MIT researchers have described a soft silicone sheet in Advanced Intelligent Systems that can sense its own 3D shape and respond to pressure, using embedded optical fibers instead of rigid electronic sensors. The 16 x 16 cm prototype contains 14 rubber-core waveguides arranged in two zig-zagged layers, each 160 mm long. An LED shines through each fiber; bends alter how much light reaches the far end, and a deliberately roughened side allows directional sensing.
In tests over three 3D-printed molds, the reconstruction error was 0.37, 0.28, and 0.45 cm. Qifan Yu, an MIT graduate student on the team, put rigid-sensor designs at around 1 to 2 cm error, making the soft sheet at least on par with existing technologies. The team also found that angling the waveguides improved accuracy more than adding more fibers. A simulation showed shape estimates stayed below 0.3 cm error with up to three of the 14 waveguides disabled, confirming that the design remains usable after some damage.
Pressure sensing runs separately from shape reconstruction and does not yet give calibrated force readings. Wearable demonstrations also used simplified scaling for wrist and elbow angles because stretching at joints interferes with the shape algorithm. Still, the researchers expect uses in physical therapy, virtual reality, robot teleoperation, and soft robotics. Co-author Kaitlyn Becker said the team hopes to help therapists track and quantify patient progress over time. The current 1 mm fibers are too thick for comfortable garments, but thinner fibers—down to tens of micrometers—could make smart clothing more practical.