Feed Servo-system Performance Analysis And Motor Selection For Heavy Machine Tools

Heavy machine tools have big workpieces, big sizes and large cutting forces. The rotational inertia of mechanical transmission components will influence the resonant frequency and dynamic performance of the system. So if inertia matching is not well solved in motor selection, the sensitivity, sevor accuracy and response speed of the whole system will be influenced. At present, it is lack of motor selection principles and motor selection software for heavy machine tools. Based on this, the inertia matching of feed sevor-system was studied in this article, and then provided the motor selection principles and developed motor selection software.To analyze the influences of inertia ratio to feed sevor-system, we selected GMC1600H/2 five-axis beam moving gantry maching center as the research object, built it's simulation model of feed servo-system using Simulink. In the model, friction was took into account and represented by improved Stribeck friction model, the unknown parameters of the model were identified through experiment; the equivalent stiffness of feed servo system was identified using least square method, to improve the accuracy of simulation model. Comparing with the position follow error, speed, roundness error etc. of experiment and simulation, the reliability of the simulation model was verified. Based on this, the influences of inertia ratio to the gain of control system, closed-loop system frequency characteristic and contour error were analyzed, as a result, suitable inertia ratio was obtained.Took the workbench drived by ball screw as example, the counting process and verification of motor selection were introduced in detail. In order to simplify the process of motor selection, a motor selection and evaluation software was developed using Matlab GUI. Various driving methods were took into account and users just need to input parameters to realize motor selection in the software. The software was applied preliminary in Wuhan Heavy Machine Tool Group Co., Ltd and Beijing No.1 Machine Tool Plant, and the reliability of the software was verified.