Flight control of a launch vehicle using an L_1 adaptive controller

摘要

This paper investigates the use of an L_1 adaptive controller direct approach to solve the attitude control problem of a launch vehicle (LV) during its atmospheric phase of flight. One of the most important difficulties in designing a controller for launch vehicles (LVs) is the widely changing system parameters during launch. Aerospace systems such as aircraft or missiles are subject to environmental and dynamical uncertainties. These uncertainties can alter the performance and stability of these systems. Unknown variations in thrust and atmospheric properties, eccentricities of nozzles, and other unknown conditions cause changes in a system. The L_1 adaptive controller ensures uniformly bound transient and asymptotic tracking for the system's signals - input and output - simultaneously. This adaptive control technique quickly compensates for large changes in the LV dynamics. The effect of feedback gain selection and robustness of this approach against system uncertainties and actuator disturbances are also discussed. The adaptive control method is then simulated with representative LV longitudinal motion. The effectiveness of the proposed control schemes is demonstrated through hardware-in-the-loop simulation.