Researchers at New York University’s Tandon School of Engineering have developed WorMa, a worm-inspired amphibious robot intended to navigate rugged coastal terrain. Approximately 50 centimetres long and weighing slightly more than one kilogram, it has five body sections connected by four joints. A central pump transfers around 300 grams of water between latex balloons in its head and tail. This movable ballast changes its centre of mass without requiring separate specialised mechanisms for each environment.
Concentrating water towards the head increases the force at the robot’s front contact points, improving traction. In tests, this configuration enabled it to climb a 19.5-degree incline, whereas alternative weight distributions caused it to slide backwards. Its cost of transport was also at least 33 per cent lower. In water, shifting weight towards the tail increased swimming speed by up to 26 per cent and efficiency by 52 per cent compared with the head-heavy configuration. To negotiate steps up to 15 centimetres high, WorMa shifts water backwards to raise its front, then forwards again once its head contacts the edge. A heavier head also provides the traction needed to pull itself from water onto a slope.
The team demonstrated WorMa crossing flat ground, a step, a slope and open water while retaining its basic wave-like movement. Potential applications include environmental monitoring and infrastructure inspection, where a single mission may involve land, obstacles and water. Researchers are developing faster pumps and sensor-based controls that could detect terrain changes and redistribute weight automatically, enabling more dynamic adaptation in coastlines, wetlands and flooded areas.
