Fuzzy Logic Based Set-Point Weighting Controller Tuning for an Internal Model Control Based PID Controller

Abstract

Controller tuning is the process of adjusting the parameters of the selected controller to achieve optimum response for the controlled process. For many of the control problems, a satisfactory performance is obtained by using PID controllers. One of the main problems with mathematical models of physical systems is that the parameters used in the models cannot be determined with absolute accuracy. The values of the parameters may change with time or various effects. In these cases, conventional controller tuning methods suffer when trying a lot to produce optimum response. In order to overcome these difficulties a fuzzy logic based Set- Point weighting controller tuning method is proposed. The effectiveness of the proposed scheme is analyzed through computer simulation using SIMULINK software and the results are presented. The fuzzy logic based simulation results are compared with Cohen-Coon (CC), Ziegler- Nichols (ZN), Ziegler – Nichols with Set- Point weighting (ZN-SPW), Internal Model Control (IMC) and Internal model based PID controller responses (IMC-PID). The effects of process modeling errors and the importance of controller tuning have been brought out using the proposed control scheme.

Keywords

• Fuzzy logic
• Set-point weighting
• Controller tuning
• IMC
• PID