采用位移外环控制的拟动力试验方法及验证

Outer displacement loop control and its verification in pseudo-dynamic tests

拟动力试验是一种重要的结构抗震试验方法。在该类试验中,试件出力大,连接件和支座往往产生滑移与弹性变形,导致试件实际位移与期望位移存在较大偏差,降低试验数据的精度和可靠性。位移外环控制,是在作动器控制回路之外直接以试件位移为控制变量的控制回路,是解决该问题的有效方法。本文阐述了PI(即比例-积分)位移外环控制的原理,分析了在非实时平台实现该控制的延迟不确定问题,详细介绍了在混合试验平台软件Hy Test中的实现架构。采用混合试验平台软件Hy Test及该外环控制方法,完成了阶跃命令试验、单自由度结构拟动力试验和6自由度结构拟动力试验模拟,研究表明该方法稳定可靠,能大幅提高位移控制精度。

Pseudo-dynamic testing is one of important seismic testing methods. During this kind of tests,slippage and elastic deformation often occur to connectors and supports because of the large force loaded,leading to discrepancy between actual specimen displacements and desired displacements. This discrepancy can reduce accuracy and reliability of test results. Outer displacement loop control is a control loop with specimen displacements treated as control variable,attached to the actuator control loop. It is an effective solution to this problem. This paper elaborates on the principle of the outer displacement loop control using PI（ proportion-integral） control,analyses difficulties of its realization on non-real time platform due to the uncertainty of the system delay,and describes in detail its realization framework on the platform software for hybrid testing,namely Hy Test. With this platform and the outer loop control method,a test of step command,PDT on a single-degree-freedom structure and simulation of PDT on a6-degrees-of-freedom structure were performed. Test and numerical simulation results show that this method is stable and reliable,and can greatly improve control accuracy of displacement loading.