Most robots achieve grasping and tactile sensing through motorized means, which can be excessively bulky and rigid. A Cornell group has devised a way for a soft robot to feel its surroundings internally, in much the same way humans do.
Most robots today have sensors on the outside of the body that detect things from the surface. The Cornell 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.
Soft lithography and 3-D printing has led to development of elastomeric sensors that are easily produced and incorporated into a soft robotic application.
The research group employed a four-step soft lithography process to produce the core (through which light propagates), and the cladding (outer surface of the waveguide), which also houses the LED (light-emitting diode) and the photodiode.
The more the prosthetic hand deforms, the more light is lost through the core. That variable loss of light, as detected by the photodiode, is what allows the prosthesis to “sense” its surroundings. The group used its optoelectronic prosthesis to perform a variety of tasks, including grasping and probing for both shape and texture. Most notably, the hand was able to scan three tomatoes and determine, by softness, which was the ripest.
>>Read more by Tom Fleischman, Cornell Chronicle, Dec. 8, 2016