In this paper, a virtual actuator-based active fault-tolerant control strategy is presented. After a short introduction to Takagi-Sugeno
fuzzy systems, it is shown how to design a fault-tolerant control strategy for this particular class of non-linear systems. The key contribution
of the proposed approach is an integrated fault-tolerant control design procedure of fault identification and control within an integrated
fault-tolerant control scheme. In particular, fault identification is implemented with the suitable state observer. While, the controller is
implemented in such a way that the state of the (possibly faulty) system tracks the state of a fault-free reference model. Consequently,
the fault-tolerant control stabilizes the possibly faulty system taking into account the input constraints and some control objective function.
Finally, the last part of the paper shows a comprehensive case study regarding the application of the proposed strategy to fault-tolerant
control of a twin-rotor system.