Design And Optimization Of Periodic Cruise Trajectory For Hypersonic Vehicle

Hypersonic vehicle has many advantages, such as high speeds, short reaction time, and the penetration ability. As a result, hypersonic vehicle is becoming more and more important in the field of military or civilian. In order to achieve long distance in the cruise phase, the design and optimization schemes of the periodic cruise trajectory are proposed for the dynamic model in this paper. Compared with the steady-state trajectory, the periodic cruise trajectory has more significant advantages, including less fuel consumption, flexible design, various forms and so on.Firstly, based on the task requirements, the hypersonic cruise vehicle is selected with the wave-rider using the scramjet engine. Followed that, the geometric shape features of the hypersonic vehicle is described using the parametric modeling methods. And then the longitudinal dynamics model is constructed based on the aerodynamic model, pitching moment model and engine thrust model. The analysis shows that the model characteristic accords with the periodic cruise trajectory for the hypersonic vehicle.Then, the cruise trajectory optimization schemes for hypersonic vehicle are proposed including the steady-state trajectory and the period trajectory. Then the trajectory optimization problem is translated into the optimization control problem with constraint which is solved by Gauss Pseudo-spectral Method(GPM) and the Sequence Quadratic Program(SQP) algorithm. Comparing two different models, the periodic cruise trajectory is superior according to the simulation results. In addition, the influence of different factors on the trajectory design is analyzed such as the different cruise points, task initial height and improved thrust system.Furthermore the trajectory tracking controller is designed based on Linear Quadratic Regulator(LQR) theory to track the designed period trajectory. The simulation results show that this controller realizes the effective tracking of periodic optimal cruise trajectory in case of initial value error, aerodynamic parameter error and changing mass for the hypersonic vehicle.Finally, the main research results are summarized and further research direction is provided.