Most robots rely on external sensors to feel the outside world. To give robots a more human-like sense of touch, researchers at Cornell ditched those bulky and unnatural sensors for an internal system.
Scientists outfitted soft robot hands with stretchable optical waveguides. The sensors can measure curvature, elongation and force.
"Our sensors are integrated within the body, so they can actually detect forces being transmitted through the thickness of the robot, a lot like we and all organisms do when we feel pain, for example," Huichan Zhao, a doctoral student at Cornell, said in a news release.
Researchers used a 3D printer and four-step soft lithography to create the elastomeric sensors. The sensors consist of a light-emitting diode and photodiode inside a light-transmitting core, insulated by cladding.
Once inside the soft robot hand, the sensors ability to carry light becomes dependent on the contortion of the prosthesis. Light is lost through the cladding as the hand deforms. The photodiode can measure the loss of light, and in turn, the curvature, elongation and force experienced — or "felt" — by the hand.
"If no light was lost when we bend the prosthesis, we wouldn't get any information about the state of the sensor," said Robert Shepherd, assistant professor of mechanical and aerospace engineering. "The amount of loss is dependent on how it's bent."
Scientists described the new soft robot hand and its internal sensors in the journal Science Robotics.
