In-Pipe Robot Mechanisms—State-of-the-Art Review

In-pipe robots are a class of robots that have been extensively studied for a very long time and many interesting solutions have been proposed and used in practical scenarios. There are many parameters and functional features that define the characteristics of these robots. An extensive review of the mechanisms that allows locomotion to the in-pipe robots is performed in this paper. A broader classification that allows more clarity on these robots for choosing them based on their capacities is provided. The designs brought out so far have limited itself to one type of scenario where there is no need for the robots to work in coordination. This perspective is different from the other review papers in that sense and is needed for the researchers to identify new design directions for improvising the performance of their robots. A new design perspective for in-pipe robots for swarm applications is also presented toward the end.