Research On BTT180Control Technology Of Terminal Entry For Hypersonic Vehicle

Rapid maneuver is made by BTT180to down trajectory quickly and complete vertical strikemission in terminal entry for hypersonic vehicle. It is important for BTT180control that how to meetrequirements of angular rate with limited rudder and compensate coupling effects caused by “rapidrolling”. BTT180control problems are solved from the aspect of engineering application in this paper.A global hypersonic vehicle dynamic model library is proposed which decouples the nonlineardynamic model into two parts that the rigid body six degree of freedom library and the aerodynamicdata library. At the same time, interface function definitions of the two libraries are given. Smalldisturbance linearized models are obtained by trim and linearization along BTT180flight trajectory.Finally, manoeuvrability and stability in BTT180phase are analyzed. Aiming at the problem of Dutchroll instability, high-precision approximation formulas are derived from the movement mechanism ofDutch roll and they are proved correctly by numerical calculation in terminal entry. The formulasindicate that β&feedback is the most efficient way to augement Dutch roll.Two typical roll control strategies for hypersonic vehicle are proposed which refer the earlyspace shuttle’s entry lateral roll control thought and fuse the method of β&feedback augementionDutch roll. The μ analysis method is used to estimate the robustness of the two kinds of roll controlstrategies for taking into account aerodynamic parameters existing strong uncertainty in entry phase.Vehicle maintains high angle of attack and unconventional BTT180control strategy is adopttedin BTT180flight phase.“BTT180control strategy based on angular rate command loop” is proposedto improve the response time of roll control. In order to meet the requirements of “rapid rolling”, thispaper researches that reducing to small angle of attack with conventional BTT180control strategy andreturning to high angle of attack with unconventional BTT180control strategy when BTT180iscompeleted. Nonlinear simulation results show that BTT180control based on angular angular ratecommand loop control strategy responses faster. BTT180control strategy for small angle of attack canmeet the requirements of60°/s “rapid rolling” and the rudder still has enough control margin. Inaddition, sideslip can be limted at±2°with the feedforward anti-sideslip controller.