Real-Time Hybrid Testing of Strut-Braced Wing Under Aerodynamic Loading Using an Electrodynamic Actuator

Real-Time Hybrid Simulation (RTHS) is an experimental framework that allows the testing of components or substructures under realistic, dynamic boundary conditions, by imposing the reactions calculated from a model of the rest of the assembly through one or more actuators. In the context of rapid prototyping of mechanical components, RTHS could be used to explore the design space of a device while at the same time physically validating its interaction with other components of the final assembly from the early stages of the design-to-production cycle. In this work, RTHS was applied for the first time to the investigation of aerodynamic gust loading alleviation devices in a highly flexible strut-braced wing. The model wing was taken as the physical substructure and tested in a low-speed wind tunnel equipped with gust generators. The load alleviation device was simulated through a real-time feedforward-feedback controller, and its response imposed via an electro-mechanical linear actuator, in contrast with the hydraulic actuators more commonly used in standard RTHS. The controller-actuator subsystem was studied in detail to assess and minimise errors at the physical interface with the wing. The behaviour of the electromechanical subsystem showed a strong dependence on the characteristics of the numerical substructure and the frequency of excitation, and resulted in a significant discrepancy between the simulated and real displacements at the interface between the actuator and the wing. A narrow-band feedforward displacement control scheme based on a model of this subsystem alone was therefore developed and shown to significantly reduce synchronisation errors at the interface.