Optimal feedback reentry guidance of hypersonic vehicle based on improved Gauss pseudospectral method

This paper presents an optimal feedback reentry guidance for the hypersonic vehicle. The proposed method implements a closed-loop feedback approach via fast computation of a series of open loop optimal control problems. At each sampling period, the optimal control problem is solved by the improved Gauss pseudospectral method (IGPM), which is an efficient method to solve the general nonlinear optimal control problem. The IGPM approximates the state and control by the polynomials at the Legendre-Gauss (LG). The costate can be obtained and the optimality of the solution is also checked easily. The proposed method can deal with the state and control constraints explicitly. The various performance can be realized by considering different cost function. Simulation results demonstrate that the hypersonic vehicle tracks the reference trajectory well in the presence of the uncertainty of aerodynamic force.