Temperature control of Koji process by using fuzzy PD controller

The purpose of this research is to use the fuzzy PD control technique in order to achieve automatic control for a packed-bed reactor in the solid-state fermentation. The lump mathematical model of Koji process is employed in the development of the fuzzy PD controller. Koji process is done by fermenting 4 kilograms of wet soybeans with 200 grams of rice flour and 6 grams of Aspergillus oryzae in 40-litre packed-bed reactor for 48 hours. When the temperature is higher than 40 degree Celsius, most of Aspergillus oryzae will die. The fuzzy PD controller must be able to maintain the bed temperature not to exceed 30 degree Celsius. The result shows that the fuzzy PD controller yields better performance than the conventional PID controller.