A Model-Based Pre-feedback Decoupling Control Framework for Ground Flutter Simulation Test

Ground flutter simulation test (GFST), which simulates the unsteady aerodynamic force on the structure through the excitation forces generated by shakers, is a semi-physical simulation test method on the ground to verify the aeroelastic stability boundary of the real structure without the wind tunnel. However, when the structure is excited by multiple electrodynamic shakers, the dynamic characteristics of the shakers and the coupling effects between the structure and shakers make the actual exciting forces acting on the structure are usually not equal to the required values that is supposed to be, such as the simulated aerodynamic forces. To deal with this issue, a model-based decoupling control framework for aerodynamic loading system is proposed to trace the simulated aerodynamic force for each shaker, which is divided into the following two parts: (1) the modeling of aerodynamic loading system; (2) the pre-feedback compensation decoupling controller. The state space model of aerodynamic loading system is established with substructure synthesis method, which couples the FEM model of structure to lumped parameters model of shakers. In order to enhance the robustness and control accuracy of the controller, genetic algorithm is used to optimize the model parameters of the aerodynamic loading system model before the decoupling controller is designed. Subsequently, both the excitation force waveform control experiments and the GFSTs are conducted on the GFST system composed of a fin model and four shakers to demonstrate the proposed method. Results show that the aerodynamic loading system can trace the simulated aerodynamics forces accurately within the target frequency range. The model-based pre-feedback compensation decoupling method can effectively eliminate the coupling effects among the shakers, and have the advantage of a simple decoupling network, a wide control frequency range and good robustness. Therefore, using the aerodynamic loading system with the proposed control method can effectively expand the application of ground aeroelastic simulation test.