调压铸造计算机控制系统设计与控制方法研究

【作者】 王晶；

【导师】 卢京潮；

【作者基本信息】 西北工业大学 ， 控制理论与控制工程， 2003， 硕士

【摘要】 本文在简要介绍调压铸造工艺流程的基础上，提出了采用自动／手动两种方式对TY-1型调压铸造控制系统进行控制的设计方案，给出了根据铸造工艺要求所设计的气路系统结构图，分别介绍了分布式计算机控制系统和手动控制系统的概况。文中详细介绍了分布式计算机控制系统中上位测试计算机系统的硬件结构和用工控组态软件LabVIEW实现的上位机应用程序，包括压力传感器标定程序、串行通讯程序、曲线输入程序、铸造流程显示程序和故障报警程序等。同时，作者深入研究了LabVIEW与其他语言的接口技术。为了在上、下位机之间传送数据和命令，本文基于RS232标准，设计了简便的适合于本系统的串口通讯协议，并在软件上实现了发送和接受数据及命令的功能。 论文通过机理分析方法确定了系统模型的结构，利用系统辨识方法进一步确定了模型的参数。通过极点配置的方法分别对上、下腔子系统设计了常规PID控制器，进行了仿真研究，在现场通过了调试并应用于实际铸造系统上。实践证明，这种控制器能满足指标要求。针对系统中被控对象参数随压力发生变化的实际情况，作者提出了一种变参数PID控制器的设计方法，仿真结果表明这种方法对改善系统的性能是有效的。为了提高系统的抗干扰性，保证调压铸造系统中最重要的指标—压差的控制精度，作者又提出了模糊加PID混合控制器方案，并且进行了仿真验证，取得了满意的效果。更多还原

【Abstract】 Based on the brief introduction about the technical procedure of adjustable pressure casting, this paper puts forward a scheme on TY-1 adjustable pressure casting control system. In the system, the process of adjustable casting is controlled by using two modes-manual control mode and automatic control mode. With regard to the distributed computer control system, the paper gives a detailed description of the hardware structure of the measure computer and provides an application software of the measure computer system which is programmed with a graphical programming language known as LabVTEW. The software consists of data acquisition program, asynchronous serial communication program, animated process-monitoring program, reliable alarm program etc. In addition, the method of using external code in LabVIEW is elaborated. And in the 4th chapter, by the standard of RS232, the system works out and realizes a convenient communication protocol which suits the asynchronous serial communication between the measure computer and the control computer.After acquiring the rough model of the system by analyzing the work principle, the system gives the accurate mathematical models of the upper and lower system by identification method-least squares estimation, then it adopts the method of pole assignment to design classical PID controller for each system. The simulation results show that this algorithm produces a satisfied effect, so it is used on the real casting system. After that, an adjustable parameter PID controller is proposed to compensate the change of parameters in the plants. Both the two kinds of PID controllers are simulated, the comparison of the results show out that the second proposal attains a more remarkable effect. Finally, the Fuzzy -PID compound controller is presented to restrain the noise and improve the control precision of the pressure deviation and differential pressure deviation. The simulation results of the design are well met the requirement.更多还原