Loss-of-Efficiency Fault Detection and Diagnosis for Launch Vehicle Thrust Vector Control Systems

Abstract

Thrust Vector Control (TVC) systems are critical components of space launch vehicles, as actuator faults can significantly compromise mission success. With ElectroMechanical Actuators (EMAs) increasingly adopted in launcher TVC systems due to their cost-effectiveness and reduced integration complexity, this paper introduces a model-based Fault Detection and Diagnosis (FDD) strategy specifically targeting Loss-of-Efficiency (LoE) faults in EMA-driven TVC systems. The proposed approach leverages the nullspace method, a linear model-based FDD technique, while handling the vehicle-induced loads and uncertainties. The system dynamics and synthesis model under LoE fault conditions are thoroughly explained. The FDD system is validated through Monte-Carlo simulation campaigns using both a perturbed linear TVC model and a high-fidelity nonlinear model.