Fiber redirect system, multi-axis robotic wrist and fiber placement apparatus incorporating same and related methods

1. A fiber redirect system for use in association with a multi-axis robotic wrist having at least one section configured to articulate about a pitch axis, a yaw axis and a roll axis, the system comprising:

a first redirect mechanism configured to alter a path of at least one fiber tow engaged therewith, the first redirect mechanism being centered about an intersection of the pitch axis and the yaw axis of the multi-axis robotic wrist;

at least a second redirect mechanism configured to alter the path of the at least one fiber tow, the at least a second redirect mechanism being centered about an intersection of the yaw axis and the roll axis of the multi-axis robotic wrist.

2. The fiber redirect system claim 1 , wherein the at least one redirect mechanism further comprises a third redirect mechanism centered about the roll axis of the multi-axis robotic wrist.

3. The fiber redirect system of claim 2 , wherein the at least one fiber tow comprises a first tow band having a first plurality of spaced apart collimated fiber tows and at least a second tow band having a second plurality of spaced apart collimated fiber tows, the first tow band being spaced apart from the at least a second tow band, and wherein the first redirect mechanism, the second redirect mechanism and the third redirect mechanism each includes a first redirect roller for engagement with the first tow band and at least a second redirect roller for engagement with the at least a second tow band.

4. The fiber redirect system of claim 3 , wherein the third redirect mechanism is configured to redirect a path of the first tow band and a path of the at least a second tow band so as to cause the first tow band and the at least a second tow band to converge and collimate with one another.

5. The fiber redirect system of claim 2 , wherein the at least one fiber tow includes a plurality of fiber tows and wherein the first, second and third redirect mechanisms are configured to define a collective fiber path of the plurality of fiber tows which passes through the pitch, yaw and roll axes.

6. A robotic wrist for a fiber placement system comprising:

a first section;

a second section coupled with the first section;

a third section coupled with the second section, wherein the first section, the second section and the third section are configured to articulate about a first axis, the second section and the third section are configured to articulate about a second axis and the third section is configured to articulate about third axis; and

at least one redirect mechanism configured to alter a path of at least one fiber tow engaged therewith, the at least one redirect mechanism being centered about at least one of an intersection of the first axis and the second axis and an intersection of the second axis and the third axis.

7. The robotic wrist of claim 6 , wherein the first axis is a pitch axis of the robotic wrist, the second axis is a yaw axis of the robotic wrist and the third axis is a roll axis of the robotic wrist, and wherein the at least one redirect mechanism further includes a first redirect mechanism centered about the intersection of the pitch axis and the yaw axis and a second redirect mechanism centered about the intersection of the yaw axis and the roll axis.

8. The robotic wrist of claim 7 , wherein the at least one redirect mechanism further includes a third redirect mechanism centered about the roll axis, and wherein the at least one fiber tow includes a first tow band having a first plurality of spaced apart collimated fiber tows and at least a second tow band having a second plurality of spaced apart collimated fiber tows, the first tow band being spaced apart from the at least a second tow band.

9. The robotic wrist of claim 8 , wherein the first, second and third redirect mechanisms each includes a first redirect roller for engagement with the first tow band and at least a second redirect roller for engagement with the at least a second tow band.

10. The robotic wrist of claim 9 , wherein the third redirect mechanism is configured to redirect a path of the first tow band and a path of the at least a second tow band so as to cause the first tow band and the at least a second tow band to converge and collimate with one another.

11. The robotic wrist of claim 8 , wherein the at least one fiber tow includes a plurality of fiber tows and wherein the first, second and third redirect mechanisms are configured to define a collective fiber path of the plurality of fiber tows which passes through the pitch, yaw and roll axes.

12. The robotic wrist of claim 8 , further comprising a first bearing coupled between the first section and the second section to accommodate relative rotation of the second section and the first section about the second axis, wherein an opening is defined through the first bearing and wherein a path of the at least one fiber tow extends through the opening of the first bearing between the first redirect mechanism and the second redirect mechanism.

13. The robotic wrist of claim 12 , further comprising a second bearing coupled between the second section and the third section to accommodate relative rotation of the third section and the first section about the third axis, wherein an opening is defined through the second bearing and wherein the path of the at least one fiber tow extends through the opening of the second bearing between the second redirect mechanism and the third redirect mechanism.

14. The robotic wrist of claim 13 , further comprising structure defining an annulus about the opening of the first bearing, the annulus being configured to receive at least one transmission line therethrough.

15. The robotic wrist of claim 6 , further comprising a placement head coupled with the third section and configured to apply a portion of the at least one fiber tow proximate a surface of a mandrel or proximate a surface of a work piece disposed about the mandrel.

16. The robotic wrist of claim 15 , further comprising a consolidating member configured to contact the applied portion of the at least one fiber tow and press the applied portion against an underlying surface.

17. The robotic wrist of claim 16 , further comprising at least one actuator configured to motivate the robotic wrist about at least one of the first, second and third axes.

18. The robotic wrist of claim 17 , wherein the at least one actuator is configured to motivate the first, second and third sections about the first axis.

19. The robotic wrist of claim 17 , wherein the at least one actuator is configured to motivate the second and third section about the second axis.

20. The robotic wrist of claim 17 , wherein the at least one actuator is configured to motivate the third section about the third axis.

21. The robotic wrist of claim 17 , wherein the at least one actuator is configured to be operatively coupled with a control system.

22. A fiber placement system comprising:

a creel assembly including a supply of at least one fiber tow; and

a robotic wrist comprising:

a first section;

a second section coupled with the first section; and

a third section coupled with the second section, wherein the first section, the second section and the third section are configured to articulate about a first axis, the second section and the third section are configured to articulate about a second axis and the third section is configured to articulate about a third axis;

at least one redirect mechanism configured to alter a path of the at least one fiber tow engaged therewith, the at least one redirect mechanism being centered about at least one of an intersection of the first axis and the second axis and an intersection of the second axis and the third axis.

23. The fiber placement system of claim 22 , wherein the creel assembly further comprises at least one tensioning device for maintaining the at least one fiber tow at a desired level of tension.

24. The fiber placement system of claim 23 , further comprising a structural platform, wherein the robotic wrist is movably positioned on the structural platform.

25. The fiber placement system of claim 24 , wherein the first axis is a pitch axis of the robotic wrist, the second axis is a yaw axis of the robotic wrist and the third axis is a roll axis of the robotic wrist, and wherein the at least one redirect mechanism further includes a first redirect mechanism centered about the intersection of the pitch axis and the yaw axis and a second redirect mechanism centered about the intersection of the yaw axis and the roll axis.

26. The fiber placement system of claim 25 , wherein the at least one redirect mechanism further includes a third redirect mechanism centered about the roll axis.

27. The fiber placement system of claim 26 , wherein the supply of the at least one fiber tow further includes a plurality of spools, wherein each spool of the plurality provides an individual fiber tow.

28. The fiber placement system of claim 27 , wherein the creel assembly includes structure for gathering a first plurality of individual fiber tows from the plurality of spools to form a first tow band of collimated fiber tows and for gathering at least a second plurality of individual fiber tows from the plurality of spools to form at least a second tow band of collimated fiber tows.

29. The fiber placement system of claim 28 , wherein the first, second and third redirect mechanisms each includes a first redirect roller for engagement with the first tow band and at least a second redirect roller for engagement with the at least a second tow band.

30. The fiber placement system of claim 29 , wherein the third redirect mechanism is configured to redirect a path of the first tow band and a path of the at least a second tow band so as to cause the first tow band and the at least a second tow band to converge and collimate with one another.

31. The robotic wrist of claim 26 , wherein the at least one fiber tow includes a plurality of fiber tows and wherein the first, second and third redirect mechanisms are configured to define a collective fiber path of the plurality of fiber tows which passes through the first, second and third axes.

32. The fiber placement system of claim 26 , further comprising a mandrel holder positioned adjacent the robotic wrist and configured to rotate a mandrel about a defined axis.

33. The fiber placement system of claim 32 , further comprising a placement head coupled with the third section and configured to apply a portion of the at least one fiber tow proximate a surface of the mandrel or proximate a surface of a work piece disposed about the mandrel.

34. The fiber placement system of claim 33 , further comprising a consolidating member configured to contact the applied portion of the at least one fiber tow and press the applied portion against an underlying surface.

35. The fiber placement system of claim 34 , further comprising at least one actuator configured to motivate the robotic wrist about at least one of the first, second and third axes.

36. The fiber placement system of claim 35 , wherein the at least one actuator is configured to motivate the first, second and third sections about the first axis.

37. The fiber placement system of claim 35 , wherein the at least one actuator is configured to motivate the second and third section about the second axis.

38. The fiber placement system of claim 35 , wherein the at least one actuator is configured to motivate the third section about the third axis.

39. The fiber placement system of claim 35 , further comprising a control system operatively coupled with the at least one actuator.

40. The fiber placement system of claim 26 , further comprising a first bearing coupled between the first section and the second section to accommodate relative rotation of the second section and first section about the second axis, wherein an opening is defined through the first bearing and wherein a path of the at least one fiber tow extends through the opening of the first bearing between the first redirect mechanism and the second redirect mechanism.

41. The fiber placement system of claim 40 , further comprising a second bearing coupled between the second section and the third section to accommodate relative rotation of the third section and the first section about the third axis, wherein an opening is defined through the second bearing and wherein the path of the at least one fiber tow extends through the opening of the second bearing between the second redirect mechanism and the third redirect mechanism.

42. A method of conveying at least one fiber tow from a creel assembly to a placement head of a fiber placement system, the method comprising:

coupling a robotic wrist with the placement head and configuring the robotic wrist to be movable about a first axis, a second axis and third axis;

locating a first redirect mechanism to be centered about an intersection of the first axis and the second axis;

locating a second redirect mechanism to be centered about an intersection of the second axis and the third axis;

locating a third redirect mechanism to be centered about the third axis;

passing the at least one fiber tow from the creel assembly to the first redirect mechanism;

passing the at least one fiber tow from the first redirect mechanism to the second redirect mechanism; and

passing the at least one fiber tow from the second redirect mechanism to the third redirect mechanism and from the third redirect mechanism to the placement head.

43. The method according claim 42 , wherein the at least one fiber tow includes a plurality of fiber tows and wherein the method further comprises dividing the plurality of fiber tows into a first tow band of collimated fiber tows and at least a second tow band of collimated fiber tows.

44. The method according to claim 43 , further comprising maintaining the first tow band and the at least a second tow band spaced apart as they are passed from the creel assembly to the third redirect mechanism.

45. The method according to claim 44 , further comprising joining the first tow band and the at least a second tow band into a single tow band containing all of the plurality of fiber tows as the first tow band and the at least a second tow band pass from the third redirect mechanism to the placement head.

46. The method according to claim 42 , further comprising defining the first axis as a pitch axis, defining the second axis as a yaw axis, and defining the third axis as a roll axis.

47. A method of conveying a plurality of fiber tows, the method comprising:

providing a robotic wrist having at least one section configured to articulate about a first axis, a second axis and a third axis;

arranging the plurality of fiber tows into a first collimated tow band and at least a second collimated tow band spaced apart from the first collimated tow band;

defining a collective fiber path to pass through at least one of an intersection of the first axis and the second axis and an intersection of the second axis and the third axis and defining a portion of the collective fiber path to be along the third axis; and

maintaining the first collimated tow band and the at least a second collimated tow band substantially symmetrically about the collective fiber path.

48. The method according claim 47 , further comprising merging the first tow band and the at least a second tow band into a combined collimated tow band at a position along the third axis.

49. The method according to claim 47 , further comprising defining the first axis as a pitch axis, defining the second axis as a yaw axis, and defining the third axis as a roll axis.