Experimental and numerical implementation of robust control for attenuation of buffet loads

This paper presents a robust control design for aerodynamically efficient slender wing. Incoming flow and buffet loads can easily excite the aeroelastic modes of the slender wings. A schematic design procedure based on infinity norm presents a way to attenuate the excited modes of the wing. It facilitates the robustness of the system even in the absence of high-fidelity structural and aerodynamic model. Multi Input Multi Output (MIMO), Linear Time Invariant (LTI) aeroelastic state-space system representing the multiple control surfaces and sensors of X-DIA wing forms the base of this research. Novel technique transfers a system from Multi Input Multi Output (MIMO) to Single Input Single Output (SISO) aeroelastic state-space system. Moreover, using the complexity of aeroelastic system to our advantage, mode selection reduces the order of the state space model, as a prerequisite to avoid higher order of a robust controller. The results of the reduced order model matched precisely with the full state model. Real Time Application Interface (RTAI) performs data acquisition to implement the robust control scheme in the wind tunnel tests. The test campaign validates the numerical implementation of robust control law. The developed robust control scheme added damping and attenuated the first bending mode significantly. Frequency response is presented to illustrate the results for both numerical and experimental results.