Aerostructural Control with Reduced Sampling Rates Using State-consistent Reduced Order Models

Active aerostructural control is a promising technology that could allow for safe operation of lightweight, flexible aircraft at high flight speeds. However, there still exist several obstacles before the methods can be used reliably. One such issue is that realistic control architectures may impose reduced sampling rates making traditional high-rate control strategies insufficient. Designing aerostructural controllers at low sampling rates is challenging due to aliasing of fast aerodynamic states, loss of stability, and inconsistencies in ROMs across flight conditions. This study presents a sampled-data linear quadratic gaussian (LQG) framework which builds upon data-driven, state-consistent ROMs. An exact discrete-to-discrete down sampling method is developed to construct low-rate models that preserve intersample dynamics and state-consistency. The method also implements an aggregated linear quadratic cost and aggregated process noise covariance to ensure proper LQG synthesis at the reduced sampling rates. The proposed methods result in closed-loop stability for sampling rates as low as 150-300 Hz with minimal losses in control performance compared to high-rate systems (>3 kHz). The efficacy of the approach is demonstrated through closed-loop system poles and time-domain responses. Additionally, the state-consistency of the ROMs and controllers is maintained, allowing for smooth interpolation across the flight envelope. The framework enables reliable aeroservoelastic control at reduced sampling rates while retaining interpolation capability, offering a practical path for flexible aircraft control.