Researchers have developed a three-fingered soft robotic hand with embedded, stretchable fiber optic strain sensors. By using fiber optics, the researchers were able to embed 14 strain sensors into each of the fingers in the hand, giving it the ability to determine where its fingertips are in contact, and to detect forces of less than a tenth of a newton.
A single optical fiber can contain several sensors; all of the sensors in each of the fingers of the hand are connected with four fibers, although theoretically, a single fiber could do the job. And the optical sensors are impervious to electromagnetic interference.
Each of the fingers on the robotic hand mimic the skeletal structure of a human finger, with a fingertip, middle node, and base node connected by joints. The skeletal “bones” are 3D-printed hard plastic, and incorporate eight sensors for detecting force. Each of the three sections is covered with a soft silicone rubber skin embedded with a total of six sensors that detect where contact has been made.