title: An online tuned novel nonlinear PI controller for stiction compensation in pneumatic control valves.
abstract: A novel Nonlinear PI Controller (NPIC) has been proposed for effective control of flow process employing a sticky pneumatic control valve. The proposed control scheme has been inherited from a classical PI control structure with a difference that the integral gain has been varied in accordance with the instantaneous error and the rate of change of error. The tuning of controller has been carried out online using Differential Evolution algorithm. To evaluate the effectiveness of the proposed controller, a comparative study with the conventional PI controller has also been carried out for the setpoint tracking, disturbance rejection and robustness to parameter uncertainties on account of operating point change on a laboratory scale nonlinear flow process. Based on these intensive experimental evidences, it has been concluded that the NPIC performed far better than the conventional PI controller for all the case studies and suppressed effectively any stiction induced oscillations.
authors.affiliation: Division of Instrumentation and Control Engineering, Netaji Subhas Institute of Technology, New Delhi 110078, India. Electronic address: puneet.mishra@ymail.com.
authors.forename: Puneet
authors.initials: P
authors.lastname: Mishra
authors.affiliation: Division of Instrumentation and Control Engineering, Netaji Subhas Institute of Technology, New Delhi 110078, India. Electronic address: vineetkumar27@gmail.com.
authors.forename: Vineet
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Division of Instrumentation and Control Engineering, Netaji Subhas Institute of Technology, New Delhi 110078, India. Electronic address: kpsrana1@gmail.com.
authors.forename: K P S
authors.initials: KP
authors.lastname: Rana
keywords: Deadband; Flow control; Limit cycles; Nonlinear PI controller; Pneumatic control valve; Stiction