Robust trajectory tracking controller for quadrotor helicopter based on a novel composite control scheme

摘要

Robust trajectory tracking problem is dealt with for the under-actuated quadrotor system, which is decomposed into two subsystems, i.e., the inner-loop rotational subsystem perturbed by the time-varying disturbances (e.g., parameter variation, model mismatches, payload changes, wind gusts), and the outer-loop translational subsystem subjected to both the uncertain disturbances and time-varying measurement-delay simultaneously. The novel composite control scheme integrating a nominal controller with robust compensators is hierarchically developed. Composite observers consisting of time-varying disturbance observer (TDO) and time-varying measurement-delay observer (TMO) are incorporated into the nominal backstepping control (NBC) as robust compensators, to compensate for the time-varying uncertainties by estimating the disturbance dynamics and system states. Stability of the closed-loop control system is analytically proved based on the Lyapunov-Krasovskii theorem, and the proposed controller theoretically guarantees that the tracking error converges to a small neighborhood around the origin. Comparative flight performances under different controllers for the quadrotor helicopter, in the presence of uncertain disturbances and time-varying measurement-delay, are presented to demonstrate the effectiveness and superiority of the proposed controller. (C) 2018 Elsevier Masson SAS. All rights reserved.