基于气膜形状控制的主动气浮支承动刚度增强机制与扰动抑制方法

Aerostatic bearings are key components in precision manufacturing equipment. The crucial issue for their applications in ultra-precision machining is to improve the dynamic stiffness and ability of disturbances suppression. Conventional approaches for dynamic stiffness enhancement are to increase pressure of air supply, to reduce air gap, or to optimize the structures. However, this might cause local turbulences in gas film which result in deterioration of stability. Besides, these kind of aerostatic bearings still lack of ability to actively suppress disturbances such as geometrical error of guide way and load variation. This project tries to improve dynamic stiffness and disturbances suppression by means of actively control the shape of gas film via piezoelectric actuator array, so as to guarantee stiffness and stability of aerostatic bearings. Focused on the following two key scientific challenges, i.e., 1) the generation mechanism of load capacity and dynamic stiffness due to dynamic changes of gas film, and 2) the method for film shape control under multi-physics effect, this project will carry out the following studies: multi-physics modeling and analysis of active aerostatic bearings, analysis of the relationship between dynamic change of gas film and the dynamic stiffness, optimal design of active aerostatic bearings with piezoelectric actuator array, on online measurement and control of suspension status, and development and experimental verification on active aerostatic bearing prototype. Based on the aforementioned researches, the influences of dynamic gas film shape on the load capacity & dynamic stiffness will be revealed, and the mechanism of dynamic stiffness enhancement via gas film shape control by means of piezoelectric actuator array will be clarified. Research achievements of this project will facilitate development of high performance suspension components in ultra-precision manufacturing machines both scientifically and technically.

空气静压支承是超精密制造装备中的关键部件，提高动刚度和抗扰动能力是使其满足超精密加工需求的核心。通常通过增供压、降膜厚、优化支承结构等手段来提高动刚度，但这易导致气膜内局部气流紊乱而降低稳定性，且仍不能主动消减导轨误差和负载扰动。本项目试图利用阵列式压电智能结构主动调控气膜形状，提高支承动刚度并主动抑制扰动，从而保证支承刚度和稳定性。为此，围绕动态变化气膜的承载力和动刚度形成机制、多物理量/场作用下气膜形状的主动调控方法两个科学问题，开展以下研究工作：多物理量/场统一建模与分析，动态气膜形态与动刚度的关系解析，含压电智能结构的主动气浮支承结构优化设计，支承状态的在线测量与控制方法，主动气浮支承原型的搭建与实验测试。通过上述研究，揭示气膜形状及其动态变化规律对的承载力和动刚度的影响规律，阐明阵列式压电智能结构主动调控气膜形状、增强动刚度的机制，为高性能运动支承部件的设计提供理论和技术支持。

面向超精密制造装备中工作台气浮支承部件的高承载、高刚度需求，以内嵌阵列式压电结构的主动气浮支承为对象，围绕压电结构作动下气膜形状的变化规律及其对支承动刚度的影响机制问题，开展多物理量/场统一建模与分析、动态气膜形态与动刚度的关系解析、主动气浮支承的结构优化设计、支承特性的测量与控制方法、主动气浮支承原型搭建与实验测试等研究，取得以下主要成果：.1.针对主动气浮支承中复杂流场计算规模大、难收敛的难题，提出一种分区域的混合计算方法，在节流孔邻域和气膜区域分别采用N-S方程和雷诺方程求解，在同等计算精度的前提下，计算速度提高8-12倍；.2.基于摄动法揭示了气膜摄动频率及幅值对空气静压支承动刚度的影响，研究发现动刚度对气膜摄动频率的敏感度远高于气膜摄动幅值，提高摄动频率对动刚度增强极为有效，当摄动频率达200Hz时，支承动刚度可提高1倍；.3.综合考虑动刚度主动调控的幅度和频宽需求，研究了圆盘形主动气浮支承中压电结构的阵列方式及作动规律对气膜锥度及褶皱特性的影响规律，据此优化了主动气浮支承的结构，研制了主动气浮支承原型；.4.搭建了主动气浮支承动态特性试验系统，提出了基于压敏材料的气体流场压强分布测量新方法，采用直流偏置+微幅谐波的激励方式，驱动压电结构动态调控气膜形状，使主动气浮支承的动刚度提升50%以上。.完成了项目任务书规定的各项考核指标。揭示了气膜形状动态变化对承载力和动刚度的影响规律，阐明了通过压电结构调控气膜形状来增强动刚度的机制，提出了基于气膜形状控制的主动气浮支承新构型和控制方法，为高性能空气静压支承的设计提供了理论指导。.研究成果在“极大规模集成电路制造装备及成套工艺”国家科技重大专项相关项目中得到成功应用，指导了65nm光刻机双工件台的精密气浮支承动态特性分析与优化，并为面向45-22nm节点的硅片颗粒污染检测工作台研发了精密气浮转台，有力支撑了相关项目的顺利实施。