《专业英语unite14.ppt

* * UNIT 14 Automatic Control Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. What is the control system? How to distinguish automatic from control system? Unit14 Automatic Control Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 14.1 Introduction A control system may be regarded as a group of physical components arranged to direct the flow of energy to a machine or process in such a manner(方法,方式) as to achieve the desired performance. 可认为控制系统是由一组物理部件构成，通过对它们的适当布置使其能使能量流向机器或过程，以达到预期的性能。 Unit14 Automatic Control Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 14.1 Introduction 机械制造系统图 原料或毛坯 存储 运输 制造 检验 成品 信 息 系 统 能源 能 量 系 统 物质流 信息流 能量流 Unit14 Automatic Control Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Vc Vo C r Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 14.2 Open-Loop Control and Closed-Loop Control Water flows from the tank via(通过) a valve Vo and enters the tank from a supply via a control valve Vc. The control valve is adjustable, either manually or by some type of actuator(执行器). This may be an electric motor or a hydraulic pneumatic cylinder(液压气动缸). Very often it would be a pneumatic diaphragm actuator(气动膜片执行器). 水通过阀门Vo从水箱流出，并通过一个控制阀门Vc进入水箱。控制阀是可调的，可手动或由一些执行器来操作。 Unit14 Automatic Control Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. In general, increasing pneumatic pressure above the diaphragm(隔膜) pushes it down against a spring and increases valve opening. 通常，增加隔膜上的气压从而向下推压弹簧以提高阀门的开度。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Open-Loop Control Open-loop control, w