Title: Frequency domain-based auto tuning controller for plants with uncertainties using well known tuning formulas

Authors: G. Saravanakumar, R.S.D. Wahidabanu

Addresses: Department of Instrumentation and Control Engineering, Manipal Institute of Technology, Manipal-576104, Karnataka, India. ' Department of Computer Science, Government college of Engineering, Salem-636011, Tamilnadu, India

Abstract: Adaptive control which adequately adjusts controller gains according to the changes in plants, has become attractive in recent years. The controller proposed in this paper is tuned automatically with various tuning formulas based on the results of frequency domain system identification for the plant. The controller first estimates the frequency response of the plant using FFT. The controller gains are automatically tuned so as to minimise the error between the open loop frequency response of the reference model and that of the actual system at a few frequency points. For the three example processes, reference models are derived. The frequency responses of the reference models and that of the actual processes are obtained. The controller gains are determined by applying the least squares algorithm. The responses of the plants are verified in time domain and frequency domain after tuning the I-PD controller.

Keywords: system identification; adaptive control; I-PD controller; auto-tuning controllers; uncertainty.

DOI: 10.1504/IJAAC.2007.015844

International Journal of Automation and Control, 2007 Vol.1 No.4, pp.284 - 294

Published online: 25 Nov 2007 *

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