Perching UAV with releasable crawler

1. An unmanned aerial vehicle (UAV) comprising:

a fixed frame including:

peripheral propellers and corresponding motors for flying the UAV; and

a central electronics enclosure for housing electronics used to control the UAV; and

a rotating arm pivotably coupled to the fixed frame at a central axis between the propellers and configured to rotate with respect to the fixed frame about the central axis, the rotating arm including:

magnetic feet at a first end of the rotating arm and configured to perch and magnetically attach the UAV to a ferromagnetic surface;

a docking station at the first end and configured to release and dock a releasable crawler on and from the ferromagnetic surface; and

a battery at a second end of the rotating arm opposite the first end and configured to supply power to the motors and the housed electronics, and to counterbalance the first end about the central axis.

2. The UAV of claim 1 , wherein the first end of the rotating arm is adjustable to accommodate vertical and horizontal pipes as the ferromagnetic surface.

3. The UAV of claim 2 , wherein the rotating arm extends along a longitudinal axis perpendicular to the central axis and going through the docking station, and the first end of the rotating arm is reconfigurable to rotate the first end about the longitudinal axis relative to a remainder of the docking station by 90°.

4. The UAV of claim 3 , wherein the rotation arm further comprises a payload motor powered by the battery and configured to rotate the first end of the rotating arm about the longitudinal axis relative to the remainder of the docking station.

5. The UAV of claim 1 , wherein the rotating arm is further configured to:

rotate its first end down with respect to the fixed frame in order to perch the UAV and release the crawler on a top of the ferromagnetic surface;

rotate its first end up with respect to the first frame in order to perch the UAV and release the crawler on a bottom of the ferromagnetic surface; and

rotate its first end even with respect to the fixed frame in order to perch the UAV and release the crawler on a side of the ferromagnetic surface.

6. The UAV of claim 1 , wherein the magnetic feet are further configured to passively pivot in a first orientation in order to perch and magnetically attach the UAV to a flat ferromagnetic surface, and passively pivot in a second orientation different from the first orientation in order to perch and magnetically attach the UAV to a curved ferromagnetic surface exhibiting cylindrical curvature.

7. The UAV of claim 6 , wherein the magnetic feet are further configured to passively pivot in the second orientation in order to perch and magnetically attach the UAV to a curved ferromagnetic surface exhibiting cylindrical curvature with a first radius of curvature, and to passively pivot in a third orientation different from the first and second orientations in order to perch and magnetically attach the UAV to a curved ferromagnetic surface exhibiting cylindrical curvature with a second radius of curvature different from the first radius of curvature.

8. The UAV of claim 1 , wherein the magnetic feet comprise switchable magnets powered by the battery and configured to switch their magnetism on and off under control of the housed electronics, the switchable magnets being further configured to:

switch their magnetism on in order to magnetically attach the UAV to the ferromagnetic surface during a perching of the UAV on the ferromagnetic surface; and

switch their magnetism off in order to magnetically detach the perched UAV from the ferromagnetic surface during a takeoff of the UAV from the ferromagnetic surface.

9. The UAV of claim 1 , further comprising a rotation motor powered by the battery and configured to rotate the rotating arm with respect to the fixed frame about the central axis under control of the housed electronics during flight of the UAV.