【作者】 张仕海；

【导师】 伍良生；

【作者基本信息】 北京工业大学 ， 机械工程， 2012， 博士

【摘要】 高速加工技术作为一种先进、实用的制造技术，正成为制造业的主流，并以其独特的优点得到了世界各国的普遍关注，具有强大的生命力和广阔的应用前景。由于高速主轴的转速很高，即使微小的动不平衡量，也会产生很大的离心力，引发振动，进而对机床的可靠性、使用寿命、加工精度等方面产生不利影响。因此，动平衡是高速、高精密数控机床生产、制造过程中必须解决的一个基本问题，其优劣程度直接决定机床的工作性能和使用寿命，对高速机床产品的质量产生巨大影响。机床主轴在线动平衡技术具有避免频繁开关机试重，提高平衡效率和精度，同时可根据机床加工工况的改变而对不平衡量实施自动平衡等优点。因此在线动平衡具有其它平衡方法不可替代的优势。是高速、高精密数控机床和加工中心首选的平衡方式。本文以主轴系统动力学等相关理论知识为基础，以实现高速机床主轴系统高精度在线动平衡为目的，围绕机床主轴系统动力学建模及仿真，不平衡振动信号的提取，内置式在线动平衡装置及其控制系统的开发，实验效果及误差分析，双面在线动平衡在柔性主轴上的拓展应用等关键问题开展研究。论文主要内容包括以下几个方面：（1）机床主轴动力学建模及其仿真。以转子动力学理论为基础，建立高速机床主轴系统动力学数学模型，运用Labview语言设计系统仿真程序。通过系统仿真对机床主轴动力学特性进行初步分析，给出双平面影响系数以及不平衡校正量沿主轴轴向分布规律等曲线。讨论了最佳校正面的选取、不平衡量大小选取等相关问题。提出一种基于系统影响系数相位差的最佳校正面的选取方法。（2）机床主轴不平衡振动信号的提取。测量主轴径向振动信号并准确地提取不平衡振动信号是实施不平衡振动控制的前提。为提高主轴不平衡振动信号提取的精度，本课题提出首先分离出主轴测点处的形状误差，然后采用经验模态分解与最小二乘拟合相结合的基频信号提取方法。论文采用理论研究与仿真分析相结合的方法，分别从数理统计法在主轴形状误差分离中的应用，最小二乘法对主轴基频振动信号的拟合及其效果分析，经验模态分解及其自适应滤波原理等方面开展研究。为提高经验模态分解的滤波效果，课题提出采用相关函数对信号中异常事件进行处理的方法。文中分析表明，方法的综合应用能够有效地提高不平衡振动信号的提取精度。（3）双面在线动平衡装置及其控制系统设计。针对高速机床主轴的结构特点，提出一种气动盘式在线动平衡装置的结构理念，并针对装置的功能实现、整体结构、硬件控制系统、关键部件的设计或选取等方面开展研究。根据系统的功能要求，采用Labview与Matlab语言混合编程技术，针对信号采集、信号分析与处理、平衡试重、自动监控系统、控制信号输出等方面展开设计研究。（4）实验数据及平衡误差分析。为检验所设计的双面在线动平衡系统的实用性，课题针对平衡盘定位精度、影响系数测算及动平衡效果等方面开展实验研究。并从测量误差、平衡盘位置调整误差、平衡盘固有不平衡量误差、平衡盘与主轴的配合间隙、平衡盘质量分布误差、传感器安装误差等方面分析各种误差对系统平衡精度的影响，并提出一定的改进措施。（5）当工作转速接近或者高于转子系统第一阶临界转速时，应当按照柔性转子来对待。考虑到课题所设计双面在线动平衡系统的通用性，课题在对柔性转子动平衡方法进行分析的基础上，提出一种用于在线动平衡的自适应增益调度控制法。并在理论分析的基础上通过仿真及实验对该方法的平衡效果进行验证。论文整体从实际应用出发，开展高速机床主轴双面在线动平衡关键技术的研究，论文在不平衡振动信号的提取、动平衡装置及其控制系统的开发等方面取得了一定的阶段性成果。然而，由于系统的复杂性，系统在某些方面的研究还需要进一步完善或改进。更多还原

【Abstract】 High speed processing technology, an advanced and practical manufacturingtechnology, is becoming the mainstream in manufacturing industry. With uniqueadvantages, it acquires the wordwide attention and gets stronger vitality and broaderapplication prospect. Because of the very high speed of the spindle, even tiny dynamicunbalance will cause huge centrifugal force and induce vibration of the spindle, whichwill subsequently influence the reliability, the service life, the working accuracy, etc.of the machine tool. Therefore, dynamic balance is an essential problem that must besolved in the manufacturing process of high speed, high accuracy CNC (computernumerical control) machine tool. The quality of dynamic balance will directlydetermine the work performance and service life of the high speed machine tool, andgreatly influence its quality.Avoiding frequently turning on and off the machine to adjust weights, thetechnology of online dynamic balance on machine tool spindle also has advantages inimproving balance efficiency and accuracy as well as producing automatic balance onimbalance according to the change of working condition. Therefore, the technology isincomparable and has become the first choice in high speed and high accuracy CNCmachine tool manufacturing center.This thesis is based on the spindle system dynamics and the related theory andaimed to realize the precisely online dynamic balance of high speed machine toolspindle system. The author carried out the research on the following key problems:the dynamics modeling and simulation of the spindle system, the extracting ofunbalance vibration signal, the development of built-in online dynamic balance deviceand its control system, the analysis of experimental effect and error, the application ofdouble-face online dynamic balance on flexible spindle, etc. The main contents of thethesis as follows:(1) The dynamics modeling and simulation of machine tool spindle. Based onrotor dynamics theory, the dynamic mathematical model of the spindle system wasestablished and the system simulation programs were designed by Labview. Spindledynamic characteristics were analyzed preliminarily by the application of simulationprograms, and the axial distribution curve of the double-face influence coefficient anddynamic unbalance adjustment value were proposed. The selection of the idealadjustment face and unbalance adjustment value were discussed. The selectingmethod of the ideal adjustment face based on the phase difference of system influencecoefficient was put forward in the thesis.(2) The extraction of unbalance vibration signal of the machine tool spindle. To measure and correctly extract the radial unbalance vibration signal of spindle is theprecondition of dynamic balance. In order to improve the extracting precision ofunbalance vibration signal, a new method was put forward in the project. Theprocessing of the method was to extract the form error of monitoring points on spindlefirst, and then to combine EMD (Empirical Mode Decomposition) and least squaremethod to extract fundamental frequency signal. The correlative study issues includedthe application of mathematical statistics in the spindle form error extraction, thetheory of fitting fundamental frequency with least square method and the practicaleffect analysis, the principle of EMD and its filtering, etc. The theory analysiscombining with simulation was adopted in the project. To improve the filtering effectof EMD method, the correlation function was employed to eliminate abnormal eventsin the original signal. The analysis showed that the signal extracting accuracy ofunbalance vibration was effectively improved by adopting these methodssynthetically.(3) The design of double-face online dynamic balance device and its controlsystem. According to the structure characteristics of high-speed spindle, a kind ofpneumatic online dynamic balance device was designed. The realization of the devicefunction, the overall structure, the hardware control system, the design or selection ofthe key parts, etc. were studied in the paper. Based on the requirement of the systemfunction, the mixed programming technology combining Matlab with Labview wasadopted to develop software control system. The software function included signalacquisition, signal analysis and processing, weight test, automatic monitoring andcontrolling, the control signal output, etc.(4) The analysis of experimental data and balance error. To examine thepracticality of double-face online dynamic balance system designed in the project,experimental researches were executed on location accuracy of balance disc, themeasure and calculation of influence coefficient and dynamic balance effect. The keyerrors and their influence on system balance accuracy were analyzed, such as themeasurement error, balance disc position adjustment error and inherent unbalancevalue error, the fit clearance between balance disc and spindle, the balance discquality distribution error, sensor installation error, etc. Some measures forimprovement were also put forward.(5) The rotor should be taken as flexible when work speed is close to or beyondthe first critical speed of rotation. Considering the generality of the double-face onlinedynamic balance system designed in the project, an adaptive gain dispatcher’s controlmethod applied in online dynamic balance was put forward based on the analysis ofdynamic model and balance method of flexible rotor. The dynamic balance effect of the method was proved by simulation and experiment analysis on the basis oftheoretical analysis.The paper was based on practical application, and the research was carried outon double-face online dynamic balance for high-speed spindle and its keytechnologies. The correlative research has achieved its tentative goals respectively inthe extraction of unbalance vibration signal, the development of dynamic balancedevice and its controlling system, etc. However, because of the complexity of thesystem, further research or improvement of some aspects are still necessary.更多还原