Nonlinear Tracking Control of an Elastically Supported Flapping Thin Airfoil

A control law for a self-excited system using state feedback linearization and coordinate transformation is developed. The system consists of an elastically supported hinged thin airfoil, which is subjected to a uniform steady airflow A nonlinear aerodynamic model is used to account for the fluid-solid interaction mnechanism. A chaotic behavior of the open-loop system at certain control parameters is observed experimentally and checked numerically. It is shown that the controllability of the system is guaranteed using a torque source at the leading edge of the airfoil. Furthennore, good tracl4rg of time-varying desired angle of attack is achieved using the developed controller. Finally, a SIMULINK%N model is developed to facilitate time-domain analysis, control design and future real-time control implementations.