A Prediction approach to introduce dead-time process control in a basic control course

Abstract

This paper presents a methodology to introduce the control of dead-time processes using a simple and intuitive predictive approach. A trivial solutionfor the control of a process with a dead-time is first proposed. From this strategythe idea of the predictor based controller is derived. Open-loop predictors andclosed-loop ones are then used to analyze the obtained solution. A simple tuningof the proposed structure for a first order plus dead-time process together with apolynomial approximation of the dead-time allows to derive apidcontroller. Thus,the approach based on the idea of prediction can be used to interpret the use of apidto control a dead-time process. It is illustrated how the performance of thepidcontroller is limited by the modelling error introduced in the approximation. Thepresented approach gives a measurement of the achievable performance. Severalsimulation examples illustrate the results.