December 2000. This robot was built for demonstrating the 'Adder/Subtractor' type of drive transmission. The entire geartrain is visible from the bottom side for this reason. This type of transmission takes two mechanical inputs (A and B) and outputs both the sum (A+B) and difference (A-B) on separate output shafts. Connecting motors to the two inputs and drive wheels to the outputs gives us a configuration where one motor can be used for turning and the other for forward/reverse motion. Running both motors at the same time causes one wheel to stop and the other to turn at twice the normal speed yielding a turn with a pivot point directly under the stopped wheel. This robot has one rotation sensor per wheel for measuring distance traveled. It also has a forward collision detection bumper and a down facing light sensor for line sensing.
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