Active fault-tolerant flight control systems design using the linear matrix inequality method

This paper discusses the issues of robust control law design for fault-tolerant systems. Based on the assumption that the effects of faults can be expressed in linear-fractional-transformation (LFT) forms, a fault-tolerant control systems design problem is formulated and solved via a linear matrix inequality (LMI)-based synthesis approach. In order to recover the convexity of the design problem whilst considering the robust performance and robust stability against faults and uncertainties simultaneously, a constrained optimisation approach is used. The simulation results of a design example (a longitudinal motion flight control problem for an unmanned aircraft in the case of suffering battle damage on its wing ) show that robust stability and satisfactory performance have been achieved.