Simultaneous Blade–Vortex Interaction Noise and Vibration Reduction in Rotorcraft Using Microflaps, Including the Effect of Actuator Saturation

Abstract

The effectiveness of a sliding microflap to simultaneously reduce rotorcraft vibrations and noise was examined at a descending flight condition of advance ratio 0.15 with significant blade–vortex interactions (BVI). two configurations, namely dual and a five-microflap configuration, were considered. Closed-loop control studies were conducted on a hingeless rotor configuration resembling MBB BO-105, using the adaptive higher harmonic control algorithm. The performance of the microflap was also compared to a conventional trailing-edge plain flap. The results demonstrate the effectiveness and control authority of the microflap for simultaneous BVI noise and vibration reduction in rotorcraft. Finally, a new saturation control algorithm is developed for limiting the microflap or flap deflections such that the best utilization of on-blade controllers implemented through multiple control surfaces is achieved. The performance of the new algorithm is compared to the existing ones on the dual and five-microflap configurations.