Nonlinear Adaptive Control of an Aeroelastic Two-Dimensional Lifting Surface

Abstract

Adaptive control of a nonlinear two-dimensional wing-flap system operating in an incompressible flowfield is studied. An output feedback control law is implemented, and its performance toward suppressing flutter and limit cycle oscillations, as well as reducing the vibrational level in the subcritical flight speed range, is demonstrated. The control law proposed here is applicable to minimum phase systems, and conditions for stability of the zero dynamics are provided. The control objective is to design a control strategy to drive the pitch angle to a setpoint while adaptively compensating for uncertainties in all of the aeroelastic model parameters. It is shown that all of the states of the closed-loop system are asymptotically stable. Furthermore, an extension is presented to include flap actuator dynamics. Simulations have been presented to validate the efficacy of the proposed strategy. Pertinent conclusions have been outlined.