基于多传感器集成的三坐标测量机自动检测规划系统研究

为了充分发挥多传感器集成的优势，提高检测自动化水平，提出了该环境下三坐标测量机自动检测规划系统的体系结构。构建了专家规则库来制定检测策略，选择检测设备。重点分析了接触式测量检测规划的流程，提供了零件定位、测点自动生成等模块的解决方案。讨论了光学自动检测规划的要点。通过中性文件的使用和映射，实现了CAD与三坐标测量系统的集成，从而为产品的自动检测和质量控制提供了保障。     

面向三坐标测量机应用的检测特征自动提取和识别

为了解决三坐标测量机(CMM)中手工输入检测信息的问题,提出了自动提取和识别检测特征的方案。应用特征技术,实现了基于CAD模型公差特征的自动提取。利用CAD模型中几何要素标识唯一的特点,建立了STEP和QDAS中性文件的匹配,解决了几何信息和检测信息在CAD和CMM之间的传递和识别问题。在Unigraphics上进行了二次开发,使其能自动输出匹配好的STEP和QDAS文件,并能被CMM软件识别和应用。     

基于三坐标测量机的凸轮轮廓自适应测量

对数学模型未知的凸轮轮廓测量,通常采用均匀分度测量法,测量时间较长、精度差、数据量大,为后期数据分析带来不便。凸轮曲线为规律曲线,有着严格的数学模型,没有必要对轮廓上全部点位进行测量。基于以上原因,为了提高凸轮轮廓曲线的检测速度和精度,较好的反应凸轮轮廓信息,提出了基于三坐标测量机(Coordinate Measuring Machine,CMM)的凸轮轮廓自适应测量方法。测点分布及数量由凸轮轮廓本身物理特性决定,测点数量明显降低,测量结果可反映轮廓光顺度,测量过程成闭环形式,自动计算探测矢量。实际测量结果表明,自适应测量法操作简便,效率高,精度可控,具有较高的应用推广价值。     

三坐标测量机的矢量检测功能及其应用

随着数控技术的发展 ,产品中以自由曲面为主要特征的零部件的数量不断增多 ,对制造质量的要求也在提高。这些工件的CAD模型是已知的 ,并成为加工和事后检查的依据 ,轿车车身就是最有代表性的例子。从图 1可以看出 ,整车有一个确定的坐标系 ,车身上的任何零部件———无论是单一的冲压件、拼合后的焊接总成 ,还是整个车身 ,它们的CAD模型均以这个坐标系为基础。图 1　　1　关于曲面测量中的误差表述为了对组成这类工件的自由曲面进行准确的测量和作出评定 ,具有矢量检测功能的现代CNC坐标测量机发挥了重要的作用。那么 ,为什么要强调“矢…     

CAD功能在三坐标测量机中的应用

三坐标测量机作为一种高精度的通用测量设备已经有了几十年的发展历史，其在工业生产领域中的使用越来越为广泛，也越来越受到生产型企业的重视。而三坐标测量软件中对CAD功能的引入，更是将三坐标测量机的应用领域和易用性推到一个新的高度。     

智能三坐标测量机检测规划问题的研究综述

从测头和测头方向的选择,测量点数目及其他位置的确定,检测路径的规划,碰撞检查和碰撞规避问题等几方面对自动检测规划的研究和发做了较全面的综述,并对提高检测规划的可靠性和效率提出了几点建议。     

三坐标测量机在自由曲线检测中的应用

论述了三坐标测量机在自由曲线检测中的应用。     

三坐标测量机的矢量检测功能及其应用

在当代制成品工业中,随着数控技术的发展,产品中以自由曲面为主要特征的零部件的数量不断增多,对制造质量的要求也在提高。这些工件的CAD模型是已知的,并     

Integration of inspection planning system and CMM via DMIS

INSPEX is a computer-aided knowledge based inspection planning system for preparing inspection plans from CAD toleranced component models of rotational components. To achieve the complete automation of the inspection process, INSPEX has been integrated with CMMs (computer controlled coordinate measuring machines) via DMIS (Dimensional Measuring Interface Specification), where DMIS has been as a data exchange standard. The inspection procedures produced by INSPEX can be automatically converted into DMIS data format file by the DMIS pre-processor described in this paper, which can be fed into any CMMs with a DMIS interface for executing the inspection procedures.     

基于OpenCASCADE的CAM软件平台研究与开发

研究开发了基于OpenCASCADE的CAM软件平台。该软件平台导入CAD造型软件生成的IGES乖STEP203格式的数据文件,并可根据实际应用在该软件平台的基础上自由开发模型处理程序,具有很大的灵活性。     

Adaptive sampling method for inspection planning on CMM for free-form surfaces

Coordinate measurement machines (CMMs) have been widely used in inspecting mechanical parts with higher accuracy. Both the distribution and the number of the sampled points on measurand have an important effect on the efficiency and quality of the measurement of CMMs. In this paper, an adaptive sampling method is proposed for inspection planning on CMM for free-form surface. The points are iteratively sampled from a form error model, which is constructed by superimposing appropriate form errors on the nominal data. Moreover, a modified algorithm is introduced to determine the deviation of two point sets for the improvement of the inspecting accuracy, and the inspection uncertainty is also analyzed. A comparison is performed between the proposed method and the two well-known sampling methods, which are the equi-parametric method and the patch mean Gaussian curvature-based method, both simulated and experiment results show the effectiveness and robustness of this method.     

Towards an intelligent approach for CMM inspection planning of prismatic parts

This paper presents a model of prismatic parts (PPs) inspection planning on CMMs, in terms of an intelligent concept of inspection planning. The developed model is composed of Inspection Feature Construction, Sampling Strategy, Probe Accessibility Analysis, Automated Collision-Free Generation, and Probe Path Planning. In this model, the simulation of a measuring probe path is based on three algorithms: Algorithm for Measurement Points Distribution, Algorithm for Collision Avoidance, and Algorithm for Probe Path Planning. The simulation output is a measuring protocol for CMM UMM500. An experiment was performed on two PPs that have been produced for the purpose of this research. The inspection results show that all tolerances for both PPs are within the specified limits. The proposed model presents a novel approach for the automatic inspection and a basis for the development of an integrated, intelligent concept of inspection planning. The advantages of this approach imply the reduction of preparation time due to an automatic generation of a measuring protocol, a possibility for the optimisation of measuring probe path, i.e. the reduction of a time needed for the actual measurement and analysis of a workpiece, and an automatic configuration of measuring probes.     

基于专家CAD平台的坐标测量机实例库技术与面向MC的产品设计

基于专家CAD平台的坐标测量机实例库技术以设计单元实例类为核心,用设计单元的分级层次结构组织实例库。实例类以设计单元为载体,是设计单元的抽象,提供了设计单元的属性及检索、修改等方面的信息。该设计单元实例库以商用CAD系统与专家系统集成构成的专家CAD系统作为平台。在该系统的GUI下,设计人员的经验和启发式思维方式直接面向专家系统,通过实例检索和约束设计进行设计单元实例的修改,方便快捷地完成定制产品的设计。该系统在一定程度上实现了坐标测量机面向大规模定制制造的设计理念。     

基于专家CAD平台的坐标测量机实例库技术与面向MC的产品设计

基于专家CAD平台的坐标测量机实例库技术以设计单元实例类为核心,用设计单元的分级层次结构组织实例库.实例类以设计单元为载体,是设计单元的抽象,提供了设计单元的属性及检索、修改等方面的信息.该设计单元实例库以商用CAD系统与专家系统集成构成的专家CAD系统作为平台.在该系统的GUI下,设计人员的经验和启发式思维方式直接面向专家系统,通过实例检索和约束设计进行设计单元实例的修改,方便快捷地完成定制产品的设计.该系统在一定程度上实现了坐标测量机面向大规模定制制造的设计理念.     

Optimal localization of complex surfaces in CAD-based inspection

Complex surface inspection requires the optimal localization of the measured surface related to the design surface so that the two surfaces can be compared in a common coordinate frame. This paper presents a new technique for solving the localization problem. The basic approach consists of two steps: 1) rough localization of the measured points to the design surface based on curvature features, which can produce a good initial estimate for the optimal localization; 2) fine localization based on the least-square principle so that the deviation between the measured surface and the design surface is minimized. To efficiently compute the closest points on the design surface of the measured points, a novel method is proposed. Since this approach does not involve an iterative process of solving non-linear equations for the closest points, it is more convenient and robust. The typical complex surface is used to test the developed algorithm. Analysis and comparison of experimental results demonstrate the validity and applicability of the algorithm.     

Optimal localization of complex surfaces in CAD-based inspection

Complex surface inspection requires the optimal localization of the measured surface related to the design surface so that the two surfaces can be compared in a common coordinate frame. This paper presents a new technique for solving the localization problem. The basic approach consists of two steps: 1) rough localization of the measured points to the design surface based on curvature features, which can produce a good initial estimate for the optimal localization; 2) fine localization based on the least-square principle so that the deviation between the measured surface and the design surface is minimized. To efficiently compute the closest points on the design surface of the measured points, a novel method is proposed. Since this approach does not involve an iterative process of solving non-linear equations for the closest points, it is more convenient and robust. The typical complex surface is used to test the developed algorithm. Analysis and comparison of experimental results demonstrate the validity and applicability of the algorithm.     

A PC-based system integrating CMM and CAD for automated inspection and reverse engineering

A personal computer (PC)-based system integrating a manual CMM and a CAD system has been developed for on-line capture of 3D point data, resulting in the automation of the inspection process. The sequence of steps taken to measure a master component using the CMM is stored in a measurement program in teach mode and replayed for repetitive measurement of a batch of identical components in the replay mode. The measurement program guides the CMM operator regarding the geometric entity to be measured, the number of points to be input and the direction to be followed for taking the points on the CMM. The operator has simply to follow the sequence displayed on the computer screen. The program automatically computes the dimensions and the deviations from the corresponding dimensions of the master component. The 3D measurement data from the CMM are transferred to a CAD system in real time. Programs have been developed to create 3D cubic splines and surfaces from the 3D point data taken on the CMM. The full features of the CAD software can be used to manipulate the 3D point data for CAD applications.     

A feature-based inspection planning system for coordinate measuring machines

A feature-based inspection planning system is proposed in this research to develop more efficient measuring methodology for a CMM for complicated workpieces having many primitive form features. The proposed strategy is composed of two stages; global inspection planning and local inspection planning stages. In the global inspection planning stage, the system generates an optimum inspection sequence of the features in a part. The sequence is determined by analyzing the feature information such as the nested relations and the possible probe approach directions of the features, and by forming feature groups. A series of heuristic rules are developed to accomplish it. In the local inspection planning stage, each feature is decomposed into its constituent geometric elements, and then the number of sampling points, the locations of the points and the optimum probing sequence are determined. Also, an effective collision avoidance methodology is proposed. After required simulation, the effectiveness of the proposed system is verified .