一种集成三维微力传感器的微夹持器研制

微操作中力的检测与控制是实现无损伤操作的关键。因此,该文提出了一种以压阻检测技术为基础,集成三维微力传感器的微夹持器。传感器标定实验结果表明,该传感器具有耦合小,测量分辨率高,线性度好的优点。传感器量程为-10~ 10 mN,在x、y向的分辨率均为2.4μN,z向的分辨率为4.2μN。微夹持器采用压电陶瓷驱动两级柔性放大机构,实现张合量300μm,完成了微夹持实验。     

面向三维组装的微纳平台设计与研究

针对20~40μm尺寸范围的微对象夹持需求,设计了一种压电驱动的微组装夹持器平台。使用有限元分析优化了夹持器的结构参数。该平台可以实现两指与三指操作模式的转换及对多种微对象的柔性操作。该文绘制了实验平台中压电陶瓷的驱动电压与执行末端位移的关系,单指的驱动范围0~41μm。压电陶瓷对该平台的输出位移分辨率达到了0.5μm/V。以直径20μm、40μm两种尺寸的硼硅酸盐玻璃球为操作对象,完成了夹持、释放及三维模型组装实验。     

仿生超疏水表面在微夹持器钳口端面的应用研究

微夹持器是微操作系统的重要组成部分。作为微操作系统末端执行器,微夹持器钳口端面在工作过程中容易出现磨损、吸附杂质、结冰或结霜等问题,而且目前微夹持器大多是一体化加工而成,整体更换将造成资源浪费。本文设计了一种可拆卸式微夹持器,利用中心波长为1064 nm的纳秒激光器,在执行操作的钳口端面上加工出粗糙的微纳结构,使用无毒害的硬脂酸溶液浸泡改性,获得仿生超疏水表面。通过电化学实验,测试了仿生超疏水表面在酸、盐和碱环境中的耐腐蚀性能,通过自清洁、抗结冰和抗菌实验测试了该表面的防污、防冻和防菌性能。实验结果表明：仿生超疏水表面能够有效抵抗酸、盐和碱环境中的腐蚀,具有良好的防腐性能;有效防止灰尘、水滴和细菌等杂质粘附于钳口端面,保证钳口端面的清洁与卫生;在低温环境中,有效防止端面结霜或结冰,使微夹持器能够在恶劣环境中正常工作。     

基于压电材料的引线键合微夹持器设计

引线微夹持器是IC/LED键合系统的关键模块.该文综合采用压电智能材料与柔性联接的组合结构,设计了键合系统的引线微夹持器.利用有限元法,计算了微夹持器的振动模态与静力特性,获得了系统的固有频率、振动模态及电信号驱动下的支臂端部张开量.在实验上,通过高速摄像系统的跟踪实验,捕获了系统支臂端部的运动行为,获得了系统张开量与驱动电压的关系;并用激光非接触测量技术,获得系统端部的振动特性.该文计算与实验均为引线微夹持器的可靠性应用提供基础.     

组合式微夹持器控制系统的研制

将微直线电机宏动机构与双晶片压电悬梁微动机构结合,研制高精度、大范围的组合式微夹持器．针对宏微结合的结构形式,设计组合式微夹持器宏微控制系统。采用仿人智能PI控制方法,提高了控制精度。测试实验表明,闭环控制系统取得较好效果．     

硅基微光学平台的设计和制作北大核心

微型的、可重复装配的、硅基的微光学实验平台和操作平台对于实现光学分析仪器的微型化具有重要的研究意义。设计制作了一种硅基的微光学平台,它包含有微光学基板和微光学夹持片。首先采用有限元分析软件Comsol对微光学夹持片的关键结构即弹片进行了应力仿真,确定了弹片在被拉伸过程中断裂时的最大位移,而后在此基础上设计了一种微光学基板和几种微光学夹持片。实验中采用微电子的工艺,通过配合使用电感耦合等离子体(ICP)干法刻蚀和各向异性湿法腐蚀工艺制备了微光学基板和微光学夹持片的样品。最后将二者装配在一起,从而建立起一个硅基的微光学平台。并且,夹持片可以在基板上实现滑动和重复装配。     

压电微夹钳钳指位移与夹持力的自感知研究

采用双晶片型压电执行器,对微夹钳进行了结构设计。根据压电陶瓷晶体变形的本质是极化及极化与表面电荷的关系,提出了基于积分电荷的钳指位移与夹持力的自感知方法。基于Jan G.Smits的压电悬臂梁静态模型,建立了钳指位移与夹持力的自感知数学模型。实验结果表明,静态或低频情况下,自感知的钳指位移同传感器获得的钳指位移具有很好的一致性;自感知方法所获得的夹持力(最大值为0.072N)大于微量电子天平的测量结果(最大值为0.052N),通过对自感知夹持力曲线进行相应的系数修正,自感知方法所获得的结果能很好地反映夹持力的真实大小。     

压电微夹钳钳指位移与夹持力的自感知研究

采用双晶片型压电执行器,对微夹钳进行了结构设计。根据压电陶瓷晶体变形的本质是极化及极化与表面电荷的关系,提出了基于积分电荷的钳指位移与夹持力的自感知方法。基于Jan G.Smits的压电悬臂梁静态模型,建立了钳指位移与夹持力的自感知数学模型。实验结果表明,静态或低频情况下,自感知的钳指位移同传感器获得的钳指位移具有很好的一致性;自感知方法所获得的夹持力(最大值为0.072N)大于微量电子天平的测量结果(最大值为0.052N),通过对自感知夹持力曲线进行相应的系数修正,自感知方法所获得的结果能很好地反映夹持力的真实大小。     

局部环状电极压电驱动器制备与夹持力测试

采用丝网电极印刷法制备了局部环状电极压电驱动器,并对其动力进行了测试研究。搭建了夹持力测试平台,对局部环状电极压电驱动器和传统压电驱动器的径向夹持力进行测试和分析。实验结果表明,分别在频率为0.2 Hz和峰值200 V的方波和正弦波激励下,局部环状电极压电驱动器带电极区的径向夹持力峰值分别为0.60 N和0.58 N,两种夹持力峰值响应分别是传统元件的2.72倍和2.76倍。无电极区的反向夹持力峰值为0.29 N和0.28 N,其略大于传统元件的夹持力峰值,实验结果同时验证了局部环状电极压电驱动器的正交异性。     

快慢自适应大夹持力机构设计及实验验证

通过快慢自适应夹持机构的锁紧和开启可以实现部件之间紧密地连接和分离,为保证提供足够且稳定的垂向夹持力,在该机构设计过程中采用了大杠杆比例的机械原理;同时考虑到部件之间的连接需要快速完成,在该机构设计过程中考虑了气路原理设计和电气控制逻辑及方案,共同完成自动判断夹持快慢的时间段。利用精密力传感器对该机构进行夹持力的测试,测试结果表明该设计具有足够的可靠性及稳定性。     

Design,manufacture, and clamping operation of a 4-DOF piezoelectric micro-gripper

To improve the operational flexibility of the piezoelectric microgripper, a new four-degree-of-freedom piezoelectric microgripper was designed and fabricated. The clamp fingers can move both along the clamping direction and along its vertical direction. Also, clamping experiments were conducted on a φ 300 μm × 20 mm micro-shaft. Based on the transverse inverse piezoelectric effect of two groups of vertical intersections, a new configuration of a four-degree-of-freedom piezoelectric micro-gripper is designed. It can produce micro-displacement along the clamping direction and vertical clamping direction simultaneously. According to the Euler-Bernoulli beam equation, the Lagrangian function method and Hamilton variational principle are used to model the four-degree-of-freedom piezoelectric micro-gripper. Then, based on the optimization of the geometric parameters of the fingers, the static and dynamic characteristics of the microgripper are analyzed by the finite element method. After that, the micro-gripper is made using lithography, gluing, and laser cutting. Finally, the piezoelectric microgripper's static and dynamic characteristics and the micro-shaft's clamping operation are tested by experiments. The experimental results show that the maximum displacement, response time, and natural frequency of the designed micro-gripper along and perpendicular to the clamping direction agree well with the finite element simulation. The designed microgripper exhibits a promising prospect in practical micromanipulation applications.     

Modeling and analysis of electrostatic force for robot handling offabric materials

Electrostatic force has received considerable interest in recent years for handling small objects in microsystems and microengineering applications, but little work has been carried out to study its use in handling large-size objects. This paper discusses the principles of a robotic electrostatic gripping device for the handling of large-size fabric plies. A theory is derived to describe the dynamic behavior of the charging/discharging processes of the gripping surface. Mathematical equations are developed to relate the dynamic performance of the gripping force to the device's design parameters and the properties of materials being handled. An automated experimental process is employed to validate the theory. The theoretical modeling and analysis of the gripping force has allowed optimization of the gripper's design parameters for practical materials handling applications. The design and construction of an electrostatic gripper for fabric handling in aerospace applications are discussed     

Characteristic analysis of a novel in-pipe driving robot

Gas and liquid pipelines are all around us in today’s society. The frequent inspection and maintenance of such pipeline grids is very important, especially for urban areas where there are dense populations. Many driving mechanisms for in-pipe crawling have been reported in previous studies. In this paper, a novel in-pipe drive design is presented. The proposed design uses modular helical drives. In between helical drives is a conic coil spring that allows extension and retraction. Since conic springs can be designed with telescopic feature, the proposed design can be made very compact. Furthermore, the proposed design also has much better mobility when turning a bend due to its flexible body (conic springs make the inchworm robot a compliant mechanism). The proposed design can be controlled with three modes of motion: synchronized motion (for small load), inchworm motion (for medium load), and rigid motion (for heavy load). Analysis on gripping force, locomotion force, together with experimental results will be presented as well.     

微进给刀架中位移放大机构的优化设计

基于压电陶瓷驱动的刀具微进给机构是满足精密加工的重要途径,为进一步增加微进给刀架驱动位移,在微进给刀架中增加一种柔性铰链微位移放大机构,增加压电陶瓷驱动器输出位移。该文设计了4种微位移放大机构,理论计算了静态刚度,利用ANSYS软件对4种微位移放大机构进行了建模和有限元数值仿真分析,对比了不同类型的微位移放大机构的放大倍数、负载能力和应力情况等静态特性,为优化设计刀具微进给机构打下良好基础。     

Identification and control of a sensorized microgripper for micromanipulation

This paper presents the design and control of a sensorized microgripper using a voice coil motor and a flexure mechanism. To increase the gripping sensitivity, shape design and determination of sensor attachment position are performed using finite element analysis. Empirical models of the microgripper are acquired for the design of position control and gripping force control. By using the identified models, both the perfect tracking controller for position control and the adaptive zero-phase error tracking controller for force control are implemented. The effectiveness of the proposed model-based control methods is verified by experimental studies.     

Device for nanoobject manipulation based on two-layer composite with shape memory

A device for gripping of microand nanoobjects (nanotweezers) with a working body made of bimetal composite (fast-quenched Ti₂NiCu alloy with shape memory and platinum layer) is developed and studied. A method for manufacturing of the composite material using local ion etching and ion-stimulated deposition from gas phase is proposed. A structure of nanotweezers based on such a composite and experiments on gripping and displacement of submicron objects are presented.     

轴向压缩悬臂梁压电双晶片动静态特性研究

研究施加轴向压缩力于悬臂梁压电双晶片端部以增大端部输出位移和力的问题,对其进行了有限元分析,并推导了弹性力学解析解及模态方程,得到了符合程度较好的结果。研究结果表明,在120V电压及5.5N轴向力作用下,端部阻塞力达0.25N,输出位移较原来增大3倍以上(达5mm),而一阶特征频率随轴向力增大而加速减小。当轴向力达到一阶临界屈曲时,一阶特征频率趋于0,但当轴向力取一阶屈曲力的70%时,其1阶固有频率仍有45Hz,相较于普通伺服舵机有较大的优势,可有效提高微小型飞行器的操稳性。     

微加工硅表面基于AFM的纳米压痕测量与分析

原子力显微镜 (AFM )在完成对单晶硅的微加工后 ,其金刚石针尖被用做一个纳米压痕头以实现微加工区域内外机械性质的测量与分析。结果表明 ,以安装有金刚石针尖的AFM在经过化学机械抛光的硅基片上所进行的微加工 ,即使使用极小的切削力也会在加工表面形成变质层 ,但是其厚度值要小于化学机械抛光的硅表面变质层。由AFM测量的纳米级硬度值要大于由传统的Vickers和Hysitron硬度测试仪所测量的值。另外 ,随着AFM压入载荷的减小 ,纳米级硬度值呈现出增加的趋势 ,这是由于在很小的压入载荷下所呈现出的压痕尺寸效应所导致     

A compliant dual-axis gripper with integrated position and force sensing

This paper proposes a new flexure-based dual-axis gripper driven by two piezoelectric actuators (PEAs). For achieving two degree-of-freedom (2-DOF) micromanipulation in terms of grasping and rotating operation, the gripper is designed with an asymmetric structure which can be divided into left and right parts. Each part of the structure includes a two-stage amplification mechanism to accomplish displacement enlargement and motion transmission. Three groups of strain gages are integrated to measure the jaw displacements and the gripping force. To realize decoupling between the grasping and rotating function, the motion-guiding mechanisms of the two parts are elaborately designed with an orthogonal configuration. Analytical models of the gripper are derived using pseudo-rigid-body model (PRBM) method. Finite-element analysis (FEA) simulations are conducted to obtain the optimal geometric parameters and to evaluate the performance of the gripper. A close-loop position/force switching control strategy based on incremental PID algorithm is proposed to compensate the hysteretic nonlinearity of PEAs and guarantee precise and stable operation of the gripper. After that, a prototype gripper is developed and experimental investigations are conducted to verify the effectiveness of the gripper by executing a grasping-rotating-releasing operation of a metal wire. The experimental results indicate that the proposed gripper is capable of delicate and dexterous micromanipulation.     

微惯性开关设计技术综述

微惯性开关作为微惯性传感器中的一类特殊器件在设计方面因应用背景的差异存在多种技术方案。通过描述惯性开关的工作原理和分类,介绍了国内外微惯性开关的研究概况,针对线性低g值微惯性开关闭合接触力小,触点接触弹跳,硅基导电性较差等共性问题进行了分析和讨论,提出了引入静电力或磁力以增大接触力,采用柔性接触结构以实现平稳接触,采用硅金属化工艺以实现良好的导电性等解决办法,可供微惯性开关结构设计时参考。