Adaptive Radau pseudo-spectral optimization for descending trajectory of a hypersonic cruise vehicle

Abstract

During descending flight of a hypersonic cruise vehicle (HCV), the flight environment is complicated due to the drastically changed atmosphere. It is necessary for the flight trajectory to perform accurate and fast optimization. To solve the nonlinear optimization problem, in this paper, a global adaptive Radau pseudo-spectral method, which is introduced with an hp adaptive strategy (p method to increase the number of points in time interval and h method to refine the interval) is presented. The maximum range and the shortest engagement time are considered, respectively, as performance index to optimize controlling of the attack angle. Using Lagrange interpolation polynomial approximation, the optimal control problem is transformed into a problem of nonlinear programming and solved by a sequence quadratic programming algorithm. Simulation results have shown that the presented method has high computational efficiency and desirable accuracy, with the flying constraints satisfied. It is an effective trajectory optimization method for HCVs.