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

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 high-frequency 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.