Aircraft Active Flutter Suppression: State of the Art and Technology Maturation Needs

H∞ Control Design for Active Flutter Suppression of Flexible-Wing Unmanned Aerial Vehicle Demonstrator

“…The interest in the application of AFS in aircraft is not new, and a thorough historical review is provided in [5]. The advances in AFS come from the desire to reduce aircraft weight, which leads to a reduced separation between rigid-body and flexible modes.…”

“…Another important experience, but with highly flexible UAVs and not directly focused on the AFS problem, was reported under the X-HALE project [14]. For more detail on the history of developments on AFS, the reader is referred to [5] and references therein. Even though considerable research effort has been devoted to the development of AFS, Livne ranks "control law design and implementation methods" as one of the five areas of importance for future research on AFS methods and adds that "it would [ : : : ] be an important contribution to the state of the art from the certification needs perspective to invest in the development and testing of such methods and architectures" [5].…”

Identification of Aeroelastic Models for the X-56A Longitudinal Dynamics Using Multisine Inputs and Output Error in the Frequency Domain

“…In Reference [18], a state-space implementation of the Waszak-Schmidt model is used to fit computed frequency response data of the X-56A operating under closed-loop control with input mixing. Additional case studies in the literature, including less recent works, are summarized in Reference [19].…”

Passive Gust Loads Alleviation in a Truss-Braced Wing Using an Inerter-Based Device

“…It was found that the controller was effective in suppressing flutter and stabilizing the aircraft during a gust encounter, however only a single gust gradient was considered during the controller design and the overall level of loads reduction is not quantified. Whilst active control schemes have been shown to suppress flutter and provide GLA, the certification of these systems and their integration into the design process does present a number of challenges [11], hence why other methods of loads alleviation been proposed such as folding wing tips [12], aeroelastic tailoring [13] and morphing structures [14]. In this paper an alternative approach to loads alleviation in a truss-braced wing is presented, which is to use a two-terminal vibration absorber embedded within the truss structure to reduce the gust response.…”