链篦机—回转窑计算机测控系统的设计

【作者】 王东旭；

【导师】 黄运生；

【作者基本信息】 中南大学 ， 控制科学与工程， 2010， 硕士

【摘要】 针对目前链篦机-回转窑球团烧结测控系统相对落后的现状,研究开发了基于工业以太网的计算机测控系统,用于链篦机-回转窑球团烧结实验参数测控和过程控制,为球团生产厂提供最佳原料配比,对球团生产具有重要的现实意义。在分析链篦机-回转窑烧结工艺的基础上,本文提出了链篦机结构的改进方案,节省了硬件投入,提高了使用效率。根据系统功能分析结果,研究了基于PLC、智能仪表与工控机的两级控制系统。将智能仪表应用到链篦机-回转窑计算机测控系统中,使其具有良好的信号检测精度及可靠性。采用Delphi7.0开发了上位机监控软件,实现了对试验过程的在线监控。为满足系统对实时性、可靠性的要求,采用了工业以太网以完成智能仪表、PLC及工控机相互间的通信任务。在回转窑中进行的焙烧是球团烧结过程中最重要的阶段,故窑温的控制成为关键因素。本文针对回转窑窑温存在的大时滞、非线性、时变等工艺特点,采用了窑温模糊自适应PID-Smith复合控制策略,并根据回转窑热平衡分析结果及Smith预估器的特点,用继电辨识方法辨识出不同窑温下的温度控制模型,以离散的方式逼近系统实际模型的连续变化,最终减少因模型不匹配造成的预估补偿误差。本文利用西门子S7-200PLC作为核心控制器,在监控软件的配合下通过梯形图实现了该控制策略,并利用Matlab中的Simulink对控制策略进行了仿真,仿真结果验证了该控制算法的可行性。系统投入现场运行取得了良好的效果。更多还原

【Abstract】 In view of the situation that the measure and control system for pellet sintering of grate-kiln is relatively backward, this paper discusses a computer control system based on Industrial Ethernet, which could be used for parameter detect, parameter control and process control. This research can provide pellet plant the best ratio of the raw materials and have the vital practical significance to the pellet production.After analysising the grate-kiln sintering technology characteristics, in this paper a improved grate structure program has been proposed, which reducts the hardware investment and improves the efficiency. According to the analysis of system functions, this paper studied a two-level control system based on Industrial Computer, Intelligent Instruments and Programmable Logic Controller. The application of Intelligent Instruments improves the system’s control precision and reliability. The monitoring software is designed based on Delphi 7.0, and realized online monitoring of the detect process. To meet the requirements of real-time and reliability, the system used Industrial Ethernet to complete the communication tasks between Industrial Computer, Intelligent Instruments and Programmable Logic Controller.The roasting in the kiln is the most important stage during the process of the pellet sintering, so the control of the kiln’s temperature is the key factor. According to the features of the kiln’s temperature such as nonlinearity, large time-delay, time-varying, this paper applied the kiln’temperature fuzzy adaptive PID and Smith composite algorithm, as well as used the relay-identification method to identify the temperature control system of the kiln under different tempereture according to the analysis result of the heat balance and the characteristics of Smith predictor. In order to reduce the compensation error which results from the unmatched model, the method is used in the paper, that using the discrete model to approximate the continuous change of the actual model. The main controller is the SIEMENS S7-200 PLC, and in conjunction with the monitoring software, the control strategy has been achieved by the ladder language.Simulink in the Matlab was used to do the strategy simulation,and the result proved the control strategy is feasible. The grate-kiln computer control system has been put into use and runs well.更多还原