Ice Dart Drone Grips Near-Vertical Ice Walls With Cat-Claw Spines

The Ice Dart, a quadcopter from researchers at the Université de Sherbrooke in Quebec, is the first drone able to land and hold its position on near-vertical ice walls, a new paper in IEEE Transactions on Field Robotics reports. Standard rubber-footed drones lose grip on slopes as gentle as 9 degrees, and on a 60-degree wall gravity presses an aircraft down with half its usual force.

The drone uses perching, a robotics approach borrowed from how birds, insects and geckos grip surfaces, landing and shutting down its noisiest systems to become a fixed sensor rather than hovering. "The inspiration for the retractable spines in the feet came from looking at a cat's claws and their ability to deploy only when needed," said Isaac Tunney, a postdoctoral researcher at the Université de Sherbrooke and the study's first author.

Each of the drone's four carbon-fiber legs ends in a foot with two spring-loaded spines pointing opposite ways, so one grips whether it lands facing uphill or downhill. The 2.65 kg (5.84 lb) aircraft uses 38 friction disks in its landing gear to absorb impact without bouncing, and its motors briefly reverse thrust on contact to shove the drone into the wall and help the spines dig in.

Flown along Iceland's Fjallsjökull glacier in 0-10°C (32-50°F) temperatures and winds past 30 km/h (18.6 mph), it stuck 24 clean landings on slopes up to 58 degrees, a 100% success rate; lab tests reached 60-degree slopes at 3 m/s (6.7 mph) landing speeds. "The ability to land rather than hover can fundamentally change how drones are used in the field," said Alexis Lussier Desbiens, an engineering professor and study co-author.

The Iceland trials relied on a human pilot backed by a second drone for visual inspection rather than full autonomy, and the Ice Dart has not yet been tested on a drifting iceberg in open water — closing that gap is the team's next step.