大型数控转台机电特性分析

Mechatronic Analysis of Large-scale CNC Rotary Tables

大型化的发展增加数控转台机电特性研究的难度。针对某大型数控转台,综合考虑结构动力学、运动学和伺服控制系统的交互作用,详细建立其机电系统模型,并进行转台转速响应特性分析。为进一步辨识机械传动链各部件柔性对转台振动性能的影响,进行了传动链部件的模态灵敏度分析。理论分析与试验结果表明,大型数控转台机械传动链的柔性迟滞了转台的转速响应,是影响和限制数控转台性能的主要因素;库仑摩擦有利于迅速衰减数控转台转速响应的振动,但库仑摩擦太大会消耗系统的能量,合理调整库仑摩擦的大小,有利于提升转台的整体性能;电动机轴的转动惯量和蜗杆轴的扭转刚度对大型数控转台的振动性能影响最大。

With the development of CNC rotary tables for the trend of large scale, the difficulty of the research on the mechatronic characteristics is increased. Taking a large-scale CNC rotary table as an example, based on the consideration of the structural dynamics, kinematics, servo control system and its interaction, a detailed mechatronic model is established, and the speed response of the CNC rotary table is analyzed. In order to identify the effect of each compliant element of the mechanical transmission chain to the vibration performance of the CNC rotary table, the modal sensitivity analysis of the transmission chain is performed. The theoretical analysis and experiments indicate that the speed response of the rotary table is delayed due to the compliance effect of the mechanical transmission chain, and the compliance is the main limited factor for the performance of the CNC rotary table. The Coulomb friction is benefit to quickly damp the oscillations of the speed response, and a suitable Coulomb friction contributes to the performance of the rotary table. The rotary inertia of the motor shaft and the torsional stiffness of the worm are the biggest performance problems of the large-scale CNC rotary table.