Design and Experimental Validation of Gust Load Alleviation Based on H2-Optimal Blending of Inputs and Outputs

Abstract

The next generation of commercial aircraft might feature high-aspect-ratio wing configurations to enhance efficiency and reduce emissions. However, these wings are more susceptible to increased gust and maneuver loads, which can result in higher overall airframe weight. Active control technologies have the potential to mitigate these issues or even achieve weight savings. Experimental studies are indispensable to further understand and refine these load alleviation techniques. This paper outlines the synthesis and the experimental verification of one gust load alleviation controller developed as part of the DLR oLAF project (optimal Load-Adaptive Aircraft). The oLAF demonstrator is a wind tunnel model with a flexible, swept wing equipped with multiple trailing-edge flaps and acceleration sensors, representative of a long-range transport aircraft configuration. The controller design employs H2-optimal blending of control inputs and measurement outputs, enabling the isolation of target mode(s) and individual mode control through a single-input-single-output controller. This approach prioritizes simplicity and facilitates effective scheduling of the single-input-single-output controller to cope with varying operating conditions. Wind tunnel tests show a maximum reduction of 61% in the incremental wing root bending moment when the demonstrator is subjected to continuous gusts.