Fault-Tolerant Control for Quadrotor Slung Load System With Predefined-Time Prescribed Performance Considering Cable Elasticity

Abstract

This article investigates the trajectory tracking and load swing suppression problem of a quadrotor slung load system under cable elasticity and actuator faults, with predefined-time prescribed performance guarantees. The cable is modeled as a spring–damper system to establish an enhanced dynamic model, and the overall system is decomposed into quadrotor position, load swing, and attitude subsystems. A hierarchical control framework is then developed to address the strong coupling among these subsystems, where the desired roll and pitch angles are jointly generated by the position and load swing loops, while the attitude loop ensures fast and accurate attitude tracking. Moreover, an adaptive fault-tolerant compensation mechanism is proposed to handle partial loss of effectiveness and bias-type actuator faults without requiring prior fault information. Lyapunov-based analysis proves that all closed-loop signals remain bounded and that all tracking errors enter and remain within the prescribed performance bounds within the predefined time. Comparative simulation results demonstrate that the proposed method achieves superior trajectory tracking and effective load swing suppression under actuator faults while ensuring the prescribed transient and steady-state performance.