Finite-time fault-tolerant control of compound actuator faults for unmanned aerial vehicles

To solve the problem of finite-time trajectory tracking control for quadrotor UAVs with actuator gain loss and bias fault, a Finite-Time Adaptive Sliding Mode Fault-Tolerant Control (FT-ASMFTC) is developed by combining fast terminal sliding mode control with a certainty equivalence adaptive mechanism. Adaptive laws are constructed to achieve real-time estimation of composite fault parameters, while hyperbolic tangent function is employed to suppress sliding mode chattering. Using finite-time Lyapunov stability theory, the closed-loop system states are rigorously proven to converge to the equilibrium point within a prescribed-time after the occurrence of faults. The adaptive process boundaries are constrained through the sliding mode surface, and the dependence of traditional adaptive control on precise fault parameter identification is overcome, achieving collaborative optimization of robust stability and finite-time convergence for the system with composite faults. Quantitative comparative analyses among FT-ASMFTC, Robust Global Fast Terminal Sliding Mode Control (RGFTSMC) and Asymptotic Adaptive Control (AAC) are given and demonstrate that the faulty system controlled by FT-ASMFTC method exhibits fast transient response, high steadystate accuracy, strong robustness, and good fault-tolerant control capability.