A Comparison of Flight Control Strategies for Hypersonic Reentry Vehicles with Lateral-Directional Coupling Dynamics

During long-span flights, hypersonic reentry maneuvering vehicles have always faced the problem of severe lateral-directional coupling, which leads to instability, difficult control, and lack of control effectiveness. For the problem, a model of lateral-directional coupling in stability axes system is built and the main modal characteristics are extracted in this paper. Then the effects of compensating and utilizing coupling on control strategies, which suppress sideslip for coordinated roll or induce sideslip to control rolling motion, are analyzed, and estimation formulas for control effectiveness of control strategies are proposed. Through comparative analysis of multiple states, it is shown that hypersonic reentry vehicles have correspondingly suitable lateral-directional coupling control strategies under different parameter conditions. The aileron-rudder interconnect parameter and the lateral control divergence parameter of stability axes system can be taken as description parameters for the selection of control strategies. Finally, through the simulations and verification in a typical state, control strategies arc evaluated in terms of control performance, stability margin, and control effectiveness requirement. The results try to provide favorable references for evaluations and selections of coupling control strategies.