Inspection method using a perching UAV with a releasable crawler

A method of inspection or maintenance of an outwardly curved ferromagnetic surface exhibiting outward cylindrical or spherical curvature by a crawler flown to and released on the outwardly curved ferromagnetic surface by an unmanned aerial vehicle (UAV), the method comprising:

• flying the UAV and attached releasable crawler to a proximity of the outwardly curved ferromagnetic surface exhibiting the outward cylindrical or spherical curvature;
• perching the UAV and attached releasable crawler on the outwardly curved ferromagnetic surface, comprising:
• passively articulating legs of the UAV toward the outward cylindrical or spherical curvature of the ferromagnetic surface through magnetic attraction using corresponding magnets in the legs while approaching the outwardly curved ferromagnetic surface;
• magnetically attaching the articulated legs of the UAV to the outwardly curved ferromagnetic surface using the corresponding magnets;
• and
• maintaining the magnetic attachment of the legs to the outwardly curved ferromagnetic surface throughout the perching;
• detaching the attached crawler onto the outwardly curved ferromagnetic surface from the perched UAV;
• maneuvering the detached crawler on the outwardly curved ferromagnetic surface while magnetically attaching the crawler to the outwardly curved ferromagnetic surface using magnetic wheels of the crawler;
• and
• inspecting or maintaining the outwardly curved ferromagnetic surface using the magnetically attached crawler.