"Three Wheeler"
 

Some of our team members have suggested a three wheeled forklift type robot. More specifically a squarish drive base with independently driven traction wheels at each of the front corners and a free-wheeling pivoting wheel (or two together) at the rear in the centre. Any thoughts?

Re: "Three Wheeler"
 

Robots of this type tend to be more stable with the driven wheels in the back due to the center of gravity shifting to the rear while it is being powered. That being said, we used shopping-cart style "caster steering" in 2013 and do not recommend it in any way whatsoever. Unless you have the programming and sensor implementation skills to back it up, it will be very unstable to drive.

Re: "Three Wheeler"
 

If you have a 4 wheel drive with traction wheels at the front and omni wheels at the back you will get the effect of pivoting at the front of the robot with none of the headaches of having a caster ie. (reversing direction leads to unpredictable movements)

Re: "Three Wheeler"
 

Just don't use castors (except maybe a ball castor).

Seriously, they wreak havoc when trying to line up or make small turning adjustments.

Re: "Three Wheeler"
 

One of the biggest things (in my opinion) when deciding your drive train for the year is how well will your driver be able to drive with the chosen drive train? Always make sure they get plenty of practice, even if it is just with a drive base.