Optimal Multi-harmonic Control of Active Twist Rotor for Aerodynamic Performance Enhancement

Active Twist Rotor enhances aerodynamic performance by altering the distribution of aerodynamic loads. High-precision CFD simulation of the rotor is computationally expensive and not suitable for optimization. In this study, a numerical model based on moderate deflection beam for predicting the isolated rotor power and aerodynamic loads in level flights is deployed and validated. The optimal multi-harmonic control waves for power reduction of flight conditions with different advance ratios are obtained using an optimization framework based on the genetic algorithm. The limitation of variables and control wave amplitude are considered. The findings indicate that the active twist rotor redistributes the lift on the rotor disk, increasing the lift-drag ratio near the 90° azimuth, thereby enhancing the rotor aerodynamic performance. As the advance ratio increases, the effectiveness of active twist control becomes more significant. Optimal active control reduces rotor power by 3.995 and 7.41% at advance ratios of 0.25 and 0.35, respectively.