A couple days ago, my FLL team was designing a robot for next year's robot game, when we came to an unanswerable question: Should we use 4wd or 2wd?
Being their mentor, I encouraged a more 'scientific' way of deciding by creating a chart, and this is what they came up with:
4 Wheel Drive
Being their mentor, I encouraged a more 'scientific' way of deciding by creating a chart, and this is what they came up with:
4 Wheel Drive
- Slippage occurs during turning
- Navigates more terrains smoothly
- Uses more battery power
- Capable of in place turning
- Goes straighter
- The robot has more support
- Must use gears / pulleys to transmit power but has unnecessary gear lash
- The chassis usually becomes a boxy shape
2 Wheel Drive
- Free-er turns
- It is more difficult to navigate all terrains
- Uses less battery power
- No in place turning
- More likely to drift
- Have to use a caster wheel or other means of support
- Could be directly connected to motor and not risk slop
- The chassis usually becomes a rectangular kind of shape
Both drive systems have been used successfully in the past. A good example are the two 1st Place Robot Peoformance Winners: 1221 Built on the Rock had a stable and versatile 4wd robot while 4 Mindstorms Troopers had a simple and speedy 2wd drive robot.
We would also like to ask you to contribute to our comparison. So comment away!
Robolab 2.9