隔震桥梁地震反应的最优主动控制力特性研究

Characteristics of optimal control force for seismically excited isolated bridges

采用经典二次型LQR主动控制算法,研究隔震桥梁支座处主动控制装置的控制力特性。研究表明:主动控制力主要表现为阻尼力;当采用适当的状态反馈控制向量及控制权矩阵时,主动控制力与支座的速度基本接近线性关系。在此基础上,提出了基于主动控制算法的隔震桥梁最优被动粘滞阻尼器设计方法。被动粘滞阻尼器的最优阻尼系数既可以由LQR的控制增益直接得到,也可以通过线性拟合在实际地震波作用下的主动控制力与速度的关系曲线得到,且二者的结果极为接近。进一步的仿真分析结果表明,优化的被动粘滞阻尼器完全可以达到主动控制的减震效果。

The characteristics of control force of an active device located between a bridge deck and a pier for an isolated highway bridge are first analyzed based on classical LQR（Linear quadratic regulator） control algorithm.It shows that the active control force mainly behaves as a damping force,and there is an approximate linear relationship between the force and velocity of the control device on the condition that the suitable state feedback and weighting matrix are adopted.On this basis,the method of designing optimal linear viscous dampers based on LQR control algorithm for seismically excited isolated bridges is proposed.The optimal viscous damping coefficient for a viscous damper can be either directly obtained from the control gain of LQR control or derived from the linear fitting of the relationship between the control force and velocity when the bridge is subjected to real seismic excitations.The parameters optimized from the two methods are quite close to each other.Effectiveness of the designed optimal passive control is further demonstrated by comparing the control performance with that of ideal active control based on numerical results.