Research On Strong Robust Control For Flexible Hypersonic Morphing Vehicle

Hypersonic vehicle possesses the characteristics of fast and high maneuverability,which enables it has fast response capabilities and strong space shuttle capabilities.It can make the vehicle have optimal flight performance by activating deformation,however,the complex aerodynamic characteristics caused by the shape morphing,especially the uncertainty of vehicle model is brought by the flexibility effects.In this paper,robust attitude control of hypersonic flexible morphing vehicle is investigated,the research contents are shown as follow.1.Rigid-elastic coupled dynamic model of morphing vehicle was established by multi-body dynamic theory.The fuselage of the vehicle is regarded as free beam because the shear and bending moments on both ends are zero.The additional attack angle and the additional rudder deflection caused by the longitudinal flexibility effects are obtained based on the small deformation assumption.The additional force and moment caused by morphing and flexible deformation are analyzed,which constitutes a complete sixdegree-of-freedom model of the hypersonic flexible morphing vehicle.2.Dynamic surface control scheme of flexible hypersonic morphing vehicle is investigated.Firstly,the control-oriented six-degree-of-freedom model is simplified by summarizing the flexible and aerodynamic deviation effects into matching uncertainties and non-matching uncertainties,therefore,the attitude control equation in the form of strict feedback is established,the adaptive laws is designed to attenuating uncertainties based on backstepping.The closed-loop system stability is proven via Lyapunov analysis,simulation results under nominal and deviation conditions are given to demonstrate the effectiveness and robustesse of the proposed scheme.3.RBFNN adaptive control scheme of flexible hypersonic morphing vehicle is proposed.Firstly,disturbance observer is designed to perform nonlinear approximation of uncertainties by using neural network,the system is designed by backstepping recursion,the adaptive laws is designed to attenuating uncertainties based on backstepping and the closed-loop system stability is proven via Lyapunov analysis,simulation results are given to demonstrate the effectiveness of the proposed scheme and improved control accuracy.4.A finite-time control scheme of flexible hypersonic morphing vehicle is proposed.The problem of filtering error and unguaranteed convergence time exists in traditional backstepping is solved.Higher-order sliding mode(HOSM)is utilized to estimate external uncertainties,the tracking error is proven to asymptotic converge to zero in finite time,the closed-loop system stability is proven via Lyapunov analysis,simulation results are given to demonstrate the faster convergence and improved control accuracy by comparing to the third point.In this paper,robust attitude control of flexible hypersonic morphing vehicle was investigated,a complete six-degree-of-freedom model of the hypersonic flexible morphing vehicle is established,the control-oriented six-degree-of-freedom model is simplified,dynamic surface control scheme,RBFNN adaptive control scheme and finitetime control scheme is proposed to uncertainties,the effectiveness of schemes to suppress flexible addition is demonstrated by simulation results.