Researchers at Carnegie Mellon University’s Robotics Institute recently completed tests of a modular snake robot in an Austrian nuclear power plant. The multi-jointed robot with a camera on its head, can crawl through a variety of steam pipes and connecting vessels, and can be a valuable inspection tool, feels the researchers.
The modular snake robot is two inches in diameter and 37 inches long and tethered to a control and power cable. Its body consists of 16 modules, each with two half-joints that connect with corresponding half-joints on adjoining modules. The robot body has 16 degrees of freedom, enabling it to assume a number of configurations and to move using a variety of gaits — some similar to a snake’s, but others that take advantage of the robot’s unique mechanical characteristics.
Though the robot’s body twists, turns and rotates as it moves through or over pipes, the view from the video feed is corrected so that it was always aligned with gravity.
Howie Choset (Robotics Professor, Carnegie Mellon): Our robot can go places people can’t, particularly in areas of power plants that are radioactively contaminated. It can go up and around multiple bends, something you can’t do with a conventional borescope, a flexible tube that can only be pushed through a pipe like a wet noodle.
A nuclear power plant contains miles of pipes to carry water and various stages of steam and, despite the potential for corrosion and other damage, much of that piping is difficult to inspect because radioactivity limits access by people.
The snake robot has been tested in urban search-and-rescue environments in which it crawls through the rubble of collapsed buildings, in archeological excavations and in conventional fossil fuel plants.
Further development of the robot could enhance its inspection capabilities, including a next-generation robot that will be waterproof. The researchers also envision designing a “tether runner” device that could move along the robot’s tether and position itself around bends in a pipe, ensuring that the robot can be retrieved.
Further development could also enable the snake robot to perform simultaneous localization and mapping (SLAM), a robotic technique that would produce a map of a nuclear plant’s pipe network as it exists.
[Image courtesy: Carnegie Mellon University]