This robot can tell when sewers need repairing by scratching the walls

A four-legged robot that inspects concrete can walk through underground sewage tunnels and detect when they need repairing. Hendrik Kolvenbach at the Swiss Federal Institute of Technology (ETH Zurich) in Switzerland and his colleagues have developed a robot that scratches one of its legs against concrete to determine the condition it is in. The robot is waterproof and it can wade through water and climb over obstacles. Because many modern sewage systems were built decades ago, constant underground monitoring is needed to prevent major leaks.