title: An improved auto-tuning scheme for PI controllers.
abstract: Ziegler-Nichols tuned PI and PID controllers are usually found to provide poor performances for high-order and nonlinear systems. In this study, an improved auto-tuning scheme is presented for Ziegler-Nichols tuned PI controllers (ZNPICs). With a view to improving the transient response, the proportional and integral gains of the proposed controller are continuously modified based on the current process trend. The proposed controller is tested for a number of high-order linear and nonlinear dead-time processes under both set-point change and load disturbance. It exhibits significantly improved performance compared to ZNPIC, and Refined Ziegler-Nichols tuned PI controller (RZNPIC). Robustness of the proposed scheme is established by varying the controller parameters as well as the dead-time of the process under control.
authors.affiliation: Department of Instrumentation and Electronics Engineering, Jadavpur University, Sector III, Block LB/8, Salt-lake, Calcutta 700098, India. rkmudi@yahoo.com
authors.forename: Rajani K
authors.initials: RK
authors.lastname: Mudi
authors.forename: Chanchal
authors.initials: C
authors.lastname: Dey
authors.forename: Tsu-Tian
authors.initials: TT
authors.lastname: Lee
mesh_terms: D000465:Algorithms; D016014:Linear Models; D015233:Models, Statistical; D017711:Nonlinear Dynamics; D013672:Technology / Q000379:methods* / Q000706:statistics & numerical data