Propeller Aircraft Noise Reduction Simulation And Experimental Research Based On Synchrophasing Control

When using propeller synchrophasing noise reduction,the propeller noise model need be identified by the measured data under certain flight conditions firstly,and then the optimal synchrophase angle is calculated based on the noise model,finally the optimal synchrophase angle will be used for propeller.In this paper a synchrophasing ground test platform was built to study the characteristics of noise reduction,based on the test platform,the performance of master-slave control scheme and all-slave control scheme are studied by simulation.The cascade PID controller of speed control and phase angle control is designed on the basis of the all-slave control scheme,in order to achieve reliable control performance,the problem of phase discontinuity in PID controller is dealt with specially.In the process of noise model identification,due to the influence of flight speed,height and air flow changes,the measured data often fluctuates greatly,which affects the accuracy of the identification model and the optimal synchrophase angle.In this paper,a minimum fluctuation noise data selection method based on wavelet filtering and three parameter sine fitting method is proposed to improve the accuracy of noise model identification,the noise model identificated from the minimum fluctuation data can effectively reduce the impact of data fluctuations and improve the accuracy of identification model,that is proved by the experimental results.After identifying the model of propeller noise,the propeller synchrophasing angle optimization is studied in this paper.Based on the SQP algorithm and genetic algorithm,an optimization algorithm is proposed which shows excellent performance in the optimization test.Finally,the experimental study on the global noise reduction in the cabin is carried out.In order to achieve the global noise reduction,the noise model of various positions in the cabin is measured,and their weighted values are used as global noise model.After that,by selecting an appropriate synchronization angle the minimum global noise of 88.4dB and the maximum noise reduction of 18.4dB are achieved.