Real-time simulation and visualization of robotic belt grinding processes

Real time simulation and visualization are important for robot programmers to verify and optimize the path planning for the robotic belt grinding process. A new free-form surface representation based on discrete surfel element is developed to facilitate the system implementation, which exploits the advantage of the new development of point-based rendering technology in computer graphics. A local process model is integrated to calculate the material removal rate by considering the local geometry information and non-uniform force distribution. The final surface grinding error is easy to be assessed and visualized for quality evaluation. The experiments show that the simulation error is below 15%, even for a non-uniform contact under stable cutting conditions.     

面向复杂曲面的机器人砂带磨抛路径规划及后处理研究

针对机器人砂带磨抛复杂曲面叶片问题,对叶片内外型面和进排气边的磨抛路径规划及后处理技术进行了研究,对复杂曲面叶片的机器人砂带磨抛路径规划的计算效率及加工效率进行了分析,提出了一种将基于等残留高度法的笛卡尔空间计算的磨抛行距转化为参数域空间的磨抛行距的方法,并将机器人砂带磨抛复杂曲面叶片接触轮的中心坐标位置、支撑轴矢量以及轴线矢量数据后处理为机器人的位姿信息,利用机器人砂带磨抛系统装备实验平台对复杂曲面叶片进行了实际的加工实验。研究结果表明:所提出的刀路规划和后处理技术能够有效地解决机器人砂带磨抛复杂曲面叶片的问题,具有加工路径总长短以及路径条数少的特点,计算简单、加工效率高、加工表面质量好。     

叶片机器人砂带磨抛点云匹配算法优化

为解决机器人磨抛路径中工件坐标系难以计算的问题及校正工件装夹误差,将三维点云配准技术应用到叶片机器人砂带磨抛系统中。由三维激光扫描仪扫描工件型面获得工件点云,采用基于主成分分析(PCA)的全局配准算法和改进的迭代最近点(ICP)算法完成了扫描点云和工件模型离散点云间以及不同工件扫描点云间的匹配,以获取工件坐标系和校正工件装夹误差。相关仿真和试验结果表明,优化后的算法在匹配速度与精度上有了长足改进,且加工后产品精度和质量都能满足实际加工要求。     

In-process endpoint detection of weld seam removal in robotic abrasive belt grinding process

This paper proposes a novel approach for in-process endpoint detection of weld seam removal during robotic abrasive belt grinding process using discrete wavelet transform (DWT) and support vector machine (SVM). A virtual sensing system is developed consisting of a force sensor, accelerometer sensor and machine learning algorithm. This work also presents the trend of the sensor signature at each stage of weld seam evolution during its removal process. The wavelet decomposition coefficient is used to represent all possible types of transients in vibration and force signals generated during grinding over weld seam. “Daubechies-4” wavelet function was used to extract features from the sensors. An experimental investigation using three different weld profile conditions resulting from the weld seam removal process using abrasive belt grinding was identified. The SVM-based classifier was employed to predict the weld state. The results demonstrate that the developed diagnostic methodology can reliably predict endpoint at which weld seam is removed in real time during compliant abrasive belt grinding.     

The selection of optimal cooling parameters for the multi-cavity die

The subject of this study is a finite element and abductive network method application for the multi-cavity die. In order to select the optimal cooling system parameters to minimise the warp of a die-casting die, the Taguchis method and the abductive network are used. These methods are applied to create an efficient model with functional nodes for the considered problem. Once the cooling system parameters are developed, this network can be used to predict the warp for the die-casting die accurately. A simulated annealing (SA) optimisation algorithm with a performance index is then applied to the neural network for searching for the optimal cooling system parameters, and obtains a rather satisfactory result as compared with the corresponding finite element verification.     

多体系统仿真分析平台参数化建模技术研究

针对复杂多体系统建模效率低、建模过程修改频繁等问题,研究了多体系统仿真分析平台的参数化建模技术,提出了一种工程约束推理求解和模型元素更新机制相结合的参数化方法.该方法采用点参数、设计变量参数和元素属性参数构建多体系统参数化模型.通过规则约束和表达式约束,描述了元素属性参数间的工程约束关系.针对工程约束的过程无关性,使用有向图作为参数化求解的内部表达,根据参数间的偏序关系获得工程约束求解序列.结合多体系统模型元素关联关系的特点,提出了一种事件驱动的模型参数化更新机制.最后通过轿车参数化建模实例,验证了该方法的有效性和可靠性.     

基于Mobile-Android小型移动机器人平台控制系统

针对目前小型移动机器人控制系统存在的设计成本高、平台搭建困难、过度依赖网络的问题,将软件设计模式中的MVC模式应用于移动机器人控制系统设计,同时,在Android平台和Arduino控制板上使用Java、C语言进行了实验。提出了基于Android移动计算平台、结合蓝牙通信和无线局域网（WiFi）通信的小型智能移动机器人平台Mobile-Android。详细地描述了该平台的系统结构、控制软件,包括GUl界面模块、运动控制模块、命令配置模块、上位机与下位机通信协议等的设计与实现。在原型系统上初步的测试结果表明,该智能移动平台方案既能够实现智能移动机器人系统硬件平台的快速搭建,又能够充分发挥移动机器人的运动特性与智能手机的强大信息处理能力和控制能力;结合两者长处,获得了一个完整的智能移动机器人系统。     

数控砂带磨床故障分析

为了研究某型号数控砂带磨床的可靠性水平,找出机床的薄弱环节,对整机进行了故障模式影响及危害性分析;综合故障部位、故障模式、故障原因以及危害度分析的结果,得出砂带磨削装置和数控系统是该机床的薄弱环节,为机床的可靠性设计和分析提供了依据。     

六轴联动叶片型面砂带磨削方法及加工仿真研究

依据砂带接触轮与叶片型面的最佳接触条件,提出了叶片型面六轴联动砂带磨削加工方法,并进行了叶片砂带磨削的刀位点计算;采用VERICUT构建了虚拟数字机床并进行了仿真加工实验,验证了叶片型面砂带磨削加工刀位点以及轨迹计算的正确性.     

Developing an end-of-arm tooling for robotic grinding machining application

Cleaning castings is a common process in manufacturing and there have been various kinds of robotic applications in deburring, polishing, etc. However, robots have not been applied to surface machining because of difficulties in metal removal control. Robotic Vision Systems Inc. is currently engaged in a research effort to develop a robotic disc or wheel grinding unit for surface machining applications. Novel design features, such as passive compliance and visual feedback, will provide system performance that offers more consistent quality and lower production costs than manual methods.     

Analysis of the robotic disc grinding process

Two major aspects of the robotic rigid disc grinding process, namely, disc wear and grinding forces have been examined in the present study. The disc wear is observed to be nonuniform, being greatest at the outer edge of the disc. A simple wear model has been developed by assuming that the amount of wear can be approximated as having a triangular cross section. The dynamic grinding force model developed includes the effects of disc wear and nonlinear stiffness of the robot system. Experiments have been conducted on an actual robotic grinding system to verify the validity of these system models. Several practical issues which should be considered during robotic grinding are discussed.     

基于OpenGL无心外圆磨削仿真系统的研究

无心磨削是一种精密、高效的加工方法,在机械制造领域占有重要地位,以切入式外圆无心磨削为研究对象,介绍了仿真系统中各功能模块,对系统开发过程中所使用到的技术要点进行探讨,并对3DS模型在仿真系统中的读取与重现进行了分析,采用OpenGL技术实现了无心外圆磨削加工过程的仿真系统,提出了根据工件中心高的理论优化值计算托板高度的方法,在时域中对工件真圆度和磨削力进行了仿真,为进一步研究无心磨削的动态特性和提高磨削加工精度提供了依据。     

基于数值模拟核主泵水力优化设计平台开发

核主泵是压水堆核电站核岛内唯一长期高速旋转的装备,是核电站的心脏。该文针对第三代核主泵AP1000的水力要求,开发基于数值模拟的混流式核主泵优化设计平台。利用该平台开展了球形压水室直径及导叶包角和导叶数对球形压水室内水力损失影响的研究。研究表明这三者对球形压水室的水力损失有着较明显的影响。实践表明该平台可用性好,效率高。     

用于焊接驻极体麦克风的锡焊机器人系统

针对手机用驻极体麦克风与柔性印刷电路锡焊的特殊要求进行了分析.根据需求设计了专用的锡焊机器人;详细介绍了原型机的机械结构特点和基于PMAC的电机运动控制、焊接压力控制、PMAC设备驱动和上位机软件总体结构;经测试证明,该原型机在运动精度、压力控制效果及焊接产品质量等方面具有一定的优势.     

普通磨床超精度磨削工艺及工艺参数选择

通过对超精度磨削机理的研究和分析，在ME1432B普通外圆万能磨床上．采用精、细修整砂轮．使砂轮上的同一颗粒等高微刃数增多的方法，达到磨削抛光作用，并对磨床导轨、砂轮主轴与轴瓦间隙进行修刮和调整，同时合理选择磨削工艺参数等方面达到超精磨削的目的。     

Cuckoo search algorithm for the selection of optimal machining parameters in milling operations

In this research, a new optimization algorithm, called the cuckoo search algorithm (CS) algorithm, is introduced for solving manufacturing optimization problems. This research is the first application of the CS to the optimization of machining parameters in the literature. In order to demonstrate the effectiveness of the CS, a milling optimization problem was solved and the results were compared with those obtained using other well-known optimization techniques like, ant colony algorithm, immune algorithm, hybrid immune algorithm, hybrid particle swarm algorithm, genetic algorithm, feasible direction method, and handbook recommendation. The results demonstrate that the CS is a very effective and robust approach for the optimization of machining optimization problems.     

基于AutoMod仿真平台的有色金属立体仓储存放系统仿真分析

建立了一种粉末状有色金属自动化立体仓库系统,介绍了基于粒子群算法,应用改进的粒子群算法对堆垛机作业系统进行了优化,应用AutoMod仿真试验平台,建立了该自动化仓储系统的实体模型,取得了详尽的模拟运行结果及试验数据.运行结果表明,系统在整个运行期间运行流畅.仿真数据表明堆垛机运行时间占总运行时间的91.2%呈现高效率状态,平均停车时间只占总运行时间的8.8%.所得到的仿真结果作为某色金属物流仓储系统的决策依据.     

六联动叶片砂带磨削编程系统的开发研究

以VC++为编程语言和UG/OPEN API为开发工具,通过对砂带磨削运动分析、磨削刀位轨迹计算和数控代码生成等关键技术研究,最终开发了一套六轴联动汽轮机叶片数控砂带磨床编程原型系统,并采用数控加工仿真软件VERICUT构建了六轴虚拟砂带磨削环境,对编程系统生成的数控代码进行叶片型面磨削仿真,验证了系统生成的磨削刀位点以及数控代码的正确性.     

基于VB和MATLAB的计算机辅助刀具与工艺参数优选系统研究

本文针对切削加工过程中的刀具和工艺参数选择不合理,效率低下等问题,采用了规则推理和权重决策的方法开发了快速合理推荐刀具的模块。用考虑了工艺系统动态特性的动力学仿真技术得到的颤振稳定域、铣削力等仿真结果作为多目标工艺参数优化的约束条件,采用基因遗传多目标优化算法优化工艺参数。为了实现人机交互式操作,借助软件工程思想,运用VB和MATLAB软件混合编程技术,开发出计算机辅助刀具与工艺参数优选系统。