Adaptive trajectory tracking control design with command filtered compensation for a quadrotor

The design of a flight controller capable of not only stabilizing attitude but also tracking a trajectory accurately for a quadrotor aircraft in presence of parametric uncertainties and external disturbances is more challenging than that in the absence of uncertainties. In this paper we propose an adaptive trajectory tracking control algorithm, based on the relationship between attitude and linear acceleration, using online adaptive approximator to estimate unknown aerodynamic parameters and external disturbance upper bounds, and a linear tracking-differentiator to eliminate the timescale separation assumption between attitude and linear dynamics in control system design. The stability of the closed-loop control system is proven subsequently. Finally, the validity and the improvement of this proposed algorithm relative to the previous work are demonstrated through numerical simulations of tracking a circular trajectory under several conditions, including basic parametric uncertainty, exogenous wind disturbance and control input oscillation eliminating via a hyperbolic tangent function instead of a sign function.