电控旋翼低频面内谐波噪声主动控制试验

为降低旋翼低频面内谐波噪声，以电控旋翼(ECR)综合试验系统为平台，开发了相应的噪声测试与控制系统，并提出了电控旋翼噪声频域自适应主动控制方法。在此基础上，开展了悬停状态下的低频面内谐波噪声闭环主动控制试验。试验中，襟翼控制频率为10Hz以桨尖平面内传声器所测噪声作为闭环反馈，另两个位置处传声器所测噪声作为监测量，同时对桨毂位置处的振动水平进行监测。施加主动控制后，控制系统历时约5s达到稳态，收敛速度较快且收敛过程无明显超调；最大可降低桨盘平面传声器位置处的低频面内谐波噪声为9.4dB，桨毂位置处旋翼通过频率振动水平则略有增大。试验结果表明该噪声测试与控制系统可有效实现电控旋翼低频面内谐波噪声控制，同时也验证了频域自适应算法用于减小低频面内谐波噪声的可行性及有效性。 

Experiment on active control of low frequency in-plane harmonic noise for electrically controlled rotor

In order to reduce rotor low frequency in-plane harmonic noise, a noise measuring system and a control system were developed accordingly and a frequency-domain active control method was proposed based on the integrated test rig of electrically controlled rotor(ECR). Then the close-loop active control experiments of low frequency in-plane harmonic noise using ECR were performed in hover state. During the experiment, the control frequency of the flap was 10Hz, the noise signal captured by the microphone in plane was used as feed-back signal and the noise signals captured by the other two microphone were used for monitoring. At the same time the vibration lever of the hub was monitored. After control, the control system took 5s to enter into a steady state, the convergence speed was fast and there was no obvious overshoot during convergence. 9.4dB noise reduction was possible at the location of the microphone in plane, and the vibration level of the hub increased a little. Experiment results showed that the developed control system was effective and reliable in reducing low frequency in-plane harmonic noise through the tests, and the feasibility and effectiveness of the frequency-domain active control algorithm in reducing low frequency in-plane harmonic noise were validated.