A Sampled Data Controller for Processes with Time Delay and Load Disturbances

Abstract Using a design approach related to Dahlin's a sampled data controller has been designed which is particularly suitable for handling load disturbances. The controller is applicable to processes that can be approximated by first order plus time delay dynamics. For very fast disturbances, e.g. set point changes, the controller becomes identical to Dahlin's controller, while for slow disturbances it promises a significant improvement over the performance of Dahlin's controller. A simulation study is used to evaluate the performance of this “Generalized Dahlin controller” in the presence of noise and model errors and to compare it to Dahlin's controller. For load changes improved control behaviour is obtained except in some cases of model errors and for high noise levels.