[Greg Peshek]

Any particular reason you have to do rear-wheel steering? (At least that's what I'm guessing you're trying) And why you can't make the turning wheels the front? That's what we're doing with our Ackermann steering setup. Of course you'll still have the problem of not turning quite as tight as you'd like because it's not true Ackermann steering, but it should help.

If you have the programming capabilities I would suggest putting a potentiometer on the rack to sense position. If you have really have the programming capabilities it would be a lot easier for your drivers if the wheels would center themselves when you bring the joystick back to center, instead of having the wheels move when the joystick moves from side to side (essentially making your globe motor a large servo). We had the same problem as you, it being hard to control, but we are remedying it with the situation I just described.

Hope you get it working well.

-Greg P.