A combined FSP and reset control approach to improve the set-point tracking task of dead-time processes

This paper presents a non-linear control scheme to deal with dead-time processes, specially for systems where fast closed-loop responses are required. The control scheme is based on the combination of two control strategies appeared in the literature to deal with dead-time processes, the Filtered Smith Predictor (FSP), which is a Smith Predictor (SP) including a filter to improve the robustness; and the PIþCI, a PI with a partial reset action on the control signal when the process output reaches the reference input. In the proposed strategy, the reset action allows to achieve very small rise times with small overshoots, improving the results from FSP. On the other hand, the use of the robust predictor allows to deal with the dead-time in a better and systematic way than the existing PIþCI solutions. The improvements of the proposed control scheme are evaluated through simulations and real experiments on an industrial heat exchanger. & 2012 Elsevier Ltd. All rights reserved.