Nonlinear substructuring control for simultaneous control of acceleration and displacement in shake table substructuring experiments
Nonlinear substructuring control for simultaneous control of acceleration and displacement in shake table substructuring experiments
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DOI：
10.1002/stc.2882
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发表时间：
2021-11
影响因子：
5.4
通讯作者：
R. Enokida
中科院分区：
文献类型：
--
作者：
R. Enokida
本文报道了非线性子结构控制（NLSC）在振动台试验中的首次应用，其中振动台的动力学受到试件的显著影响。由于振动台在实验中既是驱动系统又是子结构的一部分，因此要求振动台的加速度和位移同时控制。线性子结构控制（LSC）是控制动态子结构系统的基本方法，是线性子结构控制的改进版。本文首先描述了采用多自由度结构的振动台试验子结构的公式和子结构的NLSC设计。具有三个控制器的NLSC的稳定性分析变得更加复杂，比传统实验中观察到的更频繁地表现出条件稳定性。为了评估各种条件稳定系统，本文提出了一种可以系统地计算Nyquist图中临界点的包围圈的等效方法。在稳定性分析中，NLSC对子结构参数变化的鲁棒性优于LSC。此外，LSC和NLSC的误差反馈控制器都增强了对变量的鲁棒性。本文通过数值和实验研究了振动台结构非线性试验的控制性能。在试验中，NLSC达到了预期的位移和加速度控制，并且稳定且精度合理，而LSC则不能。研究发现，误差反馈控制器的设计对于进行具有严重非线性特性的振动台子结构实验至关重要。
This paper reports the first application of nonlinear substructuring control (NLSC) to shake table experiments in which the table dynamics is significantly affected by the specimen. Substructuring experiments using a shake table require simultaneous control of acceleration and displacement of the table because it functions as both an actuation system and a part of the substructure in the experiments. NLSC was developed as an enhanced version of linear substructuring control (LSC), the basic method for the control of dynamically substructured system. This paper first describes the formulation of substructures for shake table experiments using a multiple‐degree‐of‐freedom structure and NLSC design for the substructures. The stability analysis of NLSC, which has three controllers, becomes much more complicated, more frequently showing conditional stability than is observed in conventional experiments. To assess various conditionally stable systems, this paper proposes an equivalent approach that can systematically count encirclements of the critical point in Nyquist plots. In the stability analysis using the proposed approach, NLSC is more robust against parameter variations in the substructures than LSC. In addition, the error feedback controller in both LSC and NLSC enhances the robustness against the variations. This study numerically and experimentally examined control performances for shake table substructuring experiments involving nonlinear characteristics. In the examinations, NLSC achieved the expected displacement and acceleration control with stability and reasonable accuracy, whereas LSC could not. The error feedback controller design of NLSC was found to be essential for performing shake table substructuring experiments with severe nonlinear characteristics.