The design and implementation of a fuzzy gain-scheduled PID controller for the Festo MPS PA compact workstation liquid level control

Abstract

Due to the high-quality standards required by the process control industry such as liquid-level control, it is desired to implement sophisticated controllers that ensure the proper functioning of the process. Currently most industrial controllers are of the classic PID type. These controllers do a good job in reducing the system error and have simple structure and can be tuned easily when compared to fuzzy gain scheduled PID controllers. However, classic PID controllers do not perform well when the controlled system possesses largely varying dynamics at different operating conditions. Another limitation of classic PID controllers is that their operation depends on the tuning of the proportional, derivative, and integral gains. This paper presents a comparative study between a fuzzy gain scheduled PID controller and a classic PID controller commonly implemented in the process control industry. A comprehensive mathematical model for the Festo MPS PA compact workstation is developed for future use for control system design of the MPS PA compact workstation. Based on the experimental results, the fuzzy gain scheduled PID controller demonstrated supremacy on the PID control strategy. The presented analysis is verified by the implementation of the fuzzy gain scheduled PID control algorithm in the MPS PA compact workstation using custom-built LabVIEW interface. Experimental results verified the effectiveness of the proposed control scheme.