车身冲压线中端拾器的仿真设计

介绍车身冲压线中端拾器的总体设计架构、建模、虚拟装配及其程序开发。该系统是基于C/S和B/S相结合的架构,采用VisualBasic.NET对CATIA进行二次开发,通过ADO访问数据库Oracle9i来建立的。而且,为了使计算机模型具有可扩充性和智能性,形成智能化的设计系统,对基于知识工程的计算机建模、参数化的虚拟装配进行了研究。     

基于遗传算法的汽车覆盖件冲压方向优化设计

为了实现覆盖件模具工艺的优化设计,将遗传算法引入覆盖件冲压方向的优化设计中,在研究和总结冲压方向选择原则的基础上,以参考方向的转角为设计变量,以初始接触面积、接触点的个数和分散均匀程度为目标函数,建立了冲压方向选择的优化模型,并在VC环境下实现了代码编程。同时,对三维造型软件UG进行了二次开发,使优化程序与UG本身功能高度集成在一起,实现了汽车覆盖件冲压方向的自动优化设计。通过对底板零件冲压方向的优化求解,其结果表明所开发的优化模块能够提高覆盖件模具的工艺设计质量。     

模糊评价在汽车覆盖件冲压工艺方案优选中的应用

考虑影响汽车覆盖件冲压工艺方案评价的因素复杂多样,建立了汽车覆盖件冲压工艺方案评价模型。设计了6项评价指标并根据层次分析法得出了各项指标的权重,最后应用模糊评价法对各种方案进行了评价,得出了最优方案,从而提高了方案优选工作的科学性、智能性。     

基于UGⅡ汽车覆盖件工艺补充面的参数化设计

根据汽车覆盖件拉延件设计的经验和规则 ,应用参数化和优化方法在UG平台上二次开发出拉延件设计的应用软件 ,应用实例表明 ,明显地提高了设计效率和质量     

基于知识的小型注塑模具快速设计系统的研究

针对注塑模设计与制造过程的自动化、智能化及效率高的要求,基于Unigraphics软件的二次开发平台,开发了基于知识的注塑模结构设计CAD系统.提出了该系统的整体结构框架、模块划分和数据流程,建立了知识库,分析了各模块功能的实现.     

基于CAE技术的汽车覆盖件拉延模具设计

介绍了在CAE技术基础上进行的汽车覆盖件模具设计过程,利用板料成形有限元分析软件Autoform实现了模具压料面、工艺补充面以及拉伸筋设计和覆盖件成形过程模拟。实现了在有限元软件内部进行模具的参数化设计,既缩短了模具设计时间,又提高了模具设计可靠性。     

基于实例的汽车覆盖件模具结构智能CAD

覆盖件模具的设计和制造是开发汽车新车型的“瓶颈”环节。鉴于覆盖件模具结构的特点,其设计质量完全取决于设计人员的经验和水平,难以保证。本文阐述了汽车覆盖件模具结构设计采用智能CAD的原因和意义,分析了基于实例设计（CBD）方法优势,指出CBD方法是最常用、也是最为成功的用于模具结构设计的智能CAD方法,论文提出了“实例＝实例模型＋实例数据”的描述方法,在正确处理设计尺寸参数化程度的基础上,通过建立面向装配的实例模型和推理机制,成功地进行了基于实例的覆盖件模具结构智能设计。     

基于知识的级进冲模工步排样CAD技术的发展与展望

研究了基于知识的级进冲模工步排样CAD技术，分析、总结了基于模型和基于规则两种工步排样设计知识的处理方式，提出了将基于知识的工程（KBE）思想引入工步排样设计领域的方法，并建立了系统框架。     

A study on die wear prediction for automobile panels stamping based on dynamic model

A new method for the prediction of die wear is established by studying the wear characteristics of automobile panels stamping dies. This method takes into account the contact pressure, the change of wear coefficient and material hardness along the thickness direction of the treatment layer. In order to obtain the relationship of wear coefficients with contact pressures and die hardness, a new kind of friction wear device is designed, which can simulate the wear environment of the blank-die interface in practical stamping. With this equipment, the dynamic wear coefficient considered the contact pressure and die hardness is obtained. Based on finite element software LS-DYNA, the prediction of die wear is achieved by using the dynamic coefficient and the continuously update of wear surface by means of the move of nodes. Based on wear at the feature line of an engine hood outer panel, the relationship between wear depth and stamping times is established. Comparing the prediction results of the new method and the traditional Archard method with the practical wear condition, the results show that the die life prediction method used in this study is closer to the practical condition; moreover, the accuracy is obviously higher than the traditional Archard method.     

基于特征匹配检索与区间数优势度多属性排序方法的工艺规划研究

为满足现代制造企业产品品种多样性、制造过程离散性、生产环境复杂性要求,提出将工艺规划分为两个阶段,第一阶段采用特征匹配的实例检索制定出加工零件所需的各种数据及多条加工路线;第二阶段采用基于区间数优势度多属性排序方法选择最优的加工路线,实现设备能力导航及加工时间与成本最低。最后,用实例验证了该方法的可行性。     

车身覆盖件冲压工艺多目标优化系统的集成与应用

采用有限元分析技术和优化技术,以实现车身覆盖件的冲压工艺多目标优化。定义了材料、工艺和几何3类主要设计变量,其交集为最佳设计变量空间。针对覆盖件的整体成形性,建立破裂、起皱和变形不足3类目标函数,采用增量有限元和全量有限元的整合策略,求解目标函数值。与其他算法相比,基于帕累托法的多目标遗传算法能求解最佳解空间的所有解,完全满足不同成形性之间的权衡需要。最后,以车身发动机罩外板为例,验证了该优化系统的应用。     

A model for evaluating the quality of the fixturing of the part from a machining process planning perspective

Achieving the required tolerance of positioning between two features is not obvious when features are produced in multiple set-ups where the fixture/workpiece interface plays a critical role. From a computer-aided process planning perspective, the suitability of a fixturing feature to achieve the required tolerances has to be evaluated. A model of an indicator for a locating quality is proposed here based upon the distribution of a small displacement of the workpiece compatible with the required tolerance onto the candidate fixturing surfaces.     

汽车装配工艺设计中的任务规划系统研究

传统汽车装配工艺设计中的任务规划主要依靠工艺人员手工完成。通过分析汽车装配工艺特点,提出了基于装配工艺模型的计算机辅助任务规划系统的建立方法,从而实现计算机化的装配任务的规划与管理,提高了装配工艺设计的效率和质量。     

A Fast and Reliable Tool for Estimates for Plastic Blowing Moulds

This work presents a procedure to evaluate machining costs of dies made on CNC machines. Our survey deals with companies manufacturing plastic blowing moulds, and it is limited to the unit parts, that is, to the estimation step without going to the detail of process planning. To do this, we developed a process that uses the techniques of the semi-analytical method. This method is based on the decomposition of the shape required to manufacture the cavities; every cavity is decomposed in the same way for machining complex features, in order to determine the machining process and machining time, and the volume of metal to remove and the surface produced. ID="A1" Correspondence and offprint requests to: Dr Z. Bouaziz, Department of Mechanical Engineering, Route de Soukra Km3, BP W 3038, Sfax, Tunisia. E-mail: zoubeir.bouaziz@voila.fr     

An automated arc spray tooling system for rapid die-making of large-sized automobile body panels

A creative robot wrist consisting of link mechanisms and a novel robot motion control method based on the cross-sectional vector contours of an STL-formatted model was proposed. By using the wrist and the control method, an industrial robot with five degrees of freedom for rapid tooling using metal arc spraying and electric brush plating techniques was developed. The wrist of the robot including a specially designed link mechanism can maintain the position of the spraying point on the surface of the master pattern whatever the orientation of the gun. Therefore, the kinematic nonlinear coupling between the position mechanism and orientation mechanism in a traditional robot can be avoided. The only input of the control system is the STL-formatted 3D CAD model of the pattern. Without the need of any manual programming, the metal arc spraying and brush plating (if necessary) processes can be performed automatically and efficiently after receiving the 3D CAD data of the pattern. Using this robot system in new car development and trial production, the cost and lead-time can be reduced substantially as compared with the conventional tool making method. __________ Translated from Journal of Xi’an Jiaotong University, 2004, 38 (11) (in Chinese)     

汽车覆盖件逆向工程设计研究与应用

逆向工程在汽车覆盖件设计过程中得到了越来越广泛的应用.以某车型翼子板的逆向设计为例,采用数码摄影和光学扫描相结合的非接触式基于光学原理的ATOS & TriTop系统得到数据点,针对汽车覆盖件的特点,结合逆向工程软件Imageware,详细阐述了由大量数据点进行曲线、曲面反求的汽车覆盖件逆向工程设计方法.     

Rule-based process planning by grouping features

A macro-level CAPP system is proposed to plan the complicated mechanical prismatic parts efficiently. The system creates the efficient machining sequence of the features in a part by analyzing the feature information. Because the planning with the individual features is very complicated, feature groups are formed for effective planning using the nested relations of the features of a part, and special feature groups are determined for sequencing. The process plan is generated based on the sequences of the feature groups and features. When multiple machines are required, efficient machine assignment is performed. A series of heuristic rules are developed to accomplish it.     

汽车悬架性能测试技术的研究

介绍了汽车悬架性能测试的方法和悬架性能检测的标准，以及时目前应用最多的共振式检测试验台提出了改进方法和措施。     

Development of an online machining process monitoring system: a case study of the broaching process

This paper presents a new online machining process monitoring system based on the PXI hardware platform and the LabVIEW software platform. The whole system is composed of the following interconnected packages: sensing, triggering, data acquisition, characterisation, condition monitoring and feature extraction packages. Several signal processing methods, namely, cross-correlation, resample, short-time Fourier transform (STFT) and statistical process control, are developed to extract the features of tool malfunctions and construct the thresholds of malfunction-free zones. Experimental results show that the developed online process monitoring system is efficient for acquiring, analysing and presenting sensory signals simultaneously, while the developed signal processing techniques are effective for detecting tool wear and constructing thresholds for tool-malfunction-free zones. Additionally, a sensitivity analysis of the signals acquired from alternative sensors versus those collected from a dedicated platform dynamometer has been carried out. This enables the evaluation of the possibility to employ alternative sensing techniques in an industrial environment.     

汽车外覆盖件模具高速切削工艺规划研究

高速切削技术是汽车模具数字化制造的主要支撑技术,而汽车模具高速铣削加工中的工艺规划是保证和提高模具型面加工精度与质量的重要环节,也是实现模具数字化制造的关键技术。在UG CAM软件平台上,结合汽车外覆盖件拉延模的高速加工,对数控编程策略、切削参数优化和刀具轨迹规划等问题进行研究,利用五轴高速加工中心对研究结果进行验证。