Fuzzy modified model reference adaptive controller for improved transient response

Liquid level control has been a basic control problem in almost all process industries. As the level process is nonlinear Model Reference Adaptive Controller is preferred to PID controllers in this paper. To improve the transient performance of the MRAC has been a point of research for a long time. The main objective of the paper is to design an MRAC with improved transient performance. The paper proposes a modification to the standard direct MRAC and the proposed controller is called Fuzzy modified MRAC (FMRAC) in the paper. The FMRAC uses a Mamdani-type Fuzzy inference system (MFIS) to improve the transient performance of a direct MRAC. In this study, an MRAC and an FMRAC are designed for a hybrid tank process and their transient performances are compared. The simulation results show the proposed controller gives better transient performance than the direct MRAC. It is concluded that that the proposed controller can be used to obtain very good transient performance during the control of nonlinear processes.