Adaptive Control of Flexural Waves Propagating in a Beam
Adaptive Control of Flexural Waves Propagating in a Beam
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梁中传播的弯曲波的自适应控制
DOI：
10.1006/jsvi.1993.1166
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发表时间：
1993
影响因子：
4.7
通讯作者：
L. Billet
中科院分区：
文献类型：
--
作者：
S. Elliott;L. Billet
本文从理论和实验两个方面研究了弯(弯)波在梁上传播的宽带主动控制问题。特别是，研究了一种简单实用的布置，其中利用单个检测传感器(加速度计)的输出通过前馈控制器来驱动单个二次力。前馈控制器被实现为一个自适应数字滤波器，其系数被调整以最小化来自单个下游误差传感器(另一个加速度计)的均方输出。这种主动控制系统的性能在低频和高频下都有基本极限。低频限制是由于二次源的近场破坏误差传感器的输出而引起的。由于控制器中的电气延迟，随着频率的增加，梁中弯曲波群速度的增加对性能施加了高频限制。由这些低频和高频限制施加的有用操作的带宽随着光束厚度的减小而增加。在6 mm钢梁上的实验结果证实了预测的高频限值，尽管在实践中发现控制的低频限值是由于背景噪声导致检测和误差传感器之间缺乏一致性而确定的。在100到600赫兹的频率范围内，在实验中测量到了10到30分贝的弯曲波幅度的衰减。
Abstract Broadband active control of flexural (bending) waves propagating along a beam is investigated theoretically and experimentally. In particular, a simple practical arrangement is studied in which the output of a single detection sensor (an accelerometer) is used to drive a single secondary force via a feedforward controller. The feedforward controller is implemented as an adaptive digital filter, the coefficients of which are adjusted to minimize the mean square output from a single downstream error sensor (another accelerometer). Fundamental limits on the performance of such an active control system are found at low and high frequencies. The low frequency limit is caused by the near field of the secondary source corrupting the output of the error sensor. The increasing group velocity of bending waves in the beam with frequency imposes a high frequency limit on the performance, because of the electrical delay in the controller. The bandwidth of useful operation imposed by these low and high frequency limits is found to increase as the thickness of the beam is reduced. Experimental results on a 6 mm steel beam confirm the predicted high frequency limit, although in practice the low frequency limit of control was found to be determined by a lack of coherence between the detection and error sensor due to background noise. Attenuations in the bending wave amplitude of between 10 and 30 dB were measured in the experiments over a frequency range from 100 to 600 Hz.