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Research On Theory And Application For Modelling And Control Of Swicthing Systems

Posted on:2004-12-20Degree:DoctorType:Dissertation
Country:ChinaCandidate:J W GaoFull Text:PDF
GTID:1118360095963125Subject:Traffic Information Engineering & Control
Abstract/Summary:PDF Full Text Request
In this dissertation, the theories of modeling and control for switching systems was researched, that switching systems is an important kind of hybrid systems. Switching systems is used in the coke oven heating automatic control system, and it realizes the control for complex industry process system.Intelligent switching control (ISC) was proposed in this dissertation, which combined intelligent control theory and switching systems (SS). Switching systems is the framework of intelligent switching control. The theories and methods of intelligent control are used in the modeling, analysis and control of ISC. ISC is the advanced level of the SS during its development, and ISC is the one of the important methods that will solve the control of complex system.Dynamic region soft partitioning method was also proposed which can reduce the complexity of analysis and modeling of complex system. Every dynamic sub-region is one aggregation which including continuous variables and discrete events, and their mutual actions. At the same time, every dynamic sub-region is one unit, which has its dynamic characters and developing rules. Region overlapping, region floating and region zooming of the dynamic sub-region was studied, that region overlapping is the exterior character of the sub-region, region floating and region zooming are inner characters of the sub-region. Fuzzy neural networks based on T-S models are used as the tools for parameters identification of dynamic sub-region.Based on dynamic region soft partitioning of complex system, flexible switching control was put forwarded. Flexible switching (FS) is one strategy for complex system control, FS would be including of hard switching and soft switching, FS can be driven by both continuous variables and discrete events, at the same time, FS has the characters of diversity and hiberarchy. Half close-loop control (HCLC) for time-delay and large inertia system with time-variant was proposed. The chief control object of HCLC based on bounding control is to satisfy the bounding stability of the out variables, and the second control object of HCLC is to satisfy zero error of the out variables. HCLC for complex system just like the control process of human controllers. On the other hand, HCLC caused by large sampling period should be avoided.Stability supervision control for flexible switching systems was proposed, that used to supervise and control the stability of the control system. There are two mainly functions of stability supervision controller. The first function is to monitor and judge the stable or unstable states and trends of the system. The second function is the control function, whichwill adjust the rules and parameters of the sub-controllers to remain or resume stable states of the control system, so stability supervision controller is also as the controller's controller.Coke oven is a complex plant with the characters of large time-delay, strong non-linear, multivariable coupling and changeable parameters. The dynamic process of the coke oven is driven by both continuous variables and discrete events. The mean flue temperature is affected by many reasons and it is difficult to control the temperature to required precision by the normal control methods. In this dissertation, the hybrid systems characters of the coke oven and its operation were discussed, and intelligent switching systems theories were be used in the coke oven heating automatic control for the first time. The control system can be adaptive of the frequently change of the working states during the coke oven producing process, maintain the stability of the mean flue temperature and good combustion status, it also can improve the quality of the coke. At the same time, the control system has great signification to reduce energy consumption, lessen air pollution and prolong the service life of the oven body.
Keywords/Search Tags:hybrid systems, switching systems, intelligent control, fuzzy neural networks, stability, soft partitioning, flexible switching, bounding control, half close-loop control, stability supervision control, coke oven, mean flue temperature
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