In-Pipe Inspection Crawler Adaptable to the Pipe Interior Diameter

Oneofthemostimportantrequirementsofrepairingandmaintainingofpipelinesistheabilitytomonitorandevaluatethepipe’sinterior.In this paper, a novel apparatus to traverse pipes is introduced.Themechanismemploysthreeindependentrubbertrackunitswhichare circumferentially spaced out 120 ◦ apart symmetrically. Theapparatus employs an active mode to adapt to a wide range ofpipelinediametersfrom250to350mm. However,thisrangecanbeeasily extended by increasing the length of the robot’s linkages. Italso has the capability of traversing vertical, horizontal and curvedpipes. Further, it can passively pass over small obstacles of theinterior surface of the pipes and navigate through various elbowjointsinthepipingsystemwiththehelpofthespecialdesignofthespringed arms. Moreover, a novel autonomous adjusting algorithmispresentedtoassisttheoperatorinbetterregulationofthecontactforce without utilizing any force sensor. Finally, a prototype unit isbuilt andtestedindifferent situations. Key Words In-pipe inspection, robot design, active pipe-diameter adaptability,tractiveforceadjusting