Research On Modeling And Control Technology Of Aerial Refueling Boom

As a landmark of combat capability of a country's air force, aerial refueling technology is continuously concerned by aviation industry. In china, although the core technology of hose-and-drogue refueling has been mastered for many years, boom refueling technology is still needed, considering its advantages in rapidly refueling a large airplane. Boom refueling technology is researched and tested in recent years. As a part of this research, dynamic modeling, stability and maneuverability evaluating, and stability augmentation system designing are carried out in this paper.An accurate mathematical model is derived for dynamically coupled refueling boom and the tanker, considering interaction forces between them. The model is simulated to analyze the dynamic behavior of the system. This simulation indicates that the effect of interaction forces on refueling boom is much more significant than on tanker, because of the significant differences of mass between them. It also indicates that the motions of boom pitching and rolling are dynamically coupling and of low damping ratio.According to the simulation results, the tanker's automatic flight control system is able to overcome the effect of disturbance from boom motion and to keep the uniform motion in a constant height, orientation and speed. Therefore, the mathematical model is simplified in ideal condition that the tanker is in steady straight level flight. Based on this simplified model, flying quality requirements and evaluation methods are established, referring to the flying qualities of piloted aircraft. The stability and maneuverability of a refueling boom are evaluated, and a stability augmentation system is then designed according to the evaluation results which are not good enough.Another problem of the system is the severe parameter perturbation. In order to solve this problem, a method, named linear matrix inequality based region pole assignment, is employed to design the control law. The poles of refueling boom with stability augmentation system are assigned in a specified circular region on the left part of complex plane. Simulation results indicate that this method ensures the damping ratios and natural frequencies of closed loop poles, and finally ensures the boom's flying qualities under parameter perturbation.