| As an important branch of intelligence control, Fuzzy control has two characters, the one is that it doesn't depend on accurately mathematic model, the other is that it has preferable robust performance. On the other hand, Heating furnace is a system of big inertia, nonlinearity and slow time variation, we don't easily build its accurately mathematic model, so we adopt the way of fuzzy control to implement the control of heating furnace, this way can effectively enhance the heat efficiency and heating quality.Fuzzy control is a kind of computer digital control technique, which is based on the fuzzy sets, fuzzy language variable and fuzzy logic reasoning. Three approaches are included in fuzzy control, which are fuzzification of exact variable;establishment of rules and defuzzification.In this paper, traditional fuzzy controller, double fuzzy controller, fuzzy PID controller, fuzzy add PID controller, self-adjusting factor fuzzy controller and several kinds of fuzzy controller are studied by simulating test, and based on it small error integral-fuzzy controller is proposed. Meanwhile , combined with the simulation result, the measure factor and d ratio factor of the fuzzy controller are demonstrated and the influence of system control performance by their selecting and adjusting is also illuminated. Furthermore, aiming at the problem of the big pure inertia of heating furnace, Smith-fuzzy control system is designed. The simulating results have showed that the improved system has good performance.Another important content of burning control of the heating furnace is the control of ratio of air/fuel. There is an extreme value characteristic between with heating efficiency and ratio of air/fuel, then a self-optimize fuzzy controller is designed, this has spread the application domain of fuzzy control. The analysis has showed that this kind of fuzzy controller with variable searching steps has better convergence character and its adjusting speed is quick. |
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