Actively steerable in-pipe inspection robots for underground urban gas pipelines

We introduce the robots called MRINSPECT (multifunctional robotic crawler for inpipe inspection) III and IV which are under development for the inspection of urban gas pipelines. The proposed robots can freely move along the basic configuration of pipelines, such as horizontal or vertical pipelines. Moreover, it can travel along reducers, elbows, and steer in the branches by using steering mechanisms. Especially, their three dimensional steering capability provides outstanding mobility in navigation that is a prerequisite characteristic in urban gas pipelines. Their critical points in the design and construction are introduced with preliminary results of experiments.