The Research On Response Points Selection Methods Of The Dynamic Force Identification

In our daily life,vibration problem exists almost everywhere,and it usually will result in harmful consequences,so it is the cause why this study has received a lot of attention.When we take public vehicles,it will vibrate for many reasons,and it will make us fill sick,we are easily to feel tired,and in extreme cases the vibration may even cause an accident.In manufacturing industry,the machining accuracy will be affected due to the vibration of the machine,increasing the defect rate.So how to solve the problem of dynamics force identification to decrease the influence of the vibration problem is very important.At present,the frequency domain method is one of the most widely used methods of dynamics force identification,which began relatively earlier.The main principle of the method is to use inverse matrix of frequency response function in frequency domain and the measured response to identify the unknown force.In the process of the dynamic force identification,the trouble of the frequency domain method lies in how to get frequency response function(FRF)matrix with smaller condition number to reduce systematic error and identify the dynamic force accurately.However,there is a relationship between the characteristic of FRF matrix and response points.FRF matrix with smallest condition number can be selected when trying all combination of response points,but the calculated amount will be too massive to meet the case of more measured response points.According to the situation of more measured response points in engineering,this paper establishes the optimal model of response point selection for the dynamic force identification by analyzing the FRF matrix of the single-degree-of-freedom system and the multiple-degree-of-freedom system.Meanwhile,the condition number of FRF matrix will be considered as the objective function.The optimization model of the response point selection belongs to discrete optimization problems,and its establishment based on the composite condition number model.This model can quickly pick out the right combination of responses point,and also can get more better approximation accuracy.In this paper,it uses Tkihonov regularization method to solve this problem,the result proved that the composite condition number response point selection model is appropriate.Finally,the results of the matlab simulation experiments prove that the model is able to select the best combination of response points quickly and effectively,even under the situation of more response points.Besides,the results also indicate that the model and its solution method have a high practical value in engineering application.