三坐标测量机夹具设计过程自动化:基于知识的方法外文翻译资料

 2023-07-31 03:07

Fixture design process automation for Coordinate Measuring Machines: a knowledge-based approach

Keywords: Knowledge Model, Inspection, Automation, Coordinate Measuring Machine.

Abstract

Nowadays, the inspection process is an essential part of the manufacturing process, where a product is subjected to verification of the geometric features, dimensions and tolerance specifications with respect to the product design specifications. One of the most interesting topics in the automation of the inspection process is the right fixture design. In the fixture design process we have used the information provided by the part design and manufacturing process. However, the lack of integration and structuring of this information results in one of the most important problems, producing an increase in the time and cost implied in the development of the fixture design and its implementation.

For this reason, this work presents a knowledge model for the inspection fixture design process for a Coordinate Measuring Machine (CMM), which allows the automation of the inspection fixture design process to be made easier, reducing time and cost associated to the inspection process and to the manufacturing process in general.

Introduction

The different forms and geometric features of the mechanical parts should be inspected to ensure that the manufacturing process fulfils the dimensional specifications, dimensional tolerances and finish tolerances. In the last decade, different research groups have developed frameworks that allow the information associated to the geometric specifications of the product to be defined. This framework has enabled information models to be developed with the objective of automating the inspection process [1]. The main objective of an information model is the description of types of ideas, facts and processes, which together form a model of a portion of interest of the real world. The possibility of implementing these information models in a computer application has introduced improvements in the time, cost and set-up of the manufacturing process.

The main research, in the field of inspection process, has employed information models, mainly in two interest areas: The planning and execution of the inspection operation, and the inspection fixture design. The majority of research has been focused on modelling the information associated to the inspection process using IDEF0 and EXPRESS tools [2] and on the structuring of the information related to automating the fixture design [3].

The inspection process provides a group of parameters (dimensions and dimensional tolerances; forms, positions, geometric tolerances orientations and finish tolerances) that allow to define and verify the specifications of the product design. These parameters can be classified with respect to the measuring elements (CMM, probe head, styli, software, etc.) and with respect to the fixture system employed.

Bearing in mind the importance of the inspection process and the complexity that it can attain, different research groups have been focused on the structuring of the information needed to automate the inspection process [2, 5]. Also using modelling techniques (IDEF0 and EXPRESS),Barreiro has established an information model for integrating the inspection process into a concurrent engineering framework. This framework describes the functional analysis of the flow activity development during the inspection process using a CMM. The information defined in the activity flow has been considered a basic element for the construction of the reference model proposed by Barreiro [6].

Using these elements, several models have been used for describing the information associated to the fixture design process [3, 坐标测量机的夹具设计过程自动化：基于知识的方法

摘要

因此，该工作提供了用于坐标测量机（CMM）的检查夹具设计过程的知识模型，使检查夹具设计过程的自动化更容易，减少检查过程和一般的制造过程的时间和成本。

应检查机械部件的不同形式和几何特征，以确保制造过程满足尺寸规格、尺寸公差和精加工公差。在过去十年中，不同的研究小组已经开发了允许定义产品几何规格相关的信息框架。这个框架能够开发信息模型，目的是自动化的检查过程。信息模型的主要目的是描述思想、事实和过程的类型，它们一起形成真实世界的一部分模型。在计算机应用中实现这些信息模型的可能性已经引入了对制造过程的时间、成本和设置的改进。

检查过程提供允许定义和验证产品设计规格的一组参数（尺寸和尺寸公差、形式、位置、几何公差取向和精加工公差）。这些参数可以对于测量元件（CMM、探头、测针、软件等）或对于所采用的固定系统来分类。

使用这些元素，已经用几种模型来描述与夹具设计过程相关的信息。这种类型的模型建立了一组参考元件，这些参考元件提供了固定装置可以倾斜以便限定固定装置的配置的基础。Kakish开发了夹具元件的知识库，定义夹具设计中使用的设计参数和规格。这种方法是在夹具设计领域中表示复杂模型的需要而开发的。

在CMM的检查夹具设计的环境中实现知识模型需要定义检查部件的几何形状、检查过程的特征和所使用的检查资源相关的不同结构的信息。此外，对推理过程的描述使得更加容易开发夹具解决方案。在这个意义上，利用这种类型的模型的实现与夹具设计相关知识的表示以及在夹具设计中采用的启发式过程的定义，Hunter开发了第一种实现加工夹具设计知识模型的方法。

本研究采用的解决方案需要对检查过程中涉及的每个信息元素进行规范和概念化。该信息应该提供对检查夹具设计中涉及的每个活动的基本属性的定义。结果提供了一个合适的方法来整合检查过程中执行的任务开发。

表示夹具知识的方法学

开发夹具要求（第一阶段）

开发夹具功能（第二阶段）

功能设计（第三阶段）

详细设计（第四阶段）

验证详细设计（第五阶段）

第一种方法建立了关于支撑、定位和夹紧元件的配置（参见图1，节点A1）。本方法在第一阶段中提出的功能要求的验证。

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