Our team (1899) started using a powered robot cart last year and we have found it very useful, and have not experienced any of the problems others are describing.
We used an old powered wheelchair base, but removed the chair, and instead added a platform for the robot to sit on with room to place tools and other equipment.
It is controlled by the original Wheelchair controller and is mounted near the back of the cart. The controller allows us to change the speed of the cart, and since it is a wheelchair base, it can turn on a dime and is extremely maneuverable.
If there is a team out there looking into making a robot cart, I would suggest giving serious consideration to modifying a motorized wheelchair.
Here is a picture of the robot cart from the front:
http://www.saintsrobotics.com/wp-con...s/img_1509.jpg
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Vivek
Treasurer, Senior Build Officer, Saints Robotics 1899
Seattle Olympic Regional Chairman's Award 2011
Seattle Olympic Regional Winner 2011 (Thanks 2990 & 3393)
Seattle Olympic Regional Best Website Award 2011