How a 1.7mm Soft Robot Reaches Unreachable Spaces
A dielectric elastomer soft robot, just 1.7mm thick, can crawl, climb, and swim through near-millimetre gaps, built for inspections no other robot can do.
Power plants, bridges, and aero-engines all require regular inspection, but their narrowest gaps block every existing robot. Researchers at the University of Nottingham built a 1.7mm soft robot that crawls, climbs, swims, and transitions between domains to reach them.
What is a thin soft robot and how does it move?
The TS-Robot uses a dual-actuation sandwich structure: two dielectric elastomer layers drive a compressible tensioning mechanism between them. By synchronising both layers, the robot extends linearly; by activating just one, it bends for undulating motion. Electrostatic adhesive pads grip surfaces on demand, enabling crawling on horizontal and vertical planes across wood, PET, PVC, and paper.
Why millimetre-scale multimodal robots matter for inspection
Most inspection robots are limited to a single locomotion mode, useful in controlled environments, but inadequate in real industrial settings where narrow gaps, liquid barriers, vertical walls, and aerial transitions all appear in the same navigation path. The TS-Robot addresses this directly.
At just 1.7mm thick, it fits through gaps that defeat rigid and conventional soft robots alike. Researchers demonstrated it crawling through the 1.2mm air gap between the rotor and stator of a Rolls-Royce AE2100 hybrid power system, a space completely inaccessible to prior tools, for inspecting permanent magnet degradation in aircraft generators. The same platform swims at nearly 20 times its crawling speed by switching to an undulating gait in liquid, and multiple units can join together to transition between horizontal and vertical surfaces collaboratively.
The force output is disproportionate to the robot's size: the Type-A actuator produces a blocking force approximately 48 times its own weight. This payload capacity allowed researchers to demonstrate a hybrid system where the TS-Robot carries a miniature drone, crawling through a tunnel too low for the drone to fly, then releasing it to cross a trench, then crawling again to deliver a payload through a 3mm gap.
Target applications include aero-engine inspection, nuclear facility access, bridge structural surveys, pipeline monitoring, and security checks in confined spaces. The design's tunable resonant frequency — adjusted mechanically rather than chemically, gives engineers a faster path to optimising performance for each task.