为准确描述液压挖掘机机械臂动力学模型，根据柔性多体动力学理论，采用模态函数描述臂架的弹性变形，利用LAGRANGE定理和虚功原理建立挖掘机臂架系统刚柔耦合的非线性动力学方程。对已建立的动力学方程利用MATLAB进行数值求解，运用仿真软件ADAMS及NASTRAN建立液压挖掘机机械臂刚柔耦合模型并进行仿真分析，通过对比二者结果表明动力学方程建模方法的正确性。运用数值求解方法进行模态计算和动力学响应分析，求解相关几何参数的一阶固有频率灵敏度，分析了影响机械臂动力学特性的主要模态参数，为进一步研究其结构优化及运动精度控制提供依据。%In order to accurately describe the dynamic model of hydraulic excavator's mechanical arm,modal functions were adopted to describe the elastic deformation of the mechanical arm.Lagrange theorem and the principle of virtual work were used to establish rigid-flexible coupling nonlinear dynamic equations of the arm frame system.The dynamic equations were numerically solved by MATLAB.The rigid-flexible coupling model of the arm was established and simulated by the simulation software ADAMS and NASTRAN.It is shown that the modeling method of dynamic equations adopted in this paper is correct by comparing the both results.The modal responses were numerically calculated the sensitivity of the first natural frequency to the geometric parameters related was investigated and the main modal parameters were analyzed which influence dynamic characteristics of the arm.The results provide the basis for the further optimization of excavator structure and the motion error control.
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