Adaptive Control Of Air-breathing Hypersonic Vehicle With Time Varying Parameters

Air-breathing hypersonic vehicle(AHV)has great potential value and strategic significance in both military and civilian fields by virtue of its high speed,large range,and fast maneuverability.However,compared with traditional aircraft,the characteristics of AHV such as strong nonlinearity,parameter uncertainty,strong coupling,and fast time-varying have brought huge challenges to its control system design.Therefore,this paper focuses on the research on the existing hot issues of AHV,focusing on solving: the problem caused by the model with time-varying,uncertain parameters and the control problem under the condition of large flight envelope.The main research contents include:Firstly,the control-oriented mathematical models of the AHVs are obtained.The elastic longitudinal channel model widely used in the field of AHV control is introduced,and a parameterized model of AHV is given through appropriate and reasonable assumptions.The mathematical expression of the saturation nonlinearity of scramjet is given,which lays the foundation for the design of the control system in the subsequent chapters.Secondly,aiming at the problem of fast time-varying and uncertain parameters of the AHV model,an adaptive controller based on parameter upper bound estimation is designed.This section relies on adaptive control as the framework.For the flight altitude tracking problem,by estimating the upper bound of the amplitude of the uncertain parameter and the parameter vector,the time-varying characteristic of the uncertain parameter can be effectively overcome.Thirdly,for the control problem of the AHV under the condition of large flight envelope,a control strategy based on the combination of switched model and adaptive control is designed.The switched model is considered to solve the control problem of the big flight envelope characteristic.By dividing the velocity and the angle of attack,the adaptive tracking controller is designed for different regions.These strategies ensure the control effect in each flight area so that the designed controller can adapt to the characteristics of large flight envelope.Finally,the tracking control problems and research results of the AHV studied in this paper are summarized,and some prospects for future work are given.