Vibration Reduction and Performance Enhancement of Helicopter Rotors Using an Active/Passive Approach

Active/passive optimization of helicopter rotor blades for vibration reduction and performance enhancement at high advance ratios is studied. Dynamic stall is the dominant source of high vibration levels for this flight regime. In the active/passive approach, active control of vibration and required rotor power is implemented with partial span trailingedge flaps operating according to a closed-loop control algorithm. The blade/flap combination is optimized simultaneously using the Efficient Global Optimization (EGO) algorithm. However, due to strong trade-offs between the objective functions, there is no single best active/passive configuration for reduced vibration levels and power consumption. Therefore, a surrogate based multi-objective function optimization approach is employed to find the active/passive configurations corresponding to the best trade-offs between vibration and performance characteristics.