Design of Model Reference Self Tuning Mechanism for PID like Fuzzy Controller

This paper presents a method for tuning the scaling factors of PID type fuzzy controllers. The method tunes the input scaling factor related to change in error and the output scaling factor related to integral output of PID type of fuzzy controller using model error, error between reference model and process. Fuzzy Controller used is typical fuzzy PID type of controller in which the scaling factors are set at their initial values using classical approach. An adaptive mechanism block based on model error is added in the classical fuzzy controller. This block tunes one input scaling factor and one output scaling factor based on function of model error. The algorithm is tested on the second order plus delay time processes. The results are compared with other methods such as PID, classical FLC and tuning method based on relative rate observer. The impact of the present method is checked using both graphical and analytical criteria.