ATMD对斜拉桥抖振减振的控制设计模型研究

Study of control design model for buffeting response control of cable-stayed bridge using ATMD

对斜拉桥的大幅风致抖振宜采用ATMD(active tuned mass dampers)减振,且为实现控制器设计需建立针对复杂模型降阶后的控制设计模型。在建立风荷载作用下斜拉桥与ATMD组合系统模型的基础上,将Hankel范数与模态分析相结合,提出目标含义明确且考虑外激励影响的ATMD/传感器配置指标,以及能够同时表征结构振动的可控可观性能和外激励影响程度的模态选择指标;采用模态叠加法,实现在控制设计模型的模态组成中模态阶次的准确定位和构成,并使模型具有良好的可控可观性能。以南京长江三桥的抖振减振为例,给出了ATMD/加速度传感器的配置优化和模态选择的实施过程,建立了ATMD对斜拉桥抖振减振的控制设计模型。数值计算结果表明,所建的控制设计模型的动力性能与原系统模型有较好的一致性。

Active tuned mass dampers （ATMDs） have proved be effective in control of large amplitude buffeting responses of cable-stayed bridges. For carrying out actuator design, a control design model needs to be developed after reduction of complex structural model. To form the control design model mathematical model of combined system of ATMDs and a cable-stayed bridge under wind loads is built firstly. By combining Hankel norms with structural mode analysis, placement indexes of AT- MDs and sensors with definite objective connotation are built respectively considering influence weight of exterior excitation. Then selection index of modes that can indicate controllability and observability for the structural vibration and express contribution degree of exterior excitation is proposed. Based on modal superstition method, accurate designation and composing of modes are realized to form the control design model. Meanwhile the controllability and observability are well kept. Taking the 3rd Nanjing Bridge over Yangtze River under construction as a case study for the buffeting response control, implementation process for the placement of ATMDs and sensors and the selection of modes are provided, and then a control design model of the cable-stayed bridge for buffeting response control is developed. Numerical results show that the dynamic characteristics of the control design mode are in good agreement with that of original system model.