Abstract
Self-Adjusting Vehicle In Pipe (abbreviated as SAVIP) is newly proposed. The SAVIP in this paper has three wheels and can locomote with ability of self-adjusting to different pipes in shape and size. The frame of the SAVIP is like scissors since two arms moving about one axis are used, thus we call the frame scissors structure. The SAVIP can move in two types of locomotion. One is tractive and the other is non-tractive.
The tractive SAVIP has a driving wheel at the fulcrum of the scissors and two sphere bearings at the ends of the scissors. The driving wheel rotates about the axis perpendicular to the plane in which the two arms move. The wheel can move sideways freely. Since stretch force of the arm to the wall of the pipe is generated mechanically by using pulleys and a spring, the SAVIP stands in the pipe by pressing the two arms in opposite directions where the pipe swells in the most. The three wheels of the non-tractive SAVIP are sphere bearings.
We analyzed the geometry of the shape of the pipe to obtain the conditions in which the SAVIP can move stably. To clarify the conditions of the SAVIP for standing, we took frictional and gravitational forces exerting on the SAVIP into consideration. The results of the simulation of locomotion of the SAVIP in the plane in which the pipe swells in the most showed the self-adjustability of the SAVIP to the shape and size of the pipe. To prove this ability, we fabricated simplified tractive and non-tractive SAVIPs. Experimental results confirmed that the SAVIPs can move in an inclined or twisted pipe with a deep angle with the self-adjustability. The SAVIP will be utilized in atomic or chemical plants to carry apparatus such as a camera or a probe for monitoring and testing inside of pipes.
