Attitude dynamics modeling of a small-scale unmanned helicopter

The attitude dynamics model is the basis for attitude control and the attitude model is very complex because the small-scale unmanned helicopter is a multivariable, nonlinear, time-varying, strong-coupling system. To reduce the complexity of the attitude model, a simplified attitude dynamics model for small-scale unmanned helicopter in hover or low speed forward flight was presented. Firstly, the linear model with unknown parameters was determined by first-principle approach and small perturbation theory. Secondly, the PEM system identification approach was used to identify the parameters of the model. The validity of the attitude model was verified using experimental data obtained in real flight. The validation results showed the effectiveness and high accuracy of the modeling method. The attitude modeling method combines the advantages of first-principle method and system identification method. The model has simple structure, it is easy to implement and can be conveniently applied in other unmanned aerial vehicles.