Longitudinal Control Law for Elastic Aircraft Based on L1 Adaptive Control

In order to deal with the elastic deformation caused by large aspect ratio flexible wing, this paper presents a design method of longitudinal damper for elastic aircraft based on L1 adaptive control. The dynamic and nonlinear parts of the elastic model are considered as the uncertainties in adaptive control. The low-pass filter is designed to filter out the frequency band where some of the elastic modal vibration frequencies are located. The appropriate projection operator is selected to design the adaptive law of L1 adaptive control, reducing the impact of elastic modal on rigid body modal. The simulation results show that the tracking error of the pitch rate converges rapidly. As a result, the adaptive controller designed can control the elastic aircraft excellently.