Abstract
Since fuzzy control was put into practical use, in Japan it has been applied in many industrial process control fields. The greatest problem in realizing fuzzy control is acquiring the operational knowledge. Therefore, many studies have been carried out on studies of automatic design and tuning methods on control rules and membership functions using optimization, neural network and other theory. However, introducing such new techniques produces some new problems, defecting advantages of fuzzy control such as easy design, understandable and linguistic representation, because the process model will be too complex to use in the practical fields. In this paper, we discuss the feature of fuzzy control for appling to process control. First, we show that it is necessary for a process control system to monitor the state and to operate it by operators, because of remaining uncertainties of plant characteristics and its changes. Therefore, we describe that it is impossible to get complete informations for control system design and it is required for operators to understand the fuzzy control system in order to monitor and operate it successfuly. Second, we suggest a design, tuning and estimation method of control rules and membership functions based on operational knowhows and data. And we discuss the function of fuzzy controller in case of the tuning of control rules and membership functions by operator for satisfying these requirements.
