Surface adhering tool carrying robot

• US 20030048081A1
• Filed: 09/09/2002
• Published: 03/13/2003
• Est. Priority Date: 09/09/2001
• Status: Active Grant

• Current Assignee: Advanced Robotics Vehicles Incorporated
• Original Assignee: Advanced Robotics Vehicles Incorporated
• Inventors: Seemann, Henry R.
• Granted Patent: US 7,155,307 B2
• Time in Patent Office: Days
• US Class Current: 318/68
• CPC Class Codes: A47L 1/02 Power-driven machines or devices
• CPC Class Codes: A47L 2201/00 Robotic cleaning machines, i.e. with automatic control of the travelling movement or the cleaning operation
• CPC Class Codes: B62D 55/00 Endless track vehicles steering aspects B62D11/00; characterised by the driver not being seated B62D51/007
• CPC Class Codes: B62D 55/075 Tracked vehicles for ascending or descending stairs, steep slopes or vertical surfacesmagnetic or pneumatic ground-engaging parts B62D55/265; chairs or multi-track cycles specially adapted for invalids A61G5/00
• CPC Class Codes: B62D 55/265 having magnetic or pneumatic adhesion
• CPC Class Codes: B62D 57/00 Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track sledges B62B; motor sledges B62M
• CPC Class Codes: B62D 57/024 specially adapted for moving on inclined or vertical surfaces endless-track vehicles for ascending or descending stairs B62D55/075; hand-carts with provision for travelling up or down stairs B62B5/02
• CPC Class Codes: B63B 59/10 using trolleys or the like driven along the surface
• CPC Class Codes: B64F 5/30 Cleaning aircraft
• CPC Class Codes: B64F 5/60 Testing or inspecting aircraft components or systems
• CPC Class Codes: E04G 23/002 Arrangements for cleaning building facades
• CPC Class Codes: G05D 1/0236 in combination with a laser lasers per se H01S

Abstract

A surface clinging robotic device. The device includes a supporting structure or base, on which is mounted (a) a lead pivoting support surface, such as a pivoting wheel, and (b) two or more traction drives, such as drive wheels. Each of the traction drives are independently driven by a separate drive motor. A plurality of vacuum cups are mounted on the bottom of the base. The vacuum cups each have a low friction foot designed for movement over a surface with minimal friction while vacuum is maintained. The low friction foot portion is provided by a generally surface direction oriented C-shaped Teflon skin. The robotic device can move over gaps or obstructions in the surface without losing vacuum in all of the vacuum cups, using a fluid limiting valve at each vacuum cup to interrupt flow in the event of loss of vacuum in that vacuum cup.

Claims

1. A robotic apparatus for traversing a workpiece surface, said apparatus comprising:

(a) a base, said base having a bottom side and an upper side;

(b) a plurality of vacuum cups, each of said vacuum cups comprising

(1) a foot, said foot having a low friction wear surface coating,

(2) a sidewall comprising one or more resilient accordion pleats (34);

(3) an outlet port, said outlet port having an inlet portion

(4) a fluid limiting valve, said fluid limiting valve located in fluid communication with and adapted to at least partially close said outlet port when said vacuum cup experiences loss of vacuum;

(c) at least three points of support for said base, said at least three points of support affixed to said base and adapted to limit the distance of said base relative to the workpiece surface being traversed, so as to limit compression of said vacuum cups between said bottom side of said base and the surface being traversed, and

(1) providing at least two contact points having driving traction relative to said workpiece surface being traversed;

(2) providing at least one pivotable contact point adapted to allow said robotic device to turn along a direction of travel;

2. The apparatus as set forth in claim 1, further comprising a vacuum header, and wherein each of said vacuum cups is in fluid communication with said vacuum header.

3. The apparatus as set forth in claim 2, wherein said vacuum header comprises a tubular frame.

4. The apparatus as set forth in claim 2 or in claim 3, wherein said base comprises a plurality of vacuum apertures therethrough, and wherein said vacuum apertures are in fluid communication with said vacuum header.

5. The apparatus as set forth in claim 4, wherein a plurality of vacuum cups are mounted on a bottom side of said base in fluid communication with one or more of said vacuum apertures in said base.

6. The apparatus as set forth in claim 1, wherein said fluid limiting valve comprises a reed valve.

7. The apparatus as set forth in claim 1, wherein said outlet port further comprises an outlet seal, and wherein said fluid limiting valve comprises a seal seat portion that sealingly seats against said outlet seal, and wherein said fluid limiting valve is responsive to fluid flow to move between (a) a normal flow, open position, wherein said valve allows fluid flow unimpeded through said outlet, and (b) a vacuum loss, closed position, wherein fluid flow toward said outlet valve closes said valve so that said seal seat portion of said valve sealingly seats against said outlet seal.

8. The apparatus as set forth in claim 7, wherein said fluid limiting valve further comprises an open minimum flow outlet, said open minimum flow outlet sized and shaped to allow a preselected fluid flow out of said open minimum flow outlet when said fluid limiting valve is in the vacuum loss, closed position.

9. The apparatus as set forth in claim 1, wherein each of said at least two drive contact points comprise wheels.

10. The apparatus as set forth in claim 1, wherein said at least two drive contact points each comprise endless resilient tracks.

11. The apparatus as set forth in claim 9, wherein each of said wheels comprise a urethane rubber wheel surface.

12. The apparatus as set forth in claim 9, wherein in said urethane rubber wheel surface comprises a urethane rubber having a durometer at least as soft as 30 Shore A hardness.

13. The apparatus as set forth in claim 9, further comprising at least two drive motors, each of said drive motors connected to drive one or more of said at least two wheels.

14. The device as set forth in claim 9, wherein said drive motors and wheels are operably connected by an endless drive member.

15. The apparatus as set forth in claim 10, further comprising at least two drive motors, each of said drive motors connected to drive one or more of said at least two endless resilient tracks.

16. The apparatus as set forth in claim 15, wherein one of said drive motors and one of said at least two endless resilient tracks are operably connected by an endless drive member.

17. The apparatus of claim 14, or of claim 16, wherein said endless drive member comprises a link chain.

18. The apparatus as set forth in claim 9, wherein each of said wheels has a idler sprocket affixed thereto, and wherein each of said drive motors has a drive sprocket affixed thereto, and wherein said one of said drive motors and one of said wheels are drivingly connected by a linked chain.

19. The apparatus as set forth in claim 9, further comprising a pair of trucks pivotablly affixed to said base, and wherein two pairs of said wheels are provided, and wherein one pair wheels is rotatably affixed to one of said trucks, and wherein each one of said wheels has an idler sprocket affixed thereto, and wherein each of said drive motors has a drive sprocket affixed thereto, and wherein said one of said drive motors and each one of said wheels on each one of said pair of trucks are drivingly connected by a linked chain.

20. The apparatus as set forth in claim 13, or in claim 15, wherein said drive motors are selected from the group consisting of (a) direct current electrical motors, (b) pneumatic motors, and (c) hydraulic motors.

21. The apparatus as set forth in claim 12, wherein each of said drive motors is independent, and wherein said robot is maneuverable via differential speed between drive motors, or by separate drive action each from the other of said drive motors.

22. The apparatus as set forth in claim 1, further comprising a laser beam retro reflector mounted on said base in position to receive and reflect a laser beam from a laser tracking unit.

23. The apparatus of claim 22, wherein said retro reflector is mounted generally centrally of said base and projects upwardly above said base.

24. The apparatus as set forth in claim 14, further comprising

(a) a surface sensor mounted on said base and disposed to ride on a workpiece surface as said robotic device traverses said workpiece, said surface sensor being movable in accordance with deviations in said workpiece surface in a second direction and at an angle to the direction of movement of the robotic apparatus, and

(b) sensors responsive to movement of said surface sensors in said second direction to generate a surface map of said surface.

25. The apparatus of claim 24, wherein said surface sensor comprises a sensing member and a mount, said sensing member adapted for sensing movement in said second direction, said second direction being generally normal to a plane extending downward through the lower runs of said endless drive members.

26. The apparatus of claim 22, further comprising biasing means for biasing said sensing member toward said surface.

27. The apparatus of claim 21, wherein said surface sensor comprises a sensing member disposed to ride on said surface, a support to carry said sensing member, a mount for mounting the support for sliding movement relative to said base in said direction.

28. A method for non-destructive inspection of an aircraft having an outer surface, comprising the steps of

(a) providing a robot as set forth in claim 1;

(b) mounting a surface sensor on said robot;

(c) positioning said robot on said outer surface, and positioning said surface sensor in contact with said outer surface of the aircraft;

(d) maintaining the interior of the aircraft at a first pressure;

(e) moving said robot in a selected path of travel over said outer surface with said sensor riding on said robot;

(f) tracking the movement of said robot and thus said surface sensor, to provide a first measurement of the spatial coordinates of said surface sensor;

(g) pressurizing the interior of the aircraft to a pressure greater than said first pressure,

(h) repeating the steps of moving the robot and tracking the movement of said surface sensor to provide a second measurement of the spatial coordinates of the sensor,

(i) and comparing the first measurement with the second measurement to determine whether the spatial coordinates at any selected location on said aircraft outer surface are outside of a given tolerance.

29. The method of claim 28, wherein the step of mounting the sensor comprises mounting the sensor for movement with the robot in a direction normal to the direction of travel of the robot.

30. The method of claim 28, wherein said first pressure is atmospheric pressure and wherein said second pressure is above atmospheric pressure.

31. The method of claim 28, wherein the step of tracking the sensor comprises mounting a retro reflector on the sensor, directing an incident laser beam from a laser tracking unit toward the retro reflector, reflecting the beam from the retro reflector back toward the laser tracking unit, and comparing the incident beam with the reflected beam to provide a measurement of the spatial coordinates.

32. The method of claim 28, further comprising the step of biasing said sensor into contact with said outer surface.

33. A surface clinging robotic device for clinging to a workpiece surface, said device comprising:

(a) a base, said base having a bottom side and an upper side;

(b) an outlet port, said outlet port having an inlet portion

(1) a low friction foot,

(2) a sidewall comprising one or more resilient accordion pleats (34),

(3) an outlet port, said outlet port having an inlet portion

(4) a fluid limiting valve, said fluid limiting valve located in fluid communication with and adapted to at least partially close said outlet port

(c) three effective points of support between said base and workpiece surface, said three effective points of support including

(1) a first truck mount pivotably affixed to said base, said first truck mount comprising a pair of wheels rotatably affixed to said first truck mount,

(2) a second truck mount pivotably affixed to said base, said second truck mount comprising a second pair of wheels rotatably affixed to said second truck mount, and

(3) a pivotable wheel affixed to said base,

said at least three effective points of support adapted to limit the distance of said base relative to the workpiece surface being traversed, so as to limit compression of said vacuum cups between said bottom side of said base and the workpiece surface being traversed.

34. The device as set forth in claim 33, further comprising a first drive motor and a second drive motor, said first drive motor affixed to said first truck and operably connected for driving said first pair of wheels, and a second drive motor affixed to said second truck and operably connected for driving said second pair of wheels, each wheel in said first pair and said second pair of wheels including contact points having driving traction relative to said workpiece surface being traversed.

35. The device as set forth in claim 33, further comprising an ultrasonic sensing system attached to said base for ultrasonically analyzing the integrity of the workpiece on which said apparatus is driven.

36. The device as set forth in claim 33, further comprising a video camera system attached to said base.

37. The device as set forth in claim 33, further comprising an umbilical tether attached to said robotic device, said umbilical tether supplying electrical power and a vacuum source to said robotic device from a remote location.

38. The device of claim 34, further comprising a locator for pinpointing the location of said robotic device on said workpiece, so that said location can be tracked, or monitored, or recorded.

39. The device as set forth in claim 38, wherein said locator is interconnected to said robotic device motors by a drive control system to selectively articulate said robotic device using said drive motors, to selectively move said robotic device along said workpiece surface.

40. The device as set forth in claim 34, wherein each of said drive motors are operable independently of one another, whereby each of said traction surfaces are independently driveable.

41. The device as set forth in claim 34, further comprising an outlet for spraying paint or other chemicals on said surface while moving said device on said surface.

42. The device as set forth in claim 34, wherein vacuum acting on through said vacuum cups causes said device to adhere to said workpiece surface, by suction;

and wherein said sliding foot of each on of said plurality of vacuum cups allows said device to be driven along said workpiece at a distance determined by said traction feet by a relatively small normal force.

43. A method of fabricating a vacuum cup for a robotic device, comprising the following steps:

(a) providing a female mold shaped in the desired vacuum cup foot shape;

(b) providing a flat Teflon sheet of desired thickness and shape to fill said female mold;

(c) providing a male mold shaped complementary to said female mold;

(d) deforming said flat Teflon sheet by heating and compressing components (a), (b), and (c) in an oven at about 375 degrees Fahrenheit for at least two hours or until said Teflon sheet conforms to the desired shape;

(e) providing a second mold for containing said conformed Teflon sheet and a poured resilient polymer in a preselected vacuum cup shape;

(f) pouring said resilient polymer in said mold;

(g) allowing said polymer to cure;

(h) removing said vacuum cup from said mold.

44. The method according to claim 43, wherein said step (d) is carried out so that said cross-sectional foot curvature is substantially a downward oriented C-shaped configuration.

45. The method according to claim 43, wherein said step (e) applies and establishes a preselected vacuum cup shape having at least two V-shaped corrugations, and wherein said corrugations take up said mold shape and hold said mold shape after removal of said cured vacuum cup from said mold.

46. The method as set forth in claim 43, wherein said resilient compound comprises at least one polyurethane rubber compound, and wherein said Teflon and said at least one polyurethane compound are joined by implicit mutually adhesive properties during production of said vacuum cup.

47. The method as set forth in claim 43, wherein said Teflon and said polyurethane are arranged in at least two layers, one above another.

48. The method as set forth in claim 43, wherein said polyurethane rubber is in said foot is at least partially surrounded by said Teflon.

49. The method as set forth in claim 43, wherein said Teflon film is at least 0.005 inches thick.

50. The method as set forth in claim 47, wherein said polyurethane layer above said Teflon layer is at least one quarter of an inch thick.

51. A vacuum cup for a robotic device, said device comprising:

(a) an upper seal ring surface (22);

(b) a sidewall comprising one or more resilient accordion pleats (34);

(c) a shaped contact foot, said contact foot having a low friction wear surface.

52. The apparatus as set forth in claim 51, wherein said low friction wear surface comprises a molded Teflon sheet.

53. The apparatus as set forth in claim 52, wherein said Teflon sheet is at least 0.005 inches in thickness.

54. The apparatus as set forth in claim 51, wherein said foot is provided in a generally upwardly opening C-shape, and wherein said foot has a width W of at least about one inch.

55. The apparatus as set forth in claim 51, further comprising, disposed between said upper seal ring surface and said shaped contact foot, an end effector.

56. The apparatus as set forth in claim 55, wherein said end effector comprises a sander.

57. The apparatus as set forth in claim 55, wherein said end effector comprises a shaft, and, operably connected to said shaft, a rotatable resilient tool mount.

58. The apparatus as set forth in claim 55, wherein said end effector comprises a brush.

59. The apparatus as set forth in claim 55, further comprising, disposed within said vacuum cup, a plurality of low friction stops, said low friction stops adapted to space said end effector an effective distance with respect to a workpiece.

60. The apparatus as set forth in claim 55, wherein said end effector includes a motor selected from the group consisting of (a) electric motor, (b) pneumatic motors, and (c) hydraulic motors.