Researchers at Delft University of Technology in the Netherlands have developed a lightweight tactile sensor that lets ultra-compact drones navigate in darkness or smoke, conditions where cameras and lidar stop working. The design borrows from nocturnal animals like mice and cats, which use whiskers to sense their surroundings without vision. The team attached two nearly 8-inch-long nickel-titanium wires to a palm-sized drone, each with three pressure sensors at the base that measure how the wires bend to estimate distance and position relative to nearby barriers.
A key hurdle was filtering out noise from the drone's own vibrations. Even with filtering, about 38 percent of detections were false positives caused by sensor drift. The researchers developed a correction algorithm that estimates drift over time while the drone is not touching anything, and combined with the filter, false positives reportedly dropped to 0 percent. They also tested six mounting angles across 72 flights, settling on 45 degrees as the angle that caused the least deviation in the drone's orientation.
The drone successfully flew parallel to transparent walls and navigated angled surfaces that laser sensors would miss. In a small room with glass walls, it found a 2.5-foot-wide exit in 90 percent of tests using an exploration method that prioritizes unexplored areas. However, the source notes that real-world disaster rubble is far messier than the test environment, and a wall-following drone could easily get stuck in corners or miss side obstacles. The researchers say the entire tactile perception pipeline runs onboard using just 34 KB of memory, leaving room for further improvements. This work is still at the research stage, and no commercial product or deployment timeline is mentioned in the source.