Roll-rate-free reduction of limit cycle oscillations in delta wings

Abstract

The wing rock motion behaves unpredictably at different Angles of Attack and is highly responsive to external disturbances. This paper presents a robust adaptive control strategy that uses an observer-based method, incorporating Bernstein polynomials to estimate uncertainties, aiming to mitigate wing rock oscillations in slender delta wings. The Bernstein polynomials are first used to capture the combined uncertainties, which include unmodeled dynamics and external disturbances. Adaptation rules, based on stability analysis, are subsequently applied to adjust the Bernstein polynomial coefficients. A vital advantage of this design is that it removes the need for an exact plant model, detailed uncertainty data, or roll rate measurements, making it both practical and cost-effective for real-world use. Applying the Lyapunov stability theorem demonstrates that the system’s error signals remain uniformly ultimately bounded. Simulations demonstrate the effectiveness and adaptability of the suggested control strategy, with results compared to three advanced approximation techniques, underscoring the controller’s precision and efficiency.