Integrated vs Decoupled Fault Detection Filter & Flight Control Law Designs for a Re-Entry Vehicle

An integrated design of a robust fault detection filter and control system for a re-entry vehicle is presented. The integrated architecture is based on the four-block Youla parametrization which allows to better and directly trade-off filter and control design objectives in the face of disturbances and uncertainties. H∞-optimization techniques are used to design the integrated controller/filter system for a re-entry vehicle with actuator faults in the transonic flight regime where the aerodynamics are highly uncertain. Finally the resulting integrated controller/filter properties are compared with a decoupled fault detection filter and flight control designs. The integrated design obtained successfully identifies the desired faults for the nominal and uncertain cases. Moreover, the integrated design minimizes the faults effects on the system response better than the decoupled design. Lastly, it is clearly shown that the actuator activity is directly related with the faults introduced.