Fan-propelled surface-adhering apparatus for automated maintenance operations
An apparatus for automated maintenance of limited-access areas on large structures. The apparatus is a rolling or sliding tool-equipped mobile platform that is adhered to a surface by operation of one or more adherence fans and then propelled across the surface by operation of one or more propulsion fans. The adherence and propulsion fans are coupled to a base made of semi-rigid material. The adherence fans produce suction forces in one or more suction zones to adhere the mobile platform to the surface. The propulsion fans produce thrust to propel the surface-adhered mobile platform in a desired direction across the surface. The tool-equipped mobile platform is capable of adhering to and moving over a non-level surface on a large structure while keeping standoff contact elements in contact with the surface regardless of surface contour. The propulsion fans, adherence fans and maintenance tool (e.g., an NDI sensor unit) are controlled by a computer system.
1. A mobile platform for performing maintenance operations, comprising:
a base having a first opening;
a first skirt attached to or integrally formed with the base and surrounding the first opening in the base, the first skirt bounding a suction zone that is in fluid communication with the first opening;
a maintenance tool mounted to the base;
a first adherence fan rotatably coupled to the base and disposed to remove air from the suction zone via the first opening in the base;
a first adherence fan motor operatively coupled for driving rotation of the first adherence fan;
first and second propulsion fans having axes of rotation which are generally parallel to the base;
first and second propulsion fan motors operatively coupled for driving rotation of the first and second propulsion fans respectively; and
a controller configured to control the operation of the first adherence fan motor and the first and second propulsion fan motors.
2. The mobile platform as recited in claim 1 , further comprising:
first and second turrets rotatably coupled to the base and fixedly coupled to the first and second propulsion fan motors respectively; and
first and second turret motors operatively coupled for driving rotation of the first and second turrets respectively, thereby enabling the first and second propulsion fan motors to swivel about respective axes of rotation under the control of the controller.
3. The mobile platform as recited in claim 2 , wherein the first opening is disposed between the first and second turrets.
4. The mobile platform as recited in claim 1 , further comprising a plurality of standoff contact elements attached to the base.
5. The mobile platform as recited in claim 4 , wherein the plurality of standoff contact elements are ball rollers.
6. The mobile platform as recited in claim 4 , wherein the plurality of standoff contact elements have surfaces suitable for sliding along a continuous surface of a structure.
7. The mobile platform as recited in claim 1 , wherein the maintenance tool comprises a plurality of sensors.
8. The mobile platform as recited in claim 1 , wherein the base has a second opening and the mobile platform further comprises :
a second adherence fan rotatably coupled to the base and disposed to remove air from the suction zone via the second opening in the base; and
a second adherence fan motor operatively coupled for driving rotation of the second adherence fan.
9. The mobile platform as recited in claim 1 , wherein the mobile platform further comprises:
a second skirt attached to or integrally formed with the base and surrounded by the first skirt with the first opening therebetween, the suction zone being bounded by the first and second skirts and in fluid communication with the first opening.
10. The mobile platform as recited in claim 1 , wherein the base is made of semi-rigid material.
11. A system for performing maintenance operations, comprising an umbilical cable and a first mobile platform attached to the umbilical cable, the first mobile platform comprising:
a first base having an opening;
a skirt attached to or integrally formed with the first base and surrounding the opening in the first base, the skirt bounding a suction zone that is in fluid communication with the opening;
a maintenance tool mounted to the first base;
an adherence fan rotatably coupled to the first base and disposed to remove air from the suction zone via the opening in the first base;
an adherence fan motor operatively coupled for driving rotation of the adherence fan;
first and second propulsion fans having axes of rotation which are generally parallel to the base;
first and second propulsion fan motors operatively coupled for driving rotation of the first and second propulsion fans respectively; and
a controller configured to control the operation of the adherence fan motor and the first and second propulsion fan motors to enable concurrent surface adherence and fan propulsion.
12. The system as recited in claim 11 , further comprising a second mobile platform configured to manage extension and retraction of the umbilical cable, wherein the second mobile platform comprises a second base and a spool mounted to the second base, a first portion of the umbilical cable being wound on the spool and a second portion of the umbilical cable extending between the spool and the first base of the first mobile platform.
13. The system as recited in claim 12 , wherein the second mobile platform further comprises a boom arm that supports the second portion of the umbilical cable.
14. The system as recited in claim 12 , wherein the second mobile platform further comprises a plurality of wheels rotatably coupled to the second base.
15. The system as recited in claim 12 , wherein the second mobile platform further comprises a plurality of propulsion fans.
16. The system as recited in claim 12 , further comprising:
first and second turrets rotatably coupled to the first base and fixedly coupled to the first and second propulsion fan motors respectively; and
first and second turret motors operatively coupled for driving rotation of the first and second turrets respectively, thereby enabling the first and second propulsion fan motors to swivel about respective axes of rotation under the control of the controller.
17. The system as recited in claim 12 , further comprising a plurality of standoff contact elements attached to the first base.
18. A method for automated maintenance of a structure, comprising:
(a) attaching a tool-equipped mobile platform to one end of an umbilical cable;
(b) suspending the attached tool-equipped mobile platform from the umbilical cable in a position adjacent to a surface of a structure;
(c) moving the suspended tool-equipped mobile platform into proximity with the surface;
(d) adhering the tool-equipped mobile platform to the surface using one or more fans to produce suction in a suction zone between the surface and a base of the tool-equipped mobile platform;
(e) propelling the adhered tool-equipped mobile platform to a first location on the surface by means of thrust produced by propulsion fans of the tool-equipped mobile platform; and
(f) operating a maintenance tool of the tool-equipped mobile platform to perform a maintenance operation while the tool-equipped mobile platform is at the first location.
19. The method as recited in claim 18 , wherein step (c) comprises moving the suspended tool-equipped mobile platform into contact with the surface, the tool-equipped mobile platform remaining in contact with and adhered to the surface during steps (e) and (f).
20. The method as recited in claim 18 , further comprising the following steps performed upon completion of step (f):
(g) propelling the adhered tool-equipped mobile platform from the first location to a second location on the surface by means of thrust produced by the propulsion fans of the tool-equipped mobile platform; and
(h) operating the maintenance tool of the tool-equipped mobile platform to perform a maintenance operation while the tool-equipped mobile platform is at the second location.
21. The method as recited in claim 20 , wherein the maintenance tool is a sensor array, step (g) comprises moving the sensor array along a scan path that follows the surface of the structure, and step (h) comprises using the sensor array to acquire sensor data representing characteristics of the structure along the scan path while the fans propel the tool-equipped mobile platform from the first location to the second location.