LQ-based design of the inner loop lateral control for a large flexible BWB-type aircraft

Abstract

Two LQ-based MIMO controllers (LQG and LQI architectures) for lateral inner loop flight control for a large Blended Wing Body (BWB) passenger aircraft pre-design model are presented. The main control goals are Dutch roll mode damping, coordinated turn, and roll response shaping. An open loop analysis shows that traditional SISO design faces fundamental limitations, so both controller variants are designed as MIMO controllers. Their performance is tuned and evaluated, and their specific properties are discussed and compared. The controllers are validated on various fuel and payload mass cases and fulfill all demanded goals. Ongoing and future research seeks to reduce structural loads and increase passenger comfort using robust control design methods.

Actuator and Sensor Positioning Optimization in Control Design for a Large BWB Passenger Aircraft

“…Control designs on the same BWB aircraft configuration that aim also at loads alleviation and flight control have been carried out in [21,22]. In [23], an LPV control design is performed and convex control design approaches are in the process of submission.…”

Robust lateral blended-wing-body aircraft feedback control design using a parameterized LFR model and DGK-iteration

“…Previous, closely related studies started on a larger BWB passenger aircraft predesign model: for LQ-based lateral control designs see [13], the application of a genetic algorithm for parameter optimization of a multiobjective H ∞ DK-iteration design has been treated in [14]. Using a Youla parameterization of the feedback control loop, a convex controller synthesis for lateral BWB control has been performed in [11] with a subsequent scheduled feedforward control design in [15].…”

Robust convex lateral feedback control synthesis for a BWB aircraft

“…These pose fundamental limitations for SISO control designs that attempt to shape side slip or yaw rate dynamics because they are far inside the required controller bandwidth. However, no slow RHP MIMO zeros appear in the MIMO plant, so MIMO designs yield satisfactory rigid-body response performance as shown in Schirrer et al [2010b]. Moreover a number of low-damped poles affect the disturbance (lateral wind) -lateral acceleration path strongly, which is relevant for passenger comfort and possibly fatigue (see Fig.…”

“…These models have been used in Westermayer et al [2010], Schirrer et al [2010b] and Schirrer et al [2010c] already. This study only considers the lateral dynamics as well as the flexible structure modes and aerodynamic lag states to design and validate lateral control laws.…”

“…Previous, closely related studies include a general integrated methodology for multi-objective robust control design (Schirrer et al [2010a]), LQ-based lateral control designs of the considered BWB aircraft (Schirrer et al [2010b]), followed by the application of a genetic algorithm for parameter optimization of a multiobjective H ∞ DKiteration design (Schirrer et al [2010c]). The feedback controller designed in this paper is incorporated in subsequent feedforward control design in Schirrer et al [2010d].…”