The research for dissolved oxygen fuzzy PID control system based on adjustment factors in biological culture

The dissolved oxygen (DO) concentration in the culture solution plays an important role within the process of biological culture. The stable and accurate control of DO can maintain the normal survival and growth of microbes, cells, and tissue. However, the DO system is a typical control system with a large inertia, a longer lag time and a certain degree of uncertain control. The fuzzy PID controller with adjustment factors is presented in this paper. The paper details the structure of the biological culture system and establishes the DO control model based on the material balance formulate. The control rules of the fuzzy PID controller and adjustment factors controller according to the hypothetical process of the DO control are discussed. The idea of variable universe is introduced to design the control algorithm. The anti-interference and dynamic tracking simulations are performed in this paper. Compared with simple PID controller and conventional fuzzy PID controller, the proposed controller has been enhanced in several the performances.