Improved Transient Response via Discrete Event Reference Control

We consider a new approach to improve the performance of reference tracking problems for closed loop stabilized continuous linear systems through the application of a sequence of reference signals initiated by the occurrence of a discrete event. By means of the internal model principle, we show that a change in the reference signal is equivalent to implementing an instantaneous change via the choice of a decision vector in the state of the reference model. The analysis of the characteristics of the resulting discrete event reference control (DERC) system is then shown to be equivalent to the analysis of a linear impulsive system. Conditions for asymptotic stability and convergence of the output tracking error for a DERC system are then expressed in term of conditions on the decision vector. In particular, it is shown how to choose the decision vectors so that a DERC system has a deadbeat tracking error response. Finally, conditions are also derived which guarantee that the DERC system has an improved transient performance compare with a conventional reference tracking system.