【作者】 贺大兴；

【导师】 周祖德；

【作者基本信息】 武汉理工大学 ， 机械制造及其自动化， 2009， 博士

【摘要】 纳米级分辨率的运动是当今超精密机床精度指标的特征标志。为了实现机床溜板1nm分辨率的运动,本文结合超精密机床的发展规律,运用优化设计的方法,在分析多种实施条件可行性的基础上,确定了两大主要技术研究对象:机床的溜板结构和驱动结构,并对其深入研究。在机床溜板结构技术研究中,为了避免导轨误差产生的流体激振,设计了无迟滞、自耦合的溜板结构;为了使溜板具有适于纳米驱动的稳定状态,针对超精密机床中的微振动进行了成因分析和特征辨识及抑制方法研究。在驱动结构中设计了高分辨率的机械传动结构与驱动控制的技术方案。最终通过实验的方法验证了设计与研究的合理性,实现了溜板1nm分辨率的运动目标。本文的主要工作有:(1)论证了影响纳米分辨率运动的测试及实施的条件技术,分析了研究的可行性并确定了多影响因素中目标的优化途径及技术的主成分。(2)设计了无迟滞、自耦合的溜板结构。对于结构中的多孔质轴承的微观分形结构、流体力学原理和特性进行了分析和CFD仿真。对于导轨副的误差引起的激振原理以及解决方法做了论述。(3)在超精密机床中提出了微振动的概念。从溜板轴承内部流体和溜板外部摄动两个方面对微振动的成因进行了分析。建立了多孔质轴承的管道模型结构。指出了控制微振动的三个基本要素。(4)对微振动的特征辨识做了研究。运用频谱分析、小波变换、非线性动力学等方法进行了辨识研究。通过功率谱分析、李雅普诺夫指数、分形维数及柯熵的研究,确立了微振动与混沌的关系。提出了基于混沌控制的微振动的抑制方法。(5)设计了高分辨率的机械传动结构并提出驱动控制的技术方案。传动结构具有两大主要特点:即径向悬浮式主导结构和差异刚性联接与隔振驱动一体化结构。在基于赫兹理论的滚动体的受力分析的基础上,设计了可调整预负荷的螺母结构和联接结构。(6)对开发的技术方案进行了分析验证。内容包括:对地基的激振扰动实验、用功率谱方法测定溜板的刚度实验、溜板与床身微振动的相序关系检验、微振动系统的相轨迹和吸引子结构、微振动抑制条件下机床金刚石刀具的切削效果验证等。最终实验证明技术方案可以实现溜板1nm分辨率的运动,并证明所开发的系统可以获得0.28nm的运动响应。更多还原

【Abstract】 Motion resolution in nanometer scale is the important characteristic indicator of ultra-precision machine tool. To achieve the target of 1nm motion resolution, two main technical-research objects, which were the mechanical structures of the carriage and the driving of machine tool, were confirmed by combining with developing feature of ultra-precision machine tool, application of the optimizing design method and on the base of analyzing feasibility under multi-condition of implement. In the research of the mechanical structures of the carriage, to avoid vibration exciting of fluid caused by the geometry error of the guideway, the carriage structure of non-hysteresis and autocoupling was designed; to acquire stable state for the carriage which was suitable for nanometer driving, the causing analyzing, the characteristic identification and suppressing methods of micro-vibration in ultra-precision were studied. In the research of the mechanical structures of the driving, high-resolution driving structure and CNC control technical scheme were proposed and analyzed. Finally, the rationality of the design and the research were verified by experiments, and the target of 1nm motion resolution was achieved.This dissertation has obtained the following innovative results:(1) The architecture environment, which affects the measurement and the implement of nanometer resolution motion, was demonstrated. The feasibility was analyzed; the optimizing routes and the main factors among the multiple affecting factors were confirmed.(2) The carriage structure of non-hysteresis and autocoupling was designed. The microcosmic fractal structure, the principle and characteristic of fluid dynamics and the CFD simulation were demonstrated and analyzed. The principle of vibration exciting of fluid caused by the geometry error of guideway and the solution methods were also demonstrated.(3) The conception of micro-vibration in ultra-precision machine tool was proposed. The causes of the micro-vibration were analyzed from two aspects: the inner fluid in the aerostatic bearing and the outer perturbation of the carriage. The pipe mould of porous bearing was built and three primary elements to suppress the micro-vibration were proposed.(4) The characteristic identification of the micro-vibration was researched by using the methods of frequency spectrum, wavelet transform and nonlinear dynamics. The relationship between the micro-vibration and chaos was confirmed under the research of analyzing power spectrum, Lyapunov exponent, fractal dimension and Kolmogorov entropy. Suppressing methods to the micro-vibration based on chaos control were proposed. (5) The mechanical structure of the high-resolution driving structure was designed and CNC control technical scheme was proposed. The driving structure has two main characters: one was radial levitation-style dominant structure and the other was integrating structure of anisotropic rigidity and vibration-isolate connector between the screw-nut and the carriage. The screw-nut structure, of which the preload can be adjusted, was designed based on roller force analysis under the Hertz theory.(6) The rationality of the design and the research were verified by experiments. The experiments include exciting disturbance to the foundation of the machine tool, measurement method of the carriage rigidity by using power spectrum, phase angle checking between the carriage and its bed, the phase loci and the attractor structures of micro-vibration, diamond cutting effect under the condition of suppressed micro-vibration. The final experiments proved: 1nm resolution motion can be achieved by developed technical scheme, and the system has the ability of 0.28nm motion response.更多还原