<p>In this paper, a robust nonlinear second-order fast terminal sliding mode controller is presented to achieve smooth and safe flight control of quadrotors. The controller is developed to facilitate finite-time convergence while eliminating the chattering issue by incorporating a PID second-order sliding manifold with the fast terminal sliding mode control concept. The comparison of simulation results validates the efficacy of the presented nonlinear control scheme relative to sliding mode control (SMC) and PID approaches in distinct scenarios. The tracking efficiency of the different controllers is evaluated using the integral of squared error (ISE) criterion. The results indicate that the proposed controller accurately tracks the desired trajectory using small control input signals. Implementing the presented controller on the quadrotor system alleviates chattering, facilitates rapid convergence, minimizes the required control efforts, ensures precise tracking of optimal challenging trajectories, and improves both transient and steady-state performance characteristics. The closed-loop stability of the quadrotor system is validated using the Lyapunov theorem.</p>