A pragmatic approach towards assessment of control loop performance

In this paper, a pragmatic approach to process modelling and control loop performance assessment is proposed. We consider the following practical scenarios: the control loop of concern is operated by a simple controller such as PI/PID controller; a simple open-loop/closed-loop step response data is available or an open-loop/closed-loop step test can be readily performed; the control loop may be subject to significant disturbances and/or measurement noises. Our objectives are: (1) to estimate a continuous-time process model from the step response data; (2) to assess control loop performance with a pragmatic benchmark in terms of both output performance and input variation, and identify practically attainable control loop performance. We will summarize the theory and algorithms developed for such a relatively comprehensive analysis. A number of simulation studies are presented to demonstrate the feasibility of the proposed methodology. Copyright (C) 2003 John Wiley Sons, Ltd.