摘要
自回归(AR)模型的定阶对其分析结果的准确性、效率和可靠性具有重要影响。对时变AR模型的定阶问题进行深入研究,提出一种基于采样频率以及分析频率之比的定阶方法。对一质量随时间变化的悬臂梁进行有限元建模,运用计算所得到的振动响应建立梁的时变AR模型,利用所提方法进行该模型的定阶,采用递推最小二乘法对梁的模态频率进行估计。对一质量时变的悬臂梁进行试验,对采集的振动响应信号建立时变AR模型并识别其振动模态频率。模拟计算和试验结果都表明,提出的时变AR模型定阶方法是有效且可行的,且识别算法具有一定的抗噪性。
The order selection of an AR model has an important influence on accuracy, efficiency and reliability of its analysis result. Here, a deep study on the order selection of a time-varying AR model was conducted and a new method for order selection based on the ratio of sampling frequency to analysis frequency was presented. A model of a cantilever beam with a time-varying mass was obtained with FEM. The calculated vibration response was used to set up a time- varying AR model and its order was selected with the proposed method. The recursive least square method was adopted to estimate the beam＇s modal frequencies. An experiment was performed using a cantilever beam with a time-varying mass. With its measured vibration response signals , a time-varying AR model was set up to estimate its modal frequencies. The simulation and the test results indicated that the proposed method for the order selection of a time-varying AR model is effective and feasible, and the method is capable of anti-noise to some extent.
出处
《振动与冲击》
EI
CSCD
北大核心
2012年第8期158-163,共6页
Journal of Vibration and Shock
基金
国家自然科学基金(10972104)
关键词
AR模型
时变系统
模态频率
AR model
time-varying system
modal frequency
