We consider flight control with control effector fault detection and reconfiguration of a tailless aircraft. We extend an earlier continuous time multiple and simultaneous actuator fault detection observer. This observer was designed by minimizing the condition number of the observer modal matrix over the eigenvector free parameters. Our contributions include (1) extending the fault detection observer to the unified delta operator model that is valid for both continuous time and sampled data operation, (2) proposing a new less conservative bound on the observer residuals that is an explicit function of the observer eigenvalues and eigenvectors, and (3) optimizing over both eigenvalues and eigenvector parameters. Then, we propose a reconfigurable control scheme by combining the new fault detection observer with our earlier eigenstructure assignment flight controller. We consider symmetric lock in place failures of either the elevons or the all moving tips for the Innovative Control Effectors tailless aircraft. We present simulation results using the linearized lateral dynamics of the tailless aircraft. Our results show that our new fault detection observer has both smaller gains and condition number than an observer designed using the earlier method. Furthermore, we show that an all moving tip failure causes the aircraft to become unstable whereas our eigenstructure assignment reconfigured flight control system yields responses that are similar to the unfailed responses.
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