Adaptive trajectory tracking control for VTOL UAVs with unknown time‐varying mass using an extended I&I estimator

Abstract

SummaryThis article presents an adaptive control scheme for vertical takeoff and landing unmanned aerial vehicles subject to time‐varying mass based on the immersion and invariance scheme in an extended form. For the varying mass parameter in the position control, a generalized I&I adaptive law is proposed with higher dimension to estimate the mass and its derivatives. The stability of the resulting estimation error manifold, which is in a cascade form, is guaranteed by introducing smooth saturation functions in the position control law. The attitude control is designed by employing a smooth function with positive integrable time‐varying function to compensate unknown time‐varying moment of inertia to achieve asymptotic attitude tracking. Simulation and experimental results verify the effectiveness of the proposed method under different cases, and the robustness to time‐varying parameter is assured.