Optimal Expansion Strategy For Winged Wing Of Near Space Morphing Vehicle

Near-space Morphing Vehicle(NMV)works in the atmosphere and near space.It can change its aerodynamic parameters to complete the relevant flight by adjusting the shape of its wing with not moving or only slightly moving its rudder surface or engine,due to its particularity of the airframe configuration.Therefore,the spacecraft not only enhances maneuverability,but also saves a lot of energy through the the expansion and contraction of its winglet.Thus,the near-space variable-wing aircraft is the research focus and hotspot in the aerospace field.In this paper,we study the overall modeling of the aircraft,the aerodynamic parameter analysis of the winglet telescopic model,the optimization of index of winglet expansion during climbing phase and the optimization strategy,and the multi-objective optimization of the winglet expansion,presented as follows:Firstly,according to the model data of the near-space vehicle published at home and abroad and the existing research results of the laboratory and taking into account the different altitudes of the aircraft,the engine thrust at different stages,the non-linear model of the near-space vehicle with the flexible wing is established combined with the features including influence of the aerodynamic characteristics of the variable-wing telescopic.The climbing corridor of variable-wing aircraft is proposed to aim at the complex and changeable climbing constraints during climbing phase,laying a solid foundation for the follow-up optimization research.Secondly,the optimal control and trajectory optimization during the climbing phase of the near-space variable-wing aircraft are studied.Various performance indexes and optimization strategies are proposed for the winglet expansion of near-space variable-wing aircraft.Considering that Gaussian pseudospectral method has good convergence and optimization effect in optimal control and trajectory optimization,therefore,the simulation experiments are carried out for the optimization models of minimum fuel consumption,minimum control output and minimum climbing time.The optimal climbing trajectory and the optimal winglet expansion state under each optimization index are obtained,which shows that different winglet expansion strategies have different benefits.Thirdly,considering the problems of large amount of calculation,long calculation time and low optimization accuracy caused by the increasing number of collocation points in the optimization process,an overall optimization strategy of winglet expansion based on improved multi-segment Gaussian pseudospectral method is proposed.According to the state of aircraft and engine,the climbing modes are divided into three climbing subsections,and then the optimization model and overall optimization strategy of the winglet expansion and contraction.The minimum fuel-consuming climbing trajectory and winglet expansion state of the whole climbing segment are obtained by numerical simulation.The improved optimization method has further improved the overall performance in terms of calculation time and optimization accuracy.Finally,in view of how the variable-wing aircraft around the space can change the telescopic wing to achieve optimal flight conditions in the multi-evaluation system,the multi-objective optimization model of small wing extension is established.Through combinging traditional weighted summation and advanced evolutionary algorithm,the multi-objective optimization evolution algorithm based on personal preference is designed to solve the above model.The simulation model of the established model is obtained.Under the multi-evaluation system,the optimal flight state curve and the amount of telescopic state of the winglet satisfying personal preference provide an effective reference value for the future variable-wing aircraft to climb the flight of the winglet in multi-target.In summary,this thesis about near-space variable-wing aircraft mainly focuses the aircraft modeling,aerodynamic parameter analysis of the winglet telescopic model,the optimization of the climbing winglet expansion optimization index and the optimization strategy,and the multi-objective optimization of the winglet expansion.The flight trajectory and the winglet telescopic state under different reference performances of the climbing phase are given,which provides a certain research basis for the climbing flight of the variable-wing aircraft.