Flight Test of Explicit and Implicit Rotor-State Feedback Fly-By-Wire Control Laws

Rotor-state feedback (RSF) technology uses tip-path-plane measurements of the rotor to improve the tracking response of the aircraft in winds and turbulence, and provide improved stability margins. Three fly-by-wire control systems were designed and flight tested on the RASCAL JUH-60A aircraft to determine the benefits of RSF. A Baseline control system that used only conventional fuselage feedback but was optimized for Level 1 performance was compared to two control systems that used both rotor-state and fuselage feedback (and were also optimized for Level 1). The Implicit RSF control system implemented fuselage feedback and estimated (implicit) rotor-state feedback. The Explicit RSF control system implemented fuselage feedback and measured (explicit) rotor-state feedback via a laser measurement system installed on the aircraft. The sensor characteristics, frequency response validation, handling qualities ratings, and MTE tracking performance for hover/low-speed are discussed in this paper.