A kind of reconfigurable rotorcraft unmanned aerial vehicle (RUAV) is presented. Its actuators consist of the major rotor inside the duct, four auxiliary rotors surrounding the major rotor and two ailerons at the end of the duct, and the auxiliary rotors have some similar functions as that of the major rotor and ailerons in order to achieve reconfigurable control of the system. The Newton-Euler method is adopted to build 6-DOF (degree of freedom) dynamic model of the RUAV. Based on the model, the controllability of the system in different fault cases is analyzed near the hover state. Then, the fault-tolerance performance of the system with different fault degrees is analyzed based on the notation of control reconfigurability, and the analysis helps to build the multi-model reconfigurable controller. At last, the dynamic response characteristics and reconfigurable control performance of the system are analyzed by simulation, respectively. The result shows that the RUAV has good dynamic response characteristics and robustness to some kinds of failures. The proposed model and related analysis provide some theoretical basis for the fault-tolerant design and control of the RUAV.
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