Control-centric Modelling and Nonlinear Control of the Blade Sailing Phenomenon

A reduced control-centric model of a particular behaviour associated with maritime helicopter rotor systems, known as Blade Sailing Phenomenon (BSP), is developed. BSP is a transient aeroelastic phenomenon described by the large undesired flapping motion of the helicopter rotor blades during low rotor speeds under high wind and elevated sea conditions. The developed model utilizes the Unified Airloads Model to capture the aerodynamic loads and the Intrinsic Nonlinear Beam Model to capture the structural behaviour of the blade. Integrally Actuated Twist (IAT) is used as the actuation strategy and a nonlinear feedback controller based on the Lyapunov stability theorem for autonomous dynamical systems is developed to counter the BSP.;To evaluate the performance of the designed controller, the reduced BSP model is then discretized in the space domain using the Galerkin Spectral Discretization Method. The results prove the promising potential of the designed controller in countering the BSP in the reduced model. A further assessment of the controller is carried out by testing its performance in a comprehensive BSP model validated against experimental data. The results prove the capability of the controller to counter the BSP in a more accurate blade model and a more realistic simulation of a maritime environment.