Universal Mechanism Modeling Method in Virtual Assembly Environment

Motion simulation and performance analysis of mechanism are important methods for analyzing assembly quality after finishing assembly simulation in virtual assembly environment. However, most simulation systems have no function of mechanism motion simulation due to the randomicity of mechanism and lack of universal mechanism modeling method. In order to realize the simulation of any mechanism after finishing assembly simulation in a virtual environment, a new universal mechanism modeling method is presented. Two main models are contained in the mechanism model： information model and mathematical model. Firstly, the information model of mechanism is proposed to describe the data structure of mechanism which contains bottom geometry data, information of constraint, link, kinematic pair and physical data. Because the object of mechanism simulation is the assembly, which is assembled during the process of assembly simulation, the information of mechanism can be obtained automatically through mechanism automatic search method. Secondly, mathematical model of mechanism is presented. The mathematical model uses mathematical method to express the mechanism. In order to realize the automatic expression of any random mechanism, basic constraint library is presented, consequently random mechanism can be described based on the basic constraint library. Finally, two examples are introduced to validate the method in the prototype system named VAPP（Virtual Assembly Process Planning）. The validation result shows that the mechanism modeling provides a universal modeling method for mechanism motion simulation in virtual assembly environment. This research has important effect on the development both of mechanism motion simulation and virtual assembly.

Force Feedback Coupling with Dynamics for Physical Simulation of Product Assembly and Operation Performance

Most existing force feedback methods are still difficult to meet the requirements of real-time force calculation in virtual assembly and operation with complex objects. In addition, there is often an assumption that the controlled objects are completely flee and the target object is only completely fixed or flee, thus, the dynamics of the kinematic chain where the controlled objects are located are neglected during the physical simulation of the product manipulation with force feedback interaction. This paper proposes a physical simulation method of product assembly and operation manipulation based on statistically learned contact force prediction model and the coupling of force feedback and dynamics. In the proposed method, based on hidden Markov model （HMM） and local weighting learning （LWL）, contact force prediction model is constructed, which can estimate the contact force in real time during interaction. Based on computational load balance model, the computing resources are dynamically assigned and the dynamics integral step is optimized. In addition, smoothing process is performed to the force feedback on the synchronization points. Consequently, we can solve the coupling and synchronization problems of high-frequency feedback force servo. low-frequency dynamics solver servo and scene rendering servo, and realize highly stable and accurate force feedback in the physical simulation of product assembly and operation manipulation. This research proposes a physical simulation method of product assembly and operation manipulation.

Creation and Evaluation of a Multi-sensory Virtual Assembly Environment

The multi-modal information presentation, integrated into the virtual environment （VE）, has potential for stimulating different senses, improving the user＇s impression of immersion, and increasing the amount of information that is accepted and processed by the user＇s perception system. The increase of the useful feedback information may reduce the user＇s cognitive load, thus enhancing the user＇s efficiency and performance while interacting with VEs. This paper presents our creation of a multi-sensory virtual assembly environment （VAE） and the evaluation of the effects of multi-sensory feedback on the usability. The VAE brings together complex technologies such as constraint-based assembly simulation, optical motion tracking technology, and real-time 3D sound generation technology around a virtual reality workbench and a common software platform. The usability evaluation is in terms of its three attributes： efficiency of use, user satisfaction, and reliability. These are addressed by using task completion times （TCTs）, questionnaires, and human performance error rates （HPERs）, respectively. Two assembly tasks have been used to perform the experiments, using sixteen participants. The outcomes showed that the multi-sensory feedback could improve the usability. They also indicated that the integrated feedback offered better usability than either feedback used in isolation. Most participants preferred the integrated feedback to either feedback （visual or auditory） or no feedback. The participants＇ comments demonstrated that nonrealistic or inappropriate feedback had negative effects on the usability, and easily made them feel frustrated. The possible reasons behind the outcomes are also analysed by using a unifying human computer interaction framework. The implications, concluded from the outcomes of this work, can serve as useful guidelines for improving VE system design and implementation.

Research on an Integrated Modeling Method of Virtual Ship Assembly

A new method of virtual ship assembly modeling which integrates ship three-dimensional design and ship construction planning was described in this paper. A workflow model of simulation modeling based on the virtual ship assembly process was also established; furthermore, a method of information transformation between the ship three-dimensional design and ship construction plan was formulated. To meet the requirements of information sharing between different systems in the ship virtual assembly, a simulation database was created by using the software engineering design method and the relational data model. With the application of this database, the information of ship three-dimensional design, construction planning, and virtual assembly can be integrated into one system. Subsequently, this new method was applied as a tool to simulate the virtual assembly of a ship, and the results guarantee its rationality and reliability.

Comparison of the Feasible Schemes for HT-7U Assembly Simulation

The whole superconducting HT-7U Tokamak is a high-cost and large-scale complicated device. The assembly requirement of HT-7U device is arduous and strict. At present, there have been no guiding principle for the assembly of the device, but assembly simulation can help the engineer plan and make decision by an intuitional and visual way before its actual assembly. The problem is that which scheme is most suitable should be solved primarily. From current research situation and technology progress of assembly simulation, this paper explained and analyzed four kinds of technological schemes of assembly simulation in common use. Finally, we got the most feasible scheme that was suitable for HT-7U assembly simulation by comparing their technological issues and difficult points of simulation among the four kinds of feasible schemes.

基于Plant Simulation的航空用柔性制造系统仿真优化

针对航空发动机柔性制造单元,利用Plant Simulation仿真软件建立了制造单元设备模型,使用实际数据设置参数,分析制造单元布局、产量、设备利用率和缓存库位等生产信息。实际仿真结果表明,单元布局得到了合理优化,产量可达到优化前的2倍,模型能够准确分析出各制造单元是否存在瓶颈工序,同时分析缓存库位,给出库位需求。此外,运用D-H法建立机器人运动模型,对制造单元内机器人的几何运动开展路径优化和干涉分析等虚拟运动仿真,并建立人体模型及动作设置,开展了人机工程分析。上述仿真优化实际应用到航空用环形件柔性制造系统关键环节的设计中,缩短了航空柔性制造系统工程设计研发周期、降低成本、减小建设及生产安全风险。

Virtual assembly framework for performance analysis of large optics

Background A longstanding technological challenge exists regarding the precise assembly design and performance optimization of large optics in high power laser facilities,comprising a combination of many complex problems involving mechanical,material,and laser beam physics.Method In this study,an augmented virtual assembly framework based on a multiphysics analysis and digital simulation is presented for the assembly optimization of large optics.This framework focuses on the fundamental impact of the structural and assembly parameters of a product on its optical performance;three-dimensional simulation technologies improve the accuracy and measurability of the impact.Intelligent iterative computation algorithms have been developed to optimize the assembly plan of large optics,which are significantly affected by a series of constraints including dynamic loads and nonlinear ambient excitations.Results Finally,using a 410-mm-aperture frequency converter as the study case,we present a detailed illustration and discussion to validate the performance of the proposed system in large optics assembly and installation engineering.

增强现实环境下装配操作感知方法研究

现有的自然虚拟装配操作交互模型对双手协同操作和单步操作工作量的表达存在不足,针对这个问题,提出增强现实装配操作感知模型,实现机械装配操作参数化表达。提出基于装配运动特征的虚拟物体位姿计算方法,建立模型的真实手部元素与被操作虚拟物体元素的运动关联,满足模型对虚拟物体位姿求解的需求。提出基于模型元素的模型关键状态计算方法,满足模型运行需求。开发了应用案例,实验表明,模型可表达五种常见装配操作,满足装配培训需求。

垂荡模拟联合视觉虚拟涌浪防晕动症习服训练的效果研究

目的研究正弦垂荡刺激、视觉虚拟现实(VR)涌浪刺激和两者联合刺激条件下的防晕动症习服时间和习服效果。方法通过海上实航6 h筛选120名极重度晕动症者,随机分为4组(n=30):垂荡训练组、VR训练组、垂荡+VR训练组和对照训练组。采用Graybiel量表评估训练期间每日的症状严重程度,记录VR训练组的弹性踏台掉落次数,以连续3 d Graybiel评分为0分和/或弹性踏台掉落次数为0次判定为完全习服。采用比筛选时更恶劣海况条件下的海上实航验证训练效果。结果垂荡训练组、垂荡+VR训练组的Graybiel评分及VR训练组的弹性踏台掉落次数均随着训练天数的增加而下降,并分别于训练第3天、第5天和第2天达到习服水平。垂荡训练组、垂荡+VR训练组、VR训练组的最长习服时间分别为8、8、5 d,平均习服时间分别为3.6、3.9、2.7 d,5 d习服率分别为93.33%(28/30)、76.67%(23/30)、100.00%(30/30),海上实航验证期间习服训练有效人数占比分别为86.67%(26/30)、96.67%(29/30)、66.67%(20/30),训练有效率分别为85.19%、96.30%、62.97%。结论3种训练方法均有明确的防晕动症习服训练效果,且习服时间仅为5~8 d。垂荡和垂荡+VR训练的习服效果优于VR训练。

VR技术在船舶分段装配实训教学中的应用

VR技术与传统教学的融合是现阶段教育教学的一个发展趋势。基于当前VR技术在实训教学中的现状,探讨VR技术在船舶分段装配仿真实训教学中的作用和意义,并具体分析了VR技术在船舶分段装配实训教学中的应用。通过调查分析证明了VR技术在船舶分段装配仿真实训教学中的应用效果,最后提出推进VR技术在船舶分段装配仿真实训教学中的具体操作建议。

微电阻率扫描测井仪推靠系统运动精度可靠性分析

微电阻率扫描测井仪具有高井壁覆盖率、高分辨率、直观可视等特点,能够提高测井精度,尤其是在薄层识别上,能够进行清晰准确地判别。为研究微电阻率测井仪推靠系统运动精度可靠性,通过应用MATLAB和ADAMS两个软件,基于Monte-Carlo方法,针对推靠系统的极板、推杆支臂和相应杆件及间隙进行运动仿真,并进行运动精度可靠性分析。结果表明,推靠系统误差模型测量点位移变化比速度和加速度变化更加明显,位移变化对可靠性的影响比速度和加速度对可靠性的影响更大。应用MATLAB软件计算得出的运动精度可靠度为0.9830,应用ADAMS软件虚拟样机仿真得出的运动精度可靠度为0.9887。两种方法可靠度计算结果接近,误差为0.57%。

基于三维运动捕捉技术构建蒙医震脑术三维虚拟仿真平台的视觉呈现

背景:基于三维运动捕捉技术可以构建精准的、客观量化的医学虚拟仿真模型,有利于临床学习者精准、深入理解和掌握各种传统疗术。目前中医虚拟仿真模型已有报道,但蒙医传统疗术的虚拟仿真模型尚未见报道。目的:构建一种基于三维运动捕捉技术的交互式三维可视化的蒙医震脑术虚拟仿真模型。方法:使用Motion Analysis三维光学运动捕捉系统和足底测力台采集蒙医专家的运动捕捉数据,在Motion Builder软件中构建震脑术三维动作模型,使用Maya软件构建角色模型并与动作模型相匹配,运动Unity3D软件构建蒙医震脑术虚拟仿真系统,系统整合蒙医震脑术操作3D动画、运动学和动力学参数信息。结果与结论:通过三维运动捕捉技术和计算机仿真重现蒙医震脑术操作,能够显示施术者和受试者的运动姿态,记录关节运动的关键空间位置参数与变化情况,得出运动过程中的运动学、动力学参数。运用交互式三维虚拟仿真技术,实现蒙医震脑术的三维虚拟仿真的视觉呈现,为蒙医震脑术手法的标准化、数字化、可视化研究奠定基础。

虚拟仿真技术在舞蹈编创与教学中的应用

舞蹈教学与编创向信息化和数字化发展是时代潮流。随着虚拟仿真技术的快速发展,其在舞蹈领域中的游戏娱乐、演出、教学和编舞等方面已经得到了广泛地研究和应用。本文从上述方面的研究现状出发,归纳介绍了舞蹈虚拟仿真中的动作捕捉、舞蹈数据库、建模和动作编创等技术,分析了这些技术的实现机理和特点,最后展望了虚拟仿真技术在舞蹈教学与编创中的发展前景。

基于虚拟仿真技术的收割机零部件智能化装配研究

为准确实现收割机零部件智能化装配,并获取最佳收割机零部件智能化装配路径,该文设计了基于虚拟仿真技术的收割机零部件智能化装配方法。首先采用Pro/E软件构建收割机零部件三维模型;然后构建收割机零部件智能化装配结构树模型反映收割机与零部件间的父子关联特性,并设计零部件装配约束条件,以约束条件完成收割机零部件智能化装配;最后利用遗传蚁群算法获取收割机零部件智能化装配规划的最佳路径。实验表明,该方法既可实现收割机零部件智能化装配,又可计算出收割机零部件智能化装配规划的最佳路径,提升收割机的智能化装配速度。

基于专业教学资源库的模具拆装虚拟仿真实训构建

传统模具拆装实训受到设备条件、空间场地、安全隐患等因素影响,限制教学效果的提升。专业教学资源库、虚拟仿真系统等数字化平台的建设为该类实训的开展提供了新的载体和模式。模具专业教学资源库为该实训提供离散化、模块化的全过程数字资源支撑。虚拟仿真系统作为专业教学资源库的特色资源,为该实训提供可交互的立体操作平台。依托以上数字资源,构建了“三段式”模具拆装实训翻转课堂。

基于RobotStudio的齿轮减速器虚拟装配工作站仿真研究

齿轮减速器装配是矿山机械装备制造中的重要生产环节之一,针对矿用大型齿轮减速器装配工序复杂、人工装配作业劳动强度大、自动化程度不足等实际突出问题,以二级圆柱齿轮减速器虚拟装配为研究对象,利用三维建模软件和RobotStudio仿真平台搭建了齿轮减速器虚拟装配仿真工作站。根据齿轮减速器零部件装配工艺流程,基于RobotStudio仿真环境确定了以ABB机器人为主的齿轮减速器虚拟装配空间布局,配置了所需的I/O信号,创建Smart组件以实施装配仿真模拟,进行轨迹规划、程序编制、仿真调试并且优化虚拟装配路径。通过对工作站进行碰撞检测和TCP跟踪,进行数据对比分析,验证了工作站可行性与准确性。该仿真设计为矿用大型减速器智能化装配提供了重要工程参考,对于矿山机械装备的智能制造及智慧化发展具有重要的指导意义。

垂荡模拟联合视觉虚拟涌浪防晕动症习服训练改善认知作业能力的效果

目的探讨正弦垂荡刺激、正弦垂荡联合视觉虚拟现实(VR)涌浪刺激2种防晕动症习服训练方法对极重度晕动症者认知作业能力下降的改善作用。方法根据海上连续航行6 h期间Graybiel评分,筛选出极重度晕动症者90名,随机分为垂荡训练组、垂荡+VR训练组和对照训练组(n=30)。利用自主开发的认知作业能力评测软件对受训者习服训练前后的警觉性、记忆力、快速计算能力、信息处理能力、视觉操作控制能力进行评测。结果垂荡训练组、垂荡+VR训练组受训者在训练第1天的警觉性测试遗漏目标数增加,短期记忆、快速计算、信息处理、视觉操作控制反应时间均延长,快速计算效率下降。经训练达习服水平后,垂荡训练组、垂荡+VR训练组受训者的警觉性测试遗漏目标数恢复至训练前水平,短期记忆、快速计算、信息处理、视觉操作控制反应时间及快速计算效率均得到明显改善。结论垂荡刺激和垂荡联合视觉VR涌浪刺激引起的晕动症可导致警觉性、短期记忆力、快速计算能力、信息处理能力、视觉操作控制能力下降,防晕动症习服训练对以上认知作业能力有明显的改善作用。

基于LabVIEW的农业采摘机器人虚拟运动仿真研究

通过对采摘机器人正运动学分析,建立农业采摘机器人运动学逆解求解方程,为采摘机器人控制过程提供输入参数。基于SolidWorks中的Motion运动模块中的直线插补和圆弧插补两种方法,建立采摘机器人执行机构运动轨迹,通过LabVIEW与SolidWorks联合的方式建立采摘机器人虚拟运动仿真模型。果蔬采摘机器人执行采摘机构运动轨迹仿真结果表明:通过直线插补和圆弧插补两种方式相互结合的方式,可以获取采摘作业过程中的精准运动轨迹。

工业设计协同虚拟现实教学系统设计研究

元宇宙理念将增强现实、虚拟现实等沉浸式技术应用于教学,将学生的感知从二维课本转向三维沉浸式虚拟空间,也对人才的培养提出了更高的需求。为了使学生更形象的了解发动机构造及工作原理,增强教师在虚拟教学中的作用,开发了基于元宇宙理念的工业设计协同虚拟现实教学系统。系统运用Rhino、3ds Max建模软件构建了工业设计发动机模型和教学场景模型,并实现了发动机总体构造、工作原理、拆装实训的可视化;使用Unity 3D虚拟现实开发引擎,以客户端/服务端模式实现教学活动,最终在HMD(头戴显示器)等虚拟现实设备上进行学习。系统经实验验证,在可用性和有效性上得到良好的反馈。上述系统设计实现为空间性和协作性较强的课程提供了一种新的教学思路与方法。

基于VL Motion的装载机工作装置耦合仿真分析研究

针对装载机工作装置系统响应缓慢、液压缸位移跟踪效果差等问题,借助Virtual Lab Motion中内嵌的Catia软件,根据HT25-J装载机具体尺寸建立了工作装置三维模型,在VL Motion中定义了构件、添加运动副和耦合仿真相应驱动接口,形成了机械系统动力学模型。通过对装载机工作装置电液系统进行分析,利用AMEsim建立了工作装置电液系统模型,同时添加了相应的VL Motion无缝集成应用接口,最终通过两者间的接口进行变量的数据交互,实现了在VL Motion耦合仿真分析平台上进行耦合仿真分析。通过采用经典PID闭环控制系统控制改善了工作装置液压缸性相应速度和位移跟踪效果等性能。仿真结果表明,借助VL Motion和AMEsim耦合仿真分析平台,在PID闭环控制下的装载机工作装置综合性能较之前有较大的提高,响应迅速,并且跟踪位移误差可以控制在2%以内。