高频响测力仪固有频率的理论分析与试验

摘要

Concerning the low natural frequency of dynamometers for high speed cutting to acquire forces signals,a initial model of high frequency dynamometer was designed and its natural frequency can be as 9 kHz.Based on the method of Dunkerley,a simplified model of the dynamometer was built to achieve the theoretical natural frequency and the computational formula.Meanwhile,the simulation values and actual values of the natural frequency were obtained by modal analysis with the use of the finite element simulation and vibration modal test,and the high speed cutting test was conducted for the validation.The results indicate that theoretical values and simulation values are a little greater than the actual values,and the dimensions of key structure have an great impact on the natural fre-quency,which provide a necessary reference for the structure optimization of similar dynamometers.%针对现有测力仪固有频率较低而无法准确测量高转速下铣削力的难题，基于附加弹性测力原理设计了高频响测力仪，测力系统的固有频率达到9 kHz 以上，运用邓克莱法建立了测力仪的简化模型，推导出固有频率的解析式；进行了有限元仿真与模态试验，获得了测力仪固有频率的仿真值、实测值以及振型；最后进行了高转速铣削力验证试验。研究结果表明，该测力仪固有频率的解析值和仿真值略大于实测值，但三者较为接近，测力仪关键结构尺寸与其固有频率密切相关，利用简化模型和有限元法进行高频响测力仪的结构优化设计合理可行，为同类测力仪的结构优化设计提供了参考依据。