Magnetic gearbox could power robots to crawl or jump inside your body

A gearbox driven by an external magnetic field can power tiny but powerful robots that crawl like a caterpillar or jump almost 40 times their own height, despite having no batteries or motors on board. The technology could lead to medical robots that can travel through the human body, taking samples or delivering drugs. Soft robots – which have no batteries, motors or electronics and are powered and controlled remotely by light or magnets – are a popular field of research because their simplicity enables them to be highly miniaturised. But they may be lacking in power when the task requires puncturing skin or opening collapsed cavities. Now, Chong Hong at the Max Planck Institute for Intelligent Systems in Germany and his colleagues have created a gearbox that measures around 3 millimetres across and is equipped with cogs as small as 270 micrometres in diameter.