By: David Gitz, EE, Electrical/Programming Team Mentor FRC #1208

Programming Team Members

Electrical Team Members

Wheels 2WD/4WD 6WD/West Coast Track Holonomic/Mecanum Crab/Swerve

Swivel Caster Ball Caster

KoP Wheel Plaction Wheel Omni-Wheel Mecanum Wheel

simplerear wheel drive

simplefront wheel drive

simpleall wheel drive

simplecenter drive

6 wheeldrive

tracked drive swerve/ crab drive other?

2WD 4WD 6WD

Omni/Mecanum

The Good More easily controlled Pretty simple to build Better traction

The Bad Turning in place is

more difficult Compromise between

stability and maneuverability

Typically, one wheel is offset from the others to minimize resistance to turning Rocking creates two 4WD

systems, effectively Typical offset is 1/8” – ¼” Rock isn’t too bad at edges

of robot footprint, but can be significant at the end of long arms and appendages

One or two sets of omniwheels can be substituted for offset wheels.

Pushing power increased Mechanically more complicated

Need to have adequate track tension

Throwing a track and/or breaking one can be easy and very hard to fix

Slower, much more power intensive

Applications HEAVY duty pushing Climbing

Mechanically as complicated as a 4WD System A lot of times can substitute normal wheels for Omni/Mecanum in

tight situations.

Less pushing power, more maneuverable Control can be more complicated (especially with

Mecanum) More parts that can break

Extremely mechanically and program complex Lots of parts to make/buy/fix Highly maneuverable Requires (normally) precise engineering Takes up a lot of space, uses a lot of motors

Pure 4-Crab: 5 Pure 4-Swerve: 8!

Steering vs. Drive Systems In FRC, there are no “Tank” Drive Systems.

There is Tank Steering and Track Drive Systems. These terms are NOT interchangeable.

Tank Steering:▪ Uses 2 Joysticks, Left Joystick controls speed of Left

motors, Right Joystick controls speed of Right motors. Arcade Steering:

▪ Uses 1 Joystick, controls speed of Left and Right motors together.

1. http://www.usfirst.org/roboticsprograms/frc/content.aspx?id=10934

2. http://www.andymark.biz3. Drivetrain_Fundamentals_v2.14. FRC_Drive_Train_Design_and_Implementation

1. Describe the Drive Train FRC Team #1208 (us…) used in the FRC 2010 Competition.

2. Name 1 advantage and 1 disadvantage of using a Meccanum Drive System.

3. What is the difference between Tank Steering and a Track Drive System?