Prediction of dynamic characteristics for load- and position-dependent 5-axis machine tools using Nadam algorithm

The dynamic characteristics of a double turntable five-axis machine tool during milling are affected by milling loads and machining position, and differ from those at rest. In this paper, the joint stiffness model of the machine tool under milling loads was established. This model was integrated with dynamic modeling of machine tools. The research derived the dynamic parameters of the machine tool under milling loads, and validated the model by the dynamic characteristic test method of the machine tool under milling condition. The prediction of the dynamic characteristics of the machine under milling loads reduces the error of the results by a maximum of 11.5 % compared to the results at standstill. An orthogonal experiment was designed and a k-fold cross-validation method was applied to extend the testing dataset. By integrating the Nadam algorithm, a predictive model for the dynamic characteristics of the double turntable five-axis machine tool was established. This study indicated the influence of milling load and machining position on the machine tool dynamics. This study offered theoretical guidelines for optimal machine tool design and machining process planning.