Dynamic Propeller Noise Reduction Using Synchrophasing Control Based on an Extremum-Seeking Algorithm

The noise radiated from distributed propellers could be a main problem for novel electrified aircraft concepts. This paper explores an aircraft propeller phase control technique for noise reduction over sensitive areas on the ground such as infrastructure near airports. The synchrophasing method proposed in this paper is based on an Extremum-Seeking Controller with improved gradient estimation through an extended Kalman filter. This method is evaluated via simulations for various configurations of the propulsion system, taking into account different number of propellers, number of blades, and other parameters. It was observed that the algorithm achieves better noise reduction when more degrees of freedom (number of propellers) are available for control. In some cases, an average reduction of almost $15$~dB has been reached.