Review of the wafer stage for nanoimprint lithography

Nanoimprint lithography (NIL) has been flagged as one of the most promising processes for next generation lithography due to its simplicity, low cost, high replication fidelity and relatively high throughput. As a key subsystem, the ultra-precision positioning substrate stage plays a particularly critical role for NIL machines. This paper summarizes firstly various schemes of substrate stages. Subsequently, the issue of actively controlled stages versus passive compliant stages is to be discussed. Furthermore, based on the investigation for numerous ultra-precision positioning stages and considering the practically functional requirements for the step and flash imprint lithography (SFIL) machine, two preliminary schemes to implement the six-degree-of-freedom active control for SFIL stage with multi-step and multi-level functions were proposed. Finally, some useful conclusions are presented. As a result, the objective of the investigation is to offer some proposals and schemes to develop a practical SFIL stepper and further improving the performance of current SFIL machines.     

复合型柔性腕的新型结构设计

文章主要致力于大位移误差补偿问题,对复合柔性腕的开发以及设计进行了有关结构方案的研究.针对柔性腕的特殊使用要求,在传统RCC(Remote Center Compliance远中心柔顺结构)的基础上,对普通的RCC进行了结构创新,开发设计了复合柔顺手腕.     

I/O互联技术及体系结构的研究与发展

I／O互联技术及体系结陶正在发生重大变革,相继涌现了一系列新兴高性能I／O互联技术,包括PCIExpress、RapidIO、HyperTransport以及InfiniBand。该文对它们分别予以研究介绍,针对各自的体系结构、技术特性和应用领域,分别提出了一种合理的系统结构方案。并对这几种I／O互联技术的主要技术特性进行了简要而全面的比较,分析了I／O互联技术及体系结构的现状与发展趋势。     

双向压电驱动的二维快速伺服刀架

快速伺服刀架能够提供精确、快速的微纳米级运动.为了获得双向和二维运动,该文研制了一种双向压电驱动的二维快速伺服刀架.该刀架采用对称结构设计,结合柔顺放大机构和位移解耦机构,末端执行机构实现较大的输出位移,同时减小耦合位移.基于伪刚体模型,建立快速伺服刀架的静力学和动力学模型,得到机构的输出位移、输出耦合比、最大应力和固...     

压电双晶片驱动的仿生柔性扑翼机构研究

分析了昆虫的翅膀-胸部运动系统,并以此为基础,仿生设计出压电双晶片驱动,柔性双摇杆机构放大位移并带动仿生翅拍动的扑翼系统.分析了压电双晶片的工作原理,讨论了柔性四杆机构的自由度和运动学,并对整个系统的准静力学进行探讨,以确定能否产生足够的力克服空气阻尼.仿真和实验结果表明,通过柔性机构放大压电双晶片位移,能实现仿生翅所需运动,同时进一步的优化设计将有助于改进扑翼机构的运动性能.     

Topology optimization of compliant mechanisms using the homogenization method

A procedure to obtain a topology of an optimal structure considering flexibility is presented. The methodology is based on a mutual energy concept for formulation of flexibility and the homogenization method. A multi-objective optimization problem is formulated as an application of compliant mechanism design. Some examples of the design of compliant mechanisms for plane structures are presented. © 1998 John Wiley & Sons, Ltd.     

边界层控制法减阻技术研究进展

船舶及水下航行器减阻技术一直备受关注,通过控制其壁面边界层的流态是实现减阻的有效途径之一。该文对当前世界范围内边界层控制法减阻技术进行了整理和归纳,着重介绍了肋条减阻、柔顺壁减阻和疏水减阻3种减阻技术的含义和研究现状,并分别对其减阻机理进行了系统分析,同时简要介绍了气幕减阻、壁面吸入法以及壁面加热和冷却法等其他减阻技术。最后,针对目前研究中存在的不足,提出应重视减阻机理研究、多种减阻方式相结合以及理论研究与工程应用相结合的几点建议。     

重载液压机械臂末端夹持装置柔顺控制器研究

灾难救援机器人能够在危险环境下代替人类实施救援任务,由于灾害现场复杂多变,空间紧张,救援机器人往往需要在重载条件下进行工作。大型液压机械臂末端夹持装置,存在阻尼低、刚度弱、易振荡等固有缺陷,且夹持装置直接与环境接触,其耦合规律复杂,阻尼/刚度性能难以精细调控,夹持装置不能实现柔顺控制,极大限制了机械臂与环境的交互,甚至会造成人员伤亡和财产损失。采用阻抗控制中的导纳控制,对救援机器人的末端液压夹持装置进行柔顺控制,通过AMESim-Simulink联合仿真平台,搭建夹持装置模型进行仿真验证。仿真结果表明,采用导纳控制器的夹持装置与环境柔顺交互,取得了较好的控制效果。     

基于双向渐进结构优化法的柔性机构设计

基于双向渐进结构优化法提出一种面向柔性机构的拓扑优化设计策略。由于采用0/1离散拓扑设计变量和启发式变量更新机制,双向渐进结构优化法一般适用于结构刚度相关的凸优化设计问题。柔性机构以最大化驱动端的位移为设计目标,属于典型的非凸优化问题,难以直接应用该方法开展相应的设计。针对于此,通过定义一种由驱动位移和刚度特性（柔顺度）加权平均的优化目标函数,实现基于双向渐进结构优化法的柔性机构设计。该优化目标函数具有双重功效：（1）通过逐步（设计迭代步）衰减刚度特性的贡献,实现优化问题由刚度设计向驱动设计的动态演化,可应用双向渐进结构优化法开展机构的拓扑构型设计;（2）通过调节加权系数,实现对设计机构的驱动性能和刚度特性的灵活匹配调控,可有效抑制铰链的形成、防止应力集中引起的失效。典型算例的设计结果显示,提出的发展的演化式设计策略可实现稳健且高效的柔性机构设计。     

Optimized Flexural Hinges for Compliant Micromechanisms

In this work a procedure for the optimal design of flexural hinges to be microfabricated by a lithographic process is proposed. The structural optimization problem is approached by coupling a parametric finite element model to an optimization algorithm. A computer code was developed to generate the mesh at each optimization step accordingly to the values of the design parameters provided by an optimization toolbox. The objective function is the rotation of the mechanism, which must be maximized. The solution is constrained by strength and kinematical requirements. The notch shape is described by spline functions according to an original procedure developed by the authors. Results show that, with respect to the usual design approach, the proposed method permits a significant improvement of the hinge characteristic to be obtained.Francesco De Bona Born in Udine (Italy), on July 8th, 1959. Graduated Mechanical Engineer in 1983 and PhD in Applied Mechanics at Politecnico di Torino in 1987. Head of the Micromechanics laboratory at Sincrotrone Trieste from 1988 to 1995. Since 1996 in staff at DIEGM, Università di Udine. Since 2000 full professor of Applied Mechanics at Università di Udine. Research activity in computational and experimental mechanics for biomedical applications, aerospace, microfabrication and microsystems design. Scientific coordinator of 3 European Union research projects on microsystems. More then 70 scientific publications, 3 patents.Mircea Gh. Munteanu Born in Brasov (Romania), on April 5th, 1946. Graduated Mechanical Engineer in 1968 and PhD in Applied Mechanics at Transilvania University of Brasov, Romania. Since 1979 in staff at Stress Analysis and Mechanical Vibrations, Transilvania University of Brasov. Since 1993 full professor Stress Analysis and Mechanical Vibrations, Transilvania University of Brasov. Invited professor at Università di Udine, Italia, in the framework of a grant related to microsystems design. Research activity on static and dynamic FEM analysis of mechanical structures, multibody systems, precision engineering, microsystem design. More then 100 publications on national and international journals and congresses, several books.