05.2 - Flight Dynamics and Control (UAV related)
SYSTEM IDENTIFICATION OF A SCALE HELICOPTER IN HOVERING FLIGHT
F.C. Reis¹, E.M. Belo¹; ¹Escola de Engenharia de São Carlos - USP, Brazil
The present work aims to study and obtain the linear dynamic model of a rotary wing aircraft from data of hovering flights. These flight tests aim to excite an actual scale model of a radio-controlled helicopter instrumented with a set of sensors and systems for managing activities in flight, so that the input and output are stored. The linear model is determined by the study of the aerodynamic forces and moments generated in the main and tail rotors and physical characteristics aircraft. The linear model is presented in the form of Newton's equations for the forces and moments acting on the free body in space in a trimmed condition, so the linear model is an approximation of the nonlinear model for a given flight regime. The parameters of the linear dynamic model for hovering flight is achieved with the use of an algorithm to identify gray box type systems iteratively. This has as inputs the data from the flight tests, the state space model and a set of parameters from the simulation of the nonlinear model, which provides the boundary conditions and limits for numerical solution. Because this is an experiment, the results should be verified and validated. Thus, the obtained dynamic model for a given flight test receives the input signals from another one and compares the outputs, so that it is valid if the error is less than or equal to the accuracy of sensors used.