Recasting Discrete 1-Cosine Gust Requirements as Frequency Domain Specifications for Load Alleviation Control Design

Abstract

In the context of active gust- and turbulence-load alleviation function design, control designers optimize the response of the closed-loop system to satisfy the criteria of the certification specifications (e.g. EASA CS-25.341). This includes time-domain criteria specifying the peak response to discrete gusts as well as frequency-domain continuous-turbulence criteria. Both types of criteria cannot be easily considered simultaneously with commonly-available control design software. A frequency-domain formulation of 1-cosine discrete gust criteria is proposed and demonstrated on a publicly-available gust load alleviation benchmark. One of the examples also demonstrates how to apply it in combination with continuous-turbulence specifications. In principle, it can also be combined with any other relevant frequency-domain specification, such as passenger comfort metrics.