Abstract of Thesis presented at COPPE/UFRJ as a partial fulfillment of the requirements for the degree of Master of Science (M.Sc.)

Modeling, Identification and Altitude Control of a Small-Scale Helicopter

Willian Vairo dos Santos

April/2005

Advisors:

Ramon Romankevicius Costa Liu Hsu

Department:

Eletrical Engineering

      This work addresses the modeling, identification and altitude control of a small-s­cale helicopter. An 11th order linearized hover model was obtained from a simplified analytic helicopter dynamic model. Using this complete linearized model, the vert­ical dynamics was focused with the purpose of identifying its stability derivatives for, later, designing a controller to regulate the altitude in a desired value. In or­der to identify the derivatives, an electronic assembly composed of an ultrasonic altitude sensor and an embedded computer was developed for flight data acquisit­ion. The correctness of the identified derivatives was verified by their comparison with the values obtained theoretically. After that, these derivatives were used for the design of a PD altitude controller. The robustness of the controller to para­metric uncertainties and altitude measure noise was verified through simulation in Matlab/Simulink environment. The algorithm of the controller was implemented in the same embedded computer used for parametric identification. To reduce flight accident risks, a second independent embedded microcomputer circuit was develop­ed with the function of switching the aircraft altitude control between a human pilot and the embedded PD controller. The developed controller was able to regulate the altitude in a desired value and to track the altitude commands sent by a human pilot using a radio-control unit.