基于弹性负载的地震模拟试验控制策略

Control strategy in earthquake simulation test based on elastic payload

传统地震模拟试验控制方法多将试件假定为刚性负载。针对该控制方法在实际应用中精度差的缺点,提出一种基于弹性负载的地震模拟控制策略,通过分析弹性试件力学模型,合理设置内环伺服控制参数,实现各种负载下系统传递特性的近似统一。在此基础上,优化外环振动控制辨识方法。振动台系统能在无预试验步骤情况下获得较高地震波形复现精度。试验表明:该控制策略无需预试验,在优化的伺服控制参数下,能在首帧地震模拟试验中获得85%以上的输入输出信号时域相关系数;经数帧试验,通过对系统驱动信号进行更新,地震模拟输入输出信号时域相关系数能稳定在90%以上。

The specimen is assumed to be rigid payload in traditional earthquake simulation test control. To overcome the poor control precision of this kind of control, an earthquake simulation control strategy was proposed. In the control strategy, servo-control parameters were set reasonably by analyzing physical modes of elastic payload, so the transfer function of the shaking table can keep approximately unvaried under a variety of different loads. On this basis, the system identification method of vibration control was optimized. The shaking table system can achieve high simulation precision for seismic wave without pre-test step. The experimental results on the Zhejiang University shaking table indicate that with the control strategy, the first frame correlation coefficient between reference signal and control signal in time domain can be above 85% without pre-test step in the case of parameter optimization; and after several frames of earthquake simulation test, the correlation coefficient can reach 90% through identifying the transfer function continuously.