Title: Performance analysis of various Smith predictors for integrating processes with longer dead-time

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

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. ' Department of Instrumentation and Control Engineering, Manipal Institute of Technology, Manipal 576104, Karnataka, India

Abstract: Processes that contain a large transport lag[exp (–τ_DS)] can be difficult to control because a disturbance in set point or load does not reach the output of the process until τ_D units of time have elapsed. The control strategy known as dead-time compensating controller is also referred to as a Smith predictor. The control algorithm in a Smith predictor is normally a PI controller. This paper describes the advantage of modified Smith predictors which has the advantage over the dead-time compensating controllers. Although it contains five parameters, only three are adjusted by the operator namely the gain, the integral time and the dead-time. The controller is also suited for processes with varying longer dead-times and can be tuned manually in the same way as a PID controller and has the advantage over the other Smith predictor based controllers.

Keywords: integrating processes; Smith predictors; dead time compensating control; tuning; disturbance; performance evaluation.

DOI: 10.1504/IJAAC.2009.025245

International Journal of Automation and Control, 2009 Vol.3 No.2/3, pp.248 - 263

Published online: 17 May 2009 *

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