Trajectory tracking for RLV terminal area energy management phase based on LQR

A new longitudinal trajectory tracking law for the Terminal Area Energy Management (TAEM) phase of the Reusable Launch Vehicle (RLV) is presented in this paper. The conventional PID method controls the height and the velocity by the angle of attack and the angle of airbrake respectively, and no coupling is considered. To improve the tracking precision, the new tracking law is designed based on the linear quadratic regulator (LQR) theory where the coupling is taken into account. Finally, the trajectory tracking law based on the LQR is simulated and compared with the conventional method. Simulation results indicate the effectiveness and the robustness of the new tracking law.