Predictor-corrector guidance for reentry hypersonic vehicle based on feedback linearization

Abstract

This paper presents an improved predictor-corrector reentry guidance law for hypersonic vehicle based on the feedback linearization theory. Considering the overload as intermediate variable, a new conversion of constraints is proposed based on the Quasi Equilibrium Glide Condition (QEGC), and all the path constraints are converted to constraints of overload variable. Using the theory of feedback linearization to gradually eliminate the deviation of line of sight between the vehicle and target location, the required longitudinal and lateral overload can be obtained respectively. Using the elevation-angle of line-of-sight to predict the terminal velocity, and the lateral maneuver strategy is added to make the vehicle deceleration. A feasible flight path is generated and the vehicle is smoothly and safely guided to the Terminal Area Energy Management (TAEM). An important aspect of reentry missions is how to make the vehicle recover to the original mission in case of random perturbations or failures. If random perturbations or failures occur, the current states and the aerodynamic coefficient will change obviously. Simulation results are presented to show the performance of the guidance law in the nominal trajectory. Numerical results under the different deviation of states or aerodynamic coefficients, determined the robustness and fault-tolerant redundancy for this guidance law.