The Design Of Robust Controller For Near Space Vehicle Based On Dynamic Surface

Near space vehicle is currently the focus of countries competing for aerospace power as its great military and civil values. For near space vehicle has a big flight envelope, together with near space has low atmosphere density, the execution efficiency of aero-surfaces will decline even become invalid because of instantaneous saturation. Aerodynamic/Thrust vector Composite control is an effective important method used to solve these problems. In the thesis, according to the characters of near space vehicle with aerodynamics and thrust vector blended of strong coupling, nonlinear and time-varying system, the desing methods law of near space vehicle are studied.Firstly, based on the literature review describes the near space vehicle research background and significance, the characteristics and difficulties of the the near space vehicle control are analysed. At the same time, the development history and research status of the near space vehicle are expounded.Secondly, a series of mathematical models of near space vehicle are established. The winged-cone configuration USA NASA Langley Research Center released near space vehicle as the object,12 6-DOF equation of state, Attitude affine nonlinear model of near space vehicle, attitude uncertainty nonlinear model of near space vehicle, longitudinal model of near space vehicle.Thirdly, a controller of near space vehicle is designed with recursive method. Since longitudinal motion model of near space vehicle is highly nonlinear, very complex, and backstepping is a a very effective control method for processing of nonlinear problems, so suitable Lyapunov function is selected to design dynamic surface robust controller.Fourth, a controller of near space vehicle is designed with dynamic inversion. Although backstepping control method is very effective construction methods, but it has the problem of calculation expansion, to reduce the algorithm complexity of the differential term expansion. The control system can be divided into fast subsystem and slow subsystem based on time-scale separation, and then the control laws of the near space vehicle model are designed based on the dynamic inversion in each subsystem. The simulations carried on proportionality factor control distribution show that, the effect of control method is excellent. But simulation at the condition that violent aerodynamic parameter proves the robustness of dynamic inversion.Finally, the results of the thesis are summarized and the thesis indicates some problems which deserve further study.