Smooth robust adaptive sliding mode control of 2-DOF helicopter system

Abstract

This paper investigates the development of a tracking control system for a 2-degree-of-freedom (2-DOF) helicopter under parameter uncertainties and time-varying external disturbances. A nonlinear mathematical model of the 2-DOF helicopter system is first established. Subsequently, a conventional sliding mode controller (SMC) is designed, and its limitations in handling parameter uncertainties and external disturbances are analyzed. To address these limitations, the paper proposes a smooth, robust adaptive sliding mode controller for the 2-DOF helicopter system, ensuring convergence of closed-loop signals. The robust stability of the proposed controller is rigorously proven using Lyapunov stability theory. The system is simulated in MATLAB/Simulink with both the conventional and proposed controllers. Comparative simulation results demonstrate that the proposed adaptive robust controller outperforms the conventional sliding mode controller and fully meets the control requirements.