Antiwindup Spinning Guidance for Fixed-Trim Entry Vehicles by Active Disturbance Rejection Control

Abstract

This paper investigates a novel guidance algorithm for fixed-trim maneuverable entry vehicles with limited control authority. The previous work, which depends on simplified models, lacks effectiveness in addressing the limited control authority issue in the presence of disturbances. The contributions of this paper address this by developing a novel spinning guidance algorithm to steer the vehicle to the target with high precision and strong robustness in dynamic environments with notable uncertainties and disturbances. To this end, a pseudoactuator-limit framework is designed to resolve the inherent limited authority and disturbance issues. Based on this framework, an extended state observer is introduced from the active disturbance rejection control theory, and a new spinning guidance algorithm is proposed to consume the redundant lift through continuous rotation of the lift vector, instead of performing high-frequency bank reversals. Furthermore, an observer-based antiwindup scheme is developed to enhance the robustness and control capability of the algorithm. The convergence of the proposed guidance law is explored from a theoretical perspective. The accuracy and robustness of the proposed guidance algorithm are demonstrated through typical case simulations and Monte Carlo evaluations under a variety of dispersions. Simulation results show that the miss distance is reduced by about 90% when compared to the existing guidance laws.