Quote:
Originally Posted by Hachiban VIII
The perfect configuration of wheels for tank-style steering is one wheel at each corner of a square. But because most robots are rectangular, teams solve this issue by using six wheels with the center wheel lowered. As a result the drive train functions as two four wheeled robots - tipping back and forth.
If you try and mount 4 wheels at each corner of the kitbot chassis you will quickly understand what I mean  |
Exactly. By lowering the center wheels, you achieve the turning characteristics of a 2WD robot with the drivability and traction of a 4WD robot.
When driving forward, gravity will "push" the robot onto the front wheels, and when driving backward, gravity will "push" the robot onto the rear wheels. But when you turn, in theory, the robot should support itself on it's 2 center wheels only, making turns a breeze.
You can't have too much rocker, or play in the wheels though. Somewhere between 1/4"-1/2" is ideal. Too much can be a problem.