title: Performance improvement of PI controllers through dynamic set-point weighting.
abstract: Responses of high-order systems under Ziegler-Nichols tuned PI controllers (ZNPIs) are characterized by excessive oscillation with a large overshoot. Although, a fixed set-point weighting based PI controller (FSWPI) may decrease the overshoot considerably, it fails to reduce the oscillation in the set-point response. Moreover, both FSWPI and ZNPI exhibit equally poor load regulation. Keeping in mind an overall improved performance, we propose an online dynamic set-point weighting technique for ZNPIs. The dynamic set-point weighting factor (β(d)) is heuristically derived from the instantaneous process trend. Performance of the proposed dynamic set-point weighting based PI controller (DSWPI) for various second- and third-order processes including a pH process shows a significant improvement during both the set-point and load disturbance responses over other methods. Stability and robustness of the proposed DSWPI are addressed. Effectiveness of the DSWPI is demonstrated through the real-time implementation on a practical DC position control system.
authors.affiliation: Department of Instrumentation & Electronics Engg., 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
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D006863:Hydrogen-Ion Concentration; D007221:Industry / Q000379:methods*; D048088:Informatics; D016014:Linear Models; D015233:Models, Statistical; D015203:Reproducibility of Results; D012371:Robotics