Structural Blending for Active Flutter Suppression

Kurzfassung

This paper presents structural blending, a control design methodology for active flutter suppression that derives static sensor and actuator blending matrices from the wind-off finite element mode shapes and the generalized aerodynamic forces. The methodology is validated on a rectangular wing model exhibiting bending-torsion flutter, instrumented with eight distributed accelerometers and eight control surfaces. The output mode shape matrix PHIzf and the instantaneous generalized aerodynamic force matrix Qfx underlying the blending computation are real-valued, velocity-independent, and physically interpretable: each blending weight corresponds to a mode shape amplitude at a sensor station or an aerodynamic force contribution at an actuator station. Their condition numbers kappa(PHIzf) and kappa(Qfx) serve as scalar quality metrics bounding noise amplification and effort amplification, respectively. Pseudoinverse-based output and input blending compresses the eight-input, eight-output plant onto a two-channel virtual interface targeting the first bending and first torsion modes; a geometric mode isolation variant enforces exactly zero coupling to the residual structural modes. A low-order structured H-Infinity controller is synthesized on the reduced virtual interface with prescribed gain and phase margins across a multi-model velocity envelope. On this model, the structural blending controller attains greater disturbance attenuation at the flutter frequency with reduced peak actuator effort relative to an H2-optimal blending baseline. The factored controller structure enables sensor fault tolerance: algebraic recomputation of the output blending matrix from the reduced mode shape matrix preserves flutter suppression under arbitrary sensor failure patterns, without re-synthesis of the dynamic controller. This paper is accompanied by MATLAB code for reproducibility.