Robust Stabilization of a Twin Rotor System Using Event-Driven Observer-Based Fault-Tolerant Sliding Mode Control Under Actuator Failure

Twin rotorcrafts, such as helicopters with their capability for vertical take-off, hovering, and maneuverability, pose intricacies in missions like search and rescue, medical transport, and operations in challenging environments. Twin rotor MIMO systems (TRMS), which emulate helicopter dynamics, face significant challenges due to nonlinearities, rotor coupling, external disturbances, and limitations in sensors and actuators. These factors hinder controller design, particularly in ensuring stability and precise positioning. Furthermore, undetected faults, the need for real-time sensor data processing, and acoustic interference exacerbate control difficulties, necessitating robust solutions for effective TRMS operation. To address these challenges, this study proposes a fault-tolerant sliding mode controller (FT-SMC) as a robust control solution for TRMS. The controller is designed to manage parametric uncertainties, exogenous disturbances, and faults, ensuring reliable performance. To address the dearth of actual parameter values, a fault-tolerant sliding-mode observer (FT-SMO) was also set up to figure out uncertainties and sensor/actuator imperfections. Implementation of FT-SMC demonstrated significant improvements in the issues related to parametric uncertainties, external disturbances, and faults. A comprehensive Lyapunov stability analysis confirmed the stability and convergence of the proposed control strategy, ensuring reliable TRMS operation under challenging conditions.