Cutting Force Estimation Using Feed Motor Current Signatures And Table Position In Milling

With the development of modern industrial intelligent, the demands of customers is increasingly personalized, diversified and precision. Implement of online monitoring of cutting force is an important part of intelligent manufacturing. Indirect Estimation of the cutting force by feeding current is a low-cost monitoring method. Compared with the dynamometer and other direct measurement methods, it is more suitable for use in the actual production with advantages of easy installation, wide application and others. Therefore, the indirect measurement of cutting load by feeding current has important theoretical significance and value in practical application.In this article, indirect method of improving estimation accuracy of the multi-axis machine tool cutting force has been mainly studied, and the friction torque and equivalent moment of inertia of feed system are the key factors affecting the accuracy of the estimation has been determined. At the same time, the overall research programs and experimental platform are designed.For pretreatment process of current signal, frequency domain analysis is applied, and the interfering frequencies of current signals are analyzed to determine that the interference bands are from the feed motor phase current frequency and screw frequency. And appropriate filtering program is designed to achieve significant signal.For the affection of estimation precision of the cutting load to friction torque,the classic model Lugre and Stribeck are applied to describe micro and macro slip sliding friction area separately, and determine the affection of table position to friction torque. The improved model for the machine tool feed system is proposed. And calibration methods of the improved model are analyzed to determine the most simple calibration method, it is found that the calibration time is reduced by half.As to the affection of equivalent moment of inertia of the system to estimation precision of the cutting load, the model reference adaptive algorithm is used. The measurement of rotational inertia on-line of the feed system is realized, and selection of adaptive parameters is analyzed. And the accuracy of the estimation algorithm is verified by experiments.In addition, in order to verify the effectiveness of this method of estimation, experiments about parameter calibration are performed on the DM4600 machine, and experiments about uniform feeding and shifting feed with different parameters are designed to verify precision of estimation algorithm of cutting force under different parameters. Finally,experimental results show that the proposed method can effectively estimate the cutting force.