Between fuzzy-PID and PID-conventional controllers: a good choice

The main problem in the synthesis of a control system is its parameter adjustment. Fuzzy logic controllers (FLC) have been proved to be very efficient in controlling complex and difficult-to-model processes. One of the main problems of these fuzzy controllers is that there is no systematic procedure for tuning. So, the necessity of methods for guiding the initial selection of the fuzzy controller parameters is clear. We propose an indirect method of tuning. It consists of describing the FLC like a classical controller from the external point of view. This allows the plant operator to feel comfortable with this regulator because he knows the direct influence between the variation of the FLC tuning parameters and the system response. It also facilitates the selection of some initial values that assure a reasonable behavior for the FLC, that could be improved by the qualitative tuning of these parameters.