Fuzzy Temperature Control For Tea Fixation Machine

The issue of fuzzy control techniques for tea water-removing machine has been addressed in this thesis. A novel tea water-removing machine has been invented by using fuzzy temperature controller based on requirements of tea processing. The researches of the thesis were conducted on an automatic production line for green tea.By analyzing the current temperature control methods for tea water-removing machine, the temperature process is featured as nonlinear, time-delay and vulnerable to be disturbed. In addition, this process is difficult to model accurate mathematically. As a result, a fuzzy controller has been developed for temperature control of tea water-removing machine, which adopted the Mamdani fuzzy control method with feedback modulation. The quantification factors are adjusted dynamically based on variable universe and human simulating intelligence, according to the feedback error. Compared with tradition controllers, the fuzzy control method has better performance in response time, overshoot and stability, which has been verified by experiments and simulation.Secondly, the necessary hardware equipments for the tea water-removing machine based on the fuzzy controller (electromagnetic valve etc) have been improved in this thesis. Because fix the hardware by making each segments has equal length cannot obtain accurate feedback temperature, a golden section method is introduced to divide the roller of tea water-removing machine into three segments and fix equipments on the right place of the roller to control the temperature of each segment independently. Production practice shows that the improved method making the equipments easy to set up and having sensitive control effect, the control system is able to obtain more accurate feedback temperature by using golden section method to divide the roller into 3 segments and the effect of tea water-removing is also improved.Finally, summarization of the thesis points out that the process of tea water-removing would reduce dependence on skilled workers by using fuzzy control and this technique can make the process of tea water-removing automatic.