The physics of drivetrain turning is all laid out quite nicely right here:
http://www.chiefdelphi.com/forums/pa...le&paperid=222
Courtesy of Chris Hibner. (I can never give this whitepaper enough props.)
Basically, you need to reduce the turning scrub.
The ways a typical 6WD system accomplishes this, is by reducing the wheel-base in the fwd-back direction at any given time.
Think about an example where your robot was half as long; it would turn much better. Since we can't permanently reduce this wheel base, (it reduces robot stability in the fwd-back direction) a 6WD solution with a lowered middle wheel rocks back and forth between 2 of these 1/2-long wheel-bases.
To understand how this shorter wheel-base increases turning, again just look to the physics of it.
I have taken one example, there are many others. All of them, relate directly back to the "turning-physics". If you understand that, you will find 10 ways to solve your problem.
Your next steps should be:
- Read the whitepaper.
- If you need help understanding what is in that whitepaper: ask for help understanding it.
Hopefully this will be a thread with engineering contributions to the discussion, and not
another one where people simply spout
garbage like "4 wheel drives dont turn ever u shud go wit a swerve".
-JV