Modeling analysis and adaptive observer based fault diagnosis for Near Space Vehicle

This paper first develops the six degrees of freedom (DOF) nonlinear dynamic model of near space vehicle (NSV) in re-entry trajectory and analyzes its model characteristics and aerodynamic parameters, then the linear model is obtained using trim technique. The problem of fault estimation based on adaptive fault diagnosis observer is studied, which can achieve accurate estimation of fault and give an effective strategy for fault diagnosis of NSV. A feasible adaptive algorithm is explored and it is shown that observer parameters can be obtained by solving linear matrix inequality (LMI). Finally, different kinds of faults are considered in the actuator of NSV, and simulation results on NSV re-entry attitude dynamics are presented to illustrate the efficiency of the proposed method.