液压重载机械臂的精确建模与模态参数识别

Accurate modeling and modal parameter identification of hydraulic heavy-duty mechanical arm

针对液压重载机械臂结构复杂、自重下挠及附属部件较多等特点,提出了使用激光跟踪仪测量机械臂模态测点的准确空间坐标,进而建立精确的模态几何模型,提高建模准确性和模态参数识别的可信度。采用单点激励多点响应法,对机械臂进行锤击试验,基于LMS模态参数算法提取机械臂的模态参数,并通过验证算法对识别出的模态参数正确性进行评估。试验结果表明,试验模态识别出的前6阶固有频率值与有限元计算分析的结果误差均在10%以内,验证了两者的相似性及可靠性。

In view of the characteristics of the hydraulic heavy-duty manipulator such as complex structure,deflection due to self weight and many accessory parts,the laser tracker was proposed to applied to test the accurate spatial coordinates of the modal testing points of the mechanical arm,thus the accurate modal geometrical model was established so as to enhance the modeling accuracy and the reliability of modal parameter identification.The method of single-point excitation and multi-point response was applied to conduct hammering test for the mechanical arm,and the modal parameters of the mechanical arm was abstracted based on LMS modal parameter algorithm.And then,checking algorithm was applied to estimate the correctness of the identified modal parameters.Test results showed the error between the natural frequency of preceding six orders obtained by test modal identification and the FEA results was within 10%,which verified the similarity of the two and the reliability of the method.