A deployable missile control fin has some structural nonlinearities because of the worn
or loose hinges and the manufacturing tolerance. The structural nonlinearity cannot be
eliminated completely, and exerts significant effects on the static and dynamic characteristics
of the control fin. Thus, it is important to establish the accurate deployable missile control fin
model. In the present study, the nonlinear dynamic model of the deployable missile control fin
is established. The deployable missile control fin can be subdivided into two substructures
represented by linear dynamic models and a nonlinear hinge with structural nonlinearities.
From dynamic tests, the nonlinear hinge parameters are identified and the nonlinear hinge
model is established by using system identification method such as Force-State Mapping
Technique. The substructure modes are improved using the Frequency Response Method. The
substructure models and the nonlinear hinge model are coupled to establish the nonlinear
dynamic model of the fin using the expanded substructure synthesis. Finally, the established
nonlinear dynamic model of the deployable missile control fin is verified by modal and dynamic tests.