一种适用于过程系统仿真培训的仿真方法

针对工业过程系统仿真培训的要求和特点，提出一种新的仿真方法。该方法由构造最小仿真模型的调度算法与变帧速仿真算法两部分组成。将该算法应用于加氢裂化、制氢、铂重整等工业过程的仿真培训系统，取得了满意的效果。     

宽带计算机网络的快速时间驱动仿真算法

本文针对离散事件驱动法仿真宽带网络仿真速度慢的缺点，提出了一种适合于网络离散系统的快速时间驱动仿真算法，该算法容许仿真误差存在，但极大地提高了仿真的速度，而且仿真误差可以控制在一定的范围内，其影响随时间的推移而消失，与离散事件驱动仿真算法的比较证实了该算法的有效性。     

数控加工仿真系统的研究与应用

介绍数控加工仿真系统的整体设计,提出格栅voxel三维实体建模方法,刀具扫描体的生成算法,实现了刀具切削工件过程的动态仿真,并对碰撞检查算法进行了初步的研究.基于以上方法,建立了蓝天数控系统的加工仿真系统,在加工前对加工程序进行验证,在加工时对刀具轨迹的执行、工件的切削过程等进行实时监控.     

虚拟加工中心加工过程算法研究

在虚拟加工环境的建造过程中，关键技术是三维实体的数据结构和加工仿真的逐步成型算法。该文重点研究了毛坯的数据结构特点，四边形离散化方法和毛坯文件的存储格式等，并且分析了三坐标加工中心的加工特点，同时还给出了虚拟加工过程中毛坯被加工成工件的逐步成型算法。该算法在虚拟加工环境中得到了成功应用，文中给出了该算法在三坐标加工中心的验证实例。     

基于虚拟环境的制造系统仿真优化平台

根据国外先进仿真优化理念，提出了一种面向制造系统的仿真优化平台，构建了基于模型与算法分离的仿真优化系统框架以及仿真优化与虚拟建模环境子系统，并设计了一种新的基于遗传算法的混合优化算法用于驱动仿真优化引擎．在以上研究成果的基础上，开发了面向制造系统的仿真优化平台——Simopt．最后，通过实例验证了该系统的有效性．     

基于非线性消除系统仿真中的病态问题

针对控制系统仿真中出现的病态问题，提出一种自适应非线性仿真步距算法，消除病态系统仿真中精度、计算速度与稳定性之间的矛盾。仿真结果表明，该算法具有计算简单、精度高、速度快、稳定性好等特点。     

ESSDRR调度算法的性能仿真与分析

鉴于已有的分组调度算法难以同时满足良好的QoS保证特性和算法的低复杂性，结合WF2Q和DRR两种算法的优点，提出了一种基于均匀服务序列的DRR算法——ESSDRR(Even Service Sequence-based Deficit Round-Robin)。为了评价其优劣性，在同一仿真条件下利用NS2对该算法以及三个类似算法做了大量仿真实验，主要考察并比较了各算法的端到端时延、短期吞吐率等性能指标。实验结果显示，ESSDRR具有良好的公平性、低时延特性及较低的复杂性。     

异形螺杆加工过程三维动态仿真技术研究

利用三角形图元造型实现了数控机床加工异形螺旋杆的仿真过程,提出了基于定义高度缓冲区的工件表示方法和简化模型,以此为基础建立了刀具与工件曲线的求交算法,以最小有向距离原理为依据提出了仿真加工过程中的干涉判定算法,分析和实验证明了上述两种算法具有良好的时间和空间复杂性.最后,利用C 和OpenGL实现了具有干涉判定功能的三维仿真系统,该系统不仅实现了以往无法达到的仿真加工速度,而且其图形具有相当强的真实感,它使整个复杂的螺杆加工过程从参数输入、刀具选择、干涉判定、插补计算、三维仿真到数控程序生成和控制加工完善地结合起来.     

轨道交通调度算法仿真平台的设计

该文着重从系统的角度介绍了轨道交通调度算法实物仿真平台的设计。整个仿真系统被划分为算法层、通信层和执行层三个功能层次，各层次由相关软硬件设备组建，通过标准接口连接，构成了一个具有很强伸缩性的系统，能较真实地模拟实际轨道交通环境。该仿真平台在实用中工作稳定、操作简便，提高了所研制交通调度算法的可信度。     

基于ITU-TG．165协议实现电话线路回波抵消的仿真研究

文章介绍了一种实现电话线路回波抵消的仿真算法。通过三个仿真单元的设计,最后实现了回波的抵消,实验结果表明,该算法能够成功地应用于系统中,取得了良好的效果。     

Estimating workpiece pose using the feature points method

The ability of a robot to estimate workpiece pose is necessary for many industrial tasks. An automatic method of visually estimating the pose of a workpiece in a robot hand has been investigated. This method is applicable to workpieces that have six continuous unknown degrees of freedom. Furthermore, partial occlusion of the workpiece by the robot hand is allowed. Workpiece pose was estimated using the three-dimensional locations of at least three noncollinear workpiece feature points. A second view of the workpiece was obtained by rotating the workpiece in front of the camera. Corresponding image features on the second view were found by searching along lines on the image which were determined by the rotation of the workpiece. A very accurate camera calibration procedure has been developed to compute rays in space from image locations. The location of workpiece features was computed by trigonometric relations between rays of corresponding image features from two views of the workpiece. The pose of a workpiece was estimated by the correspondence between the workpiece features located and the feature points of a workpiece model. Experiments have been performed on a complete functional system. The major limitation of the current system was due to the image feature extraction algorithm which only detected corners and small holes.     

Dynamic response of a workpiece in turning with continuously varying speed

In order to study the influence of workpiece speed variation on the dynamic response of a workpiece in turning operations, this paper develops a finite element model to describe the lateral vibration of a rotating Euler-beam, in which both axial force and damping effect are included and the workpiece speed changes continuously and periodically. A simplified cutting force model which depends on the feed-rate and workpiece deflection is used along with the proposed finite element model. To solve the obtained finite element equations of a workpiece in turning, the Newmark integration scheme is employed to further discretize the time domain. At each time step the resulting nonlinear equations are solved iteratively. The numerical results show the influence of the workpiece speed variation frequency and amplitude on the dynamic response of turning operations. Also, the suppression of self-excited vibration in turning by changing the workpiece speed periodically is demonstrated by using the present analytical model.     

Updating workpiece geometry using robotic sensor information gathered during contact tasks

During robotic contact tasks, geometric information of the workpiece is used to specify the position of the robot’s hand on the workpiece and the direction of force control. This geometry is idealized in a typical CAD file, but due to manufacturing precision or wear, the actual workpiece geometry is inevitably deviated from the desired geometry. Furthermore, when the workpiece is mounted, position and orientation inaccuracies emerge. In this paper, we investigate two questions: (1) Can the workpiece geometry in the CAD file be used to control a robot in contact with an inaccurately placed workpiece?; and (2) Once the task is performed, how can the robot’s sensor information be used to update the geometry of the workpiece? A methodology is developed to solve robotic control problems with workpiece position and geometry inaccuracies. Once performed, the CAD file image is displaced to fit the sensed trajectory of the robot’s hand. Finally, the workpiece image geometry is modified using a least squares approximation to fit the sensed data more accurately. In the end, the robot performs the contact task while gathering information that is used to update the original CAD file geometry. The methodologies are demonstrated through a simulation experiment that requires a robot to shave a geometrically altered face that is inaccurately positioned.     

Simulation of micro-patterns engraved by grinding process with screw shaped wheel

Grinding is an important means of realizing precision and ultra-precision machining of workpiece surface. The surface patterning of workpiece directly affects its mechanical properties such as friction, wear, contact stiffness, fitting property. Therefore, prediction of the geometry of the workpiece surface is very important to evaluate the workpiece quality to perform mechanical function accurately. In this paper using MATLAB simulation, prediction for the geometry pattern of the workpiece according to the developed shape of the grinding wheel dressed by thread cutting was studied. The model for the geometry of the grinding wheel surface was first developed and subsequently, a new simulation model for surface pattern by grinding process was established. The simulation results could be used to optimize the grinding process and to improve the workpiece surface quality or predict the surface pattern by given grinding parameters.     

视觉图像技术与机器人工件抓取的协作应用

工业机器人在抓取环节如果配置机器视觉装置,应用图像处理技术,在抓取效率和准确度方面就有优势。该文介绍机器人功能实训台的工件抓取视觉系统的组成,侧重工件轮廓的图像处理技术,以图像处理作为机器人视觉系统处理的核心目标,将视觉图像技术与机器人工件抓取技术协作应用于工业机器人实训平台的抓取环节,利用工业机器人运动过程中坐标的转换,通过相机的正确标定与抓取动作的共同控制,实现工件的精确定位,达到可靠抓取的目的。总结图像处理技术在工件抓取中的协作应用效果,期待便捷的视觉图像技术与机器人工件抓取的协作应用。     

智能获取装箱管状工件抓取位置的研究

机械手智能抓取工件时,工件抓取位置的获取是基于机器视觉精确装配的重点。针 对环境较复杂的装箱管状工件的装配抓取环节,建立合理的机器视觉系统,利用正向照明系统对 工件表面产生的反光直光条特征,提出了一种Gaussian 拟合与Hough 变换相结合的拟合算法。首 先利用Gaussian 拟合提取各光条法向上的中心坐标,然后将获取的坐标点集运用Hough 变换进行 拟合,最后根据获取的各光条中心线计算各工件的抓取位置。实验结果表明该方法能同时实现多 条光条直线的拟合,又能抑制干扰点或噪声的影响,有效实现装箱工件抓取位置的智能获取。     

一种闭合曲线去除平面工件二值图像噪声算法

在现代工业中,图像处理技术经常被用于工件的在线检测。获取的图像经过二值化后,工件信息和噪声同时存在,其中工件信息常被噪声影响。通过分析二值图像中工件边缘与噪声的特征区别,提出一种用闭合曲线去除二值图像噪声的新算法,该算法通过移动一组闭合曲线,根据每个闭合曲线与检测目标轮廓边缘的交点数目,判断该组闭合曲线所包含的各个像素点是否为噪声,将被判为噪声的像素点置零,从而提取出精确的工件边缘信息。该算法适用于具有清晰轮廓曲线的零件检测。     

基于双目视觉的工件定位与抓取研究

针对生产制造过程中工件的自动定位、识别与抓取等问题,研究基于双目立体视觉的工件识别定位方法;对每个工件进行SIFT特征提取,采用模板匹配方法实现工件的识别.用形态学方法获得工件特征点的二维信息,结合双目立体视觉标定技术得到工件的三维坐标,为机器人抓取工件提供信息;在实验中,相机标定、匹配识别与三维定位程序在MATLAB环境中执行,应用MATLAB和VC++混合编程技术将获得的工件信息传递给机器人的控制程序,实现了机器人对工件的在线实时抓取.     

基于三维特征的零件自动识别系统

提出一种基于三维特征的零件自动识别系统.系统在Unigraphics平台上开发,选取零件二阶中心矩特征矩阵的三个特征值,零件的三个主惯性矩以及体积构成了用于零件识别的特征向量,实现了对零件的快速高精度的自动识别.文章详细介绍了基于物体三维特征的自动识别原理以及系统组成.对三维零件的识别实验验证了系统的有效性.     

Identification of effective engineering methods for controlling handheld workpiece vibration in grinding processes

The objective of this study is to identify effective engineering methods for controlling handheld workpiece vibration during grinding processes. Prolonged and intensive exposures to such vibration can cause hand-arm vibration syndrome among workers performing workpiece grinding, but how to effectively control these exposures remains an important issue. This study developed a methodology for performing their analyses and evaluations based on a model of the entire grinding machine-workpiece-hand-arm system. The model can simulate the vibration responses of a workpiece held in the worker's hands and pressed against a grinding wheel in order to shape the workpiece in the major frequency range of concern (6.3–1600 Hz). The methodology was evaluated using available experimental data. The results suggest that the methodology is acceptable for these analyses and evaluations. The results also suggest that the workpiece vibration resulting from the machine vibration generally depends on two mechanisms or pathways: (1) the direct vibration transmission from the grinding machine; and (2) the indirect transmission that depends on both the machine vibration transmission to the workpiece and the interface excitation transformation to the workpiece vibration. The methodology was applied to explore and/or analyze various engineering methods for controlling workpiece vibrations. The modeling results suggest that while these intervention methods have different advantages and limitations, some of their combinations can effectively reduce the vibration exposures of grinding workers. These findings can be used as guidance for selecting and developing more effective technologies to control handheld workpiece vibration exposures.