Observer-based dynamic surface control for high-performance aircraft subjected to unsteady aerodynamics and actuator saturation

Abstract

In this article, a novel observer-based dynamic surface control scheme is designed for high-performance aircraft attitude tracking in the presence of model uncertainties, unsteady aerodynamics and actuator saturation. Attitude dynamics with unsteady effects is first established to improve model accuracy, of which properties are investigated via open-loop analysis. Based on the compound observer, precise estimation of model uncertainties and unsteady states are achieved simultaneously. The magnitude and rate saturation are approximated by sigmoid function and addressed separately in dynamic surface control synthesis, where two auxiliary subsystems are employed as well to describe the constrained actuator dynamics and solve the non-affine issue, respectively. By using adaptive laws and first-order filters, estimate and approximate errors are robust compensated and the “explosion of terms” problem is also eliminated. Moreover, tracking error can be adjusted to arbitrarily small by choosing proper design parameters. The robustness and effectiveness of the proposed control scheme are verified by numerical simulations.