Study On Trajectory Optimization And Guidance Method For Boost-Glide Missile

As a new kind of long-range maneuverable missile,the boost-glide missile is mainly composed of solid booster rocket and unpowered glide missile.Compared with traditional ballistic missile,it has strong maneuverability in middle flight phase,which provide more possibilities for trajectory design.This thesis reviewed the research of boost-glide missile trajectory design and guidance methods.Several key technologies,such as the whole trajectory optimization,multi-constraint boost phase guidance,solid rocket energy management method,reentry guidance against sensitive target and multi-constraint optimal terminal guidance law are studied thoroughly in this dissertation.The specific research contents include the following parts:Firstly,the research background and significance are expatiated.The development status of the boost-glide missile is summarized,and the trajectory optimization methods and guidance methods are introduced.The three-degree-of-freedom dynamic model is established,and the missile simulation model and the related constraint models are given.Secondly,considering of the characteristics of the boost-glide missile's large airspace flight,strong maneuverability and ballistic changeable,the optimal design for the whole trajectory is studied.First,the hp-adaptive pseudo spectrum method is adopted to transfer the problem of trajectory optimization to the nonlinear programming problem.Based on this,the influence of different reentry conditions on the glide trajectory is analyzed,and the approximate equilibrium glide trajectory is designed.Under the related constraint conditions,the boost phase and glide phase are optimized to get the different flight plans and their advantages and disadvantages are analyzed.Then,the plan of rocket continuous ignition and rocket interval ignition are studied.And the trajectory characteristic of energy management is studied based on the rocket interval ignition.Lastly,the optimization and analysis of the flight domain and no-fly zone flight trajectory based on the equilibrium glide constraint are presented.Thirdly,aiming at the multi-constraint guidance problem of the solid rocket boost phase,different guidance methods are proposed according to the different flight phases.In the dense atmosphere,a trajectory tracking guidance method is used based on linear quadratic optimal control theory.According to the longitudinal motion equations,this thesis established the small deviation linearization model,and achieve the guidance parameter design.In the thin atmosphere,a closed-loop guidance method is derived to meet the terminal multi-constraint.The constraints such as altitude,velocity,flight path angle and angle of attack are converted into corresponding constraints in height-time profile.Then the closed-loop guidance method is deduced with different spline curves according to different terminal constraints.Based on this,a rocket thrust bias energy management method is proposed to change the rocket attitude to realize the dissipation of excess energy.Fourthly,aiming at the attack time-sensitive target mission requirements,a multiconstraint reentry guidance method is proposed.The guidance method is designed in the longitudinal and lateral respectively.Longitudinal guidance is divided into initial descend phase and glide phase.In the initial descend phase.An angle of attack adaptive adjustment method and constant bank angle control method are proposed.The missile is guided to the appropriate height,and then transfer to glide phase.In the glide phase,a high-range profile and high-velocity profile joint trajectory design method is provided to design the reference trajectory,and corresponding trajectory tracking law is provided.A time-varying lateral movement boundary is also derived with regard to time-to-range.It is useful to determine the symbol of the bank angle.The proportional guidance law is proposed for zero lateral velocity pointing error in the terminal phases.Comparing with the reentry guidance methods before,the angle of attack and bank angle commands are generated online,and flight trajectory is smooth.Finally,in view of the terminal attack mission requirements,according to different degree of the fall angle constraints,the trajectory shaping guidance law and variable fall angle guidance laws are derived respectively.Based on the variable fall angle guidance law,the analytic forms of the fall angle,the seeker frame angle and the acceleration command are analyzed,and the design range of guidance parameters are determined.At the same time,this thesis proposes a terminal angle of attack control strategy by accelerating the decay of the guidance coefficient.The guidance law early degrades to proportional guidance,realizing the terminal overload command to zero,so as to realize the constraint of terminal position and fall angle,angle of attack.