Screw principle microrobot passing steps in a small pipe

In order to pass the “screw principle microrobot”, which the authors have proposed to inspect the inner wall of small pipes in plumbings, to pass a stepped portion automatically, a step climbing mechanism which does not require any special actuators nor motion control, is proposed. A prototype was designed to pass both concentric and eccentric steps at the junction between two pipes 100 mm and 75 mm in diameter. The running performance is experimentally examined for some pipes which have a step at different positions