Robot can sense internal touch just like humans
Image credit: Huichan Zhao
A tactile interface that allows a robot to sense touch internally the way that humans do has been developed by American researchers.
Current robots usually use external sensors to sense their surroundings. The technology by Cornell University engineers relies on stretchable optical waveguides instead that send the impulses towards sensors, which are inside the robot, thus mimicking the human experience.
“Most robots today have sensors on the outside of the body that detect things from the surface,” said doctoral student Huichan Zhao, who led the study. “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.”
The optical waveguides flex and elongate when touched and pressed, modifying the way light propagates through them to a sensing photodiode at the heart of the system.
“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 and principal investigator of the Organic Robotics Lab at Cornell University. “The amount of loss is dependent on how it’s bent.”
The group used its optoelectronic prosthesis to perform a variety of tasks, including grasping and probing for shape and texture. The hand was able to scan three tomatoes and determine, by softness, which was the ripest.
The team foresees the technology could have many potential uses including in prosthetics, bio-inspired robotics and space exploration.
The researchers hope to increase the sensory capabilities of the optical waveguides by 3D-printing more complex sensor shapes. They also intend to incorporate machine learning into the system to decouple signals from an increased number of sensors.
“Right now it’s hard to localise where a touch is coming from,” Shepherd said.
Optical waveguides have been in use since the early 1970s for numerous sensing functions, including tactile, positioning and acoustics. Fabrication was complicated originally, but the development of lithography 20 years ago and 3D-printing in the last decade has allowed the creation of elastomeric sensors that are easily produced and incorporated into a soft robotic application.
The study was published in the debut edition of the Science Robotics journal.