Study On Mechanism And System Identification Modeling Of Unmanned Tilt-rotor Aircraft

The tilt-rotor aircraft is a new type of aircraft and shares the common features of helicopter and fixed wing aircraft. It can take off and land vertically like a helicopter,and can fly forward at high speed like the aircraft. Because of the excellent features, it has complex structure and lots of technical difficulties. Establishing the model of flight dynamics is an important part of the research on the tilt-rotor aircraft control system.Two methods—mechanism modeling and system identification modeling—are used to establish unmanned tilt-rotor aircraft model. Firstly, we develop a complex and nonlinear dynamic tilt-rotor aircraft model by using the mechanism modeling, and extend the model so that it can also be applied to the helicopter. Secondly, we linearize the dynamics model near the equilibrium point based on a small disturbance hypothesis. Thirdly, we verify the correctness of the modeling method by trimming the helicopter. At last, system identification was conducted the initial model is developed by using subspace identification method, and the final optimized model is constructed by prediction error method. The flight mechanics mode of the tilt-rotor aircraft is successfully identified through simulation.