自动立体仓库传输系统机电一体化设计外文翻译.doc

毕业论文（设计）
外文翻译

题 目：使数控机床更开放、兼容和智能化的技术回顾

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中原工学院信息商务学院外文翻译
使数控机床更开放、兼容和智能化的技术回顾
1. 当前数控技术障碍
今天的数控机床设计已经很好的研发出了具有像多轴控制，误差补偿和多工艺制造（例如合并磨/转/激光加工与研磨机）的功能。在此同时，这些功能都使得编程任务越来越困难和机床本身较难适应。已经取得的一些成果缓解了这一问题，特别是开放式架构的趋势控制OSACA基础[5]，开放式模块化结构控制器（OMAC）[6]，其中第三方软件可在一个工作在控制器使用标准的Windows操作系统。另一项识别产业的发展是软件控制器的应用，这些软件控制器里应用的是PLC控制技术，而不是在硬件方面。虽然发展已经改进了软件工具和数控系统，但是供应商和用户仍在寻求CAD，CAPP系统，CAM和数控在集成和转化过程中，没有信息丢失的每个阶段的共同语言。尽管有许多CAM工具支持数控制造，但是从一个系统到另一个系统的适应性和互操作性问题，仍然在限制这些工具的广泛使用。
2. 产品数据的兼容性和互操作性
数控机床完成产品设计和制造周期，但往往不是要与他们的上游子系统进行通信，例如CAD, CAPP 和CAM系统。在数据交换协议发生时，如SET，德国汽车工业协会，初始图形交换规范（IGES）使用时，信息交流可以在CAD和/或CAM系统之间发生异构。但是，这是成功的，因为只有部分这些协议的主要目的是几何信息的交换，而不是完全适用于所有的CAD / CAPP / CAM的行业需求。因此，国际社会制定了ISO10303 [7]一套标准，像我们熟知的步进.
通过实施CAD系统内的步进 AP - 203 [8]和步进 AP - 214 [9]，数据交换的障碍将被删除。然而，在CAD / CAM与数控系统的数据交换问题仍未解决。CAD系统的目的是描述一个零件几何形状的精确，而CAM系统在使用计算机系统生成的生产计划和控制操作是根据CAD模型中的几何信息和对本车间的现有资源。CAM系统的最终结果是一套可以在数控数控机床上执行的程序集。步进 AP - 203和步进 AP - 214只为一个统一CAM系统输入数据。在CAM系统，有50年历史的国际标准ISO 6983（为G代码或RS274D已知）[10]仍主导着大多数数控机床控制系统。国际标准6983虽然过时，但仍广泛使用，它只支持单向的信息流从设计到制造。CAD数据没有在一台机床使用。相反，它们处理的一个后处理器只能获得一个低层次的，不完整的使修改，验证和仿真困难的数据集。在车间里所作的修改不能直接反馈给设计师。因此，宝贵的经验在车间不能被保存和再利用。
3. Inflexible 数控控制制度
ISO 6983标准侧重于编程与尊重刀具中心位置（CL）的路径，而不是机器轴相对于部分加工任务。因此，国际标准化组织6983定义的程序语句的语法，但在大多数情况下，叶片的语义含糊不清，低级别的程序执行了有限的控制在一起。这些方案，当在一台机器专用CAM系统后处理加工，成为依赖于机器的。为了提高数控机床的能力，数控控制器厂商也开发了自己定制的控制命令集，以增加更多的功能到了自己的数控控制器，延长国际标准6983。这些不同的命令集从供应商到供应商在所有的机器工具再次发生改变，进一步导致不兼容的数据。
目前Inflexible数控控制制度是指由一个CAM系统的输出没有适应性，这反过来又否认有任何互操作性数控机床。最主要的原因是，G代码程序的部分只包含低层次的信息，可描述为“怎么做”。不管多么有能力的数控机床，能做的只是忠实的按照G代码程序完成加工。这是不可能完成的智能控制或加工优化。
4. 步进数控标准
今天，一个新的标准，即国际标准确认为步进 - 数控的非正式14649 [11-16]正在由供应商，用户和世界学术机构提供一个广泛的智能碳奈米尖锥数据模型开发的新品种。数据模型是一个通用的标准，旨在专门为数控编程，使规范的数控控制器，数控代码生成工具成为现实。目前两个步进 - 数控的版本正在开发由ISO。首先是应用参考模型（亚美尼亚）（即国际标准组织14649）及其他应用解释模型（AIM）的对ISO 14649（即10303国际标准组织的AP - 238 [17]）。如需使用和它们之间的区别的信息读者可参考[18,19]。
相反，目前的数控编程标准（ISO 6983），国际标准化组织14649不是一个零件的编程方法，通常不能描述数控机床刀具的运动。相反，它提供了一个详细的和结构化数据接口，采用基于特征的方案在一系列的信息中表示，如被加工的功能，工具类型使用，操作执行一个面向对象数据模型for数控s，遵循操作顺序。尽管通过使用步进 - 数控可能定义出密切机床轨迹，但是，该标准的目的是通过使用一种智能控制器步进数控控制器，在后期做出决定。这套标准的目的就是，步进 - 数控的部分程序可能会被写入一次，在许多不同的机床控制器提供了所需的机器类型使用过程能力。在这一过程中，无论是数控机床及其控制方案作出适应性和互操作。图。 1说明了这两个几何和加工信息，现在可以双向之间的CAD / CAM系统及步进 - 数控的控制器转让[20]。一个关键的问题是刀具轨迹运动的信息是可选的，最好应在由步进 - 数控的控制器的机器产生的。
加工特征和加工操作这类几何信息被定义为“工步”。这些几何信息为制造组件提供了一个基础的“工作计划”。图二的这些数据解释的是包括钻孔，铣削等工步在内的一部分工作计划。其中重要的一点要注意的是，此代码是步进 - 数控的转移文件，它是进口/出口流入和流出的步进 - 数控的智能控制器。控制器把这些文件翻译后，使网通运营商在控制器里通过人工数据或CAD/CAM系统在工步水平上实现数据交互。下面是使用步进数控系统的一些优点。

步进数控系统提供了一个完整的和结构化数据模型，用来链接与几何和技术信息，这样在产品开发过程的不同阶段就没有信息的丢失。

它的数据元素足够充分描述面向任务的数控数据。

数据模型的技术的进一步扩展和可扩展性（与一致性类），来符合特定的CAM技术，SFP或数控的要求。

因为建立在智能优化的步进 - 数控控制器之上，所以中小型工作的加工时间可以减少。

后处理机制将被淘汰，因为接口并不需要机器的具体信息。

机床更安全，更适合，因为步进数控系统与机床厂商是独立开的。

在车间修改就可以保存并反馈到设计部门，因此，从CAD / CAM系统到数控机床的双向信息交流可以实现。

XML文件可以作为信息载体从而实现基于Web的分布式制造。
对步进 - 数控的命题详细讨论可以由OMAC 步进 - 数控的工作组编写了一份报告发现[24]和其他出版物[20,23,25]完成。
5. 步进数控系统的国际社会
在20世纪90年代后半期，国际社会通过了国际智能制造系统（IMS）的计划[26]，开始在数控编程的概念方面进行重大改革。该方案共四个，即在欧洲，韩国，瑞士和美国全球各地区的个别项目统筹。该方案的主要协调员包括西门子（欧盟），CADCAMation（瑞士），步进工具（美国）和资源中心，国际机场理事会（韩国）。
欧洲数控步进系统主要负责控制铣床和对ISO 14649标准的检查。它有15个合作伙伴，由西门子领导，它的用户有戴姆勒克莱斯勒，沃尔沃用户等，支持它的研究机构有WZL亚琛，亚琛和斯图加特大学的资讯系统部。瑞士人引领了线切割和合作模片电火花标准，如Agie，Starrag和CAM制造商CADCAMation厂商标准的发展。在韩国的工作由浦项科技大学和汉城国立大学浦项大学进行，他们负责的是车削和铣削国际标准14649兼容控制器领域的研究。其它研究小组的工作地区，包括英国和新西兰。
在美国步进工具公司出品的步进数控程序被称为“超级模特”。 由美国国家标准协会与技术研究院主办的步进数控程序取得了重大进展，通过使用数控步进程序实现了从CAD到数控生产的全自动化。该项目涉及的不仅包括波音，洛克马丁公司，通用电气和通用汽车等工业集团，还包括公认的强大的合作伙伴，如吉布斯协会和MasterCAM的供应商.
6. 更加开放和互操作性的步进数控工具
这是四种和步进数控相关的研究工作，（1）传统的数控使用步进数控的;(2)使用新的步进数控的；（3）步进数控使控制智能化；（4）协作性的步进数控加工。适应性从类型1到类型4依次增加。必须指出的是，步进数字控制和步进一起，现已形成一个呈现较完整的产品信息的通用数据模型。
（本文摘译自Computers in Industry 57 (2006) 141–152）

Making CNC machine tools more open, interoperable and
intelligent—a review of the technologies
X.W. Xu a,*, S.T. Newman b
a Department of Mechanical Engineering, School of Engineering, The University of Auckland,
Private Bag 92019, Auckland, New Zealand
1. Impediments of current CNC technologies
Today’s CNC machine designs are well developed with capabilities such as multi-axis control, error compensation and multi-process manufacture (e.g. combined mill/turn/laser and grinding machines). In the mean time, these capabilities have made the programming task increasingly more difficult and machine tools themselves less adaptable. Some effort has been made to alleviate this problem, in particularly the trend towards open architecture control, based on OSACA [5] and open modular architecture controller (OMAC) [6], where third party software can be used at the controller working within a standard windows operating system. One further recognisable industrial development is the application of software controllers, where PLC logic is captured in software rather than in hardware. Although these developments have improved software tools and the architecture of CNC systems, vendors and users are still seeking a common language for CAD, CAPP, CAM, and CNC, which integrates and translates the knowledge of each stage with no information loss. Though there are many CAM tools supporting NC manufacture, the problem of adaptability and interoperability from system to system was and is still seen as one of the key issues in limiting the wider use of these tools.
2.Product data compatibility and interoperability
CNC machine tools complete the product design and manufacturing lifecycle, and more often than not they have to communicate with upstream sub-systems, such as CAD, CAPP and CAM. In the case when neutral data exchange protocols, such as SET, VDA, and initial graphics exchange specification (IGES) are used information exchange can happen between heterogeneous CAD and/or CAM systems. This is however only partially successful since these protocols are mainly
designed to exchange geometrical information and not totally suitable to all the needs of the CAD/CAPP/CAM industry. Thus, the international community developed the ISO10303 [7]
set of standards, well known as STEP.
By implementing STEP AP-203 [8] and STEP AP-214 [9] within CAD systems, the data exchange barrier is removed. Yet, data exchange problems between CAD/CAM and CNC systems remain unsolved. CAD systems are designed to describe the geometry of a part precisely, whereas CAM systems focus on using computer systems to generate plans and control the manufacturing operations according to the geometrical information present in a CAD model and the existing resources on the shop-floor. The final result from a CAM system is a set of CNC programs that can be executed on a CNC machine. STEP AP-203 and STEP AP-214 only unify the input data for a CAM system. On the output side of a CAM system, a 50-year-old international standard ISO 6983 (known as G-Code or RS274D) [10] still dominates the control systems of most CNC machines. Outdated yet still widely used, ISO 6983 only supports one-way information flow from design to manufacturing. The CAD data are not utilised at a machine tool. Instead, they are processed by a post-processor only to obtain a set of low-level, incomplete data that makes modification, verifications and simulation difficult. The changes made at the shopfloor cannot be directly fed back to the designer. Hence, invaluable experiences on the shop-floor cannot be preserved and re-utilised.
3.Inflexible CNC control regime
The ISO 6983 standard focuses on programming the path of the cutter centre location (CL) with respect to the machine axes, rather than the machining tasks with respect to the part. Thus, ISO 6983 defines the syntax of program statements, but in most cases leaves the semantics ambiguous, together with low-level limited control over program execution. These programs, when processed in a CAM system by a machine-specific postprocessor, become machine-dependent. In order to enhance the capability of a CNC machine, CNC controller vendors have also developed their own tailored control command sets to add more features to their CNC controllers to extend ISO 6983.
These command sets once again vary from vendor to vendor resulting in further incompatible data among the machine tools.
The current inflexible CNC control regime means that the output from a CAM system has no adaptability, which in turn denies the CNC machine tools of having any interoperability. The main reason is that a G-code based part program only contains low-level information that can be described as ‘‘howto-do’’ information. The CNC machine tools, no matter how capable they are, can do nothing but ‘‘faithfully’’ follow the Gcode program. It is impossible to perform intelligent control nor machining optimization.
4.The STEP-NC standard
Today a new standard namely ISO 14649 [11–16] recognised informally as STEP-NC is being developed by vendors, users and academic institutes world wide to provide a data model for a new breed of intelligent CNCs. The data model represents a common standard specifically aimed at NC programming, making the goal of a standardised CNC controller and NC code generation facility a reality. Currently two versions of STEP-NC are being developed by ISO. The first is the Application Reference Model (ARM) (i.e. ISO 14649) and the other Application Interpreted Model AIM) of ISO 14649 (i.e. ISO 10303 AP-238 [17]). For more information on the use and differences between them readers are referred to [18,19].
Contrary to the current NC programming standard (ISO 6983), ISO 14649 is not a method for part programming and does not normally describe the tool movements for a CNC machine. Instead, it provides an object oriented data model forCNCs with a detailed and structured data interface that
incorporates feature-based programming where a range of information is represented such as the features to be machined, tool types used, the operations to perform, and the sequence of operations to follow. Though it is possible to closely define the machine tool trajectory using STEP-NC, the aim of the standard is to allow these decisions to be made at a latter stage by a new breed of intelligent controller—STEPNC controller. It is the aim that STEP-NC part programs may be written once and used on many different types of machine tool controller providing the machine has the required process capabilities. In doing this, both CNC machine tools and their control programs are made adaptable and interoperable. Fig. 1 illustrates that both geometric and machining information can now be bi-directionally transferred between a CAD/CAM system and a STEP-NC controller [20]. One critical issue is that the tool path movement information is optional and ideally should be generated at the machine by the STEP-NC controller.
Geometric information is defined by machining features (similar to AP-224 [22]) with machining operations termed ‘‘Workingsteps’’ performed on one or more features. These Workingsteps provide the basis of a ‘‘Workplan’’ to manufacture the component. Fig. 2 illustrates an actual extract of such data for a part with aWorkplan consisting ofWorkingsteps for slotting, drilling and pocketing. One important point to note is that this code is the STEP-NC transfer (physical) file, which is imported/exported into and out of a STEP-NC intelligent controller. This file would be interpreted by the controller, enabling CNC operators to interact at a Workingstep (i.e. machining operation) level via an intelligent manual data interface (MDI) or CAD/CAM system at the controller. Some of the benefits with using STEP-NC are as follows [23].

STEP-NC provides a complete and structured data model, linked with geometrical and technological information, so that no information is lost between the different stages of the product development process.

Its data elements are adequate enough to describe task oriented NC data.

The data model is extendable to further technologies and scalable (with conformance classes) to match the abilities of a specific CAM, SFP or NC.

Machining time for small to medium sized job lots can be reduced because intelligent optimisation can be built into the STEP-NC controllers.

Post-processor mechanism will be eliminated, as the interface does not require machine-specific information.

Machine tools are safer and more adaptable because STEPNC is independent from machine tool vendors.

Modification at the shop-floor can be saved and fed back to the design department hence bi-directional information flow from CAD/CAM to CNC machines can be achieved.

XML files can be used as an information carrier hence enable Web-based distributed manufacturing.
A detailed discussion on value proposition for STEP-NC can be found in a report produced by the OMAC STEP-NC Working Group [24] and other publications [20,23,25].
5.STEP-NC international community
In the second half of the 1990s, an effort from the international community backed by ISO started the major change in the concept of NC programming, through an international intelligent manufacturing systems (IMS) programme [26]. The programme was co-ordinated across four worldwide regions each with individual projects namely Europe, Korea, Switzerland and the USA. The major coordinators of the programme are Siemens (EU), CADCAMation (Switzerland), STEP Tools (USA) and ERC-ACI (Korea).
STEP-NC Europe is responsible for milling, turning and inspection of the ISO 14649 standard. It has 15 partners, led by Siemens, with users such as Daimler Chrysler, Volvo, and the support of research institutes such as WZL RWTH-Aachen and ISW Stuttgart University. The Swiss are leading the development of the standard for wire-cut and die-sink EDM in collaboration with vendors such as Agie, Starrag and CAM manufacturer CADCAMation. The work in Korea has been carried out by both Pohang University of Science & Technology (PosTECH) and the Seoul National University in the areas of milling and turning architectures for ISO 14649 compliant controllers. Other research teams working in the area include those in the UK and New Zealand. The STEP-NC programme in the USA called SuperModel led by STEP Tools Inc. and sponsored by National Institute of Standards and Technology (NIST) has made major advances to fully automate the CAD to CNC manufacturing process through the use of STEP or rather AP-238. This project involved a strong group of industrial partners including Boeing, Lockhead Martin, General Electric and General Motors, together with recognised CAM vendors such as Gibbs Associates and MasterCAM.
6.STEP-NC for more open and interoperable machine tools
There are four types of research work related to STEP-NC: (1) conventional CNC control using STEP-NC; (2) new STEPNC enabled control; (3) STEP-NC enabled intelligent control; and (4) collaborative STEP-NC enabled machining. The degree of adaptability increases from Type 1 to Type 4. It is to be noted that STEP-NC together with STEP is now forming a common data model for representin