Adaptive Control of a Nonlinear Prototypical Wing Section with Reduced Order Observer

Abstract

This paper treats the question of control of an aeroelastic system with unknown parameters using output feedback. The equations of motion of the chosen aeroelastic system describe the plunge and pitch motion of a wing. A single trailing edge flap is used for the purpose of control, and plunge displacement and pitch angle are measured for feedback. Using a canonical representation of the aeroelastic system, reduced order filters are designed to obtain the unmeasured state variables. Then based on a backstepping design technique, adaptive control laws for the trajectory control of the pitch angle and the plunge displacement are derived. In the closed-loop system, the state vector is shown to converge asymptotically to zero. Simulation results are presented which show that regulation and trajectory following are accomplished in the closed-loop system in spite of large uncertainties in the structural and aerodynamic parameters of the model.