基于有限差分法的主轴-刀柄结合部刚度辨识

摘要

Aiming at the spatial incompleteness problem of lacking rotational degrees of freedom (RDOF) in traditional joint parameter identification,the study introduced the finite-difference technique to estimate the rotation angle frequency response.In order to depress the error caused by the modal truncation,the experimental data of frequency response was regenerated based on the residual compensation theory.The measured noises can be eliminated to obtain the ideal identification results.Taking the spindle-toolholder joint as the study object,the frequency responses of substructure and assembly of the spindle-toolholder system can be obtained by the hammer peening experiment.The structural coupling method was introduced to establish the stiffness identification model of dynamic joint.With the proposed method,the dynamic parameters can be identified exactly.The finite element model was established to verify and analyze the validity of the identified results.The results of the comparison experiment and the simulation show that the proposed method can exactly identify the joint parameters.%针对传统结合部参数辨识普遍存在缺失转角自由度的空间不完备问题,利用有限差分法估算转角自由度频响,从而建立了完备空间自由度的结合部参数辨识模型；基于残差补偿理论重构频响函数试验数据,降低了模态截断引起的测试误差,以避免辨识计算过程中试验测试噪声对辨识结果的影响,提高辨识精度.以主轴-刀柄系统结合部为对象,通过锤击试验获得各子结构及结合部的频响函数,利用子结构耦合法辨识出结合部等效动力学刚度,通过有限元法进行动力学建模与分析,验证辨识结果.对比试验与仿真结果验证了方法的可行性.