Controller design for a multi-fan hovering system

A multi-fan hovering system (MFHS) is a model to simulate and test roll axis performance of a vertical take off and landing vehicle. The MFHS consists of a heavy base with two poles mounted on it that support a slip ring and housing. Wires for the DC motors of the system and a potentiometer pass through the center of one of the poles to the slip ring, where its brush assembly and conduction rings connect to the motor wires. The DC motors are mounted on either end of a pivoting pole. Attached to the motors are propellers. When the motors change speed, the torque generated by the propellers moves the position of the pivot arm. A potentiometer monitors the position of the pivoting arm and is used as a feedback signal. This system behaves similar to a double integrator system with poles very close to the j/spl omega/-axis. Close to instability behavior of this system creates a challenging problem for design of a control system. As a first controller design, a PID controller was designed and implemented for this system using XPC/Simulink in MATLAB, which is a real time prototyping platform software.