MR阻尼器控制算法对斜拉索的减振效果

Vibration mitigation of long stay-cable using MR dampers under semi-active control strategy

采用基于位移和速度方向的半主动控制算法,以及基于最优控制力的多种主动控制算法(线性最优控制算法、特征结构配置法、次最优控制法、变结构滑移模态控制法)对杭州湾大桥南航道桥330m长斜拉索和MR阻尼器组成的系统进行了动力分析。以全索全时段振动响应的均方根作为振动控制效果的评价指标,从控制效果和易实施的角度评述了各种半主动控制算法。计算表明半主动控制算法对斜拉索的减振效果可优于最优的被动控制。

Long-span cables are susceptible to vibration with large amplitude under wind/rain loading or support excitation. To overcome these problems, a theoretic model for the cable-damper system is formulated by accounting for the cable inclination and sag effect based on the Hamilton principle. The discrete Magnetorheological （MR） dampers were installed on the 330m-long cable. The dynamic response performances of a cable with MR dampers are explored using Spencer photometric model. The semi-active control strategies of cable vibration are provided two ways. One is based on the direction of both displacement and velocity, and the other is based on combined the optimal damper force and the voltage control together. The optimal damper force are derived by LOC（linear optimal control）, PA（pole assignment）, QOC（quasi-optimum control） and VSS（variable structure system）. The voltage is converted by COC（clipped-optmal control）, Hrovat method and Lyapunov direct method. The primary measure of damper performance considered is the root mean square （RMS） cable deflection integrated along the length of the cable and the whole time. The comparison study among the semi-active under the strategy and the optimal passive MR damper indicated the advantages of semi-active dynamic adjust control with a better control performance when MR dampers marker is within the effective region.