考虑作动器时滞及其补偿的实时子结构实验稳定性分析

实时子结构实验中,使用液压伺服作动器作为加载设备时会出现作动器响应的时滞问题。根据作动器的动力特性,提出液压伺服作动器阶跃响应的双线性简化模型。基于该模型,以OS法(Operator-Splittingmethod)和中心差分法为例,利用谱半径方法分析了作动器时滞及其补偿对实验稳定性的影响。分析结果表明,作动器时滞使实验的稳定性降低,三阶外插补偿可以提高实验的稳定性。此外,分析结果也表明OS法的稳定性好于中心差分法。

STABILITY ANALYSIS OF REAL-TIME SUBSTRUCTURE TESTING CONSIDERING ACTUATOR DELAY AND COMPENSATION

In real-time substructure testing (RST) with a hydraulic actuator as the loading devices, there is an inevitable time delay of actuator response. This paper introduces a bilinear step response model based on the basic dynamics of an actuator. With this model, the effects of time delay and compensation of integration methods in RST are analyzed using spectrum radius method. The specific time stepping methods under investigation are the operator-splitting method and the central difference integration method. The analysis results show that the time delay will reduce the stability of RST response, while the 3rd-order polynomial compensation can improve the stability effectively. The results also show that the stability of the operating-splitter method is better than that of the central difference method.