液位控制系统毕业设计外文翻译(编辑修改稿)

液位控制系统毕业设计外文翻译(编辑修改稿)内容摘要：

able close to the controller setpoint. Hence, derivative control is used to reduce the magnitude of the overshoot produced by the integral ponent and improve the bined controllerprocess stability. However, differentiation of a signal amplifies noise and thus this term in the controller is highly sensitive to noise in the error term, and can cause a process to bee unstable if the noise and the derivative gain are sufficiently large. Summary The output from the three terms, the proportional, the integral and the derivative terms are summed to calculate the output of the PID controller. Defining u(t) as the controller output, the final form of the PID algorithm is: and the tuning parameters are Kp: Proportional Gain Larger Kp typically means faster response since the larger the error, the larger the Proportional term pensation. An excessively large proportional gain will lead to process instability and oscillation. Ki: Integral Gain Larger Ki implies steady state errors are eliminated quicker. The tradeoff is larger overshoot: any negative error integrated during transient response must be integrated away by positive error before we reach steady state. Kd: Derivative Gain Larger Kd decreases overshoot, but slows down transient response and may lead to instability due to signal noise amplification in the differentiation of the error. 二 Matlab Introduction The MATLAB174。 environment is well suited to rapid prototyping and application development. The interactive programming environment, builtin math functions, toolboxes, editing and debugging tools, and deployment options all contribute to reducing your overall development time. By using the builtin math functions and the many specialized functions contained within our toolboxes, MATLAB can significantly reduce the time it takes you to develop prototypes. In addition to integrated editi ng and debugging tools, MATLAB provides a performance profiler to help you further optimize your code when programming in MATLAB. Building applications around plex algorithms and graphics is easier than ever with the GUI builder, GUIDE. GUIDE was redesigned in MATLAB 6 to save you time. It offers all the drag and drop interface options you would expect, such as text boxes, radio buttons, check boxes, listboxes, sliders, popup menus, frames and more. When you39。 re ready to deploy your application, the MathWorks offers a number of different options that allow you to either convert or interface your MATLAB application to other environments including C/C++ and the Web. MATLAB is the most productive development environment for creating scientific and engineering applications because it offers powerful tools for every step in the process to reduce your overall development time. MATLAB is a highperformance language for technical puting. It integrates putation, visualization, and programming in an easytouse environment where problems and solutions are expressed in familiar mathematical notation. Typical uses include • Math and putation • Algorithm development • Data acquisition • Modeling, simulation, and prototyping • Data analysis, exploration, and visualization • Scientific and engineering graphics • Application development, including graphical user interface building 三 DDE Introduction Dynamic data exchange (DDE, Dynamic data exchange) is realtime exchange data between applications, it is the effective method between different applications to share data a agreement. DDE agreement is a kind of open, and language unrelated, based on protocol, it allows multiple applications to any human agreed format data exchange or mand. It is application through Shared memory process of the munication between a form, also need not user intervention of good data exchange method. DDE applications can be divided into four types: client and server and client/server and the monitor. Conversation is a basic concept of DDE. DDE conversation happened in client applications and server application between. Customer is responsible for initializing and attendant session and control conversation flow, from the server application request data or services。 The server application response client applications of data or service request. Client/server applications is both client applications and server application request, it can be and can provide information. Monitor application for debugging purposes. DDE applications can have multiple burst conversation, a service applications can also have multiple client applications, a client applications can to multiple requests data service applications, and an application can also act as client applications and services applications, when don39。 t need the service application data or service, the customer will terminate session. DDE agreement must be synchronous control the news session, but in different application can switch between asynchronous session. DDE Application using the three layer identification system: Application name apply), theme name (from) and project name (Item). Application name (also called service name) is located at the top of the hierarchical structure, the service application registration for pointed out that particular DDE server application name, customer the application wants to establish session with the server application must be specified application name when this string marks。 Name in every conv。