Robotic surface preparation by a random orbital device

1. An apparatus for performing surface preparation, the apparatus comprising:

a surface preparation device for moving a backing pad in a random orbital motion;

a first ball joint connected to the device;

a second ball joint connected to the first ball joint; and

a robotic end effector, connected to the second ball joint, for pressing the device against a surface.

2. The apparatus of claim 1 , wherein the device is a random orbital sander.

3. The apparatus of claim 1 , wherein the end effector includes a linear actuator, connected to the second ball joint, for applying constant pressure to the device.

4. The apparatus of claim 3 , wherein the end effector and the linear actuator are rigid in a direction of pad motion.

5. The apparatus of claim 3 , wherein the linear actuator includes a pneumatic double compression cylinder and a pressure regulator for regulating pressure in the cylinder so a constant force is applied to the device.

6. The apparatus of claim 1 , wherein each ball joint has a rotation of no more than 15 degrees.

7. An apparatus for performing surface preparation, the apparatus comprising:

a surface preparation device for moving a backing pad;

a robotic end effector for pressing the device against a surface; and

a platform and a wedge on a surface of the platform, the wedge having a shovel-nose tip for separating a medium from the backing pad.

8. The apparatus of claim 7 , wherein the tip has a size and shape to separate middle portion of the medium from the backing pad disc before separating edges of the medium from the backing pad.

9. The apparatus of claim 7 , further comprising surface rollers adjacent the wedge for moving the device towards the wedge tip.

10. The apparatus of claim 7 , further comprising hook and loop material for securing the medium to the backing pad.

11. The apparatus of claim 7 , further comprising a first ball joint connected to the device and a second ball joint connected between the first ball joint and the robotic end effector; wherein the device is configured to move the backing pad in a random orbital motion; and wherein the ball joints move the pad to a known location when the device is stopped by the wedge.

12. The apparatus of claim 11 , further comprising means for automatically attaching media to the backing pad, including a holder for stacking media, and metal discs for separating the media; and wherein the backing pad has a magnetic portion for magnetically attracting one of the metal discs.

13. The apparatus of claim 12 , the means further comprising at least one optical sensor positioned to determine whether a metal disc is attached to the backing pad.

14. A method comprising using the robotic end effector of claim 1 to prepare a surface of an aircraft for painting; and using another robotic end effector for painting the prepared surface.

15. An apparatus comprising:

a robotic end effector;

first and second ball joints connected serially; and

a random orbital sander connected to the robotic end effector by the serially connected ball joints;

the end effector including a pneumatic cylinder connected to one of the ball joints, and a pressure regulator for applying constant pressure to the sander.

16. The apparatus of claim 15 , wherein the ball joints have a rotation of no more than 15 degrees.

17. The apparatus of claim 15 , wherein the pneumatic cylinder is a pneumatic double compression cylinder.

18. The apparatus of claim 15 , wherein the medium is held to the pad via hook and loop material.

19. A method comprising using a robotic end effector coupled to a random orbital sander to attach and remove sanding media from a backing pad of the sander, wherein attaching a sanding medium includes:

stacking a plurality of sanding discs interleaved with thin metal discs, with each sanding disc being above its corresponding metal disc; and

using the robotic end effector to move the sander, which has a magnetized backing pad, over the stack so that the metal disc is magnetically clamped to the backing pad, whereby a sanding disc is clamped between its corresponding plate and the backing pad and thereby fastened to the backing pad.

20. The method of claim 19 , wherein removing the sanding medium includes using the robotic end effector to move the sander along a roller platform until the backing pad abuts against a shovel-nosed portion of a wedge and thereafter separates a sanding disc from the backing pad.