[PhilBot]

Originally Posted by zivo123

one question about your drivetrain...WTF is going on there???

The drive train is pretty simple: It's based on a soap-box derby style steering x 2. Two axles, that each pivot on the frame. Each axle has two CIM/banebot gearbox and custom made 4" traction wheel combination. A 3:1 gear ratio makes for a fast, torquey drive.

The axles are conneced diagonally with a tie-rod so they pivot in opposite directions to make turning a dream. A fifth motor (van door) is used as a closed loop steering motor to get predictable turn rates. We use a steering wheel to drive. The axle angle is slaved to the steering wheel, like a real car.

Body stability is handled by using two lazy-susan bearings on the axles, with a central bolt for strength. Our center of gravity is at about 6" when retracted, but it never gets more than about 12" high at any time.

Four pressure tanks for pneumatics. The hurdle force is provided 50/50 by springs and pneumatics. Pneumatics charge the springs, and then the scoop is latched. We can then vent the cylinders ready for launch. When we are ready to hurdle, we charge the other side of the cylinders and then relase the latch. Sepparate solenoids are used for pressurizing each side of each cylinder to provide independant control with high flow rates.