Walking Robot for Internal Inspection of Thin-Wall Ducts

A walking robot connected to external instrumentation via a tether has been proposed to enable visual inspections, retrieval of loose objects, and some repairs inside thin-wall round ducts. The ducts in question are made of sections about 4 ft (1.2 m) long, joined by flexible seals that accommodate axial gaps and lateral misalignments of as much as 1/4 in. (6 mm) between sections. The sections can be oriented horizontally or vertically. Some duct sections include, variously, changes in diameter, bends, and openings into side ducts. The robot is required to negotiate all such sections at distances up to 60 ft (18.3 m) from the point of entry, without damaging the thin duct walls. The robot is required to be able to enter a duct through an opening as small as 4.5 in. (11.4 cm) and to move along the duct.