The Trajectory Design and Guidance Method for Hypersonic Facial Symmetry Vehicles with Strong Constraints

For the gliding guidance problem of the hypersonic facial symmetry reentry vehicles with strong constraints, this paper proposes an on-line trajectory design and tracking based guidance method. The preset control command is generated on-line with the metrical information at the reentry initial point. Using the kinetic equations and the on-line metrical information, the trajectory profile is designed on-line. After the generation of trajectory, the control mode of ‘feedback plus feedforward’ is used to track the trajectory profile. The preset control command is used as the feedforward to achieve high tracking accuracy. In addition, to guarantee the lateral safety, this paper proposes a lateral pipe control method. The composite criterion composed of the lateral attitude and the trajectory deflection angle is used to decide the reverse condition. The numerical simulation results verify the high precision and strong robustness of the proposed method. With large initial deviations and limited perturbations of flight environment parameters, the trajectory inclination angle tracking accuracy is as high as 0.085º. Compared with the initial point, the vertical attitude accuracy increases by 70%. The lateral pipe control strategy works well and the tracking trajectories are all within the lateral pipe.