Research On Maneuvering Flight Control Based On Characteristic Model For Hypersonic UAV

Hypersonic aerocraft has becoming a new competitive points in the aerospace field in differentcountries, the western air power as the representative of the United States has its own hypersonicresearch program, and many important research results have been obtained, while it is still in theinfancy stage in china. There is a tremendous challenge to the design of Flight Control System，because of strong coupled, high nonlinear,and the complex operation of the flight environment, awide range of high-speed maneuvering characteristics in hypersonic aerocraft. According to the aseries of issues, hypersonic unmanned aerial vehicle (HUAV) is selected as the object of study,meanwhile，the modeling and its analysis, Characteristic Mode and control, the BTT controller ofattitude maneuver and flight trajectory controller design are studied.Firstly, according to the documents published home and abroad, available HUAV model isselected and the kinetic equation is established. The improved ramjet is used as propulsion device inHUAV, thereinto, The coefficients of aerodynamic force and moment are the functions of attack angle,Mach number and control surface deflections. Rigid-body mass and the inertia moments aretime-varying functions of vehicle weight. Flight envelope gives the range of flight parameters of theHUAV maneuvers. Open-loop dynamics demonstrate that the proposed model can embody thecharacteristics of complicated nonlinearity, strong coupling, fast time-varying and uncertainties. Andit also shows that the selected model is typical enough.Secondly, both the Characteristic Model (CM) and the control law design based on the CM aregiven. CM describes critical points and critical information of the system by using characteristicquantities, in which the precise mathematical model of controlled object is unnecessary, while thecharacteristics relationship among characteristic quantities are given. Using CM for describing, simplestructure, easy to understand, and its good performance in the nonlinear controller design foruncertain strong coupling system are the significant advantages. In addition, CM covers a wide rangeanalysis, which shows that the intelligent PID control, the control based on neural networkidentification model, essentially, is also control based on CM.Then, excellent features such as large lift-drag ratio, strong aerodynamic stability and compatiblewith the ramjet inlet design in BTT Control are analyzed. Considering the high nonlinearity, strongcoupling and uncertainty of HUAV while maneuvering, the adverse effects such as nonlinearity can be reduced. BTT adaptive attitude controller of HUAV is designed by Characteristic Modeling, andsimulation results show the effectiveness of the controller. Furthermore, the maneuervering range ofattitude angle by using BTT controller is analyzed under specific conditions.Finally, the tracking control algorithm for HUAV’s trajectory maneuvering is designed andsimulated. The algorithm is consist of two parts, the forward part and error correction feedback part.The first part adopts inverse dynamics and analytical method to solve nominal thrust and attitudecommand, while the second part uses self-learning neuron adaptive control to revise the tracking error.The simulation shows that the validity of the designed control algorithm.