The Reentry Trajectory Planning And Tracking Control Of Hypersonic Vehicles

The lifting hypersonic reentry vehicle has the advantages of fast speed,long range,and maneuverability.The development of its technology will have a far-reaching impact on the future military strategy and the construction of defense systems.In the reentry process,the design of the reference trajectory and the design of the tracking control law are the key to the successful completion of the reentry task.Reentry reference trajectory planning and tracking control is studied for common aero vehicle in this work.The main contents of this paper include:(1)For the reference trajectory planning,two different planning methods are proposed.The first method is dynamic adjustment method for angle of attack,which converts the path constraints to the boundaries of the bank angle based on quasi-equilibrium glide condition.The phugoid oscillation phenomenon can be avoided by applying the dynamic adjustment method for angle of attack.The second method transfers the path constraints into constraints on the flight path angle and the other constraints are satisfied by planning an appropriate profile of the flight path angle.The reference trajectories obtained by this method can meet the path constraints,and the phugoid oscillation phenomenon can be reduced effectively,thus ensuring the reliability of the reentry reference trajectory.(2)A algorithm how to avoid no-fly zone is proposed.In order to avoid the no-fly zone,a new algorithm is designed in this work.The avoidance of the no-fly zone is achieved by setting the heading error angle boundaries which are adjusted in real time and changing the sign of bank angle to constrain the azimuth angle.(3)A tracking control law is adopted and multiple-planning algorithm is proposed.For the design of reentry reference trajectory tracking control law,the reference trajectory is tracked by designing a linear quadratic regulator(LQR)using the nominal guidance method.Meanwhile,in order to satisfy the terminal constraints,multi-planning algorithm is presented to minimize the tracking error.The Monte Carlo simulations for multi-planning algorithm and single planning algorithm are conducted with the consideration of initial state uncertainty and atmospheric density interference.The simulation results show that the reference trajectory can be well tracked by proposed tracking guidance law and the multi-constraints are satisfied.The dispersion results of the multiple-planning algorithm are better than the single-planning algorithm.The research can provide a reference for the design of the reentry guidance and the overall design of the reentry task.