封闭空间主动噪声控制试验平台

发布时间：2018-11-15 10:51

【摘要】：近年来，消费者愈加追求安静的驾驶乘坐环境。而在汽车轻量化的设计趋势下，车内低频噪声很难通过被动控制的方法取得很好的降噪效果。而主动噪声控制技术，由于不需要添加大质量的吸声材料，可以在汽车经济性和舒适性中找到平衡点。另外，随着汽车技术不断更新，小排量的技术路线、断缸技术的应用以及新型能源车辆的开发，都给汽车NVH性能带来新的挑战，而主动噪声控制也能适应这些发展需求，支撑汽车新技术的发展。因此，研究主动噪声控制具有极其重要的实际意义。为了系统研究汽车主动噪声控制技术，满足不同配置车辆的主动噪声控制效果验证需要，本文进行实验室环境下主动噪声控制试验平台研究。以实验室现有车内噪声重现系统为基础，建立模拟实车环境的主动噪声控制系统硬件在环仿真模型，在实验室内搭建硬件平台，并开发相应的软件。考虑到主动噪声控制的系统延时不利系统的收敛和稳定，本文基于FXLMS算法的自适应滤波控制理论，建立了带延时补偿的改进自适应控制算法，以提高系统的稳定性。并对带延时次级通道滤波估计的计算、块采集情况下自适应滤波权值系数的更新算法进行了探讨。此外，通过仿真计算选择控制算法中的步长因子，并通过计算分析了延时偏差对主动噪声控制效果的影响。发现延时偏差在一定范围内不会降低主动噪声控制的效果。利用这一特点，提出了半在线延时识别补偿方案。利用所搭建的主动噪声控制平台，采用单通道系统，对单频稳态声场进行控制，在控制点处降低噪声26dB，验证了带延时补偿的自适应控制算法的正确性以及半在线延时识别补偿方案的可行性。考虑到卷积计算耗时长，将影响多通道系统控制的实时性。本文讨论了有限冲击响应滤波器的卷积算法优化。利用快速傅氏变换优化的卷积算法计算时间为原来的1/50。最后，采用以实车扬声器为次级声源的多通道系统，对单频稳态声场进行控制，在控制点处降噪10～16dB，且对控制点以外的其他测点也有一定的降噪效果，，综合降噪效果为5dB；以汽车行驶噪声为对象，在控制点处降噪5～15dB，综合各测点降噪3～5dB。
[Abstract]:In recent years, consumers increasingly seek quiet driving environment. However, in the trend of vehicle lightweight design, it is difficult to achieve a good noise reduction effect by passive control of the low frequency noise in the vehicle. However, the active noise control technology can find a balance between economy and comfort because it does not need to add high quality sound absorbing material. In addition, with the continuous renewal of automotive technology, the technical route of small displacement, the application of broken cylinder technology and the development of new energy vehicles, all of them bring new challenges to the performance of automobile NVH, and active noise control can also meet these development needs. Support the development of new automobile technology. Therefore, it is of great practical significance to study active noise control. In order to study vehicle active noise control technology systematically and to meet the need of verification of active noise control effect of vehicles with different configurations, the active noise control test platform in laboratory environment is studied in this paper. Based on the existing vehicle noise reproduction system in the laboratory, the active noise control system hardware in loop simulation model is established to simulate the real vehicle environment, the hardware platform is built in the laboratory, and the corresponding software is developed. Considering the convergence and stability of the delay unfavorable system with active noise control, an improved adaptive control algorithm with delay compensation is established based on the adaptive filter control theory of FXLMS algorithm to improve the stability of the system. The calculation of secondary channel filter estimation with delay and the updating algorithm of adaptive filter weight coefficient in the case of block acquisition are discussed. In addition, the step factor in the control algorithm is calculated by simulation, and the effect of delay deviation on the control effect of active noise is analyzed. It is found that the delay deviation does not reduce the effect of active noise control in a certain range. Based on this feature, a half-line delay recognition and compensation scheme is proposed. Using the active noise control platform and single channel system, the steady sound field of single frequency is controlled, and the noise is reduced by 26dB at the control point. The correctness of the adaptive control algorithm with delay compensation and the feasibility of the semi-online delay recognition and compensation scheme are verified. Considering the time consuming of convolution calculation, the real-time control of multi-channel system will be affected. This paper discusses the optimization of convolution algorithm for finite impulse response filters. The computation time of the convolution algorithm optimized by fast Fourier transform is 1 / 50 of the original time. Finally, a multi-channel system with real vehicle loudspeaker as the secondary sound source is used to control the steady sound field of single frequency. The noise reduction at the control point is 10 ~ 16dB, and the noise reduction effect of other measuring points other than the control point is also certain, and the comprehensive noise reduction effect is 5 dB; Taking the vehicle driving noise as the object, the noise reduction at the control point is 5dB, and the noise reduction at each measuring point is 3 ~ 5dB.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB535

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