Research On Guidance Method Of Terminal Area Energy Management For Reusable Launch Vehicle

With the rapid development of manned space technology,the space transportation began to catch more and more attentions,some new spacecrafts emerged,and Reusable Launch Vehicle(RLV)was one of them,which had great military value and economic military value.Through decades of efforts,RLV is safer and reliable,and the cost is reduced greatly.This paper focuses on the guidance method of Terminal Aera Energy Management(TAEM)of RLV.The main contents include the following parts:For the convenience of assumptions,a three degree-of-freedom model is established according to physics.Besides,aerodynamic characteristics of the vehicle are analyzed,and these works lay a solid foundation for trajectory design and guidance design.Aiming at nonnegligible coupling between longitudinal and lateral trajectory when needing wide-range lateral maneuver,a three-dimensional trajectory propagation algorithm is proposed.Longitudinal trajectory tracks dynamic pressure profile which can be changed to adapt to different ranage.The lateral trajectory is expressed by several curves whose shapes can be changed.Through the three-dimensional trajectory deduction algorithm,a feasible trajectory can be generated rapidly.In the case of initial energy and initial position deviation,the simulated results verify the adaptability of the algorithm.The high terminal accuracy and disturbance deviation have greatly increased the difficulty of the design of guidance law.In order to improve the self-adaptability of guidance,the Linear Quadratic Regulator and the PID controller are combined to track the longitudinal reference trajectory.Lateral lateral guidance is used to track the ground geometrical trajectory,erasing position error and heading angle error through lareral maneuver.The numerical simulations show that the guidance method has good robustness in the presence of deviation of aerodynamic coefficients and atmospheric density error and so on.Finally,on the basis of the theoretical analysis of the guidance system,the aided analysis and design platform is established,which can complete the modification of the relevant data,display and graphic output by interaction.Under this platform,the Monte Carlo value simulation is completed.