Electronic skin could help robots get in touch with their feelings

A new type of energy-generating synthetic skin could create more affordable prosthetic limbs and robots capable of mimicking the sense of touch, scientists say. In an early-view paper published in the journal IEEE Transactions on Robotics, researchers from the University of Glasgow describe how a robotic hand wrapped in their flexible solar skin is capable of interacting with objects without using dedicated and expensive touch sensors.

Instead, the skin puts the array of miniaturised solar cells integrated on its soft polymer surface to clever dual use. The cells generate enough energy to power the micro-actuators which control the hand’s movements, but they also provide the hand with its unique sense of ‘touch’ by measuring the variations in the solar cells’ output. As objects get closer to the surface of a cell, they reduce the amount of light that reaches it. The amount of power the cell generates drops as the light gets dimmer, eventually reaching zero when an object touches and covers it. By making clever interpretations of the levels of power produced in each cell, the skin is capable of detecting the shape of an incoming object.
 
The second set of simple LEDs, integrated between the solar cells in the skin, transmit infra-red light towards objects. By measuring the time the light takes to reflect from the object, the skin can sense the distance between the object and the hand. Combining the information collected from the solar cells and LEDs allows the skin’s processor to deduce an object’s proximity, location, and edges, replicating many of the parameters measured by more traditional touch sensors. Together, the data allows the hand to grasp objects like rubber balls placed in front of it.