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1、Production Automation1.1.1 Automation Concepts Automation may be defined as a system that is relatively safe-operating .Such a system includes complex mechanical and electronic devices and computer-based system that the place of observation,effort,and decision by a human operator. It is a system tha
2、t exhibits properties of human being by following predetermined operations or responding to encoded instructions.1.1.2 Computer process control Process control involves the control of variables in a manufacturing process, where one or any combination of materials and equipment produces or modifies a
3、 product to make it more useful and hence more valuable. In process control controls continuous operations. Two kinds of control systems are the open loop and the closed loop.In an open-loop control system, the computer dose not itself automate the process .That is ,there is no self-correction.The p
4、rocess remains under the direct control of human operators,who read form various sources of information such as instruments, set calibrated dials for process regulation, and change the controlling medium.Closed-loop control systems use computers to automate the process. He computer is directly in ch
5、arge of the process. It sdjusts all controls form the information provided by sensing devices in the system to keep the process to the desired specifications, a technique that uses a feedback mechanism . Feedback is the action of measuring the difference between the actual result and the desired res
6、ult and using that difference to drive the actual result toward the desired result. The term feedback comes forms from a measured sample of the output of the process (production) function that becomes the input of the control function . That is ,the output of the control function ,meeting special de
7、signed requirements is the input to the control system . Thus ,the signal begins at the output of the controlled production function and end at the input to the production. Typical functions of process control systems are moonitoring ,data logging, quality control, maximizing profit for a given out
8、put, supervisory control , and factory information systems (FIS). Benefits of computer process control system are increased productivity , improved product quality ,and enhanced efficiency , safety , comfort ,and convenience.1.1.3 Management Information Systems (MIS)Management information systems ar
9、e designed to aid in the performance of management functions.These systems are generated by computer systems and are developed to provide executives with up-to-the-minute information about the operations of the enterprise.When required, information systems are used to aid management in the decision-
10、making functions of the enterprise . Viewing CIM (Computer Integrated Manufacturing) as an informations system for the enterprise for decision-making , CAPACS must be informations interconnected . As a result , there are many software packages associated with the CAPACS in Fig . 1 . 2 . Typical of t
11、here are CAPP , DCS , FIS and CAD . The concept of an MIS is a design objective , its goal being to get the correct information to the appropriate manager at the right time . As a result , MIS implementation varies considerably among manufacturing enterprises because of each organizations function ,
12、 type of production , informations resources available , and organizational commitment to MIS .1.1.4 Engineering Computer are used extensively in most engineering functions . Engineering is a profession in which a knowledge of the natural sciences is applied with judgment to develop ways of using th
13、e materials and forces of nature . Typical engineering functions using CAPACS are design , process planning , analysis and optimization , synthesis , evaluation and documentation , simulation , modeling , and quality control planning . Using CAPACS in engineering increases the productivity of engine
14、ers and improves the quality of designs . For example ,the application of computers to an engineering design process is performed by a CAD system Engineers can design and thoroughly test concepts quickly and simply from one workstation . Computers permit engineers to take a concept from its original
15、 design through testing to numerical control (NC) output , or a combination of steps in between . They perform complex scientific and engineering computations rapidly with high accuracy , calculate physical properties before actual parts are made and provide a fast , easy method to create models of
16、even the most complex parts . The computer has influenced the way products are designed , documented and released for production . As technology develops , engineering operations are becomeing more and more automated and are relieving the engineer of many tedious manual calculations . 1.1.5 Producti
17、on Applications of computers to the production process encompass such functions as computer monitoring , supervisory computer control , direct digital control ( DDC) , material handing , product fabrication , assembly and test/inspection operations . New ideas and technology developments are gaining
18、 acceptance on the factory floor . More important , the integration of more computers into the production process increases automation on the factory floor . Computer automation helps to organize , access , and provide vital information in a common date base system for use by all manufacturing opera
19、tions . Computer automation helps to control and to schedule machines and process , and to control raw materials and parts . A computer automated system concept is shown in FIG . 1 . 3 . Each function in manufacturing has its own area controller under the control of a host computer in order to share
20、 information with other operations . 生产自动化1.1.1自动化概念自动化可以被定义为一个操作比较安全的系统。这个系统，包括复杂的机电设备和由一个人为操作员观察、尝试并决定其方位的电脑系统。它是一个按照事先确定的操作或应对编码指示来展现人的性能的系统。1.1.2计算机过程控制过程控制涉及到生产过程中的控制变量，在此生产过程中，一种或任意一种材料和设备联合生产或修改产品，使其更加有用，因此更有价值。过程控制控制不间断运行。控制系统有两种，即开环控制系统和闭环控制系统。在一个开环控制系统中，计算机本身不会使过程自动化。也就是说，没有自我更正.这个过程仍然直接受控
21、于人为操作员，他阅读各种信息来源，如工具，建立校准盘的过程监管，来改变控制的媒介。闭环控制系统，使用计算机来实现过程自动化。电脑直接负责其过程。它根据传感装置所提供的信息对所有控制适时调整，以保持这一过程所需的规格及使用一个反馈机制的技术。反馈是衡量实际结果与期望的结果之间差异的行为，利用这种差异，以推动实际结果向所期望的结果的进展。期限反馈根据过程（生产）功能输出的测量样本而形成格式，进而转为控制功能的输入。也就是说，控制功能的输出，如果满足了特殊设计的要求即可转变成控制功能的输入。因此，信号始于控制生产功能输出之时并结束于生产功能输入之时。 过程控制系统的典型功能是操作，记录数据，控制质量
22、，为某一输出，监控，和工厂信息系统（电）提供最大限度的好处 。计算机过程控制系统的优点在于能够提高生产率，改进产品质量和提高效率，且安全，舒适和方便。1.1.3 管理信息系统（ MIS ） 管理信息系统用来为管理功能的实施提供帮助。这些系统由计算机系统产生，并被用来为管理人员提供有关企业运作的最新信息。我们可用信息系统来帮助企业制定决策。例如，可把计算机集成制造（计算机集成制造）作为一个信息系统，为企业决策， CAPACS必须是相互关联的信息。其结果是，有许多与CAPACS的图1.2 相关的软件包。典型的有 CAPP系统，集散控制系统，模糊推理系统和计算机辅助设计。 管理信息系统的概念是一个设
23、计目标，其目的是在合适的时间，得到正确的信息并给适当的经理。因此，制造企业之间各组织的功能，生产类型，信息资源及组织对 MIS的承诺，会造成系管理信息系统的实施不尽相同。1.1.4工程电脑被广泛应用在工程领域。工程学是一门职业，在这门职业中，我们可通过所获取的自然科学知识加判断识别力来形成使用材料和自然力量的方法。使用CAPACS的典型工程功能是设计，工艺规划，分析和优化，合成，评价和记录，仿真，建模，和质量控制规划。工程使用CAPACS可以增加工程师的生产并提高设计质量。 例如，工程的设计过程使用计算机是由CAD系统的工程师负责的，他们能够迅速而简单地设计出来自工作站的方案并对其进行彻底检验
24、。计算机允许工程师通过测试数字控制（数控）输出，或者两者之间的步骤，采用原来的设计方案。他们能迅速而精度地进行复杂的科学和工程计算，能在实际零部件被生产数之前计算出物理性能，并提供了一个快速，简单的方法，用于建立模型，即使是最复杂的部分。计算机已经影响了产品设计，记录和发布生产的方式。随着技术的发展，工程业务也在广泛采用自动化，给工程师减少了许多繁琐的人工计算。 1 .1.5 生产计算机应用于生产过程有以下功能，包括监测计算机，监督计算机控制，直接数字控制（ DDC） ，材料处理，产品制造，组装和测试/检查行动。工厂车间也正在接受新的观念和技术的发展。更重要的是，伴随着更多的计算机被用到生产过程，工厂车间自动化程度加深了。 计算机自动化协助组织，存取，并提供资料库中的重要信息，供所有的制造业务。计算机自动化控制，并帮助安排机器和过程，同时还可控制原材料和零部件。计算机自动化系统的概念图.1.3.所示，在制造业领域，每种功能都会在主机电脑的控制之下行使自己的控制范围，这样方便了与其他操作共享信息。