The Design Of Hot-Pressing Fuzzy Controller For MDF

Middle Density Fiberboard has been the main building materials and decorative productin the market. The hot-pressing is an important manufacturing process to play a decisive role inproducing quality and yield.On the basis of reviewing the development and technology of medium density fiberboard,this paper first researches MDF hot-pressing principle and mechanism of heat and masstransfer process, then analyze and verify the mathematical model of the ideal heat transfer. Themathematical model of the rapid warming phase and slow warming phase in drying MDFprocess is established. That is important to optimize process parameters.In the production process, fuzzy control theory is applied to medium density fiberboardproduction lines because of the object is nonlinear and delays. Hot-pressing time fuzzycontroller and the output power of the pump motor fuzzy controller are designed based onfuzzy control theory. The arithmetic of the Mamdani theorization and synthesizing is used foroff-line programming. To achieve the control tasks, the synthesis operations of fuzzy inferencerules are simplified by inquiring the querying table directly. Depending on the two establishedfuzzy control models of hot-pressing time control and pump output power control, time fuzzycontroller is compared with traditional PID controller in the performance of the typical secondorder system. From the simulation result the fuzzy control has more advantages: fine stability,fewer overshoot, turbulence reduction and so on. The fuzzy control improves the active andstatic performance of the control processes. It is superior to the conventional PID regulator inthe aspects of enhancing system resistance to interference and robustness of parameterconsolidation. Compared with the switch control, the pump output power control can make theparameter in the setting range and has good quality and fine adaptability.In order to improve the performance of fuzzy controller, the fuzzy logic controller is usedto optimize control rule sets and membership functions simultaneously using geneticalgorithms to realize the design of MDF hot-pressing control system. In the dissertation, thegenetic algorithm is employed to combine with fuzzy control to design and implement the hot-pressing control system. The simulations show that the fuzzy control system optimized by GAhas higher control accuracy, better robustness and resistant disturbance capability.