迭代算法与柔性结构对离心机振动台控制性能影响

Influences of iterative algorithms and flexible structures on control performance of centrifugal shaking table

目前迭代算法和柔性结构对离心机振动台控制性能的影响尚缺乏认识,尤其铰接装置作为柔性连接结构在许多离心机振动台上得到应用,以减小离心力荷载下台面和吊篮变形对作动器安全带来的危险。以一套负载1500 kg离心机振动台为样本,采用不同强度、频带的典型地震波为控制目标,探讨了有无迭代算法、柔性结构条件对离心机振动台的控制性能影响。结果表明:20~200 Hz频宽范围内,迭代算法对最大峰值误差、平均峰值误差、平均谱面积误差的影响可忽略。采用迭代算法前后平均峰值误差分别为5.90%,6.15%,平均谱面积误差分别为5.02%,4.94%。柔性结构对于加速度峰值≤7.5g地震波的复现精度有显著影响,尤其是80~150 Hz高频段;对于加速度峰值≥20g地震波的复现精度影响,在频宽20~120 Hz可忽略,但对于120~170 Hz频段的小幅值成分的复现能力影响不容忽略,逊于无柔性结构条件。同时,在无柔性结构条件下对比了不同负载、同一输入荷载的实测输出波,发现两输出波的峰值误差与谱面积误差均无明显差异,证明了离心机振动台具有良好的重复性和稳定性。研究方法和结论,对提高离心机振动台控制性能的影响因素认识和改进设计方法,具有重要指导价值和科学意义。

Currently,there is a lack of understanding regarding the impact of iterative algorithms and flexible structures on the control performance of centrifugal shaking table.In particular,the hinge devices,serving as the flexible connecting structures,have been widely applied in many centrifugal shaking tables to diminish the risks posed by deformations of the platform and bucket under centrifugal force loads to the safety of the actuators.Using a centrifugal shaking table with loads of 1500 kg as a sample,the typical seismic waves with different intensities and frequency bands are selected as the control targets.The influences of the iterative algorithms and flexible structures on the control performance of the centrifugal shaking table are investigated.The results indicate that under the frequency bandwidth varying from 20 to 200 Hz,the impact of the iterative algorithms on the maximum peak error,average peak error and average spectral area error can be neglected.The average peak errors before and after using the iterative algorithms are 5.90% and 6.15%,respectively,and the average spectral area errors are 5.02% and 4.94%,respectively.The flexible structures significantly affect the reproduction accuracy of seismic waves with acceleration peaks≤7.5g,especially in the highfrequency range of 80 to 150 Hz.For the seismic waves with acceleration peaks≥20g,the impact on reproduction accuracy is negligible in the frequency range of 20 to 120 Hz.However,the influences on the reproduction capability of small-amplitude components in the frequency range of 120 to 170 Hz cannot be ignored,which is inferior to the condition without the flexible structures.Simultaneously,under the condition without the flexible structures,a comparison of the measured platform output waves for the same input load under different loads reveals no significant differences in the peak errors and spectral area errors between the two output waves.This proves the good repeatability and stability of centrifugal shaking table.The research methods and conclusions have significant guiding value and scientific significance for improving the understanding of the influencing factors of the control performance of the centrifugal shaking table and improving the design method.