The document discusses various robot drive train options including 2 wheel, 4 wheel, 6 wheel, 8 wheel, and mecanum drives as well as treads and swerve drives. It covers traction fundamentals and factors like weight distribution and coefficient of friction. Recommendations are provided for transmission types from AndyMark and BaneBots. Tips emphasized designing for repair ability, alignment, and avoiding long cantilevered loads. Championship winners from 2008-2010 used a variety of drive types showing many can work with the right drive team.

1. FIRST Robotics Drive Trains Dale Yocum Robotics Program Director Catlin Gabel School Team 1540

4. Traction Basics Terminology The coefficient of friction for any given contact with the floor, multiplied by the normal force , equals the maximum tractive force can be applied at the contact area. normal force tractive force torque turning the wheel maximum tractive force Normal Force (Weight) Coefficient of friction = x weight Source: Paul Copioli, Ford Motor Company, #217

5. Traction Fundamentals “Normal Force” weight front The normal force is the force that the wheels exert on the floor, and is equal and opposite to the force the floor exerts on the wheels. In the simplest case, this is dependent on the weight of the robot. The normal force is divided among the robot features in contact with the ground. normal force (rear) normal force (front) Source: Paul Copioli, Ford Motor Company, #217

6. Traction Fundamentals “Weight Distribution” more weight in back due to battery and motors front The weight of the robot is not equally distributed among all the contacts with the floor. Weight distribution is dependent on where the parts are in the robot. This affects the normal force at each wheel. more normal force less normal force less weight in front due to fewer parts in this area EXAMPLE ONLY Source: Paul Copioli, Ford Motor Company, #217

7. Weight Distribution is Not Constant arm position in rear makes the weight shift to the rear front arm position in front makes the weight shift to the front EXAMPLE ONLY normal force (rear) normal force (front) Source: Paul Copioli, Ford Motor Company, #217

9. Base Choices Everything is a compromise

15. 8 Wheels Team 177

17. Holonomic Drive 2047’s 2007 Robot

20. Wild Swerve Based on Wildstang Design

21. Wild Swerve 8.4 lbs per wheel (less motor and chain)

22. Transmissions

23. AndyMark Toughbox 12.75:1 Ratio Options for 6:1 and 8.5:1 Long shaft option 2.5 lbs (options for -.85lbs) Encoder option One or two CIMs $88 (two came in last year’s kit)

24. Toughbox Mini 12.75:1 Ratio Options for 6:1 and 8.5:1 Long shaft option 1.95lbs (options for -.56lbs) Encoder option One or two CIMs $90

25. Toughbox Nano 12.75:1 Ratio Options for 6:1 and 8.5:1 Long shaft option 1.9 lbs (options for -.28lbs) Encoder option One CIM $78

26. BaneBots Many gear ratios 3:1- 256:1 Long shaft options $103 2.5 lbs Avoid dual CIMs Planetary not quite as efficient Order Early!

27. AndyMark Gen 2 Shifter 11:1 & 4:1 Ratios 3.6 lbs One or two CIMs Servo or pneumatic shifting Two chain paths Encoder included $350

28. AndyMark SuperShifter 24:1 & 9:1 standard ratios + options Made for direct drive of wheels 4 lbs without pneumatics. (-.6 option) One or two CIMs Servo or pneumatic shifting Direct Drive Shaft Includes encoder $360

29. Wheels

32. AndyMark.biz

33. Innovation FIRST

34. Skyway

39. Questions