Adaptive output feedback control of a nonlinear aeroelastic structure

Based on a backstepping design technique, a new adaptive controller For the control of an aeroelastic system using output feedback is derived. The cho sen dynamic model describes the nonlinear plunge and pitch motion of a wing . The parameters of the system are assumed to be completely unknown, and on ly the plunge displacement and the pitch angle measurements are used for th e synthesis of the controller. A canonical state variable representation of the system is derived, and filters are designed to obtain the estimates of the derivatives of the pitch angle and the plunge displacement. Then adapt ive control laws for the trajectory control of the pitch angle and the plun ge displacement are derived. In the closed-loop system the state vector asy mptotically converges to the origin. Simulation results are presented, whic h show that regulation of the state vector to the equilibrium state and tra jectory following are accomplished using a single control surface in spite of the uncertainty in the aerodynamic and structural parameters.