Lidar-Based Gust Load Alleviation - Results Obtained on the Clean Sky 2 Load Alleviation Benchmark

Kurzfassung

This paper presents a design methodology for lidar-based load alleviation functions and the results obtained for an industrial modern jet aircraft configuration. At the heart of the methodology is a multi-channel structured H-inifinity preview-control synthesis in discrete time. The load alleviation function works in a pure feedforward manner, which ensures that the handling qualities are not modified. The design methodology contains a couple of iterative loops permitting the refinement of the design and the fine-tuning the tradeoff between all control objectives. At the end, the objective function contained forty objectives, resulting from combining ten performance channels with four different local models (different flight conditions and mass cases). The complete lidar-based load alleviation system was evaluated using a multi-rate hybrid simulation environment with the load alleviation controller running at 80 Hz and including the lidar sensor simulation and an online gust/wind estimation algorithm. The obtained results are very promising: the objective of 10% wing bending moment reduction was achieved along the entire wing except at the wing tip while keeping the loads on all other stations within the design loads (often improving them as well). The controller was optimized to achieve this goal with the smallest control deflections and deflection rates possible.