Soft sensor gives robots a better sense of touch

Researchers at Shanghai Jiao Tong University have developed a tiny optical force sensor designed to give robots a more accurate sense of touch for delicate tasks such as surgery, the university said. The sensor measures 1.7 millimeters wide, roughly the size of a grain of rice, allowing it to fit inside advanced surgical tools. Unlike traditional electronic sensors, the device uses light to measure force from every direction, including pressure, sliding movements and twisting. A soft material at the tip of an optical fiber deforms slightly upon contact, altering light patterns that travel through the fiber to a camera. A machine learning model then translates those patterns into precise force readings. In testing, the sensor detected a hard sphere hidden inside a soft gelatin block, mimicking a tumor in human tissue, by sensing differences in stiffness. Researchers acknowledged that challenges remain, including consistent manufacturing at scale, simplifying the setup process and conducting long-term stress testing required for medical devices. The team is now working to integrate the sensor into actual robotic surgical tools for testing in environments closer to real operating rooms.