| Today, with social science and technology developing and economic globalization deepening, all walks of life usher in unprecedented opportunities, but also face various challenges at the same time. In order to meet demands of development and enhance competitiveness of industry, tobacco enterprises have to make further research on current production technology and equipment, and keep continuous innovation and improvement. The article selected Hangzhou tobacco factory’s demand as topic background. In the original stem silk line, Stem Silk Puffing Drying technology has always been implemented by COMAS puffed towers. Even though the expansion effect is acceptable, there’re some imperfections such as large-size equipment, too many pipelines that stem silk passing, much breakage, high comprehensive energy consumption, and constant operation maintenance. Through various efforts, the BD drying technology has been applied finally, but control system of the device and total control system of the existing stem silk have compatibility problems, and in addition, control precision is not high, so it cannot meet demands of the enterprise.Basing on site investigation of stem silk production flow, we analyze control object features and control requirements by referring to relevant domestic and abroad technical data. Meanwhile, we consider heat ex-changer of BD dryer has a feature of temperature hysteresis. A kind of tobacco stem silk drying control method basing on fuzzy PID control is put forward. The method not only retains the advantages of traditional PID, but also adds the artificial intelligence to the system through setting error range and combining fuzzy control with PID control. The article’s main research work and achievements are as follows:(1) Through field investigation on stem silk production process, overall control scheme has been researched and designed on the basis of mastering working principles, performance indicators and control requirements of production equipment in the process of BD drying;(2) According to the control object properties and electrical design specification, we have completed hardware design of the system, including hardware selection, hardware configuration and electrical control cabinet assembly;(3) Through characteristic analysis on control requirements of stem silk BD drying process and the field equipment, we have studied the realization of fuzzy PID control algorithm, and completed the program writing;(4)We have mastered program editing software Step7 and the monitoring software WinCC application, combined with practical requirements of control system, completed system hardware configuration and software writing, and then downloaded to the PLC, and finally realized WinCC’s real-time dynamic monitoring on stem silk BD drying control system.The tobacco stem silk drying process control system designed on the basis of the fuzzy PID control has been debugged and improved continuously, the system is in operation, and it can be seen from the result feedback that the system is safe, reliable and of high control precision. All indicators have reached the desired effect. Moisture content accuracy of output stem silk is controlled within +/-0.5%.The system has successfully obtained affirmation of the enterprise. |
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