Anti-windup compensation of rate saturation in an experimental aircraft

This paper describes the design, flight testing and accompanying analysis of two anti-windup (AW) compensators for an experimental aircraft - the German Aerospace Center´s (DLR) advanced technologies testing aircraft (ATTAS). The AW compensators were designed to reduce the deleterious effects of rate-saturation of the aircraft´s actuators on handling qualities. The AW compensators were flight-tested and assessed using the resulting pilot comments, in the form of handling qualities ratings (HQR´s) and pilot-involved-oscillation ratings (PIOR´s), and flight test data. These media demonstrate that the AW compensators improved the predictability and handling of the aircraft. The results also provide an initial understanding of the relationship between the theory and design choices for AW controllers and the response of the piloted aircraft during periods of rate saturation.