very sensitive and reacts to exposure in milliseconds.
In tests, a robotic limb covered with artificial skin was able to gently manipulate objects and touch fresh raspberries without crushing them. Engineers say technology can be used in many fields of activity requiring precise sensory control, such as surgery or production lines with soft fruits, eggs. In the future, such a coating will allow robots to independently perceive objects and calculate how much force needs to be applied to them..
The ability of robots to sense the world just like humans will be the penultimate stage towards the formation of fully autonomous artificial intelligence.
text: Ilya Bauer, photo: Courtesy of Bao Lab / Stanford University