Stability Analisys of a Four Rotor Helicopter

In this paper the lifting operators are presented and applied to a multifrequency system to carry out the analytical study of the system stability without using non-linear operators. A four rotor helicopter prototype has been constructed with the idea of studying the results obtained with different strategies in order to find the one that allows to reach the best control of the helicopter. The prototype is provided with different types of sensors for determining its position and orientation with respect to the floor. These sensors send information to the control system at different frequencies, which justifies the use of the lifting methodology in order to simplify the analytical study of the closed-loop system stability.