Observer based fault diagnosis of aircraft active landing gear system

Abstract

A landing gear system is vital in aircraft landing and taxiing. In this paper, an observer-based fault detection and fault reconstruction means is adopted for the aircraft’s active landing gear. Firstly, a six-degree-of-freedom (6-DOF) landing gear model is established by analysing the dynamics of the fuselage and landing gears. By analysing the fault mechanism of actuators and sensors, the fault model of actuators and sensors is established. Secondly, according to the above model, the unknown input observer (UIO) is designed to obtain the residuals, and the fault detection of actuators and sensors is realized according to the comparison between residuals and thresholds. On this basis, an adaptive unknown input observer (AUIO) is designed, through which the state values and fault values can be reconstructed. Finally, simulation experiments are tested under different fault types to prove the validity of the fault detection and reconstruction based on UIO and AUIO.