Robust Fault Diagnosis strategies for Spacecraft Application to LISA Pathfinder experiment

This paper presents research activities conjointly led by EADS Astrium Satellites and the European Space Agency on innovative and robust health monitoring system for the next generation of spacecraft. Two robust FDI schemes are presented to detect and isolate faults affecting the micro-Newton colloidal thrust system of the LISA Pathfinder spacecraft. The first FDI strategy is based on a bank of eight H∞/H− residual generators designed according to the Generalized Observer Strategy whereas the second strategy consists of Kalman-based projected observers. The efficiency of the proposed FDI techniques is assessed through non linear simulations performed under realistic conditions (physical parameter uncertainties, disturbances, measurement noises, measurement delays, thruster jet misalignment,…). The results are quite encouraging, illustrate the effectiveness of the proposed techniques and suggest that the solutions could be practical viable candidates.