L_∞-Optimal feedforward gust load alleviation design for a large blended wing body airliner

Abstract

The potential advantages of Blended Wing Body (BWB) aircraft in terms of fuel e©ciency are opposed by technical challenges such as the alleviation of gust loads. Due to the low wing, loading gusts, generally, have a more severe impact on BWB aircraft than on conventional aircraft. This paper presents the design and optimization of a Gust Load Alleviation System (GLAS) for a large BWB airliner. Numerical simulations are performed with an aeroelastic model of the aircraft including GLAS in order to compute time series of modal displacements for deriving equivalent static load cases which are used for the resizing of the aircraft structure.

Dynamic Load Alleviation in Wake Vortex Encounters

“…9,35,38 However, since a feedforward system cannot reject all gust excitations perfectly, due to control surface constraints, sensor limitations, actuator dynamics or model mismatch, 9 a feedback controller, K, is included to suppress possible residual structural excitations. Hence, for the feedback control loop strain measures at the wing roots suffice.…”

Applications of the unsteady vortex-lattice method in aircraft aeroelasticity and flight dynamics

“…This is particularly critical in the case of very flexible UAVs, which still face a major structural integrity risk in adverse weather conditions [199]. To address this, the response of such non-conventional aircraft concepts to these disturbances has been studied recently by different authors, including flying-wing configurations [8,147,200], blended-wing-body airliners [163], and flexible HALE platforms [134]. In fact, both the sizing of the structure and the design of Flight Control Systems (FCS) are intimately linked to the response of the aircraft to atmospheric disturbances.…”

Active gust load alleviation system for flexible aircraft: Mixed feedforward/feedback approach

“…The aircraft model used for loads analysis and design and validation of the GLAS is based on aerodynamic and structural data of the BWB configuration NACRE developed in the European project NACRE and modified in ACFA2020 [33]. The aircraft model was not originally developed for dynamic analysis.…”

“…Necessary modifications were made so that the dynamic analysis could be performed. Components such as cockpit, elevator and wing's leading edge, engine pylons and structures were added as concentrated point masses [33]. Non-structural masses of systems and equipment as well as operational masses were integrated into the structural model.…”

“…Current Gust Load Alleviation systems work primarily on the error feedback principle [5,30,33]. The first peak in the wing root moments (induces maximum load in the construction) determines the required sizing of the wing root joint reinforcement.…”