Multiple Constraints Integrated Guidance And Control Design Approach For Boost-glide Vehicle

The hypersonic boost-glide vehicle,represented by HTV-2,is typically characterized by fast flight speed,strong maneuverability and high penetration probability.Therefore,it has attracted wide attention from all over the world.However,the guidance and control design of the boost-glide vehicle during both the boost phase and the diving phase is more challenging and difficult.During the boost phase,the coupling between centroid dynamic and rotational dynamic is more severe,because of the engine thrust's influence on both of them.Besides,a large-scale lateral maneuver is required to achieve the effective dissipation of excess energy,which leads to a strong coupling between the pitch and yaw channels.During the diving phase,the relative motion information changes rapidly,and the time constant of the guidance system gradually becomes smaller.Consequently,the coupling between the guidance and control systems will be more significiant.In order to ensure the structural safety,the normal operation of the payload and the stable flight attitude,various constraints,such as overload constraint and angular rates constraint,need to be satisfied.Under the modes of strap-down guidance and side-window detection,the rotational dynamic and the line-of-sight(LOS)should meet a certain constraint so that the target can be located in the seeker's field-of-view(FOV)during the whole engagement.In this dissertation,the aforementioned issues will be studied in-depth,and an integrated guidance and control(IGC)design approach,suitable for such a special research object,is proposed.It can serve as a reasonable and effective solution to the related problems,caused by the characteristics of the boost-glide vehicle.The main research work of this dissertation are listed as follows:During the boost phase,the actuator might suffer from the limitation of magnitude due to the rapid turn and large-scale lateral maneuver.The span of the flight airspace is large,and the engine mass flow rate and specific impulse will deviate from the nominal values,resulting in the atmospheric uncertainty and body structural parameters uncertainty.To deal with the aforementioned problems,a finite-time extended state observer(FTESO)based anti-saturation IGC algorithm is proposed.Combined with the trajectory linearization method,a control-oriented integrated design model with the strict feedback form is obtained.In order to realize active disturbance rejection and improve the robustness of the control system,FTESO is used to estimate the complex uncertainties and model deviation,caused by ignorance of the higher-order terms in linearization.Based on the dynamics of attitude angle,a novel third-order FTESO is constructed to handle the problem that the common second-order FTESO cannot effectively estimate the uncertainty of the angular rate loop during the third-stage flight.Meanwhile,the adaptive algorithms are employed to eliminate the errors between the actual uncertainties and estimations.Moreover,the anti-saturation auxiliary system is designed to dynamically adjust the tracking error of the angular rate loop by feedback bounded compensation to achieve the goal of desaturation.The proposed method can also achieve an excellent tracking of the desired reference trajectory.During the diving phase,the relative motion information changes rapidly,and the flight vehicle possesses the fast varying characteristic.So as to guarantee the LOS angular rates convergent to zero quickly and meet the requirement of the rapid change of control commands,the actuator may be subject to saturation.To address the above-mentioned issue with the full state constraints,a multi-constraints adaptive finite-time IGC design method is proposed.Above all,the IGC design with the impact angle constraint and the unmeasurable line-of-sight(LOS)angular rates,is investigated.More specifically,FTESO is employed to estimate the LOS angular rates and the uncertainties,which can solve the engineering implementation problem of the algorithm and improve the robustness of system.Based on the non-singular terminal sliding mode in integral form,a FTESO based finite-time IGC design with the impact angle constraint is designed.Moreover,the influence of full state constraints and input saturation on the performance of the guidance and control system is researched comprehensively.The modified piecewise saturation function and barrier Lyapunov function(BLF)are adopted to restrict the nominal virtual commands and the dynamic tracking errors,by which the state constraints will never be violated.Meanwhile,the auxiliary systems are constructed to eliminate the adverse effect,suffered from possible saturation.As a result,it can coordinate the allocation of control capabilities among subsystems effectively and avoid significiantly excessive control.To deal with the design problem of the guidance and control system of the boost-glide vehicle under strap-down guidance and side-window detection modes,an integral BLF based IGC method under strap-down guidance mode and a time-varying asymmetric BLF based finite-time IGC method are put forward.The flight-target relative motion model,established in the body-LOS coordinate system,is introduced to describe the guidance problem with the FOV constraint accurately.Besides,it can effectively avoid the engineering realization problem,caused by the inability to measure the inertial LOS angular rates in the strap-down guidance mode.Based on the characteristic of the above-mentioned relative motion model and the dynamics of the body angular rates,the IGC design with FOV constraint can be converted to an output constraint problem of a low-order nonlinear system.The integral BLF-based IGC design method is proposed to deal with the symmetrical FOV constraint.Furthermore,the problem of asymmetrical FOV constraint under side-window detection mode is investigated.The desired reference trajectory of the body-LOS angles is designed to meet the FOV constraint and the terminal accuracy requirement simultaneously.A time-varying asymmetric BLF-based finite-time constrained IGC design method is proposed to achieve an excellent tracking of the desired reference trajectory.