On comparison of a conventional proportional-integral plus derivative controller versus a fuzzy proportional-integral plus derivative controller: a case study of subsystem failure

A conventional PI+D controller is a practical structure of PID typed controllers, widely used in industry and mechatronic applications. In addition, many fuzzy control-based versions, embracing the linear structure of the conventional PI+D controller, have been designed and implemented. Although there are many reports proving a superior performance of these fuzzy versions over the conventional ones, there is still argument over the trade-off between the simplicity and the effectiveness with regard to the implementation as "pros and cons" for these two types of controllers. To help clarify these concerned issues, the paper presents a detailed study on comparison of conventional PI+D controller versus a fuzzy PI+D controller in the case of a subsystem failure. Simulations on an induction AC motor are carried out as part of the investigation. In case of failure in the feedforward path of the PI control subsystem, the finding shows that the conventional controller fails to perform whereas the fuzzy controller remains working very well.