导　　师： 李庆祥

学科专业： 080401

授予学位： 硕士

作　　者： ;

机构地区： 清华大学

摘　　要： 论文综述了微夹持器的研究进展、发展趋势和技术特点。总结了微机械悬臂梁的静电、压电、热、电磁等驱动技术，推导了计及边缘效应的梳状静电驱动器静电力公式。 本文设计了大深宽比梳状静电驱动形式的微夹持器，采用了导电型并接地连接的微夹持臂，对被操作对象无特殊要求，且可防止静电对操作的影响。将梳状静电驱动微夹持臂设计成柔性结构，有效解决了静电力小与硅材料的弹性模量高之间的矛盾，使得微夹持器的力输出大大增加。建立了S形柔性夹持臂力学模型，同时给出考虑工艺条件、几何参数等条件下的微夹持器优化设计过程。设计中用有限元方法进行夹持臂模态分析、柔性结构刚度估计等，并对微夹持器工作电场的进行仿真，以考察静电驱动对微操作对象的影响。有限元分析表明，柔性结构使得微夹持臂的刚度降低，而且微夹持臂具有很高的一阶频率，静态设计设计即可满足要求，梳状静电驱动器不会对微操作构成影响。 设计了梳状静电驱动微夹持器的微细加工工艺，对微夹持器制作中的关键工艺进行分析，包括：钻蚀现象、滞后现象、阳极键合、金层剥落等问题。进行了大量的工艺试验和分析，特别对大深宽比的超长长度悬臂梁型夹持臂及梳状驱动结构进行了深入研究，解决了微细加工工艺中的关键技术。成功研制了一种静电驱动微夹持器，其具有大深宽比梳状驱动器，悬臂梁型微夹持臂宽度为6μm，等效长度达5471μm。 对微夹持器的特性进行了测试。采用“显微镜-CCD-微机”测试方案，微夹持器的状态信息通过数据采集及图像处理获取，得到“电压－位移”特性曲线并建立了数学方程。测得夹持器的开合范围为12～140μm，夹持力大于12μN。分析结果表明与理论设计一致，方案新颖，合理可行。 The development and characteristics of microgripper is discussed. Actuation technologies of micro-mechanical cantilever are summarized, and formula for capacitance and electrostatic force involving edge-effect of comb- drive actuator are derived. A comb-drive electrostatically actuated microgripper and its design process are described in detail. Electro-conductive fingers of gripper are connected to ground, in order to release the electric charges on the surface of fingers and gripping objects. Continuous S-shaped flexures in finger would decrease the stiffness of gripping arm, and slove the contradiction between huge elastic modulus and small surface electrostatic force. Mathematical model of S-shaped finger is setup, and optimum design process is also presented under considering technological conditions and physical dimension of gripper. Finite element method /(FEM/) is used in structure analysis and simulation of electric field. Fabrication process of the microgripper based on silicon bulk micromachining is designed. Effects of footing and lag in ICP and bonding failure are discussed as emphases. The cantilever type gripping finger that is 6μm wide and 5471μm in equivalent length was released successfully Characteristic of comb-drive electrostatically actuated microgripper is tested. Informations and statuses of microgripper are acquired by test platform of Microscope-CCD-Computer. Voltage-displacement characteristic of microgripper is obtained by image process. Analysis of characteristic equation indicates that theoretical design is consistent with experiment results. Gripper has a gripping range of 12μm to 140μm. Comb-drive actuator could generate more than 12μN gripping force.

关 键 词： 微夹持器 静电驱动 梳状驱动器 体硅工艺 有限元方法

分 类 号： [TH703]

领　　域： [机械工程] [机械工程]