基于双台台阵和界面力控制方法的子结构混合试验研究

This project aims to develop a substructure online hybrid test platform with the configuration of coupled shaking table array (containing two shaking tables), actuators, and numerical substructures. This feature renders the novel online hybrid test system a more flexible and powerful capability to trace the seismic response of very complex structures, thus providing another important approaches to earthquake engineering. This study is going to construct a new Triple Variable Control (TVC) method and use it as an outer-loop controller in combination with the inherent inner-loop controller of shaking table array. The new TVC control adopts the command shaping method for the three state variables, so that a more precise acceleration reproduction can be achieved. A real-time force control method will be proposed for the actuator. It employs the nonlinear sliding mode control technique, the Inverse Transfer Function (ITF) control, and the loop shaping method to construct a more robust and accurate real-time force controller. Considering the nonlinearity of specimens and inherent dynamic characteristics of servo-hydraulic systems, a sophisticated time-delay compensation scheme is going to proposed in this study. It is a self-adaptive delay compensation method particularly useful for progressively-developed nonlinearities, which solves the sub-dynamic system response delay as well as the synchronization problem by means of online delay identification, self-adaptive parameterization, and full-range tuning techniques. Full model simulation of the entire dynamic system is going to be studied. The dynamics of reaction foundations, servo-hydraulic facilities, and specimens will be included in this model. The transfer function of the full model can be used to construct the outer-loop controller, optimize the critical parameters of the delay compensation algorithm. Based on this simulation model, the influence of nonlinearities and signal noises on the stability and accuracy of the system can be studied. Further, a method based on the Bode plots of discrete dynamic systems is going to be developed to study the stability of the dynamic system. With the existing software and hardware, such as the Internet-based data exchange, PID controller, and interfaces to finite element software, the proposed substructure hybrid testing system will be built if the boundary compatibility and the difficulty in controlling nonlinear systems can be solved. Finally, the overall hybrid testing system will be completely examined by three rounds of shaking table tests. A mega-frame structure with base-isolated sub-frames will be used as the example. The mega-frame is a three-story frame, on each story built an isolated sub-frame. In the first test, the full structure will be examined by the larger shaking table to understand the seismic performance of the structure system. And the new outer-loop TVC controller is examined to judge the improvement of the acceleration reproduction. The second round test will take the sub-frame on the third story of mega-frame as the tested specimen on the smaller shaking table, while the rest is numerically simulated. This study is to explore the delay compensation between the numerical substructure and the shaking table. Finally, the numerical substructure is going to be replaced by a specimen on the larger shaking table. The boundary force is to be realized by an actuator. The overall hybrid test system will be examined by this test.

本项目将以振动台阵-作动器为架构建立子结构混合试验平台，使其具备更灵活、更强大的模拟复杂结构地震响应的能力，为地震工程研究提供另一重要手段。研究将建立结合成形技术的外环三参量控制方法，实现振动台对加速度波形的精确再现；提出结合滑移模态控制技术、逆补偿控制技术和回路成形技术的集中力控制器，实现作动器的动态力控制加载模式；针对非线性动力系统发展自适应的时滞补偿算法，通过时滞在线识别、自适应参数限值、全过程调节等技术解决振动台和作动器同步加载问题；以反力基础-动力系统-试验体的精确仿真模型为手段，建立外环控制算法，优化时滞补偿算法的重要参数，并拟采用离散系统Bode图分析方法，对整个动力系统的稳定性和精确性提供科学合理的解释；在已有的网络通讯、硬件控制和有限元程序接口的软硬件基础上，进一步解决边界协调技术和非线性动力特性控制难题，建设完善的软硬件平台；最终采用巨子框架结构体系进行全面验证。

本项目以振动台-作动器-数值模拟为架构建立子结构混合试验平台，使其具备更灵活、更强大的能力以模拟复杂结构体系的地震响应，为地震工程研究提供另一重要手段。本项目以显式数值积分算法、离散控制系统理论、自适应控制、最优高斯控制方法、滑动模态控制和力位移混合控制算法为理论依据。针对试验子结构的非线性提出显式无条件稳定数值积分算法；提出基于伯德（Bode）图的稳定性分析方法分析振动台混合试验系统稳定性；针对非线性多元动力混合试验系统发展自适应的时滞补偿算法，解决振动台和作动器同步加载问题；提出子结构边界交错协调算法，发展两自由度边界条件动力模拟装置，解决振动台混合试验中边界条件模拟的问题；提出子母双振动台波形再现的分频离线迭代控制方法解决双台宽频带地震波再现的问题；提出了在线迭代控制方法和基于反应谱的离线迭代控制方法提高振动台波形在线精度；提出闭环控制求解非线性方程的新方法，发展多自由度力-位移混合控制方法，用于解决作动器力控制加载的难题；在已有的网络通讯、硬件控制和有限元程序接口等软硬件基础上，进一步搭建了xPC目标机和Scramnet共享内存卡组成的实时计算控制环境，和Labview和VB、Opensees软件构成的多自由度边界协调计算通讯环境；建设完善的振动台-作动器子结构混合试验平台，采用风力发电塔地震与风耦合振动台混合试验、防屈曲支撑加固钢筋混凝土框架结构子结构混合试验和巨子框架结构体系混合试验进行全面验证，并在高速铁路车桥耦合振动研究中得到应用。研究成果对推进子结构混合试验在土木工程、交通、能源等领域的应用具有重要的科学意义和实用价值。