Nonlinear aeroelastic analyses of a missile control fin are performed considering backlash and dynamic stiffness of
actuator. Doublet-Hybrid method is used for the calculation of subsonic unsteady aerodynamic forces, and aerodynamic forces are
approximated by the minimum-state approximation. Backlash is modeled as an asymmetric bilinear spring and is linearized by using
the describing function method. The linear and nonlinear flutter analyses show that the flutter characteristics are significantly
dependent on the backlash and dynamic stiffness. From the nonlinear flutter analysis, various types of limit cycle oscillations are
observed in a range of air speeds below or above the linear divergent flutter boundary. The nonlinear flutter characteristics and the
nonlinear aeroelastic responses are also investigated in the time domain.