Precision In-Plane Hand Assembly of Bulk-Microfabricated Components for High-Voltage MEMS Arrays Applications

This paper reports the design and experimental validation of an in-plane assembly method for centimeter-scale bulk-microfabricated components. The method uses mesoscaled deep-reactive-ion-etching (DRIE)-patterned cantilevers that deflect and lock into small v-shaped notches as a result of the hand-exerted rotation between the two components of the assembly. The assembly method is intended for MEMS arrays that necessitate a 3-D electrode structure because of their requirement for low leakage currents and high voltages. The advantages of the assembly method include the ability to decouple the process flow of the components, higher overall device yield, modularity, reassembly capability, and tolerance to differential thermal expansion. Both tapered and untapered cantilevers were studied. Modeling of the cantilever set shows that the springs provide low stiffness while the assembly process is in progress and high stiffness once the assembly is completed, which results in a robust assembly. In addition, analysis of the linearly tapered cantilever predicts that the optimal linearly tapered beam has a cantilever tip height equal to 37% of the cantilever base height, which results in more than a threefold increase in the clamping force for a given cantilever length and deflection, compared to the untapered case. The linear taper profile achieves 80% of the optimal nonlinear taper profile, which would be impractical to fabricate. Analysis of the experimental data reveals a biaxial assembly precision of 6.2-mum rms and a standard deviation of 0.6 mum for assembly repeatability. Electrical insulation was investigated using both thin-film coatings and insulating substrates. Leakage currents less than 1 nA at 2 kV were demonstrated. Finally, this paper provides selected experimental data of a gated MEMS electrospray array as an example of the application of the assembly method.     

空间桁架的人-机协作装配规划与试验验证

该文以空间直立桁架结构的人-机协作装配流程为研究对象,提出一种适用于径向快装桁架模块单元的创新构型,建立了基于状态矩阵和邻接矩阵的桁架结构装配序列、装配模式和装配过程的数学模型。该文还对空间环境下桁架装配的人-机能力约束进行分析,提出基于动素分析的装配任务层级化分解方法,利用比较分配原则制定了适用编程的人-机协作装配任务流程和分配方案。基于所提出方案,通过开展人穿戴模拟宇航服与机械臂协作装配 5 m 长直立桁架结构的地面演示试验,验证了该方案的合理性和组装流程的可行性,为空间大型设施在轨构建提供了技术原理支撑。     

面向网络实验教学的虚拟协同装配技术研究

基于网络实验教学环境下对虚拟协同装配提出的不同需求,分析了其与面向设计的协同装配实现技术之间在定义、目的等方面存在的差异,提出了面向网络教学下虚拟协同装配的概念,并界定了其内涵及实现时需要考虑的因素。研究了支持协同装配的虚拟模型实验室的搭建、虚拟协同装配的语义信息表达模型和装配过程中干涉检测的方法,提出了网络协同虚拟装配实验平台体系的架构方法,并就系统的功能实现、虚拟协同装配执行过程进行了阐述,最后以柱塞泵示例了解系统的初步实现情况。     

Assembly unit partitioning for hull structure in shipbuilding

In order to solve the problem that low automatic degree to the block assembly process design will negatively influence construction cycle time and construction quality in shipbuilding, this paper presents a newly developed determination system of assembly units for the hull structure. Firstly, the assembly information model of a hull block which includes the part information and the linkage information between parts is proposed following the structural features and assembly process of the hull structure. Secondly, the assembly relation matrix is established on the basis of the fuzzy assessment rule and then the fuzzy clustering method to analyze partition of assembly units is given out. Thirdly, through analyzing the assembly ability of hull structures, the set of evaluating indexes is founded whose weights are decided by an analytic hierarchy process (AHP). Meanwhile, the model for the assessment is provided by fuzzy synthetic evaluation (FSE) and the comprehensive assessment values of assembly partition schemes can be computed to judge the final optimization scheme. A block assembly is taken as an example to verify the proposed method, and the results show that it is an effective method for solving the partition problem of hull structures.     

飞机无线电设备总装测试系统研制

为提高飞机总装生产的效率,设计了基于信息化和网络化的飞机无线电设备测试系统,该系统主要提供电子化工艺单及网络化的设备控制管理,由计算机系统辅助完成总装测试生产工作,减轻工人劳动强度,保证了生产的可靠性;本文主要论述了测试系统总体设计思路和软硬件的设计。     

Robust Motion Control for Robotic Assembly Tasks using Variable Structure Control Scheme

The success of robot assembly tasks depends heavily on its ability to handle the interactions which take place between the parts being assembled. In this paper, a robust motion-control method is presented for robot manipulators performing assembly tasks in the presence of dynamic constraints from the environment. Using variable structure model reaching control concept, the control objectives is first formulated as a performance model in the task space. A dynamic compensator is then introduced to form the switching function such that the sliding-mode matches the desired model. A simple variable structure control law is suggested to force the system to reach and stay on the sliding mode so that the specified model is achieved.The proposed method is applied to control the prismatic joint of a selective compliance assembly robot-arm type robot for the insertion of printed circuit board into an edge connector socket. Various amounts of interaction forces are generated during the operation. Experimental and simulation results demonstrated the performance of the variable structure model reaching control approach. In comparison, it is shown that the popular position controllers such as proportional plus derivative control and proportional plus derivative with model-based feedforward control are not suitable for achieving good trajectory tracking accuracy in assembly tasks which experience potential interaction force.     

面向装配序列规划的装配本体设计*

为提高装配序列规划的自动化程度,实现装配相关活动间信息的共享、重用和顺畅传递,实现装配序列规划系统与其它异构系统之间的无缝集成和互操作,将本体技术引入到装配建模中.针对装配序列规划建模需求,构建面向装配序列规划且基于装配对象的装配本体(OWL-ASP).OWL-ASP由Properties本体、AssemblyInfo本体和AssemblySeq本体组成,分别描述装配对象的装配属性、装配信息、装配顺序等.在OWL-ASP的基础上,利用语义Web规则语言刻画装配规则,形成统一的装配知识表示层次体系,实现对装配知识的严格刻画和自动推理.通过球阀装配的实例说明装配本体和装配规则的有效性.     

Assembly sequence planning of rigid and flexible parts

Assembly sequence planning (ASP) is the process of computing a sequence of assembly motions for constituent parts of an assembled final product. ASP is proven to be NP-hard and thus its effective and efficient solution has been a challenge for the researchers in the field. Despite the fact that most assembled products like ships, aircrafts and automobiles are composed of rigid and flexible parts, no work exists for assembly/disassembly sequence planning of flexible parts. This paper lays out a theoretical ground for modeling the deformability of flexible assembly parts by introducing the concept of Assembly stress matrix (ASM) to describe interference relations between parts of an assembly and the amount of compressive stress needed for assembling flexible parts. Also, the Scatter Search (SS) optimization algorithm is customized for this problem to produce high-quality solutions by simultaneously minimizing both the maximum applied stress exerted for performing assembly operations and the number of assembly direction changes. The parameters of this algorithm are tuned by a TOPSIS-Taguchi based tuning method. A number of ASP problems with rigid and flexible parts were solved by the presented SS and other algorithms like Genetic and Memetic algorithms, Simulated Annealing, Breakout Local Search, Iterated Local Search, and Multistart Local Search, and the results and their in-depth statistical analyses showed that the SS outperformed other algorithms by producing the best-known or optimal solutions with highest success rates.     

基于果蝇优化算法的多工位装配序列规划

为同时解决产品装配序列规划和多工位分配问题,提出一种面向复杂产品的基于果蝇优化算法的多工位装配序列规划方法。首先,基于果蝇优化算法设计了针对求解序列的编码体系;其次,采用多子种群并行搜索模式,重新设计了果蝇优化算法的搜索过程;然后,为了综合考虑多工位上相关装配操作成本的影响,提出了新的适应度函数表达式,并将适应度函数与优先序列矩阵结合起来对进化过程进行引导,实现了对产品装配序列和工位分配顺序的优化;最后,以飞机起落架为例,验证了所提方法在解决多目标优化问题方面的有效性。     

Multi-rule Multi-objective Simulated Annealing Algorithm for Straight and U Type Assembly Line Balancing Problems

The task of balancing of assembly lines is of considerable industrial importance. It consists of assigning operations to workstations in a production line in such a way that (1) no assembly precedence constraint is violated, (2) no workstations in the line takes longer than a predefined cycle time to perform all tasks assigned to it, and (3) as few workstations as possible are needed to perform all the tasks in the set. This paper presents a new multiple objective simulated annealing (SA) algorithm for simple (line) and U type assembly line balancing problems with the aim of maximizing “smoothness index” and maximizing the “line performance” (or minimizing the number of workstations). The proposed algorithm makes use of task assignment rules in constructing feasible solutions. The proposed algorithm is tested and compared with literature test problems. The proposed algorithm found the optimal solutions for each problem in short computational times. A detailed performance analysis of the selected task assignment rules is also given in the paper.     

Assembly simulation of multi-branch cables

Cable assembly simulation is a key issue in the computer-aided design (CAD) of products with complex electrical components. In this study, an assembly simulation method is developed to simulate the assembly process of multi-branch cables. First, based on the Cosserat theory of elastic rods, a novel scheme is introduced to model the joints of multi-branch cables. The potential energy of joints is calculated by taking the topology and anatomical features into consideration. Various physical properties are considered. Various constraints, including connectors, collars, and handles are analyzed, based on which the initial conditions of assembly simulation are determined. The configuration of the cable is then calculated by minimizing its potential energy. To increase computational efficiency, GPU acceleration is introduced, which makes the simulation run at interactive rates even for a cable with resolution up to 1000 discrete points. Finally, the proposed algorithm is integrated into the commercial assembly simulation system, DELMIA. Several simulations were performed with our system. It was demonstrated that the proposed method is able to handle cables with complex topologies. In addition, the proposed method is about four times as efficient as a previous method, and it is able to generate realistic configurations of multi-branch cables at interactive rates. Thus, the proposed method is helpful in the assembly process planning of cables.     

Assembly torque data regression using sEMG and inertial signals

Assembly torque monitoring is an important aspect of assembly process monitoring. Currently, in manual assembly lines, torque monitoring sensors are usually installed on assembly tools or assembly jigs. This approach is restricted by the working environment and assembly space. To this end, operators can use wearable devices containing sensors without being restricted by the tool and working spaces, with the added advantage of portability. To use wearable electromyography equipment to monitor the assembly torque, this paper proposes an assembly torque monitoring method using surface electromyography (sEMG) and inertial signals. Two torque regression models, one based on a heterogeneous-kernel-based temporal convolutional network (Het-TCN) and the other based on a two-stream convolutional neural network (CNN), are proposed and compared with CNN, long short-term memory (LSTM), and temporal convolutional network (TCN) models. The experimental results show that, compared with using sEMG signals alone, performing an assembly torque data regression using a combination of sEMG and inertial signals can significantly reduce the regression error. The proposed Het-TCN model has the best regression performance, with an average error of 3.31 N m an RMSE of 9.18 %, and a coefficient of determination R² of 0.72. Thus, the proposed Het-TCN along with the application of both sEMG and inertial signals can help effectively perform assembly torque data regression, which can be used for assembly torque or operation monitoring.     

Assembly sequence planning based on structure cells in open design

Advances in computer network technologies have enabled firms to increasingly utilize external resources to remain competitive. Based on the function-behavior-structure cell (FBSC) modeling and computer network technologies, consumers with design knowledge and experience, called co-designers in this research, can involve in the process of open design (OD) to share their requirements, experiences and knowledge. The structure cells (SCs) provided by the co-designers in OD and the relationships among them are critical for generating the optimal design scheme and assembly sequence planning. However, the existing assembly sequence planning (ASP) approaches mainly focus on identification of the assembly plan based on precedence relations of operations from the predefined parts in the design scheme without considering the utilization of resources available in OD. In this study, a new approach for ASP based on SCs in OD is proposed to tackle this problem. First, the assembly features of the SCs and their matching rules are described in OD, and an approach for calculating the matching intensity between SCs is developed for identifying the assembly relationships between SCs. The design scheme is generated according to the SCs and their assembly relationships. Second, the base part of the design scheme is determined by its correlation degree with other parts. The feasible assembly sequences are derived by reversing the disassembly sequences. As the increase of the number of parts in design scheme will result in the combinatorial explosion of feasible assembly sequences, a particle swarm optimization algorithm is presented to achieve the optimal assembly sequence. A case study is provided to demonstrate the feasibility and effectiveness of the proposed approach.     

复杂约束条件下的分层装配模型

为在装配建模过程中保证信息的完整性,提出基于装配对象属性的分层约束装配模型。以需求块的概念为基础,对装配对象采用先分块再分层的方法进行分组,分析各块、各层之间复杂的约束关系,构建分层约束装配图,完成装配顺序算法的设计。实验结果表明,该模型能有效表达装配形成过程的顺序,实现装配关系的分解和时序化,对象之间的交互过程简单真实且便于操作。     

基于复杂装配体特征抑制的轻量化方法

针对大型复杂三维模型加载速度慢,装配体在装配时由于零部件众多导致装配效 率低的问题,提出一种基于装配体特征抑制的轻量化方法。在充分分析装配体组织结构的基础 上,给出装配约束父子关系以及特征路径提取思路,以保留装配接口为前提,首先采用无关零 部件抑制、按体积抑制比抑制、微小特征抑制等方法,实现复杂装配体的轻量化表示;然后提 出特征恢复技术,实现轻量化模型的特征还原;最后以 Creo 2.0 为二次开发平台,结合 MFC 对话框技术开发出一套装配体轻量化系统,并应用于企业产品模型测试。实验结果表明,利用 该系统得到的轻量化模型简化效果明显,模型数据量大大减小,不仅加快了模型加载速度,而 且提高了装配效率。     

复杂产品装配执行控制系统研究

构建复杂产品装配执行控制系统的整体框架与结构，结合装配工艺流程图转化为装配节点的控制，定义装配数据元与装配状态。将工艺流程节点与装配状态一一映射，并提出基于时间轴下的装配执行状态控制算法，实现装配执行状态进行实时的监控与管理。通过实验验证该装配执行控制系统可靠性与可行性。     

虚拟环境下面向装配的设计系统的研究

虚拟环境下面向装配的设计,是一种集成虚拟现实技术和装配性评价的交叉学科研究,文中提出了一个虚拟环境下面 向装配的设计系统VirDFA(Virtual Design For Assembly)的体系结构,首先描述了虚拟人工实时拆卸的过程,着重研究在实现虚拟人工拆卸过程中,需要解决的装配体物性建模、虚拟环境下装配约束的动态管理及装配序列/路径的自动记录等关键技术,其次,从面向产品结构和装配工艺过程两方面的再设计角度,构建了装配性评价体系,提出了定量的装配效率模型和装配复杂度指标模型。并从装配成本的角度来评价产品的装配性优劣,为产品和装配工艺规划的再设计提供了依据。     

基于单点式力反馈器的虚拟装配研究

针对PHANToM Desktop 力反馈器工作空间狭小的问题,提出改进的动态 空间匹配算法和代理点移出视锥体时的漫游技术。首先分析设备工作空间在三维方向与视锥 体的匹配关系,通过对x、y 和z 轴方向进行空间匹配,实现近视点处操作精度高和远视点 处可视范围大;然后利用映射区外的工作空间进行视点漫游,可以扩展虚拟装配可视范围。 在虚拟装配过程中,实时地计算代理点与零件间的接触力,并反馈给用户,使用户可以感知 零件的几何外形与硬度特性等;同时采取弹簧质点模型计算约束力引导用户进行装配定位。     

基于集成干涉矩阵的蚁群装配序列规划

针对装配序列规划问题,构建了面向装配的蚁群算法。利用有向图进行产品的装配建模,有效地表达了装配零件之间的接触以及优先关系。探讨了装配干涉矩阵的形式和性质,提出了集成干涉矩阵的概念和变换方法,采用集成干涉矩阵以及工具列表矩阵来表达模型的基本装配信息。分析了基于干涉矩阵的可行方向推导过程、装配零件的状态转移概率以及蚁群算法的信息素更新规则。从装配可行方向的改变次数和装配工具的改变次数建立目标优化函数,从而建立面向装配的蚁群算法用于序列的搜索及构造,并给出蚁群算法的伪代码。最后通过实例对算法进行了验证说明。     

基于LabWindows/CVI的无人机燃油组件测试系统的开发

在虚拟仪器技术的基础上,对无人机燃油组件测试系统进行了设计和研究.阐述了该测试系统搭建的全过程和工作原理.采用LabWindows/CVI7.0作为该测试系统的软件开发平台,选定CompactPCI结构为本系统的硬件构成方案.试验结果表明基于虚拟仪器开发的无人机燃油组件测试系统能够满足工程和测试技术的要求.