Design and implementation of a robust fuzzy adaptive PI controller for inherently unstable systems

The desired performance of any process variable depends on the functions of the controller. The control design approach relies on prior knowledge of the process dynamics and its limitations. Many researchers in the field of control consent that controller design can be quite tedious in cases of unstable systems. Adaptive control where the controller parameters adjust them self as per the system requirements, is a candidate solution for such problem. This paper mainly focuses on the design of a MRAC Model Reference Adaptive Control based PI (Proportional–Integral) controller for an unstable system. The adaptation mechanism is generated using fuzzy logic, which makes the controller adaptable and decreases design requirements. The outcomes are compared with the traditional controller tuned using the ZN (Ziegler–Nichols) approach. Detailed simulation work and experimental validation reveal that the suggested Fuzzy Adaptive PI controller works effectively at regulating the unstable system and achieving the desired performance. A prototype experimental model is also created to validate the results.