[Katy]

I lack the picture at the moment but I will find one soon.

We took your basic 4 wheel tank drive and tilted the wheels inward. Because that was unclear: we set the wheels so that the top of the wheels was closer to the center of the robot than the bottom of the wheels. The axles, motors, chains, sprockets, everything was mounted at this new angle. It actually was pretty easy to make and did not weigh anything extra. Usually the side of one tank drive is enclosed in a long thin rectangular box. We just tiled this box and mounted them against the angles we cut on the crosspieces that went across the front and back of the robot. (about 20 degrees for us). Putting the wheels like this also makes the robot very low to the ground.

This made the robot very hard to move off course. To help us maneuver more easily we placed two casters on the front of the robot. These casters were mounted to hinges. The hinges were positioned at 90 degree angles to the bar that made up the front of the robot. The casters were on the rotating flap of the hinges (on the underside) and on top sits an extruded Al stick. These sticks are connected by a pneumatic which is suspended in the air between them. When the pneumatic fires (parallel to the front of the frame) it presses the extruded Al pieces down which presses the hinges which rotate at a 90 degree angle to the frame and press the casters down.