Research On Coupled Departure Criteria And Nonlinear Control Technology For Hypersonic Vehicle

Hypersonic vehicle is of great significance both in military and civil fields,and has become a hotspot in aeronautics and astronautics field.For the pursuit of higher flight speed,more maneuverability,hypersonic aircraft often use advanced pneumatic,structural design,making hypersonic aircraft aerodynamic,propulsion,structure and control there is a significant dynamic cross-coupling between the effects.At the same time,the aircraft model has high nonlinearity and uncertainty,leading to the hypersonic vehicle control system design is facing greater difficulties.In this paper,the hypersonic vehicle coupling excursion and fast response robust control technique are studied.First of all,fully learn from the relevant research literature at home and abroad,to understand the domestic and foreign research related to the status quo for future research to provide a theoretical basis.Based on the domestic and foreign literatures,a complete 6DOF nonlinear mathematical model is established.Based on the relevant research contents and the theory of coefficient freezing,the linearized small disturbance equation of the aircraft is deduced.Which provides the basis for the follow-up coupling mechanism analysis,the deviation criterion research and the control system design.Secondly,based on the aircraft motion model,structural layout,aerodynamic layout and other aspects,the coupling mechanism of inertia coupling and aerodynamic coupling is analyzed concretely.On this basis,several common modes of coupled motion are studied,and the typical characteristics of the aircraft are analyzed when various modes of coupled motion are generated.Thirdly,according to the expression of dynamic static stability parameter and control deviation coefficient,the physical meaning of this criterion is analyzed.Based on the small disturbance equation of the vehicle,the stability criterion for the whole channel coupling is deduced.The new stability criterion is more general than the dynamic static stability parameter and the deviation coefficient,and the scope of application is wider.Finally,in view of the problem of strong non-linearity and high uncertainty of hypersonic vehicle,the research of auto-disturbance-rejection control technology has been carried out,and the auto-disturbance-rejection control technology has been successfully applied to the control of aircraft.The autopilot technology of autopilot control is successfully designed and compared with the traditional attitude controller.The results show that the dynamic performance of the autopilot is good compared with that of the traditional autopilots,but the robustness is much better than the traditional autopilot.In addition,based on the traditional three-loop overload autopilot,a hybrid overloading pilot based on autodisturbance-rejection control technology is designed and the feasibility of the scheme is verified by simulation analysis.