Algebraic time-delay control for quadrotor attitude tracking in the presence of external disturbances

This paper proposes an algebraic time-delay control (ATDC) scheme for attitude tracking of quadrotor UAVs subject to high-amplitude, high-frequency external disturbances. The approach extends conventional time-delay control (TDC) by introducing an algebraic disturbance estimator derived from finite-difference calculus, achieving adjustable order of estimation accuracy without increasing controller complexity. The resulting controller ensures precise compensation of unmodeled dynamics and external disturbances within a simple linear structure, requiring no explicit system model. Comparative simulations with standard TDC and active disturbance rejection control (ADRC) demonstrate that ATDC provides smaller tracking error, enhanced disturbance rejection, and smooth control effort. The proposed method combines computational efficiency with high robustness, offering a promising framework for real-time UAV control.