Mechanical Engineering Project May 6, 2011

1. F.I.R.S.T. ROBOTIC DRIVE BASEHenry Sick, Rich Phelan, Jose Orozco, Shane Lentini Northeastern University Capstone Design Advisor– SinanMüftü April 19th, 2011

3. Historical research has shown that many elements of the field and regulations are exactly the same from year to year, with few exceptions

4. Designing a new drive base wastes time and puts the team at a competitive disadvantage.

5. With mentors cycling in and out every five years, knowledge and experience is lostProblem Statement

7. Northeastern has a team, mentored by college students, called the NUtrons.

9. Project Outline

11. Simple

12. Lightweight

13. Easily Maintained

14. Few points of failure

15. 8 Wheel Drive – dropped center wheels

16. Very stable, prevents rocking of base

17. Most pressure is on center wheels allowing quick turns

18. Some turning resistance adds to control – damping effect

19. Drawback 8WD

22. Low Cost

23. Easily attainable

25. Triangular Cuts for weight reduction

27. Straight on front collision (blue arrows)

28. Opposite frame rail compression (shear) (red arrows)

29. Direct corner collision (combined loading) (green arrow)

30. Forces based on data collected from actual robot collision

31. 381 pounds applied per each simulation

32. Maximum stress analysis

33. Nodal solution contour plots

34. Von Misses stresses

35. Minimum Factor of Safety

38. 30 lb drive base goal

39. 2.82 lb/CIM = 11.28 lb - 37.6% of total goal (fixed)

40. 4 lbs / Transmission = 8 lb - 26% of total goal – 42.7% of goal after motorsBall Shift is preferred transmission based on above parameters, as well as simplicity and shift on fly performance.

42. Requires 3:1 sprocket reduction (14:42) Transmission-Wheels

43. Overall reductions, Velocity, Pushing Force (6” wheel)

44. High- 8:1 14.14 fps 66.67 lbf

45. Low- 22.2:1 5.09 fps 185.19 lbf

46. Custom ball shift vs AM Super Shifter (COTS standard)

48. Shift on the fly demonstration

50. AGMA method of calculating stresses:

51. Minimum Safety Factor n=1.59 assuming worst case conditionsGear Stress Calculations

53. Weight

57. Total Weight: 38lb

58. Shift on the fly capabilities

59. 106 individual fabricated components