Ingtelligent Control Of Marine Boiler

Since 1965 professor Zadeh founded fuzzy sets theory, the fuzzy control technology have been developed rapidly and used widely in the project. Fuzzy control technology has so powerful life, because it has some other control technology can't substitute excellence: first it don't need the exact math model of the controlled object; the second is that the controlled speed fast, robust better, arise character better than other control method; the third is the fuzzy control itself has the forecast function, this function can exhibit in the fuzzy control rules. Fuzzy control rules origin from the knowledge of the experts, any expert establishes certain plan and stratagem base on the sufficient estimate and forecast, so can say that the fuzzy control itself has the forecast function, this is more excellent than the other control technology.Fuzzy control is also a new computer control method base on the fuzzy sets, fuzzy language and fuzzy logic reasoning. Because it don't depend on the exact math model of the controlled object, but imitate the thinking way of man to control the object. So it has more self adapting capability than traditional PID control, when use in middle and small marine boiler control.First the thesis base on the marine boiler principle of work by analyses the dynamic property of boiler drum water level and steam pressure, get the adjust object model of boiler drum water level and steam pressure, and through certain suppose and predigest, get the approximate model. Then the thesis lucubrate the arithmetic of boiler drum water level and steam pressure. Aim at the controlled object —boiler has nonlinear, parameters instability, and uneasy to establish mathematic model properties, so use the traditional PID control, the control effect is not good. The thesis combines the fuzzy control and PID control to bring forward use fuzzy self adapting for PID to control the steam pressure of boiler.The thesis use MATLAB to simulate the fuzzy self adapting for PID to control the steam pressure of boiler system. And use MATLB simulik tool to analyses the capability of fuzzy self adapting for PID controller. The simulation results show that it is more excellent than the traditional PID control, and it has overshoot small, transition time short, stability good, adaptability well properties. The simulation results show it can attain the anticipate control effect.