基于FPSC-FxLMS算法的车内发动机噪声主动控制

Active Control of Engine Noise in Vehicle Based on FPSC-FxLMS Algorithm

噪声主动控制的关键是对被控噪声幅值和相位的准确估计,PSC-FxLMS算法在Command信号中加入噪声信号的相位,可发出比Command-FxLMS算法更小的次级声,但会受到次级通路估计准确性和傅里叶变换相位提取速度的制约。本文以某SUV车内发动机噪声为研究对象,提出滤波PSC-FxLMS(FPSC-FxLMS)算法,将从车内4个座椅头枕处采集的噪声信号作为初级噪声,通过仿真比较FPSC-FxLMS算法和Command-FxLMS算法对2、3阶发动机噪声同时控制的效果;接着,基于DSP硬件平台对另一辆SUV进行实车试验,再次对比两种算法的效果。结果显示,在对驾驶员和驾驶员后排乘员的左右耳处的发动机噪声进行控制时,在800 r/min怠速工况下,所提出算法4阶噪声的次级声幅值比Command-FxLMS算法降低25%以上;在1 900 r/min空转工况下,2阶噪声的次级声幅值降低50%以上。说明FPSC-FxLMS算法能快速准确地提取不同转速下发动机噪声的相位信息,使扬声器发出比Command-FxLMS算法更小的次级声。

The key to active noise control is to accurately estimate the amplitude and phase of the controlled noise. PSC-FxLMS algorithm adds the phase information of noise signal onto the Command signal and thus can emit a smaller anti-noise than Command-FxLMS algorithm does,but it is restricted by the estimation accuracy of secondary path and the phase extraction speed of Fourier transform. Taking the engine noise in a SUV as the object of research,the filter PSC-FxLMS(FPSC-FxLMS)algorithm is proposed in this paper,and with the noise information collected at the 4 seat headrest positions in the SUV as the primary noise,a simulation is conducted to compare the effects of the FPSC-FxLMS algorithm proposed and Command-FxLMS algorithm in the concurrent control of2nd and 3rd order engine noise. Then a real vehicle test is also carried out on another SUV based on DSP hardware platform to compare again the effects of two algorithms. The results show that in controlling the engine noise at the left and right ear positions of the driver and the occupant behind driver,the anti-noise amplitude of 4th order noise with the algorithm proposed is lower than that with Command-FxLMS algorithm by over 25% in 800 r/min idle condition,while the anti-noise amplitude of 2nd order noise with the algorithm proposed is lower than that with CommandFxLMS algorithm by over 50% in a 1 900 r/min no-load condition. So it is demonstrated that the FPSC-FxLMS algorithm proposed can rapidly and accurately extract the phase information of engine noise at different rotational speeds,enabling the speaker emit a smaller anti-noise than the Command-FxLMS algorithm does.