Hypersonic Periodic Cruise Trajectory Optimization Based on Flexible Use of Pseudo-spectral Method

摘要

Periodical cruise can raise the fuel efficiency of hypersonic vehicle. Therefore, it is crucial to seek optimal characteristic parameters of periodical trajectory to establish a feasible guidance law in practice. In this paper, we employ the popular, mature and efficient nonlinear optimization scheme, pseudo-spectral method (PSM), to optimize the hypersonic periodic cruise in an innovative way by utilizing the symmetric property of periodic curve. Two optimization strategies, combined and entire ones, with artificial constraints for the sake of symmetry are provided and embedded within the PSM to obtain the optimal numerical solution. Then the parameters of specific periodic functions are fitted through nonlinear square method according to these numerical solutions. The numerical results of these two proposed methods and the optimal steady-state method are compared and investigated, demonstrating the effectiveness of the proposed methods.