Adaptive Terminal Sliding Mode Disturbance Observer Augmented Backstepping Integral Sliding Mode Control for Twin Rotor MIMO System

This paper provides a comprehensive exploration of disturbance/uncertainty estimation and attenuation in the Twin Rotor MIMO System (TRMS). Addressing cross-coupling effects, treated as uncertainties, along with exogenous disturbances, an adaptive terminal sliding mode disturbance observer-augmented backstepping integral sliding mode (ATSMDO-BISMC) controller is developed specifically for the complex and interrelated nonlinear configuration of the Twin Rotor MIMO System. The actuator dynamics are managed through Backstepping Control (BSC). The proposed controller and sliding mode disturbance observer's reaching conditions and stability are ensured through Lyapunov stability arguments. Simulation results demonstrate that the presented ATSMDO-BISMC effectively mitigates chattering effects and remains robust against external disturbances and cross-coupling's adverse effects. Additionally, a comparison of disturbance estimation with the Non-linear Disturbance Observer (NDO) is presented, focusing on the Root Mean Square value.