Robust Control of Ground Resonance in Helicopters Including Structural Uncertainties

Ground Resonance (GR) in helicopters is a potentially instability defined in certain rotor speed ranges. It can limit the helicopter operational envelope and become the design of this type of vehicle a difficult task. A limited number of works in literature introduces formulations to compute the controller gain to suppress robustly this phenomenon. In this context, this works introduces a methodology to design a robust active control system to stabilize GR of helicopter in presence of structural uncertainties, where each GR boundary is described in terms of polytopic convex space. The proposed approach can suppress this instability in all rotor speed range by using only one control gain and based on linear matrix inequalities (LMIs). Using convex optimization a robust control gain is computed the all unstable rotor speed range is robustly stabilized. Numerical simulations are carried out to demonstrate the effectiveness of this methodology.