深水柔性管道铺设过程的动态仿真

针对深水柔性管道铺设的一般过程,将铺设过程离散成若干典型工况,并通过非线性时域有限元法实现铺设过程的动态仿真分析。阐述仿真所涉及的基本方程、模型与基本单元、载荷工况与动态响应统计的具体处理技术。以水深1 000 m柔性管道的铺设为例,着重展示动态仿真技术在铺设设计中的应用。分析实例表明：通过非线性时域动态分析技术对深水柔性管道的铺设过程进行仿真是可行的,可以有效地为铺设设计提供指导。     

基于ADAMS对四向抗震支架的仿真研究

针对柔性四向抗震支架可以在地震作用下减缓管线的晃动问题,提出一种以Roberts Linkage减振模型为基础对柔性四向抗震支架进行等效模型处理的研究思路。引入Roberts Linkage等效物理摆法对柔性四向抗震支架进行研究,在考虑不同振动激励的情况下,运用ADAMS/Vibration软件对柔性四向抗震支架等效模型进行振动仿真试验。仿真结果表明:柔性四向抗震支架通过丝杆、钢丝绳的阻尼与弹性,可以有效减缓管线在水平方向上的振动。为柔性四向抗震支架结构优化与减振机理的研究提供参考。     

基于SIMULINK工具箱的生态工业系统仿真和柔性分析

生态工业作为一种新型的工业发展模式,兼顾了经济、资源和环境等多方面的需求,是实现可持续发展的一种重要途径。本文应用Matlab-Simulink工具箱建立了一个生态工业系统模型,进行了仿真分析,在此基础上提出生态工业系统柔性分析的影响因子法,对限制系统柔性的关键因素进行分析,提出了改进系统柔性的方案。对某工业园区的实例分析表明,该模型能够给出稳态和动态的仿真结果并较好地改善系统柔性。     

基于ANSYS排气吊耳刚度分析

本文首先建立了某汽车排气系统的有限元模型,然后利用排气系统的自由模态试验结果与仿真结果对比。验证了有限元模型的准确性。最后对排气系统进行静力学分析,得出排气系统的每个橡胶吊耳的受力和位移情况。基于整车设计及布置要求对排气吊耳刚度进行优化,得出满足整车要求的吊耳刚度。     

基于LS-DYNA的汽车保险杠碰撞仿真研究

以显式动态有限元理论为基础,对汽车保险杠的碰撞进行了计算机仿真研究.作者根据台车碰撞试验对汽车吸能装置的要求及设计的汽车保险杠的结构尺寸,用Pro/ENGINEER建立了碰撞体及保险杠的仿真模型,用ANSYS对模型作了前处理,调用LS-NYNA 求解器ls970进行了求解,最后用LS-PREPOSTD作了后处理,并对仿真结果进行了分析.通过仿真可预测出汽车保险杠发生碰撞时受力、变形和吸能情况,从而为保险杠的优化设计提供了依据.     

基于混沌遗传算法的柔性机械手滑模控制器优化设计

针对柔性机械手动力学方程的非最小相位特点,本文提出一种柔性机械手的终端滑模控制方法,将关节电机转角和柔性模态变量的线性组合定义为柔性机械手系统的输出.通过输入输出线性化,将系统分解为输入输出子系统和零动态子系统.设计终端滑模控制策略,使输入输出子系统在有限时间收敛到零;利用混沌遗传算法优化控制器的设计参数,使零动态了系统在甲衡点附近渐近稳定,从而保证整个系统的渐近稳定.本文提出的方法设计过程简单,易于实现.仿真结果证明了设计的有效性.     

核电站一回路介质非接触式监测系统优化研究

针对核电站非接触式放射性液体监测系统取样管线容易沉积放射性产物,并影响仪表监测数据准确性的问题,采用取样管线冲洗、管道残存压力泄压操作方式优化、系统取样管线布置优化,以降低取样管线沉积的放射性产物。通过对3种不同优化方案及实施效果进行对比,发现系统取样管线布置优化方案消除取样管线内放射性沉积产物的效果最好。最后对优化后的系统取样管线进行压力、监测数据测试,结果表明,系统取样管线布置优化方案可以从根本上解决放射性产物沉积,保证监测数据的有效性,为同行业和相关行业消除管线内沉积物的设计提供了参考。     

一种动态双种群果蝇优化算法求解FJSP

为了有效解决柔性作业车间调度问题(FJSP),提出了一种具有较强进化机制的动态双种群果蝇优化算法(DDFOA),该算法采用自适应移动步长,并动态地将种群划分为先进子种群和后进子种群,其中先进子种群侧重局部搜索,后进子种群负责全局搜索。同时针对柔性作业车间调度问题,设计了合适的编码转化方案。最后,对算法的收敛性进行了证明,并选用经典算例对其进行仿真实验,仿真结果验证了DDFOA求解FJSP的有效性。     

柔性机械手的鲁棒控制器设计

针对柔性机械手的动力学方程具有非最小相位的特点,运用重新定义的柔性机械手系统的输出,通过输入输出线性化,将系统分解为输入输出子系统和零动态子系统．考虑到柔性机械手系统存在的不确定性,设计终端滑模控制器,使输入输出子系统在有限时间内收敛到零．最优组合输出系数采用混沌遗传算法优化,以保证零动态子系统在平衡点附近渐近稳定,从而保证整个系统渐近稳定．仿真结果证明了设计方法的有效性．     

基于计算机虚拟样机技术的轿车悬架性能研究

采集广德试车场操纵性与平顺性试验环路的道路载荷谱,利用nCode软件对道路载荷谱进行编辑与处理,得到随机短波路、沥青振动带等多种不同路面的道路载荷,导入ADAMS中进行悬架动态仿真。因为传统的基于静态K&C特性分析的系统参数设计不足以满足复杂工况下整车对悬架的性能要求,而动态K&C试验具有更精确的响应结果,更能反应悬架的实际使用状态。最终在动态K&C试验台进行试验,对比动态、静态与台架试验的结果,验证了动态K&C仿真与试验结果更加接近,具有更精确的仿真结果。所以,对汽车悬架的动态特性研究对工程应用具有一定的帮助作用。     

A neuro-fuzzy hybrid scheme for design and simulation of human machine systems

In this article, a new neuro-fuzzy hybrid approach to human workplace design and simulation is proposed. Problems related to human workplace design such as human-machine modeling, measurement and analysis, workplace layout design and planning, workplace evaluation and simulation are discussed in detail. The complex human-machine interactions in workplace design are described with human and workstation parameters within a comprehensive human-machine system model. Based on this model, procedures and algorithms for workplace design, ergonomic evaluation, and optimization are presented in an integrated framework. With a combination of individual neural and fuzzy techniques, the neuro-fuzzy hybrid scheme implements fuzzy if-then rules block for workplace design and evaluation by trainable neural network architectures. For training and test purposes, simulated assembly tasks are carried out on a self-built multiadjustable laboratory workstation with a flexible PEAK Motus motion measurement and analysis system. The trained fuzzy neural networks are capable of predicting the operator's posture and joint angles of motion associated with a range of workstation configurations. They can also be used for design/layout and adjustment of manual assembly workstations. The developed system provides a unified, intelligent computational framework for human-machine system design and simulation. In the end, case studies for workplace design and simulation are presented to validate and illustrate the developed neuro-fuzzy design scheme and system.     

Virtual shaft: Synchronized motion control for real time testing of automotive powertrains

The complexity of automobile powertrains continues to rise, leading to increased development time and effort. Synchronous testing with spatially distributed test benches allows improvements by front-loading of the validation phase. Nevertheless, virtualization of the mechanical interaction of shaft connections is required. A virtual shaft algorithm (VSA) is investigated for synchronized motion control in separate test benches. The behavior of a rigid mechanical shaft is analyzed and modeled. The mechanical shaft is substituted by two electrical motors and a superimposed VSA controller. This virtual shaft is established between two test benches for a combustion engine and a mechanical transmission. Control algorithms for synchronized motion control, known from web machines and force feedback, are analyzed. A controller layout with separate torque and speed controllers is implemented and analyzed through transfer function mathematics. The controllers are parametrized analytically for different gears. The effect of communication delay on the VSA is analyzed by simulation. The open clutch situation is handled by deactivation of the torque feedback. Validation on real test benches shows small deviations for torque and speed. Further work will focus on the necessity of system knowledge for controller layout and on the transient behavior during shifting.     

Soft computing framework for intelligent human–machine system design,simulation and optimization

 This paper proposes a novel soft-computing framework for human–machine system design and simulation based on the hybrid intelligent system techniques. The complex human–machine system is described by human and machine parameters within a comprehensive model. Based on this model, procedures and algorithms for human–machine system design, economical/ergonomic evaluation, and optimization are discussed in an integrated CAD and soft-computing framework. With a combination of individual neural and fuzzy techniques, the neuro-fuzzy hybrid soft-computing scheme implements a fuzzy if-then rules block for human–machine system design, evaluation and optimization by a trainable neural fuzzy network architecture. For training and test purposes, assembly tasks are simulated and carried out on a self-built multi-adjustable laboratory workstation with a flexible motion measurement and analysis system. The trained neural fuzzy network system is able to predict the operator's postures and joint angles of motion associated with a range of workstation configurations. It can also be used for design/layout and adjustment of human assembly workstations. The developed system provides a unified, intelligent computational framework for human–machine system design and simulation. Case studies for workstation system design and simulation are provided to illustrate and validate the developed system.     

A distributed parameter model for the dynamics of flexible-link robots

In this paper a model is developed for kinematic and dynamic analysis of flexible robots undergoing general three-dimensional motion. For modeling robotic links, distributed mass and flexibility are considered without discretization. Some modeling issues are discussed, and parameters characterizing the real design of a robot are introduced into the analysis. The concept of a fictitious rigid link is presented to consider the rigid body motion of a link separately, and to account for possibly complex link shapes. Based on Jourdain's principle, an alternative formulation is proposed to derive the dynamic equations of flexible robots. The equations of motion are developed and analyzed in detail. The vibrations of links are described by linear, inhomogeneous partial differential equations, with homogeneous, nonlinear, time-dependent boundary conditions. © 1998 John Wiley & Sons, Inc.     

柔性机械臂运动轨迹的鲁棒自适应控制

本文针对多连杆柔性机械臂的运动轨迹问题，讨论了动力学建模，控制系统结构设计以及鲁棒自适应控制法，运用假设模记方法得到了柔性机械臂动力学所似方程，通过对柔性机械臂动力学特性分析，建立了等价动力学模型，依此提出了一种鲁棒自适应控制算法，并给出仿真研究结果。     

细长柔性空间结构几种动力学模型的比较

对于自由-自由边界的大型柔性梁式空间结构在轨搬运过程中,其大范围刚体运动和柔性振动会相互耦合,是一类典型的刚柔耦合动力学问题.建立相对准确的动力学模型是设计良好控制系统的前提,但现有文献在研究该问题时却采用了忽略刚柔耦合作用的动力学模型并依此设计控制器,因此有必要建立耦合模型,并探讨其与非耦合模型之间的区别和适用性.首先针对结构自身运动特点选择以瞬时质心为原点的浮动坐标系作为辅助坐标系,将结构两类不同的运动形式进行分解,并利用其产生的附加约束条件简化虚功表达式;其次选择Euler-Bernoulli梁变形形式描述结构变形并采用假设模态法对变形进行变量分离;基于虚功原理推导得到结构大范围运动的刚柔耦合动力学模型;通过仿真算例1对非耦合模型、零次近似模型和一次近似模型进行了对比,验证了非耦合模型的不合理性及零次近似简化模型的准确性和有效性;通过仿真算例2对零次近似简化模型和一次近似模型的对比,说明了二者的使用范围;仿真对比为后续的运动控制系统设计和振动抑制研究提供了依据.     

An efficient approach to human motion modeling for the verification of human-centric product design and manufacturing in virtual environments

The efficient and reliable human-integrated design of products and processes is a major goal of the manufacturing industry. Thus, numerous human-related product functionality and manufacturability aspects need to be verified, using simulation, in the context of the product development procedures. The natural representation of human motions in virtual environments is crucial for the reliability of the simulation results. In this context, the paper presents an efficient approach to human motion analysis and modeling with respect to the anthropometric parameters, based on real motion data. Statistical methods employed for the analysis of the data and additive motion models are derived. The models are capable of predicting human motion and driving digital humans in product and worker simulation environments. A specific test case is presented to demonstrate the application of the suggested methodology on a real industrial problem.     

Knowledge intensive Petri net framework for concurrent intelligent design of automatic assembly systems

The integration of design and planning of flexible assembly system has been recognized as a tool for achieving efficient assembly in a production environment that demands assembly with a high degree of flexibility. This paper proposes a concurrent intelligent approach and framework for the design of robotic flexible assembly systems. The principle of the proposed approach is based on the knowledge Petri net formalisms, incorporating Petri nets with more general problem-solving strategies in AI using knowledge-based system techniques. The complex assembly systems are modeled and analyzed by adopting a formal representation of the system dynamic behaviors through knowledge Petri net modeling from the specifications and the analysis of those models. A template is first defined for a knowledge Petri net model, and then the models for assembly system individuals are established in the form of instances of the template. The design of assembly systems is implemented through a knowledge Petri net-based function–behavior–structure model. The research results show that the proposed knowledge Petri net approach is applicable for design, simulation, analysis and evaluation, and even layout optimization of the flexible assembly system in an integrated intelligent environment. The integration of assembly design and planning process can help reduce the development time of assembly systems.     

运动系统稳定性的计算机仿真研究

运动稳定性对机构工作性能有重大影响。对于复杂的多参数系统，难以通过理论分析来预测系统的运动趋势，尤其对于存在弹簧，阻尼器等非线性零部件的机械系统。该文采用有限元分析对运动过程进行实时仿真（real time simulation,RTS)研究，模拟运动系统的实际运动过程，从而分析研究运动稳定性与结构参数的关系。该文介绍了这种方法的基本原理和建模方法，并分析了一组弹簧连接物体的运动稳定性。分析结果表明，该方法能够有效地在设计阶段对结构的动力学性能进行预测与评价。