Multi-Rigid-Body Modeling And Attitude Control Of Variable Structure Aircraft

The aircraft existing is applied to certain specific missions. With the development of technology in aeronautics and astronautics, in recent years high demands for new generation of aircrafts are proposed in mobility, reliability and accuracy. As a type of multi-purpose and multi-configuration vehicle, morphing aircrafts draw more and more attention. The attitude control system plays a significant part in carrying out stable flight, thus research on attitude control system has important significance. Our research work is supported by the National Natural Science Foundation of China (Grant No 60674029). In this paper we propose a robust nonlinear attitude control method for fixed-wing aircrafts, investigate modeling and control strategy for several kinds of variable structure aircrafts. Finally the progress of flight simulation is simply presented. This paper mainly comprises the following aspects:1. We deduce nonlinear attitude control scheme on the basis of partitioned backstepping method and input-to-state stability theory. This method can be applied to mathematical models of aircrafts based on Euler angles and Modified Rodrigues Parameters. With this strategy the coupling of the model attitude can be dealt naturally. A stable attitude control is achived and the scheme has a good robust property subjected to external disturbances. In theory, we realize the above attitude control methods by means of attitude control engines and aerodynamic force.2. The variable structure aircraft is divided into the primary rigid body and the slave one according to its structure. Thus we choose the center of mass of the primary rigid body and coordinate components of relevant units as generalized coordinate. In virtue of geometric condition and constraint relation, we construct multi-rigid-body dynamics models of aircrafts, utilizing kane method.3. The decoupling control condition of the generalized attitude is discussed. We put forward nonlinear control plan for pitch attitude respectively, after the establishment of multi-rigid-body dynamics model of the aircraft with a moving-mass or movable wings.4. The progress of a distributed universal 3D flight simulation platform is introduced.