Different Types of DriveTrains

In FRC, we commonly encounter three main types of chassis / drivetrain design:

• Tank tracks
  • Can be constructed with actual tracks, or with multiple linked wheels
  • Has the highest traction and pushing power
  • Is the worst at turning
  • Is generally the fastest
  • Is the easiest to build
  • Is the most common
  • Requires advanced path-planning code to control autonomously
• Holonomic
  • Can move in any direction by driving pairs of wheels
  • Has a diagonal wheel in each corner of the frame
  • Has almost no pushing power
  • Has almost no traction
  • Can turn very well
  • Is fairly easy to program
  • Is the least used
• Swerve
  • Can move in any direction by rotating its wheels
  • Has a free-spinning wheel in each corner of the frame
  • High development cost (can be over $1000 to implement)
  • High power draw
  • Generally good pushing power
  • Great traction
  • Can lock itself in place by rotating all wheels to an "X" pattern
  • Can turn very well
  • High effort to program and coordinate, but easy to use after the base code is stable

What we use at 5024

We tend to develop robots with a drop-center tank-driven drivetrain. This means that we have 6 wheels, in pairs of 3, where the center wheels are lower to the ground than the rest. This generally keeps our robots mainly resting on the back 4 wheels, and we only use the front 2 when driving over an obstacle.

Since we use a nearly identical drivetrain every year, Lib5K includes a lot of code to get this system working with very little effort, so we can spend our development time focusing on more important systems.