运行工况下数控机床结构动力学特性的温度影响机制

According to the modern machine tool structure dynamics theory the structure dynamics remained unchanged when the machine tool position is fixed. However,the latest study of the applicants and scholars showed that the CNC machine tools structured dynamics changed with the changed state of temperature, and will direct influence on machining stability.The mechanism of temperature effect on structural dynamic characteristics of CNC machine tools under running state remained unknown. Project proposed by the integration of a CNC machine tool parts and thermal characteristics of the whole machine structure dynamics, the influence mechanism research, proposed the temperature related machine structural dynamics modeling and analysis methods, and USES the machine tool based on the strain response of thermal characteristic parameters and the innovation of the structure modal parameters of synchronous decoupling method and spatial filtering dynamic characteristics of inertial incentive online identification, new methods for thermal sensitive temperature influence on the dynamic characteristics of the machine such as natural frequency, the sensitive analysis of machine tool structure link, establish thermal sensitive temperature and the whole structure more the mapping relationship between order modal response characteristics, revealing the running state under the influence law of temperature change on the machine tool dynamic characteristics.Is expected to enrich and develop the machine tool dynamics and thermodynamics theory, the optimum design of nc machine tools, intelligent control, security evaluation and test to provide theoretical basis and method, has important theoretical and engineering application value. Is expected to enrich and develop the machine tool dynamics and thermodynamics theory, the optimum design of nc machine tools, intelligent control, security evaluation and test to provide theoretical basis and method, has important theoretical and engineering application value.

现代机床动力学理论认为在确定的机床结构下模态参数是固有不变的，然而申请者和国内外研究学者发现运行中数控机床的模态参数会随工况温度变化而改变，对机床加工稳定性产生直接影响，但目前运行工况下温度变化对机床动态特性的影响机制尚不完全清楚。项目拟通过对数控机床部件和结合部热特性对整机结构动力学特性的影响机理研究，提出温度相关的整机结构动力学建模与分析方法，并采用基于应变响应的机床热特征参数与结构模态参数同步解耦的创新方法和惯性激励的空间滤波动力学特性在线辨识新方法，获取热敏感点温度对整机结构固有频率等动力学特性的影响规律，分析机床结构的敏感环节，建立热敏感点温度与整机结构多阶模态响应特征间的映射关系，揭示运行工况下温度变化对机床动力学特性的影响规律。预期将丰富和发展机床动力学和热力学理论，为数控机床的优化设计、智能控制、安全评定和试验检测提供理论依据和方法，具有重要的理论和工程应用价值。

数控装备是国民经济重点行业尤其是国防工业的关键基础装备，是先进制造的重要组成部分，随着高加速、高响应、精密/超精密等高性能加工要求的持续提升，数控机床运行工况复杂多变导致机床内外部热源交互作用的热载荷变化复杂，致使机床结构内部产生时变的温度梯度，引起结构热变形及热应力，影响到结构固有动力学特性，带来机床固有频率的变化，甚至会引起机床振动，温度影响因素已经成为了阻碍高性能数控机床加工效率和加工质量持续提升的瓶颈问题。为此，本项目对温度热影响下数控机床的模态、动力学等进行了比较系统和深入的探讨，提出了一种运行工况下数控机床温度相关的结构动力学特性的研究理论和方法，探究数控机床运行工况下结构模态参数随温度动态变化的影响机制。内容主要包括以下几个方面：.1）以传热学和热变形相关理论为基础，开展变工况条件下的机床热特性有限元方法研究，分析不同工况下的数控机床温度场、热变形场的变化规律。.2）通过大尺度的机床整机热特性、刚度特性的研究， 分析大尺度范围的整机温度场、热变形与整机刚度特性之间的关联关系，确定大尺度整机刚度、固有频率的温度敏感区域。.3）基于机床结合部柔性结合特性，围绕可动结合部滑块、导轨等部位的刚度、阻尼特性，研究其在构件间结合力作用下的能量变化特性与变形引起的结合部预紧力、接合面特性的变化规律，探究结合部模态参数对整机结构动力学特性的影响机理。.4）以普通数控加工中心为研究对象，开展数控机床整机结构动力学特性的温度相关运行状态实验研究和验证。研究热载荷作用下，基于内外多热源环境下数控机床整机结构模态参数辨识，研究时变温度场工况下数控机床主振模态数量、模态频域的变化规律。