负载特性对地震模拟振动台控制性能影响分析

The Influence on the Control Performance Caused by Load Characteristic in the Shaking Table

一般试验时将试件与台面视为整体与实际存在较大的差异,严重影响波形的再现精度。针对这一问题,对地震模拟振动台系统与试件依照弹簧-阻尼模型进行建模,并分析了负载质量、频率、阻尼等因素对地震模拟振动台控制性能的影响。仿真分析表明:无论是负载质量、负载频率和负载阻尼在各阶频率处均出现峰值,并且均以第一阶影响为主,与单自由度负载比较而言,各阶频率有相互补偿的趋势;负载对幅值的影响比对相位的影响大。针对幅值影响较大的问题,提出了压差反馈补偿算法对试件与台面间的相互作用进行了补偿,压差补偿前系统的波形再现精度0.6182,而补偿后变为0.9863,大大提高了波形再现精度。

In general tests,there is a big difference between the test piece and the table as the whole and the actual,which seriously affects the reproduction accuracy of the waveform.In response to this problem,the seismic simulation shaking table system and specimens were modeled according to the spring-damping model,and the influence of load quality,frequency,damping and other factors on the control performance of the earthquake simulation shaking table was analyzed.Simulation analysis shows that no matter the load quality,load frequency,and load damping,there are peaks at each frequency,and all are dominated by the first order influence.Compared with single-degree-of-freedom load,each frequency has a tendency to compensate each other,the load has a greater influence on the amplitude than it has on the phase.Aiming at the problem of greater influence of amplitude,a differential pressure feedback compensation algorithm is proposed to compensate for the interaction between the test piece and the table.The system’s waveform reproduction accuracy before pressure difference compensation is 0.6182,and after compensation it becomes 0.9863,which greatly improves the waveform reproduction accuracy.