Study Of Double-tank Control System

Double-tank control system is a significant controlled system in the complex modern industrial process, which is featured by strong coupling and strong nonlinearity. At the same time, the application of merely multiple single-loop controllers can hardly achieve satisfactory control performance. Therefore, decoupling control with multivariable, close coupling, and strong nonlinearity emerges as a crucial point demanding urgent solution for double-tank control. However, decoupling control of the double-tank system is encountered with great barriers since most of the existing double-tank systems can not implement complex control algorithms due to their closed structure and simplex functionality. In this background, it represents great importance and application value to launch relevant researches in aspects of software and hardware of the double-tank system and decoupling control algorithms.With the support of National Key Laboratory on Comprehensive Automation of Process Industry in NEU, the thesis researched on the double-tank control system through the following steps:(1) According to the actual structure of the level control process of the double-tank system, the thesis established the mechanism model by means of dynamic materials, and the controller design model was obtained when the mechanism model was linearized around its operating point; particular parameters about those two models were gained through parameter identification, providing materials for the future controller design and simulation;(2) Designed the decoupling controller consisting of the linear feedback controller, the decoupling compensator, and the non-linear compensator control system, and made relevant theoretical discussions and simulation, whose research results were then compared and analyzed;(3) Designed and developed a special control software for the double-tank level coupling system on the basis of the "Easy control" software platform, then conducted relevant tests and analysis on the results of the special software, and verified the validity and reliability of the designed software;(4) Achieved experimental studies of the decoupling control of the double-tank system on the basis of the special double-tank control software, finally realized satisfactory control effect of level decoupling, and compared and analyzed the results obtained.