Human Powered Submarine
A student team at the University of Michigan builds and races submarines powered by a human pilot. The pilot wears scuba gear inside the free-flooding submarine and pedals a standard bicycle crank to turn dual rear propellers. A joystick is connected to horizontal and vertical dive planes to provide up-down and left-right steering. The races are held at the David Taylor Model Basin in Washington, DC, one of the largest tow tanks in the world.
The Automated Trim System
The submarine can be difficult to steer, especially for inexperienced pilots. The submerged mass is about 3000 lbs. yielding slow, underdamped, weakly actuated dynamics. As a graduate student, I advised an undergraduate student in building an automated trim system to assist in steering. The system moves a lead weight fore and aft to provide a pitching moment. The control system measures depth, pitch, and pitch rate and moves the weight accordingly to "fly" the sub level at constant depth. The entire system is battery powered and sealed inside a watertight enclosure. The system is shaped like the letter "L" for packaging inside the sub. The weight moves on linear bearings in the horizontal section while the motor, electronics, and batteries are in the vertical section.