曲线曲面约束运动变换矩阵的计算

采用ＮＵＲＢＳ表达高副约束中的曲线曲面，在此基础上研究了高副约束运动变换矩阵的结构和计算方法，所导出的公式具有通用的结构形式和规范自动的计算性质，该组公式可应用于带曲线曲面高副约束的组合机构运动学分析以及计算机辅助曲线曲面约束的装配设计。     

RRR-RRP六杆机构的MATLAB运动学仿真

用复数推导了曲柄、RRR和 RRP 级杆组的位移、速度和加速度的复数表达式 ,并将其转化为适用于MATL AB仿真的矩阵数学模型 ,以该矩阵数学模型编制了相应的 M函数仿真模块 ,对给定的 RRR- RRP六杆 级机构为例说明如何使用这三个仿真模块建立 MATL AB仿真模型 ,并对其仿真结果的正确性加以分析。其主要思想是以组成机构的杆组为仿真模块 ,搭建各种机构 MATL AB仿真模型 ,可以对各种低副机构进行运动学仿真和分析     

RRR-RRR六杆机构的MATLAB运动学仿真

本文用复数和矩阵建立了曲柄、RRRⅡ级杆组的运动学的数学模型,并编制了相应的M函数仿真模块,对给定的RRR-RRR六杆机构进行了建模和仿真,其主要思想是以组成机构的杆组为仿真模块,搭建各种机构MATLAB仿真模型,对各种低副机构进行运动学仿真。     

RPR-RRP六杆机构的MATLAB运动学仿真

本文用复数和矩阵建立了曲柄、RPR、RRPⅡ级杆组的运动学的数学模型 ,并编制了相应的M函数仿真模块 ,对给定的RPR -RRP六杆机构进行了建模和仿真 ,其主要思想是以组成机构杆组为仿真模块 ,搭建各种机构MATLAB仿真模型 ,对各种低副机构进行运动学仿真。     

RPR-RPP六杆Ⅱ级机构的MATLAB运动学仿真

用复数和矩阵建立了曲柄、RPR、RPPⅡ级杆组的运动学数学模型，并编制了相应的M函数仿真模块，对给定的RPR—RPP六杆机构进行了建模和仿真，其主要思想是以组成机构杆组为仿真模块，搭建各种机构MATLAB仿真模型，对各种低副机构进行运动学仿真。     

基于MATLAB的CCS空间机构运动学仿真

以向量代数及回转变换矩阵为工具,建立了CCS空间机构从动构件上一点的运动学数学模型。因该模型中位移方程、速度方程及加速度方程求解时包含大量的矩阵运算。故运用MATLAB语言开发了求解该模型的应用程序,该程序对求解结果辅以二维和三维图形仿真,使该机构的运动学特性可视化。最后通过算例予以验证。     

并联微操作手的运动学分析

对６自由度并联微操作手的运动学进行了深入研究。此操作手是一个６－６型、ＰＳＳ副、带柔性铰且由压电驱动的微动并联平台。针对其微动特性,利用摄动旋转齐次变换矩阵,建立了并联微操作手的运动学方程,导出输入、输出位移的雅可比矩阵。该矩阵在整个微小运动范围内,可近似为常数阵。最后用计算机仿真分析了引入常雅可比矩阵的微操作手运动误差,结论证明了简化的合理性和有效性。     

五自由度特种机器人运动学分析研究

为分析特种机器人运动学特性,本文采用Denavit-Hartenberg坐标系,建立五自由度旋转关节型机器人运动学模型。通过4×4的齐次变换矩阵描述相邻两杆的空间关系,从而推导出"手抓坐标系"相对于"参考坐标系"的等价齐次变换矩阵,建立运动学方程,求出其正解,并采用Pual等人提出的反变换法(代数法)求出其运动学反解。     

关于高副低代的严格证明

一、前言平面低副机构的结构分析、运动分析和动力分析的原理与方法都比高副机构的分析要来得显明、易懂、简便。因此,一百多年以来,机构学中就采用平面低副(转动副或移动副)代替平面高副,即所谓“高刚低代”法。代替的方法是用两个转动副和一个构件来代替一个高副,这两个转动副的中心分别处在构成高副的两轮廓接触点的曲率中心。据说这样代替后,能保证代换的低副机构和原来的高副机构具有相同的机构自由度、瞬时速度和瞬时加速度。     

含齿轮副的平面机构自由度解析

通过对齿轮副约束个数的分析,齿轮副存在为一个高副或两个高副的情况。通过对实际情况进行分析,得出正确计算含齿轮副平面自由度的方法,为人们正确计算含有齿轮副平面机构的自由度提供了理论依据。并分析出两个原因,首先,研究平面机构自由度时会忽略构件配合间隙问题;其次,低副高副分类表述不严谨。当两齿轮作无侧隙啮合时,有两个法向约束,为两个高副;两齿轮作有侧隙啮合时,为一个高副。     

用矢量网络法实现平面动态机械系统的图形仿真

介绍了一种运用多体动力学进行机械系统仿真的新方法——矢量网络法,包括建模方法和其常规公式化的解题程序。结合具体实例编写了仿真程序并进行了结果分析。说明了矢量网络法应用性强的优点。     

非惯性系平面多体机械系统键合图模型及其动力学原理

从能量守恒的基本原理出发，讨论了键合图中的多通口元件MTF所具有的性质。以此为基础阐述了建立非惯性系平面多体机械系统键合图模型的一般方法及其动力学原理。将运动副约束反力视做未知势源加在系统键合图模型相应的0—结处，有效地解决了微分因果关系及非线性结型结构所带来的十分困难的代数问题，实现了计算机自动建摸。实际算例表明了所述方法的有效性。     

考虑刚柔耦合效应的塔机水平臂回转制动分析

着重讨论塔式起重机吊臂回转制动过程中运动弹性动力分析问题,在回转运动分析中考虑了机构大位移造成的刚体运动与结构自身弹性变形之耦合,运用柔性多体系统动力学理论在回转平面内建立了吊臂的动力学模型,给出分析与求解方法,并对某实际塔机进行了运动弹性动力分析,得出与塔机实际动力特征相符的结果.     

A Symbolic computation method for automatic generation of a full vehicle model simulation code for a driving simulator

This paper deals with modeling and computer simulation of a full multibody vehicle model for a driving simulator The multibody vehicle model is based on the recursive formulation and a conespondmg simulation code is generated automatically from AUTOCODE, which is a symbolic computation package developed by the authors using MAPLE The paper describes a proceduie for automatically generating a highly efficient simulation code for the full vehicle model, while incorporating realistically modeled components The following issues have been accounted for in the procedure, including software design for representing a mechanical system in symbolic form as a set of computer data objects, a multibody formulation for systems with various types of connections between bodies, automatic manipulation of symbolic expressions in the multibody formulation, interface design for allowing users to describe unconventional forceand torque-producing components, and a method for accommodating external computer subroutines that may have already been developed The effectiveness and efficiency of the proposed method have been demonstrated by the simulation code developed and implemented for driving simulation     

柔性多体系统动力学理论应用于轧制工业的综述

结合轧制工业的发展现状及柔性多体系统动力学的理论成果,从轧机设备的设计、改造、过程控制、系统特性、接触-碰撞问题的建模、轧制过程中多领域集成化、多体动力学软件的发展等几个方面阐述了将柔性多体系统动力学理论应用于轧制工业的可行性和必要性.     

Multibody approach for tolerance analysis and optimization of mechanical systems

A multibody approach is suitable for tolerance analysis of mechanical systems since multibody formulation can directly consider part-level tolerance variables. In this study, procedures for performing tolerance analysis and corresponding sensitivity analysis for spatial multibody systems are proposed. First, statistical formulation for performing multibody system tolerance analysis is developed to obtain system level tolerance for given part-level tolerances. One very useful aspect of the proposed formulation is that in the process of computing system tolerance, the sensitivity of system tolerance with respect to part-level tolerances can be additionally obtained. The kinematics of spatial multibody systems has been redefined in terms of both generalized coordinates and part-level tolerance variables. Tolerances in geometry of a body are specified in terms of the variations in relative locations of joint definition points and relative distance between them. Tolerances in the joint kinematics are defined through variations in vector closure equations and orthogonality equations that are two fundamental constraint equations for most kinematic joints. To demonstrate the validity and effectiveness of the proposed tolerance analysis procedure, tolerance analysis of a spatial 4-bar mechanism and tolerance optimization are performed.     

回转键合图法进行空间多体动力系统建模与仿真

为提高多能域耦合空间多体动力系统建模与仿真的效率及可靠性,提出了回转键合图法。阐述了建立空间多体系统键合图模型的一般方法及其动力学原理。基于回转键合图推导出便于计算机自动生成的系统状态方程及运动副约束反力方程的统一公式,克服了微分因果关系及非线性结型结构给系统自动建模与仿真所带来的代数困难。所述方法特别适合于多能域并存的系统,通过实例说明本文方法的有效性。     

On-line and off-line wheel/rail contact algorithm in the analysis of multibody railroad vehicle systems

An on-line and off-line hybrid contact algorithm for modeling wheel/rail contact problems is developed based on the elastic contact formulation. In the hybrid algorithm developed in this investigation, the off-line tabular search is used for predicting the location of tread contact points, while the on-line iterative search is used for predicting flange contact points. By so doing, a computationally efficient procedure is achieved while keeping accurate predictions of contact points for severe contact scenarios such as sharp curve and turnout negotiations. The use of the proposed hybrid algorithm can eliminate the time-consuming on-line iterative search for the second points of contact. Since the location of the second point of contact is pre-computed by the contact geometry analysis, the occurrence of two-point contact can be predicted by using the look-up table at the one-point contact configuration. A flange climb simulation demonstrates that the proposed hybrid contact search algorithm can be effectively used for modeling wheel/rail contacts in the analysis of general multibody railroad vehicle systems. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Hiroyuki Sugiyama received his Ph.D. from the University of Illinois at Chicago in 2005. Dr. Sugiyama is currently an Assistant Professor at Tokyo University of Science, Tokyo, Japan. His research interests include the development of computer formulations for contact problems in vehicle systems and the large deformation problems of constrained multibody systems. Kohei Araki received his BS degree in Mechanical Engineering from Osaka City University in 2006. Mr. Araki is currently a Master’s student at Osaka City University, Osaka, Japan. His research interest is in the modeling of wheel/contact problems in railroad vehicle dynamics. Yoshihiro Suda received his Doctoral degree from the University of Tokyo in 1987. Dr. Suda is currently a Professor at the University of Tokyo, Tokyo, Japan. His research interests are in the dynamics of railroad vehicles and automobiles, in-telligent transportation systems (ITS) and personal mobility vehicles. He is currently serving as an Associate Editor of the IMechE Journal of Multi-Body Dynamics.     

Research of design and analysis integrated information modeling framework for multibody mechanical system: with its application in the LHD design

Many complex mechanical products can be considered as multibody systems; 3D computer-aided design (CAD), multibody dynamics, finite element-based strength and fatigue analyses, optimization, and other CAE tools, are often used to develop this kind of product. But design is difficult and challenging because of information inconsistence among different engineering domains, and isolated information model islands exist. Lots of research are attracted to design and analysis information integration, but attentions are mainly focused on integration of CAD–finite element analysis (FEA), supporting the bottom-up design principle, while multibody dynamics analysis for analyzing global performance of a mechanical system is rarely considered, which follows the top-down design principle. In this paper, a novel multilevel system representation modeling framework for supporting both bottom-up and top-down or mixed design methods is proposed. It can integrate the product design CAD models with multibody dynamics, finite element-based strength and fatigue analyses, realizing a CAD–dynamic–FEA–fatigue analysis integration. It can also support data exchange and transfer in multidomain analyses. The framework is illustrated with a case study of a load haul dump (LHD) design using currently available software tools. Furthermore, a design case study of the working unit of the LHD is given to highlight the applicability of the modeling framework for multibody mechanical systems. It has been demonstrated that the framework can describe information exchanging and integration among CAD, FEA-based strength and fatigue analyses, and multibody dynamics analysis during a multibody mechanical product design process.     

基于键合图的多体系统耦合动力学的发展及现状

介绍了键合图理论及应用研究的概况,阐述了键合图理论在多能域耦合系统全局动力学的研究中所占有的重要地位。详细地阐述了基于键合图理论的多体系统耦合动力学的发展及现状,包括多体系统键合图模型的建立方法、多体系统键合图模型中微分因果环的解耦策略、系统状态方程及运动副约束反力方程的计算机辅助建立方法等重要问题。