基于改进频谱分解方法的多输入多输出非高斯振动控制

Control of multi-input multi-output non-gaussian vibration based on improved spectral decomposition method

相比于传统的单输入单输出方法,多输入多输出振动环境试验方法能够更真实地模拟结构在实际工作下的振动环境。不同于传统随机振动试验的频域方法所模拟出的平稳高斯信号,实际振动环境,尤其是输电塔线系统受到的风载,所模拟出的往往是超高斯信号。且超高斯振动环境中结构的应力大于高斯振动环境,因此对超高斯振动环境试验的研究十分必要。提出一种基于改进频谱分解的多输入多输出超高斯驱动信号生成方法。先根据给定的参考峭度值和响应参考谱采用相位调节法生成参考响应非高斯伪随机信号,利用改进频谱分解的方法生成超高斯伪随机驱动信号,再对伪随机驱动信号进行时域随机化处理得到超高斯真随机驱动信号。通过对一根悬臂梁模型采用两输入两输出的方法进行试验验证,结果表明两个控制点的输出响应谱与给定的参考谱之间的误差被稳定的控制在±3dB的报警限内,且响应峭度和参考值之间的误差满足工程要求。

The multi-input-multi-output vibration environment test can replicate the vibration environment endured by a structure under the practical situation more accurately than the traditional single-input-single-output manner.The traditional random vibration test with frequency domain method aims to generate a stationary and Gaussian vibration environment.But the practical vibration environments are always super-Gaussian,especially the wind load of transmission tower-line system,which can cause more damages to the structures compared with Gaussian excitations.Thus,it is significant to study the super-Gaussian test method.A method for generation MIMO non-Gaussian driving signals based on improved spectral decomposition and phase manipulation.First,phase manipulation is used to generate the pseudo random non-Gaussian responses according to the given reference power spectrum densities and kurtoses.Then improved spectral decomposition method is used to generate the pseudo driving signals.Finally,the real random non-Gaussian driving signals are obtained by time domain randomization.A two-input-two-output cantilever beam control experiment results indicate that the error between output response spectrum and reference spectrum based on the proposed control algorithm meets the requirement± 3 dB in engineering,and the kurtosis meets the reference requirement.